Methane Power – Let’s Not Burst The Bubble
Most renewable energy sources require a lot of land. Methane farming is no different, says Peter Judge, but it is still well worth doing.
Methane production seems to be gathering pace in the data centre world. No sooner had Microsoft suggested that data centres should be co-located with methane production sources, we met up with a company that is already doing just that.
Infinity doesn’t actually have a working data centre yet, but it has the power on hand, and the sheds in which to put the data centre. As we learnt on a visit to Iceland, all you need for a sustainable data centre is a source of energy and a good shed and Cold War air bases have the finest sheds and hangars money could buy in the 1970s and 1980s.
Bloom boxes and biodigesters
At the same time, Apple is going for methane in a big way with a lot of Bloom box fuel cells for its North Carolina iDatacenter.
But is methane really a prospect for widespread use? One of the most depressing parts of David McKay’s excellent Sustainable Energy Without The Hot Air is the conclusion that any renewable energy source requires a lot of land.
When Apple announced its solar power plans in North Carolina, it was quickly pointed out that to plant all the solar panels it needed, even for a small portion of its data centre power, it had to clear 171 acres of trees – which were already doing a fine job of catching solar power, as well as absorbing CO2, thank you very much.
Making industrial quantities of methane can be done with landfill sites, but to get a steady flow, Infinity’s partner AgriGen has to keep its digester fed with 25 tonnes of vegetable matter (and the odd bit of pig slurry) every day.
As it turns out, this actually is possible, and AgriGen is planning to increase that to 150 tonnes a day, producing 3.5MW of electricity. That will involve pretty much all the vegetable matter grown on 28000 acres of land (11000 hectares) and some of that material is grown specially for the digester, Agrigen’s Graham Thorne explained.
Gaps between cash crops are filled with “catch crops” which fix CO2 and nutrients, and can then be digested to create good fertiliser and methane.
Will it scale?
But that uses 28000 acres of land. Britain as a whole has 300 million acres, so AgriGen has about one ten-thousandth of the country at its disposal to make 350MW. Suppose we multiply it by 100, and put ten percent of the country (30 million acres) under methane-oriented farming (so crops still get grown for people). That would make 350MW. That is approaching one percent of Britain’s total demand which is 40GW.
There is no way we could get ten percent of the country into methane production, and if we did, it would only make a small part of our needs, so once again, renewable energy sources are in trouble because of their demands on land use.
However, that’s no reason for not doing this where possible. Since the land is also producing real crops, it avoids the big trade-off where normal biofuel culture requires a reduction in food production.
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