AN enterprising Berwickshire farmer is making massive savings on his drying charges and domestic heating after installing a straw burning heating system.
In just one year over £36,000 has been saved by installing the system at Woodend Farm Partnership (WFP) near Duns.
Farmer John Seed’s aim is to be as close to carbon neutral as possible so he has installed a biomass boiler and hot water accumulator system to operate on a year round basis.
It is designed mainly for big bales with a multi-fuel capacity that also lets it burn wood chips, light grain and other suitable biomass materials.
Fuelling the unit and removal of ash are easily performed by a tractor with front-end loader or fork lift.
WFP provide all fuel for the plant, which is mainly rape straw, although the plant can utilise cereal straw, light grain, energy crops and other suitable biomass feed stocks.
The plant is expected to utilise between 100 and 200 tonnes of straw per year, around one quarter of the straw produced annually by WFP which is otherwise chopped and ploughed in, or sold.
Ash from the unit is being used as a soil conditioner on the farm to recover phosphate and potash in the straw and thereby reduce fertiliser purchases. In 2011, WFP dried over 3,000 tonnes of cereals, beans and rape, which would have used over 60,000 litres of gas oil in the system at a cost of over £30,000.
The partners and residents on the farm used to spend around £8,500 on heating. Therefore the total fossil fuel bill avoided as a result of installing the system was £38,500.
Using rape straw to provide the same energy requires approximately 169 tonnes of straw at an average moisture content of 20 per cent at a cost of less than £2000, saving over £36,000 a year.
He will also receive the renewable heat incentive (RHI) which he reckons amounts to another £30,000.
While the system supplies heat to WFP for residential properties, its main use is for drying arable crops at harvest time on the 500 acre farm.
The biomass fired system heats air via a water/air heat exchanger for the dryer and provides heated water for a district heating system servicing all the offices, workshops and houses on the farm.
As a bio-energy specialist with over 20 years’ experience in the renewable industry, John Seed is an advocate of environmental sustainability as a driver for green economic growth and farms Woodend Farm Partnership with his wife, Louise and son Donald, as a contemporary agricultural unit that tries to be self-sufficient and sustainable in its use of natural resources.
John has worked for several of the UK’s largest successful renewable companies, including Helius Energy Plc where he is currently chairman. He is a member of Scottish Enterprise’s South of Scotland Regional Advisory Board and was chair of the Berwickshire Agricultural Association in 2009/10. He is a also a director of Borders Machinery Ring which has the aim of rationalising labour, machinery and input costs for rural businesses in the Scottish Borders and beyond. He helped to arrange a free solar deal worth over £2m to BMR’s members with ISIS Solar, a leading provider of solar power to the UK agricultural, residential and commercial market but recent changes to the UK’s FIT support have undone all that, much to his disappointment.
His new heating and drying system is a technology commonly found in northern Europe, particularly in the Nordic and Baltic states.
The system comprises a 450kw batch-fired boiler in combination with a 50m3 storage tank that can absorb the heat energy from one firing (1-4 bales). The energy content of the straw is utilised better because the boiler can operate at full load which also means that emissions can be better controlled.
The Overdahl system installed reflects the technological advances that have been made in respect of these boilers over the past 20 years with a view to achieving greater efficiency and reducing emissions.
The greatest technological advances have been in the field of batch fired boilers where the efficiency has increased from 35-40 per cent in 1980 to 77-82 per cent in 1997 and up to 83 per cent at the boiler today with a further five per cent being recovered as a consequence of routing the flue through the accumulator tank giving a combined efficiency of over 87 per cent. This performance can be ascribed in particular, to a better control of the air supply required for combustion, which is a particular benefit of the Overdahl system and emission levels are reduced considerably by increased combustion quality. The Overdahl boiler is equipped with combustion air fans, where the amount of air and the distribution of air between primary and secondary air is controlled by an electronic control unit.
The flue gas temperature and oxygen content are used as control parameters. In addition the boiler has refractory linings of firebricks in the combustion chamber in the upper part in order to secure a high combustion temperature.
Edwin Thompson, hosting a group of local young professionals and farmers, had an informative tour of the new facilities at Woodend recently, which has generated much discussion and interest.
“John’s ambitions to show how a commercial agricultural business can reduce its carbon footprint with significant financial benefits are a shining example of the future for similar businesses,” said Patrick Playfair of Edwin Thompson. “We are delighted to be assisting John and his team achieve their goals.”
To find out more contact John Seed/John Farrell tel. 0844 7407492, e-mail email@example.com
Patrick Playfair, tel. 01289 304432, e-mail firstname.lastname@example.org