PLM - 230406

Question 1

Energy conversion efficiencies

Answer 1

Artificial:
* High: large electric motor, power plant boilers, dry cell batteries (around 85-97 %).
* Low: Paraffin candle (1%), Incandescent light, steam locomotives (5%).
Natural:
* High: human lactation (80%).
* Low: Photosynthesis (mean: 0.3%, peak 5%)

Question 2

Overall efficiency

Answer 2

Coal – Power plant – transmission lines – incandescent light: overall efficiency 1.6%

Question 3

Depletable Minerals

Answer 3

Coal, oil, gas:
* Existing: Unreachable resources, very expensive, very technologically demanding
* Resource: Reachable.
* Reserves: Available resources in the market, that a company is willing to supply. We could use it.

Question 4

Energy sources

Answer 4

Coal, oil, gas(produces less CO2 than the others, contains a lot of nitrogen): 85%
Nuclear, Hidroelectricity, Renweables (5%): 15%
South and Central America (30% of renewables and hidroelectricity) better than europe or north america – Review of world energy

Question 5

Energy distribution in Germany

Answer 5

Energy charts:
* Mid May: good days lots of wind and sun.
* End of January: awful days, just gas, and coal.

Question 6

Primary energy sources

Answer 6

1800: Wood – max, replaced 1880
1920: coal – max, replaced 1950s
1960: oil – max, replaced 1980
2000: gas

Question 7

Decarbonization curve

Answer 7

The amount of carbon required to obtain a fixed amount of thermal energy. It is reducing and it almost reaches the gas carbon intensity (lowest of all fossil fuels).

Question 8

Coal

Answer 8

• Carbon + sulfur (10%) + Hidrogen (very small)
• old forests no air flow, high pressure, high temperature