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Biomass energy saving plan delivers bumper crop of efficiencies

By Western Daily Press  |  Posted: May 28, 2014

Andy Taplin from moleenergy with Somerset fruit farmers Adrian and Richard Winter. The brothers have installed new biomass boilers to warm their greenhouses, with help from Mole Valley Farmers

Andy Taplin from moleenergy with Somerset fruit farmers Adrian and Richard Winter. The brothers have installed new biomass boilers to warm their greenhouses, with help from Mole Valley Farmers

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Putting faith in new technology and taking good advice has enabled a Somerset fruit farm make significant energy cost savings, as Jeff Wells reports

By investing in two biomass boilers, one Somerset strawberry grower is on track to benefit from £160,000 a year in fuel savings and added income while enabling the business to make the most of an earlier premium market.

With 14 acres of strawberries grown undercover at Bower Farm, Bridgwater, heating costs are among the highest after labour for the Team Green Growers family business. As a result, last year the team decided to look at renewable energy options to drive down energy costs.

After seeking the advice of moleenergy – the renewable energy arm of Mole Valley Farmers – installing two biomass boilers was seen to be the most sensible and profitable route. Putting in a Viessmann 540kW and a 300kW chip Köb boiler would meet their energy demands and allow the business to gain significant income from the Government's Renewable Heat Incentive (RHI).

At a total cost of £350,000, Adrian Winter believes the biomass boiler system will bring about a £80,000 a year saving in fuel over the farm's conventional oil burning system. In addition, the Winters will receive £80,000 a year from the RHI, which on its own will enable the project to be paid back in five years.

"The cost of fuel is only going to go one way, so by putting the biomass boilers in we are future proofing the business," says Adrian. "The financial incentive means it makes sense to go down this route, plus it does help to tick the green energy box."

The Winter family, brothers Adrian, Richard and Phillip and father Albert, produce Elsanta strawberries for Sainsburys via CPM. Correct environmental temperature is crucial to maximise plant performance and help ripening, with heating essential in maintaining night time temperatures at between 8C and 14C during key parts of the growing season.

Put in at the start of 2014 by one of moleenergy's preferred installers Glevum Heating, the decision was made to use the biomass boilers to heat one 3.5acre-glass greenhouse on site. This greenhouse alone had cost £70,000 in oil to heat during the cold patch of November 2012 to April 2013.

To make the move over to renewable energy, the family invested in the two biomass boilers, buffer storage tanks, a woodchip store and heat exchange unit to link up the old system to the new biomass boilers. Adrian says the move was simple.

"We originally had two oil burners. To move over to the biomass boilers we took out one of the oil burners and plugged in the new system. It was a simple retrofit to the existing pipes," he says.

One oil burner has been kept as a back-up for the heating system and also to offer support to the biomass boilers when greenhouse temperatures drop heavily.

With a total annual requirement of 900 tonnes of woodchip to feed the boilers, creating a woodchip store was a key consideration. To house the boiler room and woodchip, a 90ft by 40ft shed has been purposely erected next to the greenhouse. Adrian says moleenergy's advice was crucial in ensuring the correct siting of the facility.

"We originally wanted to put the wood store elsewhere, but moleenergy explained that ease of access was a prime consideration to deliver the high volumes of chip needed." As a result, the shed was erected near to the farm entrance.

The store joins on to the boiler room with two woodchip bins automatically feeding chip into the boilers as necessary. All in all, the boilers require 90m3 of chip a week.

Adrian says the quality of woodchip used is an important factor in ensuring efficient energy production.

"What you put in is what you get out. To get the best calorific burn ideally you want a chip of 18 per cent moisture. We've experimented with lots of different wood. We bought-in some logs as they were cheaper, but you have to chip them on farm and wait for them to dry out. It's a gamble if you can't achieve the moisture you want and you have money tied up in wood – it's well worth buying in quality."

From now on, the Winters are looking to buy in ready chipped wood from a dedicated source that can guarantee a set moisture level.

Having sought the advice of moleenergy, the Winters also decided to put in two boilers rather than the one they originally planned. This meant they would be able to meet seasonal demand more effectively.

Andy Taplin from moleenergy explains: "The two boilers can work independently or together for more efficient energy production. Modulated output also means the 300kW boiler, for example, can work at 100kW if needed to meet demand."

As soon as there is demand for heat in the greenhouse, the boilers kick into gear. However, because they take half an hour to warm up, in the meantime a series of buffer tanks totalling 30,000 litres pump hot water immediately round the pipe network in the greenhouse. When the boilers have heated up, they then take over from the tanks.

Adrian says the fact there is no time lag before heat is delivered means there is a more consistent temperature in the greenhouse, which ultimately benefits strawberry production.

"When we were burning oil, temperatures were a lot more inconsistent. They would often go down to 4 to 5C at night and there would be a time lag before temperatures went up again.

"Because of the cost of oil we didn't want to put the burners on unless necessary. Now, because the biomass boilers basically produce free heat we can have them burning whenever the requirement is there."

Adrian believes this consistency in temperature, along with a warm spring, has helped put strawberries two weeks ahead of normal. This means the business is able to make the most of an earlier, premium market.

"There's a vast difference in price between what we get at the start of April and that at the end. Strawberries picked at the beginning of the month are worth about 66 per cent more. It also means we get the money in the door earlier," says Adrian.

Richard says consistent delivery of heat will also give the business confidence to try planting strawberries later to make the most of the premium market at the end of the season.

"We will probably plant four to five days later than normal as a trial. But for every one day later planting, you get a three-day later harvest so you need to push the plants. We can try this because of the boilers."

Adrian also believes the more consistent greenhouse temperatures has resulted in a drier environment which is beneficial to the strawberries.

"The more consistent temperature reduces condensation. I think we may have used less chemical for botrytis (rot) as a result."

Andy says biomass boilers could be hugely beneficial for anyone heating under glass.

"I think there is a huge opportunity for businesses, but I'm not sure how long the opportunity will remain as it's driven by Government policy.

"I would urge growers to look at it now and not put if off. However, make sure you're getting the right advice and assess your site carefully. The RHI is guaranteed for 20 years so it's a long journey. You want to make sure you're installing a quality product."

Adrian agrees. "It's mind blowing when you start looking into it all. You need to speak to the right people. Bad advice will put you in the wrong place and it will cost you."

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