Deep Blue NRG Group: An economical heat source

THE installation of a biomass boiler to create heating from linseed bales at a Gloucestershire farm is proving much cheaper to run than the farm’s previous oil-fired system. Geoff Ashcroft reports.

When it comes to retaining heat, most traditional farmhouses are about as effective as holding warmth as a colander is at holding water.

For Gloucestershire farmer Simon Righton of Old Farm, Dorn, the sevenbedroom, single-glazed farmhouse which forms part of the farm tenancy, is one that, until 12 months ago, has proved costly to heat.

“Parts of the property date back to the 15th century, though most of it is 17th century,” he says. “And building methods and materials from that period weren’t quite as energy efficient as they are today.

“We would typically spend about £6,000/year on heating oil,” he says. “And even then, the house wouldn’t be generously heated. And with the price of heating oil increasing in the long-term, our farmhouse running costs were set to spiral out of control. If the place cools down, it takes weeks to warm up properly,” he says.

In addition to family requirements, Old Farm operates a farm shop, and provides a farmhouse B and B enterprise too.

“We looked at several renewable energy systems, including wood chip, logs and other resources,” he says. “Woodchip looked good value but I would have to give up a large barn to keep the fuel dry. “What I really wanted was to use a fuel-source that we could produce ourselves, and straw was at the top of my agenda. Wheat straw burns well, but for us, it is too valuable to burn compared to linseed.”

After looking at many different boilers and considering different straw types for energy, Mr Righton choose a batch-fed GF125 biomass boiler from Lincs-based GlenFarrow.

“I liked the look of the GlenFarrow boiler, and they were the only firm who would see the entire job through from start to finish,” he says. “And they helped me to make the most of the financial support available through the Government’s Renewable Heat Incentive.”

With RHI support, Mr Righton receives quarterly payments which offset the cost of buying heating oil, making the boiler installation a more cost-effective investment.

“We should recover the cost of the biomass system within five years.”

The attraction of a one-stop shop for installation, commissioning and back-up mean all that was required of Mr Righton was to sign the cheque. And £28,000 and four days later, the installation was complete.

With an average output of 112kWh, the biomass boiler offers more than enough capacity to heat the farmhouse, and the Rightons now intend to extend the heat source to the newly constructed farm shop, which is currently heated electrically.

Installed on a concrete pad at one end of a traditional barn, the boiler location allows bales to be fed in by tractor and loader. Hot water is fed to the farmhouse through underground heavily insulated piping to minimise heat loss, and the system also affords a heat source for the farm workshop.

“We grow linseed, and the straw is well-suited to burning, so this is our energy source,” he says. “While the boiler door will open to allow a 4ft bale to be inserted, we’ve opted to produce 3ft linseed bales, which allows good air circulation around the straw.”

With the temperature and fan speed set, the boiler needs a bale twice a day, with the farm consuming about 500 bales over the last 12 months. Bales are barn stored, so are kept dry.

“We are very pleased with the installation and the effectiveness of the heating,” he says. “The farmhouse has been much warmer and easier to heat, and I don’t need to keep one eye on the oil level.

“However, we might switch to conventional bales when we harvest the next crop of linseed. I could drystore them in a shipping container close to the boiler and simply feed the boiler by hand - it will be much easier than having to get the tractor out for a round bale.”

Maintenance requirements are few and far between.

“We need to clean out the ash every couple of weeks, though we’re lucky if there’s a wheel barrow load,” he says. “It is very efficient. While the fire needs to go out for cleaning, there is enough of a water jacket around the boiler to contain residual heat for hours, so the farmhouse doesn’t cool down when the fire is out for a couple of hours.”

He advises others who are considering such a system to give thought to the boiler’s location and chimney positioning. “There are times when the odd bale makes a lot of smoke and if we get an Easterly wind, smoke can easily offend your neighbours.”

Mr Righton is considering using the biomass boiler for occasional grain drying too. With cropping at the 120ha (296-acre) farm split 50:50 between grass and combinable crops, and a Lexion 450 comfortably on top of harvesting requirements, the farm can afford to pick and choose its harvesting times to make use of weather conditions.

“The biomass boiler could provide a suitable heat source in summer when it is not being used to warm the farmhouse,” he explains.

“We’ve still kept the oil system in place as a back-up and we could switch from one to the other if we ever needed to,” he says. “But we now only use oil to run the Rayburn in our kitchen.”