For more information to back up this presentation, read through the fact sheets that go with this session and use the further information recommended on the reverse of these sheets
Wind power This is by no means a new technology – windmills have been used for a thousand years.
The UK has some of the best wind resource in Europe. Not always a good thing, but it’s good to know that we could benefit from this in some way! Plans are in place for a rapid expansion of our use of wind energy – it’s anticipated that by late 2009 offshore wind will have a 1 gigawatt capacity by next winter and plans are being put together for a further 33 gigawatts of offshore wind turbines.
Large-scale wind can be sited on land or sea. The larger turbines being built today can power about 3000 homes each. Population of shrewsbury is around 100,000 – so we’d need 17 large wind turbines to power all our homes (if every home has 2 people in it).
In domestic systems power is fed through an inverter to convert it to AC, which is then fed into the grid, allowing minimal disruption for the householder. The large turbine on the left is big enough to power 2-3 average homes. The building-mounted turbine is enough to power around a third of an average home’s electricity.
There are difficulties with domestic wind power though. Urban areas in particular suffer from a lot of turbulence, which make the wind buffer around, rather than flow in a steady direction. This isn’t good for wind turbines and means they won’t reach their full potential. Buildings on hills with clear open expanses around them are much more ideal. Turbulent areas can use vertical axis turbines to make the most of updrafts (right hand image)
They can be used for various different applications other than homes. Street lighting and road signs, bike lights (top) and to charge mobile phones (bottom right)
This map shows sunshine hours in the UK – a bit different to daylight hours as it takes into account cloudiness as well as daylight. Southern and coastal areas are ideal. Mountainous or northern areas will get the least benefit from using solar power.
If the sahara desert were covered in pv panels, this alone would provide enough electricity to power the whole world. But it’d be a case of putting all our eggs in one basket and could leave us dependant and vulnerable. Alternative ways of making large scale solar power include solar furnaces like the one pictured (in spain). These use mirrors to focus solar rays to a single point, making heat to make steam to drive turbines to make electricity.
Domestic solar power again passes electricity through an inverter to convert DC electricity into AC, which is then fed into the grid to take money off electricity bills. Standard panels (left) or ‘tile’ style panels can be bought.
Solar power is very adaptable and portable, which means it can be used at lots of different scales and for lots of very specialised things. This gadget top left will charge phones, mp3 players or cameras. Battery chargers have been made for all major battery types (AA, AAA, C and D). Larger solar chargers can be bought to charge laptops.
Solar hot water systems use panels on the roof to heat the water in your home – usually keeping existing heating methods as a back up for dull days. During the summer in the UK, these systems will typically provide all hot water needs. Even in winter, they will contribute and on a sunny winter day, will contribute significantly to hot water needs.
We can use this energy to make hot water through solar thermal systems… Typical systems are either ‘panel’ types where water is heated directly (bottom left) or ‘evacuted tube’ types where another liquid that is highly volatile (e.g. alcohol) is heated and transfers its heat to water (bottom right). The tube type tends to be more efficient. The top image is of a DIY panel, including copper tubing taking water through glass fronted boxes, painted black to absorb heat from the sun.
There is lots of potential for us to harness renewable energy on both a large scale and within our own communities. Community led small scale renewable energy allows us to take more control over our power and to decide ourselves how and where local energy is produced.
