Lecture material: definitions & basic descriptions Flashcards
Why is climate change mitigation so challenging?
- Uncertain in form and extent
- Gradual and insidious onset rather than directly confrontational
- Long term threat rather than immediate, but it requires action now
- Broad in impacts and remedies
- Effective remedies are beyond the scope of anyone nation; it requires international co-operation of unprecedented dimension and
complexity
Outline 4 types of measuring mitigation benefits
- Type 1: Currently measureable market impacts
- Type 2: Market impacts not readily measurable
- Type 3: Insurance value against high damages (WTP)
- Type 4: Non-market impacts
What is the cumulative carbon budget from 2011-2100 to have a 66% chance of staying below 2oC?
And the remaining budget for energy related emissions?
1,000 Gt CO2
600 Gt CO2
Outline the carbon budget approach to climate justice
Underlying principle: Equal emissions entitlement
Proportion of global carbon budget allocated on basis of population
Outline the Index-based approach to climate justice
Underlying principle: Historical responsibility
Share of mitigation determined by share of historical emissions
Outline the Contraction and convergence approach to climate justice
Underlying principle: Equal emissions entitlement
Country emissions follow a pathway where they contract to converge on the same emissions per capita by a specified date
Outline the Common but differentiated convergence approach to climate justice
Underlying principle: Equal emissions and historical responsibility
As above but countries further differentiated on their level of economic development. Countries below per capita threshold can carry on with BaU.
Outline the Cost proportional to GDP per capita approach to climate justice
Underlying principle: capacity to pay
Targets set based on equal mitigation costs
as a percentage of GDP
Outline the Income classification approach approach to climate justice
Underlying principle: capacity to pay
Targets set based on mitigation costs as a percentage of GDP but higher % for wealthier countries
Outline the responsibilities of Annex 1 countries in the UNFCCC
Annex 1: developed countries
- meant to take the lead
- Specific mitigation targets and timelines for developed countries
- Developed countries expected to provide funding and resources (technology transfer) to developing countries
What is grid parity?
the same cost as grid power per unit of energy
Advantages & disadvantages of solar PV
Solar PV: converts photonics energy from sunlight directly into electrical energy.
Advantages:
- Low ghg emissions per unit of electrical energy produced.
- Able to operate economically at a range of scales
- CPU electricity falling rapidly, reaching grid parity in many regions
- Low operating and maintenance costs, no moving parts, silent and no direct emissions.
Disadvantages:
- Intermittent
- Requires an inverter to convert from DC to AC to transmit to the grid
- Upfront capital cost remains high relative to conventional generation
Advantages & disadvantages of CSP
CSP uses lenses or mirrors to concentrate a large area of sunlight onto a small area. This light is converted into heat which drives a heat engine to generate electricity.
Advantages:
- Low gig emissions per unit of electrical energy produced.
- Time of electricity output may be controlled by storage of heat in molten salt.
- No direct emissions.
Disadvantages:
- Only economical at a large sale and in regions of high direct sunlight, must be close to an urban centre.
- Relatively expensive.
- Often large projects with long construction times and high upfront capital costs.
Outline solar thermal panels
Solar thermal panels: convert photonic energy from sunlight directly into heat to provide hot water.
Has been cost effective in many regions for over 30 years.
The IEA project cost decline of 43% in Europe from 2010 to 2020.
Advantages/ disadvantages of wind power
Wind turbines convert the wind’s kinetic energy into electrical power.
Advantages:
- Low ghg emissions per unit of electrical energy produced.
- CPU electricity is competitive with fossil fuels in many regions.
- Can be built on farms without causing long term disruption to agriculture.
- No direct emissions associated with operation.
Disadvantages:
- Intermittent.
- Upfront capital cost remains high relative to conventional generation.
- Strong local opposition to appearance and noise in some areas.
- Good wind sites are often located in remote locations, requiring potentially costly transmission to cities where the electricity is needed.
Advantages/ disadvantages of hydropower
Hydropower is the most globally deployed renewable electricity source, and generated 17% of world electricity, and 70% of renewable electricity in 2015.
Advantages
- Low ghgs emissions per unit of electrical energy produced.
- Electricity output may be controlled by release of dam.
- CPU electricity is below that of fossil fuels in many regions.
- No direct emissions associated with operation.
Disadvantages:
- Often large projects with long construction times and high upfront capital costs.
- Site specific, requiring potentially costly transmission to cities.
- Possible loss of habitat due to barrier waterlife and flooding for dams.
Relative merits of wind, nuclear & gas
Wind power:
- High capex
- low operating costs, no fuel costs
- output variable
- low GHG emissions
Nuclear power:
- High capex
- high operating costs, low fuel costs
- output constant
- low GHG emissions
Gas turbine:
- Intermediate capex
- high fuel costs
- output may be rapidly ramped up or down
- intermediate GHG emissions
5 metrics for comparing energy generation technologies
- Typical output
- Reliability of supply
- Cost
- Emissions intensity
- Land use
Electricity generation technologies do not generate at full capacity all of the time. This may be due to:
- Planned or unplanned maintenance.
- Intentional ramping up and down of supply to meet demand/ respond to economics of generating at current electricity price.
- Unavailability of fuel (including wind, sunlight, and water for renewables).
Outline system balancing
System balancing relates to the relatively rapid short term adjustments needed to manage fluctuations over the time period from minutes to hours.
Outline reliability impacts
Reliability impacts relates to the extent to which we can be confident that sufficient generation will be available to meet peak demands.
Outline the three categories of frequency response reserves
Enhanced Frequency Response:
which must provide power (or reduce demand) within one second and provide power for a further nine seconds.
Primary Frequency Response:
which must provide power (or reduce demand) within ten seconds, and provide power for a further 20 seconds.
Secondary Response:
which must provide power (or reduce demand) within 30 seconds, and provide power for a further 30 minutes.
Outline Loss of Load Probability
LOLP measures the statistical likelihood that any load (demand) is not met, and it is usually a requirement of electricity systems that LOLP is kept small.
Variable generation increases LOLP for same total generating capacity.
Outline the relation between capacity credit and LOLP
Capacity credit represents the amount of capacity reserve required per capacity credit to keep LOLP the same as using purely thermal plants.
4 methods of ensuring consistent electricity supply?
- Energy storage
- Increased connectivity
- Demand side management
- Dispatchable generation
Advantages/ disadvantages of Lead-acid battery
Lead- acid batteries consist of lead dioxide (cathode), metal lead (anode) and aqueous sulphuric acid (electrolyte).
Advantages:
- Mature technology
- Lowest cost battery technology
- Effective recycling procedures exist, >99% recycled in EU & US
- Able to respond quickly to changes in demand
- Economical at a range of scales
Disadvantages:
- Relatively low energy density: unsuitable for EVs
- Relatively low cycle life and very dependent on depth-of-charge.
- Lead is toxic and acid is highly corrosive.
- Over their lifetime, lead-acid batteries are estimated to only store twice the energy used in their manufacture, not effective for climate change mitigation.
- Requires inverter to convert back to AC and interact with the grid
Advantages/ disadvantages of Lithium-ion batteries
Advantages:
- Rapidly falling costs and technology improvements
- Relatively high life cycle (5000+ reported)
- Relatively high energy and power density
- High efficiency
- Able to respond quickly to changes in demand and provide enhanced frequency response.
- Economical at a range of scales (on and off grid).
- Over their lifetime, lithium-ion batteries are estimated to store ten times the energy used in their manufacture.
Disadvantages:
- Relatively high capital cost compared to lead-acid
- Contain potentially toxic materials and recycling procedures are not well established.
- Most designs contain cobalt and nickel, which are challenging to source ethically.
- Relatively high embedded energy compared to mechanical technologies.
- Requires inverter to convert back to ac.
Advantages/ disadvantages of Redox Flow Batteries
Advantages:
- Potential to operate at a range of scales (on and off grid)
- Power and energy decoupled, allowing versatility of design
- High life cycle (10,000+ reported)
- Vanadium electrolyte doesn’t degrade and can be recycled.
Disadvantages:
- Relatively high capital cost compared to competing technologies.
- Energy and power density too low for electric vehicles.
- Relatively little deployed compared to other technologies.
- Vanadium exhibits modest toxicity to humans.
- Requires inverter to convert back to ac.
Advantages/ disadvantages of high temperature sodium based batteries
Advantages
- Relatively high energy leading to small spatial footprint
- Abundant, non-toxic materials promise low material costs and good recyclability.
- Battery operation is independent from ambient temperatures and allows deep depth-of-discharge at relatively high cycle life.
Disadvantages
- When not in use the batteries require 10-14% own capacity per day to maintain their operating temperature and must be preheated after shutdown.
- Power density too low for EVs
- Sodium and sulphur can cause a violent reaction when the separating ceramic ruptures.
- Expertise not widespread
- Challenges surrounding corrosion of materials under harsh operating conditions, and dendritic sodium growth.
- Requires inverter to convert back to ac.
Advantages of power-to-gas storage
PtG plants convert electricity into hydrogen or synthetic methane. This gas is stored and can be re-electrified, used in transport, heat generation or in industrial applications as feedstock.
Advantages
- PtG plants can make renewable power available for other energy sectors (transport, heat) and the chemical industry.
- Large amounts of energy can be stored while utilising existing gas network infrastructure, which could make this technology particularly attractive for seasonal storage.
Disadvantages
- High electrolyser cost represents the most important barrier to PtG deployment.
- Relatively low efficiencies.
- Relatively slow response to changes in power supply
Advantages/ disadvantages of pumped hydroelectric storage
PHS involves the pumping of water from a lower reservoir to a higher reservoir at times of peak supply to be released through a turbine to generate electrical energy at time of peak demand.
Advantages
- Proven technology
- Long lifetime (40+ years)
- Relatively low carbon footprint (store over 200 times the energy required for their construction)
- Rely on robust mechanical components and no scarce materials.
Disadvantages
- Site specific
- Long construction time
- High capital cost
- Potential for impact on aquatic life
Advantages/ disadvantages of Compressed Air Energy Storage
CAES involves the compression of air at times of peak supply, which is typically stored in an underground salt cavern, to be allowed through a turbine to generate electrical energy.
Advantages
- CAES relies largely on components which are mature and well understood, and could offer a robust and affordable means of storing large quantities of energy on the grid.
- Long lifetime (35+ years)
- Rely on robust mechanical components and no scarce materials.
- Relatively low carbon footprint
Disadvantages
- Site specific
- long construction time and high capital cost
- Low efficiency
- Non-adiabatic systems rely on the combustion of natural gas during discharge, associated with some emission of carbon dioxide.
Advantages/ disadvantages of Flywheels
Flywheels are accelerated by a motor using electricity. the electrical energy is then stored as the mechanical inertia of a flywheel. This energy can be retrieved when the process is reversed with the motor, now a generator, acting as a brake to extract the energy.
Advantages
- Rapid response times (<1 sec)
- High power density
- High cycling efficiency
- Rely on robust mechanical components and no scarce materials. Long lifetime.
Disadvantages
- Suitable only for short durations (up to 15 mins) as a result of their low energy density
- Idling losses during standby lead to high self-discharge
- Due to the robust housing and operation in a vacuum, flywheels are relatively expensive.
Advantages/ disadvantages of Liquid Air Energy Storage
LAES involves the liquefaction of air during time of peak supply. This liquid air is stored in a tank, and brought back to a gaseous state at times of peak demand, and uses that gas to turn a turbine and generate electricity.
Advantages
- No specific geographical requirements for thermal technologies
- Rely on robust mechanical components and no scarce materials.
Disadvantages
- More costly than other bulk storage options (such as pumped hydro and compressed air)
- Unlikely to be suitable for very fast response applications.
- Some components require specific redesign to handle the high pressures and extreme temperatures.
Outline electrochemical, mechanical, thermal, and electrical storage technologies and give examples of each
Electrochemical stores electrical energy as chemical potential energy during charge, and reconverts it to electrical energy during discharge.
- Lead-acid batteries
- Lithium-ion batteries
- Redox flow batteries
- High temperature sodium based batteries
- Power-to-gas
Mechanical stores electrical energy in various forms through mechanical action.
- Pumped Hydroelectric Storage
- Compressed Air Energy Storage
- Flywheel
Thermal stores electrical energy as thermal energy to be reconverted to electrical energy
- Liquid Air Energy Storage
Electromagnetic stores energy in electromagnetic fields
- Supercapacitors
- Superconducting Magnetic Energy storage
Advantages/ disadvantages of supercapacitors
Energy is stored directly as the electric charge on the conductors creating an electrostatic field across dielectric material.
Advantages
- high-power, low-energy devices that react very quickly and exhibit a long cycle life (10,000+ cycles) at high efficiencies.
Disadvantages
- Very low energy density and high self-discharge lead to high energy capital costs and make them unsuitable for energy storage over longer periods of time.
Advantages/ disadvantages of superconducting magnetic energy storage
SMES store electricity in a magnetic field generated by direct current flowing through a superconducting coil
Advantages
- High-power, low-energy devices that react almost instantaneously and exhibit a long cycle life at high efficiencies.
Disadvantages
- The high cost of superconductors and the high system complexity make SMES very expensive and only suitable short term.
- The high energy requirements of the refrigeration system lead to a high daily self-discharge.
Why is industry challenging to decarbonise?
- Sector is heterogenous
- High temperature processes
- Process emissions arising rom chemical processes
- the issue of competitiveness and risk of carbon leakage
The limitations of MAC curves
- Very dependent on underlying assumptions, often not transparent.
- Interactions and path dependency
- Costs exclude indirect costs/ benefits
- Assume rational agents with perfect information
- Discount rate (social planner vs company view)
- Intertemporal issues
- No representation of uncertainty
What is the Marchetti’s constant?
the average amount of time per day that a person spends commuting.
1.1-1.3 hrs per day, independent of wealth, race of geography.
Co-benefits of mitigation in the transport sector
- Health benefits of reduced vehicle exhaust emissions
- Health benefits of increases human activity through walking and cycling
- Reduced noise
- Road transport is higher risk than other forms of transport
- Modal shifts result in reduced traffic congestion
- Improved public transport results in increased mobility for the poorest of society
Outline the main problems with Energy System Models
Energy system models
- set mitigation costs against a BAU baseline
- fail to account for the dynamics of innovation
- fail to account for human behaviour and dynamics
Energy system model exercises
- lack transparency
- do not systematically show why model results differ
- seek to project costs beyond a reasonable time horizon
Outline 4 ways energy system models are dominant in policymaking
- Setting the international context for mitigation (IPCC)
- Estimating costs of EU mitigation targets
- Setting UK carbon budgets
- Exploring consequences of technology innovation pathways
