4 main stages of a fossil fuel power plant
- Fuel - release of stored chemical energy, changed into thermal energy
- Evaporation of water - thermal energy evaporates water, steam directed into steam turbine
- Steam turns the turbine - steam turns the fins of a turbine
- Condensing in the cooling tower - hot steam condenses into a liquid and is sent back to the furnace.
Direct renewable energy source definition + example:
A renewable energy source that takes energy from a source and converts it into electrical energy directly
E.g. wind, hydroelectric, wave, tidal
Indirect renewable energy definition + example
A renewable energy source that takes energy from a source and converts it into electrical energy indirectly via a physical characteristic of the material used
E.g. Solar PV, biomass
4 stages of transmitting electrical energy across the national grid:
- Electricity produced in power station (e.g. 22kV)
- Step up transformer increases voltage to reduce heat losses (e.g. 22 to 275/400kV)
- Transmission lines send electricity across the grid
- Step down transformer - 33kV for industry - 11kV for distribution to towns - 240V to individual buildings
Smart grid definition:
A computer controlled electricity network that switches input from one energy source to another as demand varies on the grid
4 Key requirements of a smart grid:
- Can predict demand
- Can measure output from renewables
- Can adapt to give non renewable output if needs be
- Can export or import to/from other nations
Benefits of a smart grid:
- Maximizes renewables
- Minimizes fossil fuels
- Controls electricity demand - providers can alter prices to encourage consumers to use
electricity at less demanding times - Offers a potential income stream to micro generators
Efficiency difference with combined heat and power (CHP) compared to traditional power plants
Traditional power plants ≈ 40%
CHP power plants ≈ 80%
Other name for CHP:
Co-generation
How does CHP work
Steam in the cooling towers heats water in pipes which run to local homes or businesses
Advantages of CHP:
- Efficiencies can exceed 80%
- Energy loss via transmission is reduced
- Less fossil fuels needed
- Energy bills can be minimised
