Scotland’s installers of wood chip and pellet boilers have been extremely busy for several years, wood being a locally-sourced, environment-friendly and cost-effective fuel and the Renewable Heat Incentive (RHI) making the use of these alternatives to oil and gas even more attractive.

Renewable Heat Incentive tariffs have now fallen substantially for smaller systems, those below 200kW, due to the huge popularity of the scheme, but they still make the large investment attractive for commercial and large heat users and those who have easy access to their own wood fuel supplies.

Not every building can house the larger boiler and fuel storage equipment and not everyone will be prepared for the added operation and maintenance requirement compared to conventional boilers, but a wide variety of good quality systems is available and a growing number of experienced installers. Note, however, that corners cut in the design and specification often mean unnecessary hassle for ever more. Independent advice will reduce the risk of this happening.

Some readers may recall the old-fashioned straw-fuelled boilers which commonly sat in a barn and supplied heat for the farmhouse. Gone are the days of boilers which leaked about as much heat as they generated and, in the worst case, set your steading alight! Today’s straw-fuelled biomass boilers are highly efficient and safe.

Typically using around one low density straw bale per day in winter and one every three days in summer, these boilers can supply enough heat and hot water for one house using some 240 bales per year. These boilers must be readily accessible by forklift/tractor for filling with bales and removing ash. Prices vary from £12,000 to £30,000 depending on size. So, if you are an environmentally conscious arable farmer with no livestock, this could well be the ideal alternative to an oil or gas-fired heating system.

Biogas – Anaerobic Digestion

Using Anaerobic Digestion to convert slurry and plant matter, such as maize, rye grass and food processing waste, into biogas and fertiliser is common in many European countries and the technology is increasingly being applied in the UK.

Renewable Heat Incentive is payable for on-site heat use or injection of gas into the national gas network, and feed-in tariffs paid for on-site electricity generation. These systems can make good financial sense, particularly when they fulfil a variety of benefits to a business in terms of waste reduction and management, energy security and cost control.

Funders remain wary of the risks arising from the necessity for stable feedstock supplies over the long term, and a thorough resource and feasibility study is always the necessary starting point.