Whenever wind farms hit the news, critics claim they're just barmy: they'd never produce anything like the electricity we need, and the wind doesn't blow all the time either - just take a look at the "No to Whinash" website.

I have been unable to find a succinct summary of what could be provided by renewables in the UK, which is actually rather frustrating. So I decided to try and work it out for myself. For the full detailed story and all the numbers, see the page here.

From the DTI white paper “Our energy future - creating a low carbon economy” it appears that electricity generation is not the big culprit really. Energy Consumption Chart

• Transport (35%) and
• Space Heating (26%) are the two biggest.
• Add in water heating (8%) and you have a total of 69%!

Of course, since fossil-fuel power stations are only 30% efficient, any replacement of this with renewable electricity will triple the reduction of energy used to generate the electricity.

The Royal Commission On Environmental Pollution's 22nd Report: Energy - The Changing Climate is a useful reference, though at times a little vague. Their most important conclusion was that we have to reduce energy consumption by some 30% by 2050.

But nevertheless, this article concentrates on electricity generation - I'll attempt to cover heating and transport in future articles.

Current UK electricity power consumption averages at some 45GW (that is 45,000 MW).

Modern large turbines can generate 2-4MW. According to the British Wind Energy Assoc (BWEA), we currently generate about 800MW with wind power in the UK today. This is 0.6% of our electricity supply they reckon when you account for the “load factor” of some 30% (the fact that the wind doesn't blow most of the time).

According to BWEA, there is over 1 GW of offshore projects with planning consent waiting to be built, and a second round of offshore tenders from the crown estate with a total of 7.2 GW waiting for applications, equivalent to 7% of UK supply.

Ocean Power Delivery (OPD) is one UK company that makes wave energy converters. Individual convertors (as recently started in Portugal) have similar output to wind turbines.

OPD reckon a typical 30MW installation would occupy a square kilometre of ocean. So to produce something similar to the wind turbine plans of 10GW, requires some 340sq kilometers. Spread around the coastline of many thousands of miles, this seems perfectly reasonable. Again, load factors are about 30% (according to BWEA), so this amount would produce another 6% of electricity we could rely on.

Currently, 1.5GW of electricity is generated by hydroelectric plant. With load factor, this is just under 2% of our total usage. This is pretty much fixed: though it's clean, we don't want to go round damming up any more of our valleys.

Although the energy supply is reliable and plentiful, converting it into useful electrical power is not easy or cheap. Barrages (aka dams) are very expensive and have huge effects on eco-systems.

These are basically submerged wind turbines driven by tidal currents. They are much cheaper than barrages. They generate about 1MW each, and would typically be installed in farms of 10-20. So for 1GW say, at a load factor of 40%, we'd need 2500 dotted around the UK. This is probably feasible as we have a coatline of many 1000's of miles.

Another company, Blue Energy, reckons you could build large scale “tidal fences” generating GigaWatts. An obvious trick was missed in not building these sorts of things into the second Severn crossing!

It is reasonable to install 500W generating solar panel on a roof (about 5 sq m). Due to fluctuatig sunlight, this would average 50W over the year. If 1 million houses installed it, we'd get some 50MW. Sadly, this is small beer, just 0.1% of the 50GW total consumption in the UK Of course, it could be fitted to all other building roofs (offices etc), but we need about 100x improvement, which just isn't going to happen.

Here's my summary, derived from the above stuff. It shows what might practically be acheived in the next 10 years or so for electricity generation…

So from this relatively conservative analysis, it seems we can provide a significant amount of energy, 13%, in the next 10 years or so. Not overwhelming, but pretty good considering the total absence of any government leadership on the subject.

Jon

— Web Master auto generated by txt2dokuwiki