With the benefits of sustainable forest management, today’s fully automated high efficiency boiler systems and a well-developed fuel supply chain, biomass energy has the potential to be a cost-effective and reliable way of heating farms and small holdings.

A recent article in Farmer’s Guardian about how farmers can tap into the biomass energy market stuck a chord with us.

Alternatively, commercially processed wood chip and pellet can now be simply ordered and delivered to most parts of the country.

Each biomass fuel source requires significantly different levels of time, labour and equipment in terms of boiler type, harvesting and chipping machinery, plus storage facilities for the fuel – all which need to be incorporated into any time/cost/capital equipment analysis. TRECO RECOMMEND BUILDING AS LARGE A FUEL STORE AS POSSIBLE TO ENABLE BULK BUYING AND MINIMISE THE AMOUNT OF FILLS.

For instance for a farm, with its own woodlands and means of felling and transporting heavy timber, the easiest and cheapest option may be a basic log burning stove.  Other free resources such as surplus crop waste – straw bales, wheat and barley – can also be burned very economically in ‘straw boilers’ or boilers with a multi-fuel capacity.

However, this kind of agricultural waste generally produces more ash and clinker than wood-based materials, and so the boilers do need more regular maintenance, as well as frequent manual cleaning and de-ashing. ALTERNATIVELY, A MOVING STEP GRATE WILL ELIMINATE CLINKER, ALLOW THE BOILER TO COPE WITH WIDER VARIATIONS IN FUEL QUALITY AND ENABLE A MORE COMPLETE COMBUSTION.

Low cost wood chip

Farms with their own woodlands can also produce their own low cost wood chip.  SAVINGS OF UP TO 80% CAN REALISTICALLY BE ACHIEVED BY THOSE WITH ACCESS TO THEIR OWNE FUEL. However, this is a labour intensive process, as the logs need to be air dried in the fields over the summer or stored in large dedicated dry buildings in order to reduce the moisture content as much as possible.  Burning freshly cut ‘green’ wood is not recommended.

A less time and labour intensive option is to buy the wood chip, provided it is sourced locally (within a recommended radius of at least 20 miles) in order to keep transport costs and their associated CO2 emissions to a reasonable minimum.

The bulk density of the wood chip determines both the amount of storage space required and its energy content.  As the moisture content can vary from supplier to supplier, it is advisable always to buy wood chip by the kWh rather than by tonnage or volume.

Automated systems

For those farmers who do not wish to invest in the time, labour and capital equipment required to produce and burn their own wood chip or agricultural waste, fully automated wood pellet biomass systems represent a clean, simple, hassle-free and, not surprisingly, increasingly popular alternative.

As pre-processed pellets generally have a higher bulk density and a lower moisture content than wood chip, they deliver a higher energy content (typically 1m³ of wood pellet has the same energy content as 4m³ of wood chip).  Wood pellets also require significantly less storage space and can be blown easily and conveniently into the pellet store through pipes and then be fed automatically into the boiler.  This process requires very little maintenance or any kind of manual intervention.

However, the ease and convenience of using wood pellet is reflected in its proportionately higher purchase price.  Wood pellet deliveries can be from four to six times more expensive than locally supplied wood chip, depending on whether they are delivered by a full lorry load or in ten kilo or one tonne ‘dumpy bags’, although the price of pellet is still significantly lower than oil or LPG.

Cost implications

Any biomass system naturally involves a significant capital investment, however, the cost of new equipment can now be recouped through the UK Government’s Renewable Heat Incentive (RHI), which offers a 20 year revenue payment. Already in place for ‘non domestic’ installations (typically farms estates with sublet properties), confirmation of tariff rates is pending for ‘domestic’ farm buildings.  Based on our experience, the cost of a typical wood chip fuelled farm installation should be recouped within three to four years against an equivalent oil fired installation.

Additionally, specialist biomass companies offer attractive funding packages to help support the purchase and installation of equipment.

With the wide range of organic fuels, new combustion technologies and supporting finance initiatives currently available, the long-term future of biomass energy is extremely positive, as the UK moves towards its vision of a low carbon economy.