everything Felix doesn't know yet Flashcards
Steps of the energy system:
From primary energy carrier to energy service
+ examplifying real world steps
Primary energy carrier -> conversion -> final energy carrier -> consumption technology -> energy source
Crude oil -> refinery -> gasoline -> car -> transport
Where is the energy lost between primary & final energy carrier going?
Thermal energy
Three physical aspects that make electricity extraordinary
1) non-storability
2) Frequency stability
3) Easy transmission in grids
What to like about electricity?
- Versatile
- Transportable
- Clean
What is electricity?
Movement of electrons along electrical conductors (wires) that form a closed circuit.
Formula for current, power, energy
current (I) = Voltage / resistance = V / R
power (p) = V * I = voltage * current
energy = P * t
Why is electricity transmitted over long distances with high voltages?
Proportionally less losses:
Losses are proportional to current (I) ^2
Losses from 400 V to 400 kV reduced by 1 mio
What does an electrical transformer?
Changes voltage (works only in AC)
What does an electrical converter?
Changes frequency f
How does an electrical generator work?
If a conductor is moved through a magnetic field, voltage is induced/ electrons get moved.
What does a turbine do? (abstract definition)
+ physical principle of the blade
Potential energy into kinetic energy (physical principle: lift)
What does a generator do? (abstract definition)
+ physical principle
Kinetic energy into electric energy (physical principle: induction)
Gas turbines: pros and cons
Pro’s:
1. relatively small and cheap
2. doesn’t require cooling water
con’s:
1. low conversion efficiency (<40%)
2.Fuel must not contain ash, otherwise it would damage the turbine
Carnot Cycle
You can transform 100% of electricity into heat but there be be losses from heat to electricity.
Rankine Cycle
Thermodynamics of simple steam turbine.
What’s the physical priciple a wind turbine blade works with?
Lift
What do we use Annualized Fixed Costs (AFC) for?
Rather: What comparison does it help us for?
Helps to compare assets with different lifetimes
What tell us the Levelized Fixed Costs of Electricity (LCOE)?
Aggregated discounted lifetime costs, averaged per unit of output.
AFC = C fix * r * ((1+r)^y) / ((1+r)^y -1)
(How) do policies impact the LCOE?
Feed-in-tariffs for RE
Cap-and-trade system for greenhouse gas emissions
Profit in short-term model vs profit in long-term model
Short-term profit:
Contribution margin
Revenue - var. costs
long-term profit:
revenue - full costs (LCOE)
LCOE vs NPV
Similarities:
- used for investment decisions
- dynamic: Payments are discounted and aggregated
Differences:
- LCOE is a cost metric
- NPV accounts for both cost and revenues
3 reasons why people prefer consuming now over consuming later
- Impatience
- Declining marginal utility
- Risk: Future payment might not be realized
2 fundamental types of financing
- Equity
- Dept
What’s the WACC?
The ‘average interest rate’ for a mix of equity and dept financing.
Capital costs vs cost of capital: which is which?
Capital costs: Cost of the investment good, e.g. €/kW
Cost of capital: Payments for using capital, e.g. WACC in %
The silent revolution of wind turbines (how they have developed)
Higher towers, larger rotors
4 ways to interpret the MOM
- System planner
- Integrated utility (maximizes profits while meeting electricity demand)
- Central dispatch market
- Self dispatch market
Short-run vs long-run: what’s the difference, what’s the marginal cost for each?
Short-run:
Capital stock is given
marginal cost: variable cost
Long-run:
Capital stock is part of the analysis
marginal cost: LCOE
When to use a short-run / long run model?
Short-run: There’s an overcapacity in the market
Long-run: Capacity is scarce or we’re interested in investment decisions
5 underlying assumptions of the SCM
- No imports/ no exports
- zero demand flexibility
- free pricing
- no storage
- perfect competition
Two interpretations of the SCM
1. Planner model
- Tool to determine the least-cost capacity mix
- Scarcity prices: Marg. costs of increasing demand
2. Market model
- Description of the long-term equilibrium on a free and competitive power market
Functioning of an open Cycle gas turbine
Air & gas -> Compressor -> combustion chamber -> turbine -> generator (abgehend: transformer, grid) -> exhaust gas treatment -> exhaust gas
