Are farms the energy hot spots of the future?

Sensemaking / Are farms the energy hot spots of the future?

27 Apr 2011

Wind turbines and PV panels could become a mainstay of future farms, says Huw Spanner

Old MacDonald had a farm, ee-i-ee-i-o. And on that farm he had some...PV panels? With a spark, spark here, an inverter there, here a spark, there a spark... and so on. It doesn't exactly fit our childhood image of farming life, but then again very little in modern agriculture does. And at a time when many smaller farmers – and rural communities – are struggling to survive, there are compelling reasons to tap the huge potential of Britain's 300,000-odd farms to generate power and heat, save carbon, and make money in the process.

"Unlike food, energy pays well, is a reliable source of income, and requires little maintenance", says Will Frazer of Farming Futures. "Those energy farmers that have been on the pay-roll for some time now will have one defining characteristic: the ability to re-invest in their business. Ask one of the 461 dairy farmers in England and Wales that had to shut up shop last year, and you'll find that was a luxury they could ill afford."

The feed-in tariffs (FITs) for England, Scotland and Wales introduced by the last government in April 2010 (index-linked and guaranteed for 20–25 years) have certainly galvanised interest. Last summer, a survey of British farmers conducted by the National Farm Research Unit found that 70% were thinking of investing in renewables. If anything, says Andrew Rigg of the Farm Energy Project, that figure is now higher still. The recent review may sap some of that enthusiasm, but now that the seed has been planted, the idea of turning land into energy seems to have taken root. And it wouldn't be for the first time.

Two hundred years ago there were maybe 10,000 windmills across Britain, and those days may be returning. The options for farmers today range from using micro-turbines to power a single remote building all the way up to playing host to a commercial wind farm – or even installing one themselves.

"Wind turbines are brilliant in that they take almost no land out of production and the feed-in tariffs are good", says Adam Twine, who set up Britain's first community-owned wind farm in Oxfordshire. "In terms of punch per pound invested, they are solidly out in front at the moment." The 2,400 people who put up the £4.5 million needed to pay for his five 1.3MW turbines expect an annual return on investment of 12% for 25 years. In 2010, a report from the property consultancy Carter Jonas calculated that a single 330kW turbine could yield an annual ROI of over 18%.

Offering the neighbours a share in the profits can be a canny way to deal with nimbyism. In Powys, a consortium of farmers has won approval for a plan to install 29 turbines on their land. Their Llaithddu Windfarm will generate nearly 67MW – enough to power well over half the homes in the county, saving up to 150,000 tonnes of CO2 a year – and they have agreed to pay some £330,000 a year into a fund to benefit the local community. The arithmetic even allows them to buy Enercon's E70 turbine, designed by Norman Foster to be as elegant as possible, as well as exceptionally quiet and reliable.

For farmland that is sun-blessed rather than wind-swept, PVs hold out most promise. Ranging from 29 to 31 pence per kWh, the tariffs are the most generous of all. For farmers with large, south-facing roofs, at least south of the Midlands, PVs are "a bit of a no-brainer", says Jonathan Scurlock, the NFU's chief adviser on renewable energy. They have no moving parts, need very little maintenance and can be put atop barns and grain stores, dairy parlours and poultry sheds (though ammonia emissions from the latter, the NFU helpfully points out, can corrode them). Alternatively, arrays of panels can be deployed unobtrusively along the edge of fields, where they could also help to protect water courses and wildlife. Much larger installations can fill whole fields without detracting from agricultural output if the land is also used to graze hens, geese or even sheep.

Land power

Farmers who buy their own PV system, rather than renting space to a commercial operator, can expect an annual return of 8–12% on their investment, depending how sunny is their neck of the woods. Andrew Ingram, who farms 300 hectares in the Chilterns, put 156 panels on his barn roof as soon as the FITs came in. Today, he uses about one-third of the electricity they generate and sells around 14,000 kWh a year to the grid. With his capital costs written off against his taxable profits, his panels may well pay for themselves in a decade – and could conceivably last for a further 40 years.

On steeper terrain, farmers can look to harness the energy of local watercourses with micro-hydropower. A 50kW system that cost £315,000 to install might earn (after running costs) in the region of £42,000 a year – and as long as it was kept oiled and maintained, it could well run for 50 years.

Wherever the farm, one source of energy is likely to be in plentiful supply: organic waste. An anaerobic digestion (AD) plant can shift any smelly slurry from ruminants, or silage from crop waste, and turn it into biogas, for use on site or for sale. Almost as valuable a by-product is the 'digestate': a rich mix of nitrogen, phosphate and potassium. These nutrients can go straight back onto the land, and that's no small advantage.

"With oil back at over $100/barrel and firmly linked to the price of fertiliser, farmers need to think about how to maintain their real life blood, which is soil fertility", says Frazer. "We can generate energy from farms in any number of ways, but there are limited ways to make soil. AD can do it at low cost, and through natural processes."

In Germany, there are already about 4,500 farm-based AD plants in operation, but in Britain there are no more than 45. "One problem", says Andrew Rigg, "is that an anaerobic digester is like a cow: it needs looking after, and it needs feeding!" In Germany, a great deal of maize is grown specifically as feedstock, but that's not something the British Government wants to encourage. Which could explain why the FITs for AD (ranging from 9 to 11.5p/kWh) are, by general consent, disappointing – probably 5p too low to be much of an incentive.

That doesn't rule out a future for AD. In Cheshire, tomato growers A Pearson & Sons have incorporated it into their 'whole-farm' approach to sustainability. They've had a digester designed to fit the volume of disposable waste – mostly leaves and damaged fruit – which they generate. Instead of a landfill tax bill, they have home-brewed fertiliser for the tomato plants. The CO2 is blown into the glasshouses, where it ends up in both bigger and tastier tomatoes. The methane is burnt in a combined heat and power plant, to heat the glasshouses and power the packhouses. Any excess electricity goes to the local town. And the payback on both pieces of plant has been remarkably quick.

It's also proved a pull for customers, says Business Development Director Philip Pearson: "It excites them. It's hard to put a value on that, but put it this way: we mention it in every presentation we do."

AD is also attracting attention in India. Biotech Ltd, based in Kerala, has been working on systems to use food waste to make energy and fertiliser. It offers various sizes of plant, from a small one that home owners can use in their back yard to make biogas for cooking and fertiliser for their garden, to larger ones for schools, hostels and other institutions. The company, winner of an Ashden Award for Sustainable Energy in 2007, has even installed plants next to food markets, using the market waste to light the public space at night.

A strong case for growing certain crops to produce energy is made by John Gilliland, the chair of Northern Ireland's Rural Generation, who champions short-rotation coppice willows. A plantation of these fast-growing trees produces wood for burning in anything from domestic stoves to full-blown power stations. Harvested every three years, a hectare can produce 30 or more tonnes of carbon-neutral fuel, which currently fetches £110/tonne.

Some farmers prefer miscanthus, or 'elephant grass', which can be harvested every year. However, the real beauty of willow, says Gilliland, is that it helps to make agriculture more broadly sustainable. A belt of trees also sequesters carbon, filters pollutants out of waste water or the runoff from fields, helps to prevent the spread of disease between neighbouring herds and, in between harvests, provides a habitat for birds, mammals and insects. This is especially important as climate change begins to drive species northwards.

But at its core, AD is a fantastic recycling process for organic waste. "Our current farming system has high levels of waste food", says David Fulford, biogas expert and a visiting judge for the Ashden Awards. "Disposing of it through landfill or incineration is expensive, but on-farm AD means food waste can generate energy and give its fertiliser value back to the land. It creates a resource cycle that reduces farmers' dependence on outside sources of energy and fertiliser, which are both rapidly rising in price."

Which technologies Old MacDonald should invest in will depend on a number of factors; but whether he is a small farmer who needs to supplement his income with a reliable new revenue stream, or an agribusiness manager looking to maximise profits, the opportunities are clearly there for the taking.

Huw Spanner is a freelance editor and regular contributor to Green Futures.

Farmer viewpoint

Tim Downes runs an organic beef, dairy and arable farm in Shropshire. His customers include Waitrose, Morning Foods and OMSCo.

...on reducing fossil fuel dependence
We're fairly self-sufficient, but we do still use too much fossil fuel in our arable work. We're trying to reduce it. We recycle the heat from the milk cooling process to warm the water we use to wash down the dairy. We're saving a huge amount of energy that way, but we've also fitted solar panels. In June and July 2010, our electricity bill was down by 70%.

...on taking pride in the land
We take a lot of pride in looking after our soils. We haven't used nitrogen fertiliser for 12 years, which has saved a lot of money. We've been growing clover to fix nitrogen since 1984. Researchers from the Scottish Agricultural College came to run a trial, and showed us the benefits of adding it to the forage. It delivers an extra half a litre of milk per cow per day!

...on conversation
We're in the process of laying 2.9km of hedgerow this year, keeping alive old skills, but we rely on public funding for that, through stewardship schemes. We're also involved in campaigns for educational access to the countryside.

This article is taken from the Green Futures Special Edition, Tomorrow's Food, Tomorrow's Farms.

Image credits: Ary6 / istock; maxphotography / istock

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