Energy demands

Energy demands

Energy comes from burning fossil fuels and is supplied by gas or by electricity generated in coal or gas-fired power stations. Fossil fuels are extracted and transported to oil refineries and power stations. Biofuels and nuclear fuels can be used instead. Fossil fuels and nuclear fuels are non-renewable.

In a power station, burning fuel heats water in a boiler, producing steam and driving a turbine turning an electricity generator.

Biofuels are fuels taken from (recently) living organisms and can be used instead of fossil fuels. They are renewable; it is used at the same rate as it is replaced, since its biological source either regrows or is continually produced. They are carbon-neutral, because carbon the organism takes in balances the amount that is released when the biofuel is burnt.

Nuclear fuel takes energy from atoms.

Uranium fuel is in sealed cans in the core of the reactor. The nucleus of a uranium atom is unstable and can split into two. Energy is transferred from the nucleus when this occurs.

The energy of the core is transferred by a coolant (fluid pumped through the core): it is hot leaving the core. It flows through a pipe to a heat exchanger, then back to the reactor core. The energy transferred by the coolant is used to generate electricity.

Energy from wind and water

No fuel is needed to produce electricity from natural sources.

A wind turbine is an electricity generator at the top of a narrow tower. The wind's force drives the turbine's blades around, turning a generator. Power generated increases as wind speed increases, but they are unreliable since when there's no wind, there's no electricity.

A wave generator uses the waves to make a floating generator move up and down, turning a generator so it generates electricity. A cable between the shoreline and generator delivers electricity to the grid system. They don't produce a constant supply of electricity, and they need to withstand storms. Many cables and buildings are needed along the coast to connect the wave generators to the electricity grid, spoiling coastline and changing tidal flow patterns, affecting habitats.

Hydroelectricity is generated when rainwater collected in a reservoir flows downhill, driving turbines and turning generators at the bottom of the hill.

Tidal power traps water from each high tide behind a barrage and the high tide is released into the sea through turbines, driving generators in the barrage. If the estuary rapidly becomes narrower moving up river away from the open sea, it funnels…