Farm-based Biogas, a Neglected Asset in Greenhouse Gas Fight

By | March 19, 2009

John Ibbett and pigs go back a long way. “The pig manager pushed me round in a pram,” recalls Ibbett, whose family has been farming on the same site since 1939.

Now he’s proud his family farm can turn muck into electricity, using new technology paid for by a multi-million pound windfall. His Bedfordia Group is one of only a handful of companies with farm-based biogas plants in Britain.

Scientists complain that the world has so far failed to support agriculture in the fight against climate change, focusing instead on more visible emissions from factories and power plants.

Ibbett raised part of the cash for his multi-million, three-year-old venture from a property sale far beyond the reach of most family-owned farms. Although his is a rarity in Britain, more biogas plants are being established in Denmark, Germany and developing countries.

That momentum could be a precursor for much bigger climate benefits, from changing farming methods to use the soil’s capacity to store vast amounts of carbon. Experts say this is an area so far almost entirely ignored by policymakers.

Soils as well as trees can suck carbon out of the air, boosting what experts call terrestrial carbon. Farmers can nurture carbon underground as well as crops above by using longer rotations, not over-grazing pasture and ploughing less.

Ibbett’s plant, 90 km (56 miles) north of London, traps methane emissions from food and farm waste in giant vats and then burns the powerful greenhouse gas to produce electricity, so preventing it from reaching the atmosphere.

Farmers are famously not short of ideas on how to make money and the managing director of Bedfordia Group’s farming business is turning his marketing skills to a climate premium.

Trying to sell part of the farm’s annual production of 23,000 pigs for bacon to supermarket group J. Sainsbury, Ian Smith estimates the Bedfordia pigs are one-third less carbon-emitting than others.

First, the methane emissions from their manure is trapped and burned. Second, the electricity produced replaces high-carbon power. Third, the final product is a soil additive which displaces more energy-intensive nitrogen fertilizer.

“They like the concept of a low-carbon pig, but even with our size of business it’s quite difficult,” Smith said of the supermarket’s response so far, referring to economies of scale the supermarket seeks.

Low-carbon pigs may not easily fly, but directly curbing greenhouse gas emissions from farming is important. Farming contributes as much to global warming as all the world’s planes, cars and trucks, and that will increase as the world tries to feed an extra 3 billion people by 2050.

Scientists also want more focus especially on the soil at U.N. climate talks which resume in two weeks’ time in Bonn and are meant to thrash out by December a new climate treaty to replace the Kyoto Protocol.

In addition, academics have revived interest in a millenium-old technology to plough into the soil a carbon-rich type of charcoal made from heating plant, food or animal waste, called biochar.

“I think we’re already beyond the safe level of greenhouse gas concentrations and the difference could be met through this terrestrial carbon approach,” said Thomas Lovejoy, biodiversity chair at the Heinz Center for Science, Economics and the Environment.

The sticks and carrots policymakers use to drive the climate fight have so far almost exclusively focused on energy.

But soil could store as much as one-tenth of all the carbon that households and industry spew into the atmosphere, and so buy time in a gradual, global shift away from fossil fuels.

One reason the sector has not yet captured the public imagination may be that pig manure and soil are not the stuff of public relations dreams.

“Politicians can understand planting a tree and watching it grow…that it removes the carbon dioxide from the atmosphere,” said Pete Smith, lead author for agriculture on the U.N.’s Intergovernmental Panel on Climate Change. “In agriculture, it’s not immediately visible.”

All plants including trees and crops draw carbon dioxide out of the air as they grow, but trees, not soil, have been a focus for this. Farming is deep in the shadow of forests at U.N. climate talks aimed at agreeing a new treaty.

“If you look across all the (economic) sectors together, farming has equivalent mitigation potential to the energy sector and to transport and industry,” added Smith. “We really need to get agriculture in there (the climate talks).”

Farming accounts for half of all man-made methane emissions worldwide — from ruminant livestock such as cows and sheep and from stored manures — and 60 percent of the world’s emissions of nitrous oxide, a greenhouse gas some 300 times more powerful than carbon dioxide derived from using nitrogen fertilizers.

Combined, curbing these greenhouse gases and using soil sinks could remove the equivalent of up to 1 billion tons of carbon emissions annually. Storing carbon in the soil would account for about 90 percent of that.

The idea of sucking greenhouse gases from the atmosphere, rather than just curbing emissions, is gaining credibility and support as scientists say they have underestimated the urgency of fighting global warming.

Analysts estimate that the burning of forests, ploughing soils and degrading grasslands has released 200-250 billion tons of carbon in the past 300 years, about 25 times annual carbon emissions from burning fossil fuels now.

A reward scheme for systems that locking up stored carbon — like the carbon-offsetting schemes that operate under the Kyoto Protocol — are being explored in the United States.

U.S. Agriculture Secretary Tom Vilsack told farm unions last month farmers may be able to earn similar credits for locking carbon in the soil, under President Barack Obama’s planned $80 billion cap and trade scheme.

But in Britain, the marketing for Bedfordia is taking time.”I’m still talking to two supermarkets,” said Smith. “Part of the problem is people getting their head around it.”

(Editing by Louise Ireland and Sara Ledwith)

Topics Agribusiness Climate Change Uk

Was this article valuable?

Here are more articles you may enjoy.