Biogas

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Biogas

Post  MH on Wed 14 Jan 2009 - 2:27

I caught a very interesting story on Channel 4 news about biogas:

Up to half the gas used for cooking and heating British homes could be produced by renewable waste by 2020.

The findings are contained in study carried out by Ernst & Young for National Grid, which now runs Britain's gas network.



Channel 4 News, 13 Jan 2009
Wales in particular is more dependent on gas than the rest of Britain. Over half (50.6%) of our electricity is generated by gas compared with a UK average of 41.5% - and even more stations are in the (... quick, think of a better word than pipeline!)

We have large gas plants at Connahs Quay (1420MW) Deeside (498MW) and Shotton (210MW CHP) in the north, and at Baglan Bay (575MW) and Barry (245MW) in the south. Currently under construction is Severn Power at Uskmouth (850MW) and it is almost certain that the new Pembroke Power station (2000MW) will be built too. There has also been massive infrastructure investment in a new gas pipeline and LPG port at Milford Haven. I'm sure Draig will have plenty to say on that subject!

It seems quite bizzare that we are the one country in Britain furthest away from the gas reserves in the North Sea, yet have now become the most heavily dependent. It means we will be particularly vulnerable to market trends and world shortages in the future, so anything that can reduce our dependence on imported gas should be welcomed.

As the C4 report says, the big problem is not the technology, it is the legislative framework. The whole thrust of international political policy is to reduce CO2 emissions, but using biogas will actually increase them. A paradox.

The answer is that although emitting CO2 is bad, emitting methane is many times worse. If we let stuff like food waste rot, it will release methane. If we capture the methane and burn it as fuel, it will release less harmful CO2 instead ... and also mean that less methane needs to be extracted from underground. So although biofuel will increase our CO2 emissions, it will do it in a good way! According to the report, government (or the EU) needs to figure out a mechanism to recognize this financially.

The industry's gripe is that they can get ROCs by using the methane to produce electricity, but that it would be much more efficient to put it directly into the gas grid. It seems obvious to me that, because so much gas is used to generate electricity anyway, gas fired stations should get a credit in the same was as coal fired stations now do if they burn a proportion of biomass. They could buy that gas from the biofuel producer at a price which reflects the ROC. Just a thought. I can't find the Ernst Young report on the web yet, but my guess is that they'll want even more: a sum to reflect the fact that using gas for heat is much more thermally efficient than using it to generate electricity.

Yet what surprises me most is the sheer scale of the benefit. Being able to meet half of domestic consumption is a sizable amount ... even though we need to recognize that there is also commercial and industrial consumption as well as electricity generation. Domestic use is about a third of UK total use.

Another factor to consider is how food waste is collected. It doesn't take a genius to figure out that this issue will be linked with domestic waste collection. It would certainly suggest separate collections for food waste, recyclables and other waste, with only food waste being collected on a weekly basis ... and might well become linked with a pricing scheme for refuse collection. Every silver lining has a cloud.
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MH

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