A California dairyman yesterday inaugurated his very own methane-producing plant - an industrial-scale facility which can produce enough natural gas to power 1,200 homes a day.
David Albers, of Riverdale, is the brains behind the Vintage Dairy Biogas Project which processes the output of his 5,000 head of cattle, Reuters reports. The waste is first flushed into a large octagonal pit and the liquified contents then transferred into a covered "lagoon" via filters which remove solids for recycling into cattle bedding.
This "digester" tank - 10 metres deep and "the size of nearly five football fields"* - is lined with plastic to prevent leakage into the ground, and capped with a high density polyethylene cover weighted with concrete. Gas collects under the cover, and is piped to a scrubber plant which removes hydrogen sulfide and carbon dioxide to produce a 99 per cent pure methane.
BioEnergy Solutions, the Albers-led company which funded and built the facility at an unspecified cost running into "millions of dollars", supplies the gas to power utility PG&E Corp which, along with other utilities, has been ordered by California regulators to "make renewable energy at least 20 per cent of their electricity supplies by 2010".
The methane is pumped directly into PG&E Corp's pipeline, which carries it to a Northern California power plant.
Albers said: "When most people see a pile of manure, they see a pile of manure. We saw it as an opportunity for farmers, for utilities, and for California."
PG&E also sees a bright future in bovine biogas, and has partnered with another company, Microgy, to establish plants at three further California dairies. Roy Kuga, the company's vice president of energy supply, said: "With nearly 2 million dairy cows in California, the potential is great."
There is, however, one practical limitation to cattle-driven biogas plants. PG&E officials noted that not every dairy can participate simply because they are "not located close enough to the necessary gas transmission lines". ®
*Yes, we know. What's that in nanoWales, eh?