Thursday, 26 February 2009

Renewable energy: the possibilities

I've been reading Monbiot's book, Heat and the chapter on renewable energy is amazing:
Did you know that 62% of the energy generated in power stations is lost?
Here's some interesting stuff about the technology available now and what we can do with it:
- DC cables are now cheaper than AC cables and they have a major advantage: they can transmit energy across large distances without losing it. Ever wondered why these electricity pylons are so big and high up in the air instead of being buried underground?
The answer is the heat they generate: quite simply, to cool the heat generated by these cables, you would need the equivalent of 2 football stadiums underground back to back. That loss of heat is how the energy gets lost. It's the same concept as for incandescent light bulbs: they're only 90% efficient because they let so much heat escape. Why are these cables revolutionary?
If you can transmit energy over a longer distance, you can install the sources of energy much further. For wind power, this means that we can have large offshore wind farms that have large blades generating more noise and producing more energy offshore where no one will complain about them. More than 100% of our electricity in the UK could potentially be produced from wind so long as we can make adequate changes to the grid. For solar energy, it means that we can have solar panels in the sahara desert producing enough electricity for all of Europe.
The economies of scale that could be generated from both these technologies could enable it to compete with the price of brown energy and in the long run make it much cheaper.
Another interesting technology is solar thermal electricity: it's basically reflective dishes that focus the heat from the sun onto a tube containing water or another liquid. This reaches temperatures of about 400 degrees and the steam drives an engine which generates electricity. They've existed in California since the 80s. Their output costs in between 7 bto 9 pence per Kwh this compares to a current average price for brown of 10-15p per Kwh (Source:

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