In the future we will be looking at other forms of renewable energy. Below is a basic overview of the four main types:
When water falls over a drop, it releases energy. Usually this seeps away into the surroundings. Hydro power technology catches this energy and uses it to turn a generator, producing electricity. The power available depends on the total flow of water and the height over which it falls.
The best sites for hydro in Sheffield are likely to be located on the various weirs along the river Don. Average river flows are around 4 cubic meters per second and a typical fall height is about 2m. We reckon this could provide 150 megawatt hours of electricity per year, which is enough to power 35 typical homes. Some of the sites we are looking at are a bit bigger than this (say up to 100 homes) and some are a bit smaller (say 20-25 homes).
There are three types of hydro generator: water wheel, Archimedean screw and turbine. For a given site, one is usually better suited than the others. The Sheffield sites are most likely to favour either a water wheel or an Archimedean screw.
Tidal power is another form of renewable energy which involves water, but we don’t see much potential for this in Sheffield!
Solar power is energy harnessed from the sun and converted in to electricity or heat. If we could harness all the solar energy that reaches the earth it could meet the world’s energy needs.
There are two key solar technologies: solar thermal and solar-electric.Solar thermal is used to provide a low carbon source of hot water. It is a relatively simple technology and can be very cost effective.
Solar panels, or photovoltaic cells (PV), use semiconductor material to produce electricity. The semiconductor absorbs the sun’s energy, which causes electrons in the material to move, this generates a current. Metal contacts placed on the PV cell enable you to draw the current from the cell.
The most common material currently used for PV is crystalline silicon. Other PV technologies include multi junction cells, which offer the highest efficiency but are very expensive, and thin film PV cells, most commonly found on small calculators. This technology offers a flexible and lightweight cell but is expensive and does not offer the efficiencies that other types can.
The UK has more usable wind power than any other European country. Wind turbines capture this energy and turn it into electricity. They come in many shapes and sizes, from tiny ones , which fit on a small roof providing very limited power, right up to massive ones located off-shore with potential to power 1000 homes or more.
The scale of project we are interested in might lend itself to a medium sized turbine capable of generating around 450 megawatt hours of electricity per year, or enough to power about 100 homes. This would be similar to the existing turbines visible from the Parkway, on the way into Sheffield from Junction 31 of the M1.
Vegetable matter (often called biomass) can be used to generate power. The simplest way is to burn it as a source of heat, for example in a wood burning stove. It is also possible to produce refined fuels in the form of solids (e.g. wood pellets), liquids (e.g. biodiesel) or as a gas (e.g. biomethane). These can be used to generate heat or electricity or, ideally, both at the same time. Plant power can also be used to fuel cars and other vehicles.