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SERTS > Exam Prep > Flashcards

Exam Prep Flashcards

1
Q

Club of Rome

A

The human ecological
footprint cannot continue to grow at the
current rate, otherwise the carrying
capacities of the system will be reached
and the system collapses

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2
Q

Stockholm Conference

A

the UN’s first major conference on international environmental issues

turning point in the development of international environmental politics.

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3
Q

physical conversion of fuel

A

mechanical pressing of crops with high oil content. The vegetable oil obtained, a mixture of methyl esters of fatty acids, can be used directly as fuel for diesel engines or chemically treat to make biodiesel

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4
Q

Sustainable development

A

development that meets the needs of the present without compromising the ability of future generations to meet their own needs

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5
Q

Brundtland Report 2 main concepts

A
  1. The concept of “needs”, in particular the essential needs of the world’s poor, to
    which overriding priority should be given.
  2. The idea of limitations imposed by the state of technology and social organization on the environment’s ability to meet present and future needs.
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6
Q

The Triple Bottom Line

A

– People, the social equity bottom line
– Planet, the environmental bottom line
– Profit, the economic bottom line

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7
Q

Cumulative Energy Demand (CED)

A

sum of the primary energy demand associated with the whole life
cycle of a product

▪ It covers extraction, production, usage
and disposal

▪ Unit: MJ per unit

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8
Q

Analytic Tools to Evaluate Sustainability

A

(1) Cumulative Energy Demand (CED)

(2) Energy Return on Energy Invested (EROEI) / Harvesting Factor

(3) Grey Energy / Embodied Energy (EE)

(4) Life Cycle Assessment (LCA)

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9
Q

functional unit

A

a quantified description of the function of a product. It serves as reference basis for all calculations regarding the impact assessment.

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10
Q

Energy Return on Energy Invested (EROEI)

A

indicates how often a plant recovers the
cumulated energy demand (CED) during its lifetime

Output/Input

Energy delivered / Energy required to deliver the energy

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11
Q

Grey Energy / Embodied Energy (EE)

A

excludes the operational energy, i.e.
the energy demand during usage, as
well as the disposal of materials.

▪ Unit: MJ or kWh per unit weight (kg or
tons) or per area (m²)

extraction + production

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12
Q

Life Cycle Assessment (LCA) framework

A
  1. Goal and scope definition
  2. Inventory analysis
  3. Impact assessment
  4. Interpretation

models a product, service or system‘s life cycle.

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13
Q

impact category

A

a “class representing environmental issues of concern to
which life cycle inventory analysis results may be assigned”.

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14
Q

Waste management hierarchy according to the EU framework directive 2008/98/EG (5 steps)

A
  1. Prevention
  2. Preparing for reuse
  3. Recycling
  4. Other recovery, e.g. energy recovery through waste incineration
  5. Disposal
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15
Q

What speaks for the incineration of waste in the context of sustainable thinking?

A

Generation of electricity and district heating by substitutes of fossil fuels.

Increasing resource productivity through metal recovery. This production of secondary raw materials is often less
energy-intensive and produces fewer emissions than the extraction of primary raw materials.

Recovery of non-recyclable waste with high pollution loads that would otherwise be dumped on landfills.

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16
Q

What speaks against the incineration of waste in the context of sustainable thinking?

A

Generation of greenhouse gas emissions as a result of the incineration process.

Can be at the expense of material recovery (recycling) and undermine the idea of a circular economy → Conflict with
the waste management hierarchy.
(Example: In Germany, incineration capacities increasingly exceed the volume of waste, which lowers the price of waste
disposal. As a result, the attractiveness of material recycling is decreasing).

Orientation towards the idea of waste disposal. The aim should be to shape consumer behaviour in such a way that
less waste is produced.

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17
Q

System

A

definable part of relevance

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18
Q

system boundary

A

separates system from its environment

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19
Q

mechanical energy transfer

A

energy in the form of work

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20
Q

thermal energy transfer

A

energy in the form of heat

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21
Q

material flow energy transfer

A

Different types of energy (e.g. kinetic) cross system boundary with material flow

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22
Q

system types

A

isolated
closed
open

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23
Q

isolated system

A

matter and energy impermeable
no energy transit possible

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24
Q

closed system

A

matter impermeable
energy transfer in the form of work and heat

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25
Q

open system

A

matter permeable
energy transfer in the form of work, heat and material bound energy transport

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26
Q

law of conservation of energy

A

the sum of all forms of energy always remains the same, but

energy = exergy + anergy

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27
Q

exergy

A

the energy that can be convreted into any other form

the exergy share decreases in all conversion processes

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28
Q

anergy

A

the energ that cannot be converted

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29
Q

potential energy

A

force effects on the resting system

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30
Q

kinetic energy

A

force effects on the moving system

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31
Q

internal energy

A

force effects within a system

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32
Q

circular processes

A

stationary process where initial state is identical to the final state

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33
Q

thermal State variables

A

depend on the prevailing temperature

temperature
pressure
volume

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34
Q

caloric state variables

A

describe the energy content of a system

internal energy U
enthalpy H
Entropy S

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35
Q

Extensive properties

A

properties whose values result from the division of a system as the sum of the corresponding state variables of the parts (additive)

volume, internal energy, enthalpy, entropy

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36
Q

intensive properties

A

properties that are not additive when diving a system

temperature, pressure, specific internal energy, specific enthalpy, specific entropy

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37
Q

process variables

A

work and heat

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38
Q

isochore process

A

as heat is added, the volume stays constant (and pressure and temperature rise)

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39
Q

isobar process

A

the prssure stays constant when heat is added as volume and temperature rise

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40
Q

adiabatic process

A

energy is not transferred as heat to surroundings but as work

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41
Q

Energy carrier

A

physical manifestations and substances from which energy can be produced. A distinction is made between primary, secondary and final energy sources.

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42
Q

Primary energy sources

A

energy sources offered by
nature in their original form not yet treated. Their energy content is called primary energy. The primary energy sources are divided into regenerative and non-regenerative sources.

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43
Q

Secondary energy sources

A

originate from one or more processing or conversion processes (e.g. drying, desulfurization, power generation)

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44
Q

Final energy sources

A

all energy sources used by the end user to cover the energy demand

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45
Q

Useful energy

A

only the energy that is available to the consumer after the last
conversion to meet all needs is called useful energy.

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46
Q

Energy services

A

energy services are the needs satisfied or goods produced from the use of useful energy and other production factors (e.g. pleasantly tempered rooms,
information, transport, etc.)

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47
Q

Axial compressors in gas turbines

A

compress working fluid by first accelerating it (rotor) and then decelerating it (stator) in order to maintain the pressure increase. The centrifugal effect is eliminated within the blading.

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48
Q

Radial compressors

A

the air enters the compressor in an axial direction but is then conveyed outwards perpendicular to it. This exerts a strong centrifugal force.

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49
Q

Tube combustion chamber

A

in large industrial turbines. This type of combustion chamber is particularly suitable for engines with radial compressors.

Advantages:
simple design, easy maintenance and long
service life.

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50
Q

Annular combustion chamber

A

important in aerospace applications where cross- sectional area is important.

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51
Q

Tube ring combustion chamber

A

This type of combustion chamber combines the tube and ring combustion chamber and is particularly suitable for very large and powerful gas turbines because it is mechanically very stable.

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52
Q

Axial flow turbines

A

flows enter and exit in axial directions. Used in more than 80 % of all applications.

large machines
large mass flows
higher efficiencies
expensive
difficult production

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53
Q

Radial-flow turbine

A

like a radial compressor with reversed flow and counter-rotating. It is used for lower load

small machines
small mass flows
lower efficiencies
cheap
simple production

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54
Q

Clausius Rankine Cycle steps

A

1 -> 2 increase pressure through work
2 -> 3 heat feed water to evaporation temperature
3 -> 4 evaporation
4 -> 5 Superheating steam
5 -> 6 Relaxation of steam within turbine while work delivered
6->1 liquefaction of steam int he condenser while heat is released

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55
Q

Clausius Ranking assumptions

A

1-2 and 5-6 isentropic
2-5 and 6-1 isobaric

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56
Q

Firing Systems Function

A

release of chemical energy
from fuels

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57
Q

Firing methods

A

Fixed-bed or grate firing
Fluidized bed combustion:
Burner firing

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58
Q

Fixed-bed or grate firing

A

combustion of solid fuels on a
(moving) grate

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59
Q

Fluidized bed combustion

A

combustion of (mostly) solid fuels
in a fluidized bed of inert particles
through which air/oxygen flows

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60
Q

Burner firing

A

fuel is injected simultaneously with air/oxygen (finally ground solid, liquid or gaseous fuels)

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61
Q

Steam generator function

A

convert heat from firing into energy of steam

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62
Q

steam generator components

A

economizer, evaporator, superheater, reheater, air preheater and numerous auxiliary machines

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63
Q

steam turbine function

A

conversion of potential energy into kinetic energy and then into mechanical energy

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64
Q

Impulse turbines

A

Conversion of the
enthalpy gradient into
kinetic energy completely
in the guide wheel
– Inlet and outlet velocity
equal at impeller

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65
Q

Overpressure turbines

A

Conversion of the
enthalpy gradient in both
the guide wheel and the
runner

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66
Q

condenser function

A

Reversal of the evaporation
process (cooling/condensation)
and closing of the cycle
– Generation of a vacuum (steam
from turbine is expanded to lower
pressures than environment
→ higher efficiencies)

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67
Q

condenser working method

A

– Condensate and cooling medium
in two separate circuits
– Large quantities of heat to be
dissipated → as large as
possible mass flow of the cooling
medium
– Heat sink: environment
(atmosphere, waters)

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68
Q

ORC: Organic Rankine Cycle

A

Based on the Clausius-Rankine process

mainly used when the available temperature gradient between heat source and sink is too low to operate a turbine driven by steam. This is especially the case for electricity generation using geothermal energy, combined heat and power generation, solar power plants and ocean thermal power plants.

▪ thermodynamic cycle in which a low-boiling organic substance, such as hydrocarbons or silicone oils, circulates as a working medium instead of water.

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69
Q

Organic rankine cycle advantages

A

▪ Advantages:
– Smaller and cheaper turbines
– Operational advantages as the turbine is not exposed to
erosion or corrosion
– Use of lower temperatures

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70
Q

organic ranking cycle disadvantages

A

Disadvantages:
– Higher costs due to the heat exchanger
– Corrosion and fouling problems (deposits) on the heat
exchange

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71
Q

Gas turbine working fluid

A

flue gas

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72
Q

gas turbine components

A

compressor, combustor, turbine

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73
Q

gas turbine installation cost compared to steam turbine

A

lower

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74
Q

gas turbine efficiency compared to steam turbine

A

less efficient

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75
Q

gas turbine time and space requirements for installation compared to steam turbine

A

less

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76
Q

steam turbine working fluid

A

high pressure steam

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77
Q

steam turbine main components

A

steam boiler and accessories

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78
Q

Combined Cycle Power Plants

A

high inlet temperature of gas turbine with lower waste heat temperatures in water-steam process -> high efficiency

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79
Q

CCPP advantages

A

High efficiency
▪ Low specific investment, operating and
maintenance costs
▪ Short amortization period (10 to 12 years)
▪ Low start-up losses
▪ High partial load efficiency
▪ Short approval procedure
▪ Simple construction
▪ Step-by-step expansion possible
▪ Short delivery times (18 to 24 months)
▪ Low personnel requirements
▪ Locations close to consumers
▪ Short starting times
▪ High reliability (96 to 99 %)
▪ High availability (92 to 96 %)
Low requirement of cooling water
▪ Low pollutant emissions
▪ Low space requirement
▪ Further improvements in performance and
efficiency

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80
Q

Igneous rocks

A

formed from crystallization of molten rock from within the earth’s mantle.

high pressure -> high density

Granite and basalt.

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81
Q

Metamorphic rocks

A

formed from pre-existing rocks by
mineralogical, chemical and/or structural changes due to shifts in
temperature, pressure, shearing stress and chemical environment.

These changes generally take place deep within the earth’s crust.

Slate and marble.

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82
Q

Sedimentary rocks

A

formed as sediments, either from eroded fragments of older rocks or chemical precipitates

Sediments are lithified by compaction and cementation after burial under additional layers of sediment

Typically deposited in horizontal layers, or strata, at the bottom of rivers, oceans, & deltas.

Limestone, sandstone and clay.

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83
Q

prospection

A

Search and exploration of new
previously unknown deposits.

Using Geological maps and other available remote sensing information

The entire Prospection period of an exploration area is usually completed after several years of investigation with the start of the exploration phase

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84
Q

exploration

A

Follows a successful prospection phase

goal: detecting raw material deposits and extract them

usually completed after 5 to 10 years, followed by the actual exploitation of the deposit and thus extraction.

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85
Q

Drill Planning goals

A

maximize yield

minimize risks

reduce costs

comply with safety and environmental standards

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86
Q

rotary drilling method

A

The drive is located on the rig and drives the drill rod from above

To change the bit, the drill rod has to be removed and reinstalled
(“round trip”)

Method is used for vertical drilling

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87
Q

Advantage of Top-Drive in the rotary drilling method

A

installation of new drill rod is simplified

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88
Q

Downhole Mud Motor (Directional Drilling) aka turbine drilling

A

driving turbine located behind drill bit

turbine driven by hydraulic pressure

allows for change of direction at a certain depth

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89
Q

Horizontal drilling

A

carried out within the reservoir

can exploit hydrocarbon reservoir with small nr of vertical drilling holes

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90
Q

fermentation

A

biochemical transofmration where sugars converted into ethyl alcohol

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91
Q

Solid rock deposits

A

Primarily in magmatic deposits and as intrusions in hydrothermal deposits

Australia, Canada, Zimbabwe

usually found with other minerals, few of wich are economically usable

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92
Q

Brine deposits

A

salt lakes, continental deep waters, oilfield water

sometimes not economically feasible to extract from brines (only done in salt lakes currently)

in South America (Chile, Argentina, and Bolivia)

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93
Q

Lithium Demand in the Future

A

demand increase because of emobility

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94
Q

lithium extraction effects on environment

A

decrease of fresh water
large area requirements
high water demand
high energy consumption

recycling not yet established

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95
Q

CCS

A

capture of CO2 from energy intensive industries

ie. power plants, cement, iron and steel, chemicals and refining

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96
Q

CCS absorption method

A

Utilized for low or moderately concentrated CO2 in flue gas
streams.

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97
Q

CCS Chemical Absorption

A

Involves alkaline solvents (e.g., monoethanol amine - MEA) to
capture CO2.

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98
Q

CCS Regeneration

A

Heat-based release of absorbed CO2, followed by solvent recycling.

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99
Q

CCS Challenges

A

Energy-intensive due to breaking chemical bonds between solvent and CO2, contaminants in flue gas need removal

not all CO2 captured (around 90%)

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100
Q

IGCC Process (integrated gasification combined cycle)

A

converting solid or liquid carbonaceous fuels into a synthetic gas (syngas), which can then be used for power generation or the production of chemicals and fuels.

  1. Gasification: The first stage of the IGCC process is gasification, where the solid or liquid feedstock, such as coal, petroleum coke, biomass, or waste materials, is converted into a syngas through a high-temperature chemical reaction in a gasifier. The gasifier operates at elevated temperatures and pressures in an oxygen-starved environment (partial oxidation or partial combustion), resulting in the breakdown of the feedstock into its constituent gases, primarily carbon monoxide (CO) and hydrogen (H2), along with other gases such as methane (CH4) and carbon dioxide (CO2).
  2. Syngas Cleanup: The raw syngas produced from the gasification process contains impurities such as sulfur compounds, tar, particulates, and trace metals, which need to be removed to meet environmental and operational requirements. Syngas cleanup technologies, including scrubbers, filters, desulfurization units, and tar removal systems, are employed to purify the syngas and remove contaminants before it enters the power generation or chemical synthesis stage.
  3. Power Generation: The cleaned syngas is then combusted in a gas turbine to generate electricity. The high-temperature, high-pressure combustion of syngas in the gas turbine drives the turbine blades, producing mechanical energy that is used to turn an electrical generator and produce electricity. The exhaust gases from the gas turbine, which are still at high temperatures, are directed to a heat recovery steam generator (HRSG) or boiler.
  4. Steam Generation and Combined Cycle: In the HRSG or boiler, the exhaust gases from the gas turbine are used to generate steam by transferring heat to water. The steam produced drives a steam turbine, which generates additional electricity. This combined cycle configuration (gas turbine + steam turbine) maximizes the overall efficiency of the power plant by utilizing both the high-temperature exhaust gases from the gas turbine and the steam generated in the HRSG.
  5. Emissions Control: Emission control technologies, such as selective catalytic reduction (SCR) for nitrogen oxides (NOx) and flue gas desulfurization (FGD) for sulfur dioxide (SO2), are employed to reduce air pollutants and comply with environmental regulations. Additional measures may be implemented to capture and sequester carbon dioxide (CO2) emissions from the gasification process to mitigate greenhouse gas emissions.

The IGCC process offers several advantages, including high fuel flexibility (ability to use a wide range of feedstocks), potential for higher efficiency compared to conventional coal-fired power plants, and the ability to capture and utilize by-products such as hydrogen and carbon monoxide. However, IGCC plants require significant capital investment and operational expertise, and the technology is still relatively less mature compared to conventional power generation technologies.
absorption using solvents like selexol or rectisol.

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101
Q

CCS Pressure & Temperature

A

Solvent capacity increases with pressure and decreases
with temperature, and regeneration is less energy-intensive.

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102
Q

CCS methods

A

chemical and physical absorption

oxyfuel for pure oxygen combustion

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103
Q

oxyfuel for pure oxygen combustion in context of CCS

A

Combustion of fossil fuels in pure oxygen, removing nitrogen from flue gas streams.

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104
Q

Advantages CCS oxyfuel

A

Higher CO2 concentration, no need for costly CO2 capture; potential to
compress and store trace pollutants.

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105
Q

disadvantages CCS oxyfuel

A

Drawback: Production of oxygen in air separation is expensive.

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106
Q

carbon storage methods

A

geological formation - depleted oil and gas reservoirs

deep aquifers

ocean storage

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107
Q

carbon storage methods
Geologic Formation - Depleted Oil and Gas Reservoirs
▪ Environmental Safety

A

Lower risks and uncertainties compared to ocean storage.

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108
Q

carbon storage methods
Geologic Formation - Depleted Oil and Gas Reservoirs
Utilization

A

CO2 is stored in depleted oil and gas reservoirs, used by Enhanced Oil Recovery (EOR) companies for tertiary recovery.

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109
Q

carbon storage methods
Geologic Formation - Depleted Oil and Gas Reservoirs
Environmental Impact

A

Least potential environmental risk

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110
Q

carbon storage methods
Geologic Formation - Depleted Oil and Gas Reservoirs
Longevity

A

Demonstrated ability to store pressurized fluids for millions of years

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111
Q

carbon storage methods
Geologic Formation - Depleted Oil and Gas Reservoirs
Concerns

A

Possible CO2 leakage through fractures and groundwater contamination.

careful site selection and operation with regulatory oversight necessary

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112
Q

carbon storage methods - deep aquifers
advantage

A

lower transportation costs

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113
Q

carbon storage methods - deep aquifers
environmental concerns

A

uncertainty, mitigated by suitable storage site selection

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114
Q

carbon storage methods - deep aquifers
ideal aquifers

A

impermeable cap, high porosity, permeability

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115
Q

carbon storage methods - deep aquifers
storage process

A

formation of stable carbonates through chemical reactions for longer storage times

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116
Q

carbon storage methods - ocean storage
capacity

A

largest potential for CO2 storage

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117
Q

carbon storage methods - ocean storage
injection depth

A

varies, deeper depths minimize impact on marine life

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118
Q

carbon storage methods - ocean storage
methods

A

direct injection, towed pipeline, stable isolated lake formation, dry ice blocks

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119
Q

carbon storage methods - ocean storage
challenges

A

costly refrigeration and compression, impact on ocean acidity

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120
Q

Geological sequestration CCS method

A

CO2 injected at around 1 km or deeper

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121
Q

Geological sequestrration CCS primary trapping steps

A

beneath seals of low permeability rocks
1. capture
2. compression
3. pipeline transport
4. underground injection

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122
Q

Geological sequestrration CCS secondary trapping

A

dissolution, residual gas trapping, mineralization

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123
Q

United Nations Framework Classification for Resources three criteria

A

economic viability
feasibility
geological knowledge

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124
Q

oceanic crust

A

lies under oceans

thin (8-11 km)

heavy rock formed as molten rock (magma) cools

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125
Q

continental crust

A

thick (16-48 km)

lighter rock

continuously changing and moving due to orogeny and weathering/erosion

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126
Q

orogeny

A

mountain building

layers of crust folded and pushed upward by plate tectonics and volcanism

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127
Q

weathering and erosion

A

opposing forces where sediments broken down and transported

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128
Q

where does geothermal energy come from

A

areas of volcanic activity

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129
Q

UNFC tool

A

classification tool to reduce transaction costs and make risks visible

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130
Q

Try to make an UNFC characterization for a wind power project

A

UNFC Characterization for a Hypothetical Project: Sustainable Energy Development
1. Energy Resource Category:
Primary Energy Source: Wind Power
Location: Offshore Wind Farm in XYZ Region

  1. Project Phases:
    a. Exploration Phase:
    - Preliminary Wind Resource Assessment
    - Geological and Geophysical Studies

b. Appraisal Phase:
- Advanced Wind Resource Assessment
- Environmental Impact Assessment
- Technical Feasibility Studies

c. Development Phase:
- Construction of Offshore Wind Turbines
- Installation of Transmission Infrastructure
- Regulatory Approvals and Permits

d. Production Phase:
- Ongoing Operation and Maintenance
- Continuous Monitoring of Wind Farm Performance
- Energy Generation and Transmission

  1. UNFC Classification:
    a. Class 1: In-Place Energy Resources (Area):
    - Wind Energy Potential in the XYZ Offshore Region
    b. Class 2: Exploration Results:
    - Confirmed Wind Resources
    - Environmental Impact Assessment Data
    c. Class 3: Recoverable Resources:
    - Estimated Recoverable Wind Energy Reserves
    d. Class 4: Production:
    - Annual Energy Generation from the Wind Farm
  2. Quantification and Units:
    Energy resources measured in gigawatt-hours (GWh)
    Physical attributes such as wind speed, depth, and distance from shore are quantified.
  3. Environmental and Social Considerations:
    Integration of sustainable practices in construction and operation phases.
    Community engagement and benefits.
  4. Economic Viability:
    Cost-Benefit Analysis
    Return on Investment (ROI) calculations
  5. Risk and Uncertainty:
    Identification of key project risks and uncertainties
    Mitigation strategies
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131
Q

How is the UNFC interlinked with other resource declarations?

A
  1. Sustainable Development Goals (SDGs):
    goals related to affordable and clean energy (SDG 7),
    responsible consumption and production (SDG 12), and
    climate action (SDG 13)
    1. UNFCCC (United Nations Framework Convention on Climate Change):
      assessment of greenhouse gas emissions and carbon sequestration potential
  3. UNSD (United Nations Statistics Division):
    standardization of resource-related statistics
  4. UNEP (United Nations Environment Programme):
    goals of sustainable development and environmental protection promoted by UNEP
  5. Mineral Resource and Reserve Classification Systems:
    compatible with existing mineral resource and reserve classification systems, such as the Committee for Mineral Reserves International Reporting Standards (CRIRSCO) and the Society for Mining, Metallurgy, and Exploration (SME) guidelines.
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132
Q

How is coal created?

A

remains of plants that lived in swampy environments during the Carboniferous period (about 360 to 300 million years ago). As these plants died, their remains accumulated in waterlogged conditions, preventing complete decomposition

-> peat, an early stage of coal

  • Coalification: Over millions of years heat and pressure increase.

lignite, bituminous coal, and anthracite form

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133
Q

how is natural gas created?

A

remains of microscopic marine organisms, such as plankton and algae, that lived in ancient seas. When these organisms died, their remains settled on the ocean floor.

  • Organic Matter Accumulation: Over time, the organic matter from these marine organisms gets buried under layers of sediment, and as the sediment thickens, heat and pressure increase.
  • Thermal Decomposition (Maturation): The heat and pressure cause the organic matter to undergo thermal decomposition or maturation. This process results in the formation of hydrocarbons, including natural gas.
  • Migration: Natural gas can migrate through porous rocks until it gets trapped beneath impermeable rock layers, forming reservoirs.
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134
Q

How is oil created from the beginning?

A

organisms, including plankton and algae die
-> settle on ocean floor
-> buried under sediment
-> heat and pressure
-> converted into hydrocarbons
-> migrates through permeable rocks
-> settles in trap or reservoir

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135
Q

How could geothermal energy usage replace conventional, using similar infrastructures?

A
  1. Electricity Generation:
    Geothermal power plants often use similar infrastructure for electricity transmission and distribution, making the transition relatively seamless.
  2. Heating and Cooling Systems:
    Existing ductwork and distribution systems can often be adapted for geothermal heat pump installations.
  3. District Heating Systems:
    Existing district heating infrastructure can be adapted for geothermal use.
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136
Q

Where can we store CO2?

A

Deep Saline Aquifers: Deep underground saline aquifers, which are porous rock formations saturated with saltwater
-typically found several kilometers below the Earth’s surface.

  1. oil reservoirs
    enhanced oil recovery (EOR)
  2. Unmineable Coal Seams:
    CO2 adsorbs onto the coal matrix
  3. Deep Ocean Storage: limited
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137
Q

electricity - what type of energy source?

A

secondary energy source generated by primary sources like fossil fuels, nuclear, wind, solar

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138
Q

what can convert primary sources of energy into electrical energy?

A

generator, battery, fuel cell, solar cell

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139
Q

efficiency

A

electrical output (+ heat extraction) / heat input (fuel power)

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140
Q

capacity factor

A

electrical output (+ heat extraction) / heat input (fuel energy)

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141
Q

what is the difference between efficiency and capacity factor?

A

efficiency is in a point of time while capacity factor is in a period of time

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142
Q

how is electricity made?

A

results from the interaction of electrically charged particles

electrons and protons

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143
Q

electric current

A

flow of electric charge

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144
Q

Electric charge Q in Coulomb (C)

A

basic property of building blocks of matter, distinction between electron and proton

a neutral atom becomes +/e ion by addition/elimination of an electron

ions and electrons are carriers of electric charge

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145
Q

Current (amperage) I in Ampere (A)

A

Directional movement of charge carriers

Quantity of electric charge flowing through a cross section per time unit

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146
Q

I = ?

A

Q/t

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147
Q

Unit of Ampere A

A

C/s

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148
Q

Voltage U in Volt V

A

Difference between electrical potentials
Maintains the movement of charge carriers

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149
Q

Power P in Watt

A

Measure for the amount of energy transferred or converted per time unit

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150
Q

How to calculate P

A

U*I

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151
Q

Electrical resistance R in Ohm

A

Charge carriers cannot pass unhindered through the conductor
some of their electrical energy is transformed into heat, which is due to the conductors resistance

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152
Q

Ohms law

A

Resistance R is constant and not dependent on voltage or current

Increasing voltage (U) results in a proportional change in
current (I).

R=V/A

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153
Q

How to calculate R

A

U/I

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154
Q

Units of Ohm

A

R= V/A

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155
Q

Direct Current

A

if direction of movement of the charge remains constant over time

used in batteries, can be generated with fuel cells and PV modules

increasingly important as low loss transmission is possible

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156
Q

Alternating current

A

if direction of movement changes at intervals (looks like sine curve)

known from household appliances and used in electrical power distribution

time dependent

frequency of changes in direction is expressed in Hertz

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157
Q

What does 50 Hz imply

A

direction of the current changes 100 times per second

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158
Q

Lorentz force

A

resulting force on moving charges in the magnetic field

interaction between two magnetic fields

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159
Q

How to determine Lorentz force

A

Right ahnd rule

middle finger is lorentz force
thumb is direction of current

pointer finger is magnetic field

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160
Q

three phase current

A

3 coils -> 3 overlapping phases add up to zero at any moment

generator rotates

rotating magnet induces voltages in coils

for industrial appliances

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161
Q

galvanic element

A

conversion of chemical into electrical energy

potential caused by electro surplus on anode and deficit on cathode

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162
Q

redox potential

A

measure of readiness of ions to accept electrons

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163
Q

fuel cell

A

generate electricity and. heat from hydrogen and oxygen

cold combustion

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164
Q

hydrogen electrolysis
chemical reaction
what type of energy?
efficiency level?

A

H2O + Energy -> H2 and O2 through electrolysis

energy can be chemical, heat, electrical, etc.

very efficient

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165
Q

Calculating resistance parallel connections

A

1/ Rtotal = 1/ R1 + 1/ R2…

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166
Q

Calculating resistance series connections

A

Rtotal= R1 + R2…

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167
Q

theoretical supply potential

A

physical supply without “practical” boundary conditions

e.g. incident radiation * area * max efficiency

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168
Q

technically usable potential

A

consideration of the technical state of the art (exergy share, efficiency, degree of utilization). available area, integration

eg. efficiency * load max * full load hours

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169
Q

average wind speed

A

A* k-th root of 0,287k^(-1)+0,688k^(-0,1)

A: measure of characteristic wind speed
k: form factors between 1 and 4

170
Q

Energy yield of wind turbine

A

sum of (hi * Pi * T) = sum of (hi * density/2 * A* vi^3* cp,i*T)

h: how often % does wind speed i occur compared to others

P: power output of wind turbine at wind speed i

cp, i: optimum power coefficient (rotor speed)

T: hours in period

171
Q

economic potential

A

inclusion of costs. economic comparison to alternatives

172
Q

expectation potential

A

realistic estimation for a period of time, “forecast”

173
Q

environmentally sustainable potential

A

part of the technical potential whose use does not lead to “unreasonable” interference with nature

174
Q

challenges on hydropower development (reasons for declining)

A

future policies
electricity prices
project development lead times
high cost
short payback periods

175
Q

undershot water wheels

A

blades immersed in water absorb kinetic energy and transfer it to the wheel and shaft

176
Q

undershot water wheels advantages

A

little slope and water needed
little sensitivity to fluctuating water volumes
few hydraulic engineering works required

177
Q

undershot water wheels disadvantages

A

low speed
needs gearbox
large space requirements
low efficiency
not suitable for large power plants

178
Q

overshot water wheels and water turbines

A

use potential energy of water

179
Q

overshot water wheels strengths

A

higher speed
no gearbox required
suitable for any height of fall
higher efficiency

180
Q

overshot water wheel weaknesses

A

high slope required
sensitive to fluctuating water levels
extensive hydraulic engineering works required

181
Q

pelton turbine

A

high pressure
high altitude differences
low mass flow

182
Q

pelton turbine components

A

water flow
inlet nozzle
wheel
outlet

183
Q

francis turbine

A

intermediate pressure
wide range of applications
potential and kinetic energy convrted

184
Q

francis turbine components

A

water inflow
casing
guide blades
wheel
outlet

185
Q

kaplan turbine

A

low pressure turbine
less pressure so more water flow needed to generate energy

186
Q

kaplan turbine components

A

water inflow
guide blades
rotor hub
moving blades
turbine shaft
outlet

187
Q

run of river power plant

A

use flow of river to generate electricity

need high flow velocity and large volume of water (kaplan and francis)

low hight of fall with large but seasonally fluctuating water volume

188
Q

storage power plant

A

use water from reservoir to produce electricity using dams

energx depends on amount of water and height

large height of fall but relatively small volume of water

can be started and shut down quickly

189
Q

pumped storage power plant

A

has upper and lower reservoir
can go into generator and pump mode

generator mode
upper reservoir water goes into turbine
electricity produced fed into grid

pump mode
operates as motor
suppled with energy from grid and drives the pump
takes water from lower reservoir and pumps it back into upper reservoir

190
Q

power formula for hydropower plants

A

power = water density * gravitational acceleration * height difference * volume flow * efficiency

191
Q

primary biomass

A

plants and animal matter, crops

192
Q

secondary biomass

A

waste and byproducts of primary biomass

193
Q

tertiary biomass

A

products derived from primary and secondary biomass through conversion steps

194
Q

what kind of energy is stored in biomass

A

solar energy

195
Q

is biomass considered a sustainable energy source? why?

A

yes but not the best because it releases the amount of CO2 that was removed from atmosphere during plant growth

196
Q

problems with biomass

A

tank and plate controversy
land use issues
loss of biodiversity
is it CO2 neutral or CO2 absorbing sink?

197
Q

food vs fuel

A

using land for biomass enrgy production competes with food and feed production

-> food shortage

extensive land use and conversion of ecosystems, resulting in loss of biodiversity

198
Q

iLUC - indirect Land Use Change

A

displacement effects triggered by additional demand (example for bioenergy sources)

additional demand for raw materials -> food production displaced to other land -> new cropland elsewhere -> conversion of natural ecosystems -> greenhosue gas emissions

199
Q

liquid fuels first generation biomass

A

processes that are already technically mature today

only use fruit (sugar, starch, oil)

can be used in combustion engines or plants

200
Q

examples of first generation fuels from biomass

A

vegetable oil fuel
biodiesel
bioethanol

201
Q

gaseous fuels second generation from biomass

A

production processes currently under development
biomass difficult to use today (lignin)

can be turned into natural gas and fed into grid

202
Q

examples of second generation fuels from biomass

A

biomethane
cellulose ethanol

203
Q

pyrolysis

A

biomass into solid char, liquid bio oil and combustible gases by heating biomass in absence of air

400-800C

204
Q

charring

A

fuel treated with oxygen through energy imput around 380C

products are hig carbon, solid fuels

205
Q

coefficient of performance (COP)

A

quotient of the heat released into the heating circuit and the energy used

206
Q

COP formula

A

COP=Q stream heat / W stream

207
Q

maximum achievable coefficient of performance COPmax

A

limited by the reciprocal value of the Carnot efficiency

208
Q

COPmax formula

A

1/carnot efficiency = Thot / Thot-Tcold

209
Q

gasification

A

converts biomass into syngas by heating it with limited oxygen

500-1400C

products are gaseous fuels

210
Q

biogas

A

through anaerobic

methane, carbon dioxide

lighter than air

direct electricity generation

211
Q

anaerobic fermentation

A

conversion done by bacteria operating rich cellulose biomass

biogas about 65% methane

212
Q

biomethane

A

processed biogas with natural gas quality of methane content above 96%

fed into gas grid and used for electricity, fuel and heating

213
Q

steps of biogas generation

A

hydrolysis
acid formation
acetate formation
methane formation

214
Q

pressure swing adsorptio

A

removal of H2S, H2O as pretreatmnt
physical absorption
under pressure using carbon molecular sieve

215
Q

pressure washing

A

dissolve co2 in water by increasing pressure

216
Q

tidal power plants

A

built in bays

uses gravitational pull of moon and water currents to generate electricity via generator

217
Q

tidal power plants advantage

A

low operating costs
no odor or noise pollution

218
Q

tidal power plants disadvantage

A

location dependency
tidal dependency

219
Q

marine current power plants

A

rotating bodies similar to wind turbines
speed of rotation proportional to flow velocity of water
little explored, only prototypes exist

220
Q

osmotic power plants

A

energy released when fresh water meets salt water

semi permeable membrane

pressure generated by transfer of water used to generate electricity

221
Q

heat pump

A

uses electrical energy to raise heat from lower to higher temperature level

refrigerant circuit absorbs heat during evaporationa nd releases it agian during condensation

222
Q

heat pump components

A

evaporator
comperssor
condenser
expansion valve

223
Q

gas equation

A

pV=mRT

224
Q

Weibull distribution wind formula

A

h= k/A (v/A)^(k-1) e°(-v/a)^k

where k >0 : shape factor, typical for europe =2 = Rayleigh

A > 0: measure for characteristic wind speed (m/s)

225
Q

Rayleigh distribution for europe

A

Weibull distribution with k=2 and wind speed of v= 4 m/s

226
Q

conversion chain of wind energy

A

mechanical energy in wind -> mechanical energy in rotor -> mechanical energy in shaft -> electrical energy

227
Q

Mechanical energy in wind formula

A

Ewind= 0,5mv^2

228
Q

Wind power formula

A

P = E stream wind =0,5m!v^2

229
Q

rotor power formula

A

Protor= Pwind*power coefficient aka cp

230
Q

electrical energy formula

A

Pel = Protor * Wirkungsgrad elec

231
Q

Drag force

A

force that occurs when area A is perpendicular to wind flow

232
Q

drag force formula

A

D= drag coefficient * air density/2 * Area * wind speed^2

233
Q

drag coefficient

A

depends on object

eg. circle plate 1,11
open hemisphere left

234
Q

Bernoulli’s Law

A

applies to flowing liquids and gases

for frictionless flows and states

the sum of static pressure, gravitational pressure and dynamic pressure is constant

235
Q

static pressure

A

pressure measured perpendicular to flow direction

236
Q

gravitational pressure

A

pressure resulting from the weight of the liquid. changes only when a flow is not horizontald

237
Q

dynamic pressure

A

acts in the direction of flow due to the moving fluid/gas

238
Q

Bernoulli’s law formula

A

static pressure + density of flowing fluid * gravitational pull * height + 1/2 density * flow velocity ^2 = constant

239
Q

Basic components of typical horizontal axis wind turbine

A

Rotor blade
Rotor hub and blade pitch mechanism
Rotor shaft and bearings
Gearbox
Rotor brake
Generator
Electrical switch boxes and control systems
Bedplate
Yaw system
Power cables
Tower
Grid connection (transformation)
Foundation

240
Q

Difference between leeward and windward rotor?

A

Leeward: rotor runs in wind direction behind the tower

Windward: rotor runs in wind direction in front of the tower

241
Q

Windward rotor advantage

A

tower does not obstruct wind

242
Q

Windward rotor disadvantage

A

Rotor must be quite rigid and needs a certain distance to the tower

Mechanism for wind direction tracking necessary

243
Q

Leeward rotor advantages

A

passive wind direction tracking

lighter built than windward rotors

244
Q

Leeward rotor disadvantage

A

greater noise emissions, power fluctuations and higher stress on rotor blades because tower doesnt block any wind

lower fatigue strength

245
Q

tip speed ratio lambda

A

peripheral speed / wind speed

246
Q

Power curve of a wind turbine

A

shows how much electrical power is generated as a function of wind speed

247
Q

Power curve of wind turbine formula

A

P= 0,5 A * air density * cp * v^3

A is rotor area
cp is power coefficient

248
Q

What are the parameters of the power curve of a wind power plant?

A

cut in and out speed

rated power output

rated speed

249
Q

cut in speed and cut out speed

A

wind speeds defining the operating limits of the wind power plant

250
Q

rated power output

A

always specified by generator and design and corresponds to its maximum permanent electrical output

251
Q

rated speed

A

the wind speed at which the wind turbine just reaches its rated power output

252
Q

Phases of power curve of wind power plant

A

I: partial load range: speed of turbine flexibly adjusted to optimum ratio between peripheral speed of rotor and wind speed (tip speed ratio) -> maximum efficiency

II: transition range: goal: keep rotor torque and noise low

III: full load range: protect generator from overspeed, pitch angles of rotor blades adjusted as soon as nominal wind speed reached. cp (power coefficient / aerodynamic efficiency) of blades is reduced

253
Q

Difference of offshore wind turbines to onshore?

A

higher speeds -> higher electricity yield

more difficult maintenance and repair

longer distance of grid connection to coast

254
Q

Solar constant G

A

energy from the sun per unit of time received on a unit area of surface perpendicular to the direction of propagation of the adiation at mean ear sun distance outside the atmosphere

255
Q

problem with wind turbine

A

logistical challenges:
transport of large turbines (rotors)

256
Q

air mass

A

length of path sunlight travels through earths atmosphere to reach the ground

257
Q

global radiation = ?

A

direct radiation + diffuse radiaton

258
Q

types of pv cells

A

silicium (cristalline, thin layer)

tandem (gallium arsenide, CIG, CdTe)

259
Q

Photovoltaics

A

direct conversion of solar radiation into electricity

converts light into electricity using semi conductor materials

260
Q

silicon as semi conductor material

A

most important

n type doping

diamond cubic cristialline structure

261
Q

energy band model

A

bands are successively filled with electrons

  1. valence band: outermost shell
  2. conduction band: next higher band can be partially filled or empty
  3. forbidden zone:space inbetween, which receives non allowed energy states
262
Q

why are semiconductors important for PV

A

conduction band is unoccupied like in insulators but have smaller band gap

-> electrons can be lifted into conduction band by influence of radiation

-> inner photoelectric effect

263
Q

how are electric fields created through pv

A

n layer: negative doped silicon

p layer: positive doped silicon

p silicon, which was neutral before, becomes negative, while n silicon becomes positive -> internal voltage

p doped and n doped semiconductors come together -> pn junction is formed

264
Q

diode

A

component of electrical engineering which allows electrical current to pass almost unhindered in one direction, but blocks other (electrical one way street)

265
Q

short circuit current

A

current flow through solar cell when voltage across solar cell is zero

short circuit current is largest current whch may be drawn from solar cell

266
Q

open circuit voltage

A

maximum voltage available from solar cell and occurs at zero current

corresponds to the amount of forward bias on the solar cell due to the bias of the solar cell junction with the light generated current

267
Q

rank types of solar cells in terms of efficiency

A

concentrated pv cell

monocrystalline silicon cells

polycrystalline solar panels

thin film

268
Q

monocrystalline solar panel advantage

A

hgih efficiency rate (20%)

optimized for commercial use

high life time value

269
Q

monocrystalline solar panel disadvantage

A

expensive

270
Q

polycrystalline solar panel advantage

A

lower price

271
Q

polycrystalline solar panel disadvantage

A

sensitive to high temperatures

lower lifespan

less space efficient

272
Q

thin film PV advantages

A

relatively low cost

easy to produce

flexible

273
Q

thin film PV disadvantages

A

shorter warrenties and lifespan

274
Q

concentraved pv cell advantages

A

very high performance and efficiency

275
Q

concentraved pv cell disadvantages

A

solar tracker and cooling system needed

276
Q

steam reforming for hydrogen formation

A

heat + steam + carbon containig fuel (eg methane) -> hydrogen, carbon dioide, carbon monoxide

277
Q

gasification for hydrogen formation

A

organic or fossil based material (coal, biomass) + heat + oxygen / steam -> carbon monoxide, hydrogen, carbon dioxide

without combustion

high level of maturity

278
Q

pyrolyse for hydrogen formation

A

methane containing feedstock + heat -> hydrogen + solid carbon

technology readiness level of 4-5

279
Q

water electrolysis for hydrogen formation

A

electricty + water -> hydrogen and oxygen

no significant byproducts or waste

280
Q

green hydrogen

A

requires extraction from renewable sources

only sustainable option

uses electrolyzers

281
Q

green hydrogen cost trend

A

cost of electrolyzers and renewable energy decreased significantly and further cost reductions needed

282
Q

turquoise hydrogen

A

produced through methane pyrolysis process

solid carbon is produced instead of co2

283
Q

orange hydrogen

A

hydrogen produced from bioenergy like biomass, biofuels, biogas, biomethane

after use, carbon in organic materials released back into the environment (lower carbon footprint from black hydrogen)

284
Q

red hydrogen

A

produced using nuclear energy

through electricity through electrolysis or thermochemical splitting of high temperature wastewater

not considered sustainable due to challenges with uranium mining, decommissioning, and nuclear waste management

285
Q

blue hydrogen

A

grey hydrogen with ccs

transitional solution but not carbon neutral due to potential greenhouse gas releases during ccs

286
Q

white hydrogen

A

occurs naturally, esp in africa through fracking

287
Q

grey hydrogen

A

originates from natural gas, through steam methane reforming

288
Q

power to hydrogen

A

renewable electricity converted into hydrogen by electrolysis

then into methane or liquid fuels

289
Q

brown hydrogen

A

derived from brown coal

290
Q

black hydrogen

A

produced using coal, typically through gasification

291
Q

electrolyzer cells

A

very small (less than 5kW) since the surface area o0f elevtrodes is limited by mechanical vonstrains

292
Q

electrolyzer stacks

A

groups of hundred cells in series or parallel

293
Q

electrolyte - alkaline, proton exchange membrane, solid oxide electrolyzer cells

A

KOH liquid

polymer membrane

ceramic membrane

294
Q

technical maturity - alkaline, proton exchange membrane, solid oxide electrolyzer cells

A

commercial

initial commercial

research and development

295
Q

what does hydrogen based electricity storage require?

A

a flexible electrolzer that is able to withstand variable loads

296
Q

proton exchange membrane advantage over alkaline as electrolyzer

A

highly flexible

easier to operate

simple design -> potential for cost reduction

297
Q

electrolyzer hydrogen production challenges

A
  1. limited economies of svale
  2. usually operated continuously - unable to compete with steam methane reforming in terms of flexibility
298
Q

hydrogen storage

A

mainly in gaseous form (prssurized tanks, underground reservoirs)

liquid form (cryogenic tanks)

299
Q

hydrogen main challenge

A

hydrogen volatile, expensive to handle

300
Q

hydrogen storage - pressurized tanks

A

preffered for systems subject to high cycling rates because capital cost per unit of energy capacity is high and needs to be amortized by frequent utilization

economically scale uppable as long as cycling rate is high

negligible hydrogen leakage

301
Q

underground storage for hydrogen advantages

A

most competitive and energy efficient option for large scale storage

fixed construction costs

302
Q

underground storage for hydrogen disadvantages

A

limited geological availability (man made salt caverns)

303
Q

underground storage for hydrogen - what kind of recycling rates and why`?

A

allows for lower cycling rates because capital cost per unit of energy capacity is much lower

304
Q

metal hydrides as hydrogen storage

A

cycling rates between a day to week but still must demonstrate techno economic feasibility

minimal energy penalty and great handling safety

305
Q

liquid storage for hydrogen

A

mainly suitable for large scale centralized storage with long distance transport

306
Q

hydrogen blending into the natural gas grid

A

hydrogen enriched natural gas can be injected into gas grid

307
Q

avantages of hydrogen blending over methanation

A

minimal investment

no dedicated hydrogen storage required

minimal additional energy losses

existing storage and transport capacity

308
Q

disadvantages of hydrogen blending over methanation

A

H2 to natural gas ratio is technically limited to 17.25%

uncertain and very system specific, limited by grid integrity, safety, energy transport capaciy, specification sof end use application

costly adaptation of the real time hydrogen injection rate

309
Q

CCS post combustion application area

A

biomass and biogas power plants

310
Q

CCS post combustion advantages

A

highest market maturity

easy combination with existing technology

311
Q

CCS post combustion disadvantages

A

low co2 concentration impairs efficiency of separation process

312
Q

CCS pre combustion application area

A

biomass and biogas power pßlans

313
Q

CCS pre combustion advantages

A

high co2 concentration improves sorption effiviency

fully developed tech

commercially used to an appropriate extend

easy combination with existing technology

314
Q

CCS pre combustion disadvantages

A

temperature ependent heat transfer problem and efficiency losses associated with hydrogen fuel in gas turbines

high parasitic power requirements for rotary dehumidifiers

insuffiicent experience due to lack of gasification power plants on the market

high capital and operating costs for current sorption systems

315
Q

oxyfuel combustion ccs advantages

A

very high co2 concentration improves absorption efficiency

mature air separation processes available

lower gas volume, therefore smaller boiler and other equipment

316
Q

oxyfuel combustion ccs disadvantage

A

high loss of efficiency and eenergy

refrigeration co2 production costly

rust

317
Q

methanation hydrogen

A

greater energy losses and high investment required than blending but full access to gas grid and benefits from higher volumetric density of methane compared with hydrogen

318
Q

alkaline electrolyzer advantages

A

commericla

cheapest

ultra pure hydrogen output

319
Q

alkaline electrolyzer disadvantages

A

limited cost reduction potential

limited efficiency gains

complex cell design

corrosive

operates at high pressure

low response time

320
Q

PEM advantages

A

design simplicity and reliability

high efficiency, higher current densities than alkaline

very fast response time

higher cost reduction potential

321
Q

PEM disadvantages

A

high investment costs

difficult to manufacture

lifetime of membranes

requires much greater water purity

322
Q

solid oxide electrolyzer cell advantages

A

highest energy efficiency

low capital costs: high density and no noble metals

possibility of coelectrolysis of co2 or h2o for syngas production

reversible use as a fuel cell with possibility of heat recycling synergies

323
Q

solid oxide electrolyzer cell disadvantages

A

immature technology

poor lifetime

limited flexibility

324
Q

Which are the countries/regions with the highest hydrogen production potential? Is it probable/desirable from an ecological point of view that parts of the industry concentrate there?

A
  1. Middle East: abundant natural gas reserves and solar energy resources.
  2. Europe: renewable energy capacity, especially wind and solar, to produce hydrogen through electrolysis.
  3. Australia: With vast land areas and significant renewable energy potential,
  4. North America:
  5. Asia-Pacific: Japan and South Korea have been investing in hydrogen as part of their energy transition strategies. Japan, in particular, aims to import hydrogen due to limited domestic resources.
325
Q

value chain natural gas

A

upstream: exploration, production , processing

midstream: transport, storage, distribution

downstream: sale

326
Q

worldwide distribution of natural gas

A

russia

middle east

north america

austrialia

327
Q

associated gas

A
  1. Associated Gas:
    - Associated gas is found in conjunction with crude oil deposits within
    underground reservoirs.
    - When oil is extracted, associated gas is also brought to the surface along
    with the oil.
    - The gas is dissolved in the oil under high pressure in the reservoir, and as
    the pressure decreases during extraction, the gas comes out of the solution and is released.
    - The composition of associated gas can vary, but it often contains a mix of hydrocarbons, including methane, ethane, propane, and other gases.
328
Q

non associated gas

A
  1. Non-associated Gas:
    - Non-associated gas, on the other hand, is found in reservoirs that do not
    contain significant amounts of crude oil.
    - These gas reservoirs are separate from oil reservoirs, and the gas is not
    associated with the production of crude oil.
    - Non-associated gas is usually found in geological formations where the
    conditions favor the accumulation of natural gas without the presence of significant amounts of liquid hydrocarbons.
    - The composition of non-associated gas is typically higher in methane compared to associated gas.
329
Q

central components of natural gas infrastructure

A

pipelines

compressor station

LNG terminals

unterground sstorage

330
Q

radial network for gas distribution

A

tree structure

known flow direction

volume of volume flow among strands of network always clear

each point of the network can only be supplied by one route

331
Q

meshed network

A

no clear flow direction

the distribution of volume flow among the strands of the network is unclear

each point of the network can be supplied by several routes

332
Q

advantages of steel pipes for gas

A

no pressure limitation

better elasticity

good ductility

big sizes of single length possible

333
Q

disadvantages steel pipes for gas

A

corrosion

334
Q

plastic tubes for gas advantages

A

corrosion resistance

high flexibility and less weight than steel

easy to lay

pipe lengths variable for amount of needed junctions

if smaller than dn 300, usually more cost efficient than steel pipes

335
Q

plastic tubes for gas disadvantages

A

pressure limitation at 4 bar

maximum outer diameter

lwo mechanical resistance

no aging resistance

336
Q

pressure in gas pipes

A

pressure inside pipes drops continually with its length due ot friction -> speed rises

337
Q

gas compressor station parts

A

drive unit: powers compressor using natural gas a fuel

compressor: increases pressure

cooler: cools gas when it heats up during compression

338
Q

LNG advanatage

A

transport (road, rail, water) and storage possible without need for pipelines or natural gas storages

volume is 1/600 of natural gas

339
Q

lng disadvantages

A

still significantly less important than pipelines

high energy inut needed to liquify the natural gas before it is transported

continual evaporation of lng requires cooling and or liquiefaction

340
Q

process chain lng

A

natural gas -> liquification LNG

-> storage tanks

-> gas transport pipeline

.> jetty -> lng vessel -> jetty

-> storage tank -> high pressure pump

-> vaporizer -> gas transport pipeline

341
Q

where can natural gas be stored

A

dep0leted fiels (porous rock)

salt formations (daily, weekly storage in cavern)

depleted aquifers (porous rock)

342
Q

district heating - how does it work

A

heated water in central location -> hot water or steam via thermally insultaed piping system -> consumer

343
Q

heating plants

A

provide only heat using coal natural gas and oil through water

boiler systems or heat exvhangers using geothermal energy or waste heat used for heating the water

efficiency only 60%

344
Q

modern cogeneration plants

A

produces heat and electricity using energy of exhaust gas multiple times

highest efficiency - 89%

345
Q

two pipe system distring heating networks

A

supply and return line

can be operated at constant temperature

temperature control of flow temperature tale3s place only below a crtain outside temperature

346
Q

three pipe system district heating networks

A

two supply lines, one of which oprating at constant temperature and other at outside temperature

347
Q

heat exchanger

A

transfer heat from one medium to antoher

348
Q

high end temperature district heating

A

high temperature level of flow

eg berlin 130 c

high losses

349
Q

medium temperature district heating

A

medium temperature of flo ca 60 c / 35 c

in comparison to low temperature sources such as solar thermal energy and heat pumps, better integration of renewable heat supply

350
Q

low energy district heat lowex

A

renewable heat sources can be integrated more easily

only useful for supplying low temperature heat to energy renovated buildings

351
Q

why is a wobbe index needed

A

value consideres both the calorific value of fuel gas and density

because a lighter a gas is, the faster it can be moved but it doesnt necessarily mean the calorific value is changed

352
Q

wobbe index formula (upper)

A

upper calorific value of the fuel gas / square root relative density, so density fuel gas/density air

353
Q

wobbe index formula (lwoer)

A

lower calorific value / square root relative density, so density fuel gas/density air

354
Q

what doe the same wobbe index for two gases indicate

A

same heat load on burner at the same burner pressure and when identical burner nozzles used

output of burner is constant despite different calorific values of gases

355
Q

wobbe index

A

characteristic value for the interchangeability of gases with regard to heat load

356
Q

where to L gases come from

A

german and dutch deposits

357
Q

what do declining l gas production indicate

A

in the l gas network areas, the networks must be converted

358
Q

where do H gases come from

A

russia and north sea

359
Q

Value chain of electricity

A

extraction primary energy

generation

grids, transmission and distribution

trading

sale

360
Q

power grid

A

connection of spatially separated generators and consumers via lines and cables

361
Q

fundamental challenges in network operation of electricity grid

A

electricity must be generated at same time as it is consumed

fluctuating demand and generation

ensuring security of supply and frequency stability

362
Q

island grid electricity system disadvantages (stand alonoe)

A

grid frequency determined exclusively by speed of generator

if load increases
-> additional resistance in magnetic field of generator
-> braking
-> drop in frequency

363
Q

electricity grids - radial networks

A

for small/medium networks

+shortest route length
-security of supply

364
Q

electricity grids - ring networks

A

integration of several generators possible
+higher security
+easily expanded
-expensive because of longer track length and nominal diameter of the loops

365
Q

electricity grids - mesh networks

A

for large distribution
+optimal supply security
+better expansion options
-very high investment costs

366
Q

n-1 criterion - electricity grids

A

safety standard that must be met when planning and operating networks

when network component (eg transformer) can fail without causing unacceptable supply interruptions, interference propagation, without voltage exceeding or falling below permissible limits or components being overloaded

367
Q

design requirements of pwoer grid in germany

A

transport electricity

balance between generatio and consumption

voltage maintenance: control of reactive power for transport

operational management: monitoring and control of switching status, network load and resources

market management: auctions, timetable maangement, market platform

bottleneck management: network rebuilding

368
Q

Ohm’s Law

A

the greater the resistance, the less current flows at the same voltage

369
Q

what is the relationship between transmission losses and transmission voltage?

A

transmission losses decrease quadratically with increasing transmission voltage!

370
Q

system components of power grids

A

generators: conversion

transofrmers: connect networks of different voltages

lines: ac /dc (connection of networks with different frequencies)

engines: consumer

equipment: change of transmission characteristics

371
Q

transformers function

A

connect ac networks of different voltage levels

372
Q

electrical substations

A

between generating station and consumer

includes transofmrers and grounding system

with switchgear: connect, interrupt, disconnect electrical paths

373
Q

alternating current generation

A

by generators in power plants, cogenerations plants

374
Q

ac advantages

A

simple transformation

easy operation

375
Q

ac disadvantages

A

for some applications conversion to dc necessary

reactive power losses during transport through lines, esp with those with high electical capacity

376
Q

dc generation

A

by PV, chemical processes (batteries, fuel cells)

377
Q

dc advantages

A

directoperation of microelectronics possible

directly usable to charge batteries

significantly lwoer transport losses and no reactive pwoer losses

378
Q

dc disadvantages

A

operation needs upstream electronics or special designs

generation not possible by generators in power plants

379
Q

resistivity

A

termpature dependent material constant that characterizes electrical resistance of wire or resistor

reciprocal is electrical conductivity

380
Q

dielectric strength

A

critical electric field strength at which voltage breakdown can occur

381
Q

why do frequency deviations occur

A

momentary imbalances between generation and consumption

382
Q

power frequency control

A

control method for maintaining electrical parameters agreen between TSO at the limits of their control zones during normal operation and in particular int he event of a failure

383
Q

primary control - power frequency control

A

automatically acting, stabilizing control of entire interconnected grid in seconds (all power plants jointly regulated)

active reserve of power plants additional for self regulation of loads

384
Q

redispatch

A

adjustment of active power feed in from power plants to avoid or resolve occuring congestion

by lowering active power feed in of one or more power plants while at the same time increasig active power feed in of one or more other power plants, total active power feed in remains virtually unchanged

385
Q

what are possible causes for congestion in electricity grid

A

line interruptions for maintenance purposes

unanticipated incidents

weather

RE

386
Q

main parts of power transformers

A

core, windings, casing

connected to transformer bank

387
Q

advantage and disadvantage of single phase unit power transformers

A

+necessary placements
-cost of material

388
Q

parts of overhead line system

A

poles made of steel, concrete or wood

insulators of porcelain, glass, plastic

lines (alu, steel)

389
Q

what is the role of air in overhea lines

A

permanent renewing of insulation -> no aging

air dischanrges heat losses well -> short term overloads possible

lower costs of material

higher distances between lines required

390
Q

cable systems for electric grid

A

very complex (high potential differences on small distances)

use oils and resins, plastics, synethetics

thermal overloading critical for durability of cables

391
Q

cables disadvantage compared to overhead

A

fault locations not directly visible, complex detection/measuring necessary

392
Q

what does the decision overhead lines vs cables depend on

A

grid reliability
renewable/replacement costs
oüperaional costs

393
Q

what is better, overhead or cable systems?

A

cable for quality but more expensive
cable “state of the art”

394
Q

cables vs overhead lines - status detection

A

no, yes

395
Q

cables vs overhead lines - frequency of faults

A

low, medium to high

396
Q

cables vs overhead lines - consequences of faults

A

repair costs, wide range from no effect to personal damage

397
Q

cables vs overhead lines - operational costs

A

low, medium to high

398
Q

cables vs overhead lines - date of renewal

A

proactive and not based on status detection, status detection

399
Q

cables vs overhead lines - risk of renewal

A

primarily monetary, monetary and personal damage

400
Q

temperature

A

intesive property: describes systems state and not its changes

Whether a temperature is “high“ or “low“ depends on the reference system with arbitrary classification (e.g. distances on thermometers).

401
Q

Heat

A

quantity of energy that is transferred between systems of different temperature levels in form of a heat flow ሶ 𝑄 (when in contact via a diathermal* wall).

402
Q

Low-temperature range

A

▪ All processes for temperatures below 100°C, mainly hot water production for washing
and food production.

403
Q

Medium temperature range

A

This includes all processes in a temperature range from 100 to 500°C.
▪ The heat is usually supplied by steam through locally installed heating systems.

404
Q

High temperature range

A

▪ Temperatures above 500°C are required, for example, for manufacturing processes in
the ceramics and metal industry.
▪ The provision of those high temperatures places special demands on the heating
systems.
▪ Often, electrical power is used for this purpose.

405
Q

Power-oriented plant operation

A

– Selection, design and operation of the CHP system are based on the values for the electricity demand.
– The design must be such that excess heat is avoided, because excess heat has to be discharged from the
system in recooling plants.
– Insufficient infeed into the heat distribution network is provided separately by means of additional boilers.

406
Q

Heat-oriented system operation

A

– Selection, design and operation of the CHP system are based on the values for the thermal energy demand.
– Usually, they are not designed for peak load, which is also covered by a boiler system.

407
Q

district heating

A

is based on heating water in a central location and then supply domestic and
commercial consumers in form of hot water or steam via a thermally insulated piping system. The piping from
the heat generators to the load is referred to as flow and the piping from the consumer back to the heat
generators as return.

408
Q

Difference between district and local heating:

A

The differentiation between district heating and local heating is
in particular a linguistic differentiation. The term local heating covers smaller decentralized heat networks, while
district heating refers to larger networks, which usually contain large transport lines. Technically, however, this
differentiation has no great importance. For both heating approaches the basic operation is the same. Also, there
exists no general definition like the length of a network to differ between local and district heating.

409
Q

Heating plants:

A

provide only heat. Thus, the main part of exhaust gas remains unused by this plants.

410
Q

Modern cogeneration plants:

A

based on the principle of
producing heat and electricity
by using the energy of the
exhaust gas multiple times.
There are different technical
systems. Combined units are
the most advanced, they have
the highest efficiency.

411
Q

rate district heating in terms of nachhaltigkeit

A

Compared to a separate generation of electricity and heat the energy savings are between 30 and
50 percent. Therefore, the use of conventional energy carriers (hard coal, lignite, gas, oil) in those
power plants is economically reasonable. Nevertheless, the technology is mainly applied in urban areas mainly due to the limited possible transport distance for heat.

412
Q

Solar district heating systems

A

heat supply systems that supply residential and industrial areas
with solar heat via large collector fields and heat networks.

413
Q

geothermal district heating

A

three closed circuits are required.

1.000 to 10.000 households can
be supplied with heat.

▪ It is considered as 3rd generation district heating system.

▪ such systems are mainly used in the area around Munich.

414
Q

what can be done in terms of power to heat? what is possible

A

space heating
process heating

415
Q

why can not all processes be switched to electric heating

A

temperature levels (eg porcelain production require high levels of heat)

need of carbon (steel)

416
Q

heat pump

A

heat pump is a machine that generates heating energy from a low-temperature heat
source using a (electrically driven) compressor.

417
Q

parts of a heat pump

A
  1. Condenser coil (hot side heat exchanger)
  2. Expansion valve (gas expands, cools and liquefies)
  3. Evaporator coil (cold side heat exchanger)
  4. Compressor
418
Q

how does a heat pump work

A

cold liquid refrigerant pushed through with air from outside which warms it up

cold liquid refrigerant evaporates as temperature inreases. cold air is released outside

the liquid goes through compressor. pressure increases with temperature

hot air gets released inside

air condenses as it cools into liquid

liquid gets pushed through expansion valve, pressure drops, temperature drops

repeat

419
Q

what are the components of a geothermal heat collector

A

horizontal geothermal energy collector

heat pumps

storage hot water

storage heating circuit

420
Q

electrode boiler

A

water directly heated up without resistance elements. operated in ac mode to prevent electrolytic decomposition of water

421
Q

HVAC - componentns and abkürzung

A

heating ventilation air conditioning and cooling

ventilation
filtration
heat recuperation systems
other (humidifier, cooling, sound absorber)

SERTS (2 decks)

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