VL zu Energy

Question 1

Efficiency (Formel)

Answer 1

useful energy / supplied energy

Question 2

Meaning of installed power

Answer 2

= how much power (energy/second) a product/power plant can produce even when in full operation

Question 3

Meaning of capacity factor

Answer 3

= shows how much energy a power plant delivers, not how much it can deliver

Question 4

capacity factor %

Answer 4

delivered energy (Wh)/ installed power (W) * days * hours (h)
= result *100

Question 5

levelized cost of energy (LCOE)

Answer 5

costs over lifetime / electric energy delivered over lifetime

Question 6

Meaning of efficiency

Answer 6

= How much of the supply energy is converted to the useful energy, e.g. electricity

Question 7

Analogy for energy

Answer 7

How much water is in a bowl

Question 8

Analogy for power

Answer 8

How fast is the water flowing out of the bowl

Question 9

Fossil fuel: efficiency + normal installed power

Answer 9

efficiency 33%
normal installed power 2000 MW

Question 10

Solar: efficiency + normal installed power

Answer 10

efficiency 15%
normal installed power 10kW - 2000MW

Question 11

Nuclear: efficiency + normal installed power

Answer 11

efficiency 33%
normal installed power 4000MW

Question 12

Hydro: efficiency + normal installed power

Answer 12

efficiency 95%
normal installed power 4000MW

Question 13

Wind: efficiency + normal installed power + delivered energy

Answer 13

efficiency 40%
normal installed power 2MW
delivered energy 6000MWh a year

Question 14

Smart grid functions

Answer 14

• Many small power producers. Mainly wind and solar power
• more advanced measurement and control system and a built in energy storage
• Storage – pumped hydro, batteries, hydrogen(gas), flywheel
• fleet of electric cars are part of the grid
• A flexible grid: two ways power flow where consumer is also producer (“prosumer”)
• Continuous communication between consumer and producer
• Weather prediction

Question 15

Smart grid goal

Answer 15

A higher amount of variable renewable power production

Question 16

smart grid examples

Answer 16

• Your dishwasher starts when the electricity price is low (due to low energy usage or high energy availability)
• A factory shuts down low-priority activity when there is no wind
• Vehicle to grid V2G: your electric car communicates with the grid and charges when there is wind and sell electricity when there is no wind

Question 17

Energy solutions for the future

Answer 17

• Geographical distribution of the power plants
• Mix of variable sources with different characteristics
• Higher amount of renewable controllable sources (bioenergy)
• Smart grids that match production with consumption
• Increased storage of electricity (batteries, hydrogen,…) during over production
• Use the excess energy to produce district heating, hydrogen
• Better weather forecasts
• Energy efficiency
• Change our energy use. When we use and how much
• Periodically higher electricity prize

Question 18

Fossil fuels +/-

Answer 18

Positive Effects
+controllable
+scalable to any rate (fuel)
+placed anywhere
+simple

Negative effects
-emissions
-fuel costs
-mining
-Excess heat (unless it’s used)

Question 19

Bioenergy +/-

Answer 19

Positive Effects
+ Can be Co2 neutral, Co2 are released in combustion are stored by plants
+ Often rest products, waste from food, agriculture and forestry
+ Can have high efficiency. Combined heat and power <100% efficiency

Negative effects
- Intensive forestry gives monoculture, decreased biodiversity,
- Acidification of the forest
- impoverish the soil, lead to eutrophication and decrease biodiversity
- can increase food prizes
- Competition of bioenergy can give air pollution. Especially from small scale firewood
- Renewable, but limited. It takes some time to grow

Question 20

Solar +/-

Answer 20

Positive Facts
+ Renewable
+ No Co2
+ No fuel costs
+ Simple, no moving parts (long life time)
+ Only choice sometimes
+ Scalable

Negative effects
- Variable source (day/night, seasons)
- Need critical materials, i.e. mining (environmental problems, geopolitically sensitive, bad working conditions)
- Need to cover large area
- Need supporting system (batteries, hydrogen, more complex electric grid)

Question 21

Nuclear +/-

Answer 21

Positive effects:
+ Controllable (slowly)
+ High power and energy density
+ No Co2
+ Reliable and long life time (60-80 years)
+ Low area and material demand (lowest of all technologies)

Negative effects:
- Potentially dangerous
- Waste
- Excess heat

Question 22

Hydro +/-

Answer 22

Positive effects:
+ Renewable
+ Controllable
+ Can act as energy storage
+ No fuel costs
+ Simple

Negative effects:
- One of the largest impacts humans make on the planet
- Dams hinders fish migration
- Flooded area have higher Co2, due to increased decay and fewer Co2 consuming plants
- destroys/changes the ecosystem

Question 23

Wind +/-

Answer 23

Positive effects
+ No CO2
+ No fuel costs
+ Renewable

Negative effects
- Variable source
- Need critical materials, i.e. mining (environmental problems, geopolitically sensitive, bad working conditions)
- Need to cover large area (even more then PV)
- Need supporting system (batteries, hydrogen, more complex electric grid)
- Effect the local ecosystem in many ways and many animals avoid wind power parks
- Ugly, noisy

Question 24

Seasonal variations of energy plants

Answer 24

• Nuclear power: decrease when refueling
• Geothermal: Constant production
• Hydropower: follows precipitation and spring flood
• Natural gas: peaks in the summer to meet the need for air conditioning
• Wind: lowest in late summer
• Sun (PV): Very low during the winter