A new district heating system promises to slash energy bills and provide long-term income for one Devon pig farmer. Paul Spackman reports
When former Farmer Focus writer Andrew Freemantle decided to tackle soaring heating costs for his indoor farrowing unit, he did so knowing his options were limited.
At just 28ha (70 acres), Kenniford Farm doesn’t have the capacity to turn land over to solar panels or a biogas plant and Mr Freemantle feared planning would be a major obstacle for any wind turbine, especially one big enough to meet the farm’s energy needs.
Alongside 54 indoor farrowing pens that accompany the 340-sow RSPCA Freedom Foods-assured herd, there are two barn conversions, offices and a farmhouse that need a consistent heat supply, estimated at 168,450kWh a year.
After commissioning an independent feasibility study by Laurence Gould, Mr Freemantle decided a biomass boiler linked to a district heating network was the most suitable option. “It seemed the least controversial renewable energy project as there aren’t any major planning issues. It gives us the consistent heat supply needed and we are able to use existing buildings to house the equipment.”
He also knew the cost of installing other renewable technologies that generate electricity could have spiralled because of the need to upgrade the existing electricity supply to cope with power exported to the grid.
Mr Freemantle chose a 150kW woodchip-fuelled biomass boiler from Plymouth-based 5D Group. “The company was a referral from a neighbouring farmer that had just installed a large biomass system. I went to see it working, which was a really useful experience.”
The boiler and fuel hopper is housed in a redundant farm building and heats water that is piped in an insulated closed-loop system underground to the buildings. The 54 existing 250-watt electric heaters in the farrowing pens are being replaced with underfloor heating to maintain a consistent 30C, while the boiler network connects to the farmhouse and other buildings via heat exchangers linked to new central heating systems.
“One of the biggest challenges has been replumbing the farmhouse and other buildings that didn’t have proper central heating. It would be fine if they were new builds, but to retrofit things like this means there’s a lot of ‘making good’ afterwards.”
A further challenge is timing installation of the underfloor heating in the pig unit, as there is only a small window between weaning and when the next batch of piglets comes in, he notes.
A woodchip-fuelled system was chosen, as this allowed more flexibility to collect fuel when needed using the farm’s tractor and trailer, Mr Freemantle says. “It’s also a lot cheaper than pellets – around £80/t compared with nearer £200/t – but you do need more chips because they’re not such a concentrated energy source.”
Worth the wait
Work started in the summer and Mr Freemantle hopes the new system will be up and running by the end of October. The process has taken slightly longer than anticipated, but he is optimistic it will be worth the wait and cost.
The whole project, including the boiler and ancillary groundworks, plumbing and piping, will cost almost £114,000 (excluding VAT and interest charges), although annual savings and income from the Renewable Heat Incentive are forecast at more than £25,000 once the scheme is fully operational, giving a payback of around five and a half years (see panel).
“We’ve borrowed all of the money, which is costing us about £1,200 a month over 120 months. But we’re getting back and saving £2,114 a month in total and will have a new heating system when it’s all paid off.
“Lloyds Bank was fine with our plans,” he continues. “We’re lucky to be owner-occupiers with a business that is making a profit. We were able to give them a good independent report to support the business case and there are also lots of neighbouring poultry farmers putting boilers in, so it’s becoming a more familiar technology.”
Mr Freemantle advises anyone considering biomass to visit existing systems first and follow trusted recommendations. “It’s not like buying a new tractor from a dealer. There are a lot of people claiming to be experts and if you’re replacing your entire heating system, you need to be able to trust them to do the job properly.
“I would also recommend a detailed quote and a timescale of works, so both parties know where they stand.”
Kenniford Farm biomass
- Boiler size 150kW
- Output 168,450kWh
- Woodchip use (25-30% moisture) 59 tonnes
- Woodfuel cost @ £80/t £4,720
- Net fossil fuel saving (less wood cost) £11,357
- RHI income £13,981
- Payback with RHI (144,000/25,338) 5.7 years
- Payback without RHI (144,000/11,357) 12.7 years
Source: 5D Group/ Andrew Freemantle
- Boilers and wood handling equipment £36,582
- Boiler room, tanks and plant room £24,104
- Boiler room roof £6,000
- District heating pipes £8,686
- Pig pens design and plant £5,660
- Pig pen floor installation £8,000
- House installation £9,900
- Cottage/office installation £5,200
- Cottage/office central heating system £9,466
- VAT £22,720
- Total cost including interest charges £144,000
Source: 5D Group