A growing opportunity for energy crop maize

WHEN Norfolk farmer Oliver Arnold heard Surrey-based biogas company Cosigas was looking for a site for its first biogas plant to be run on wholecrop maize and grass he jumped at the chance to be involved.

With vast experience growing forage maize for his own cattle, and on contract for other farmers, he believed he had the expertise to grow the feedstock. But he also believed his farm at Taverham, near Norwich, would be the ideal setting for such a project.

Oliver and his wife Hannah run SpringFarm Partnership which manages 445 hectares (1,100 acres) of land plus the couple’s own 130-cow suckler herd.

“I have always been interested in biofuels and biogas and have spent time in Germany looking at machinery and visiting biogas plants,” says Mr Arnold.

“From an environmental point of view I believe we need to be putting something back into the environment.”

Plans have been submitted for the plant and will be heard by the local planning authority on November 4.

Cosigas’s investment for the project is almost £3.5 million, explains the company’s Philipp Lukas.

“Essentially we will be building and operating the plant and Oliver will be supplying the energy crops to run it. He may also take a hand in some of the operations too,” he says.

Megawatt

The proposed plant will produce one megawatt of electricity - enough to power 2,500 to 3,000 homes.

Mr Arnold plans to produce all the maize required for the plant - around 400 hectares (1,000 acres) - within a 10-mile radius and he will also use around 3,000 tonnes of grass from the nearby Norwich airport (thus helping to reduce the airport’s carbon footprint).

It is anticipated the plant itself will produce one full-time job and two or three further jobs in the contracting business which already employs 11 full-time staff.

Energy crop maize is a very efficient feedstock, says Mr Lukas. “In principle, one tonne of energy crop maize produces twice as much energy as a tonne of food waste, and eight to ten times as much as from slurry.”

If given the go-ahead, Mr Arnold and his team will start drilling next spring, the plant will be built over summer and will begin production during the maize harvest.

Mr Arnold has already had interest from local landowners wanting to be involved. “We are very much a light land area around us and a lot of farms are interested in growing maize,” he says.

“It is a great break crop and leaves the land open for a long time. It is also great for smothering weeds, so it ticks a lot of boxes.”

It is a great break crop and leaves the land open for a long time

Oliver Arnold

Trials of several different maize varieties proved the value of those bred specifically for energy production, he says.

“The biogas varieties all romped home - they were noticeably advanced. There is probably 20 per cent more crop than the others.”

These three energy varieties - Atletico, Fernandez and Padrino - were sourced by KWS-UK from its parent company in Germany where they are well-established varieties.

John Burgess of KWS-UK explains growing maize for energy production is all about quantity. He says: “The highest yielding forage maize varieties produce 60 tonnes per hectare fresh weight, while the highest yielding energy maize varieties produce around 80 tonnes.”

Energy varieties produce more stem and leaf and less cob than forage varieties; the tallest variety, Atletico, grows to around 17 feet (5.1m) tall.

The eastern counties offer good conditions for growing maize, says Mr Burgess. Including maize in the rotation would offer arable farmers the opportunity to ‘clean up’ their wheat crops as the herbicides available for use with maize are not showing resistance to black-grass.

“With the wheat price in the doldrums, it looks really attractive at the moment,” he says.

Local objections to the plant have included concerns over noise and smell, says Mr Arnold.

“We are trying to assure people maize and grass really does not smell and it is not in our interest to have it fermenting in the clamp because we would be losing energy, which is everything we don’t want. We could lose five to 10 per cent gas yield through mis-management.”

Having seen the same machinery up and running in Germany he is trying to reassure his neighbours that they won’t be bothered by noise either.

“It is incredible how quiet it is - the soundproofing technology is amazing.”