Glorious good wood
With fuel prices soaring and the Renewable Heat Incentive about to kick in, there has never been a better time to look at wood as a fuel source. Mark Northcott, managing director at Remeha Commercial, examines what you should look at when considering a biomass boiler installation.
Few could have failed to notice that energy prices are soaring. Good news then that there are some alternatives to fossil fuels out there. One, of course, is wood, and biomass boilers are proving very popular at the moment. As well as the reduced fuel bills on offer from the relatively low price of woodchip and pellets over gas and oil, there is the forthcoming Renewable Heat Incentive (RHI) to consider.
The RHI will certainly prove a welcome shot in the arm for this tried and tested technology. While the legislation is still to be enacted in parliament, in the commercial sector it is likely to take effect on 30 September this year and the proposed tariffs have already been announced. End users will benefit from up to 7.9 p/kWh of heat generated, making biomass an attractive proposition.
For installations up to and including 45 kWh, installers and equipment must be certified under the Microgeneration Certification Scheme or equivalent standard. Contractors may need appropriate training before applying for certification. Payments will be administered by Ofgem and will be made quarterly over a 20-year period.
Even without the RHI payments, Remeha Commercial has found that biomass installations using woodchips or pellets will achieve rapid payback on investment. The Carbon Trust has produced case study evidence that shows paybacks ranging from just 2.9 years through to 4.7 years due to the lower costs for wood over other fuels. Payback times will tumble once the tariffs offered by the RHI take effect.
The carbon benefits of biomass boilers are clear. Using solid biomass for heating typically gives reductions in carbon emissions of around 90% relative to using fossil fuel heating systems. The Carbon Trust suggests that lifetime CO2 emissions for woodchip biomass are in the range of 10-23 kg CO2/MWh. This compares with 263-302 kgCO2/MWh for natural gas.
While supply can be difficult in certain areas of the UK, availability should not be an issue for most applications. The Forestry Commission estimates that an additional 2 million tonnes of wood could be harvested from currently under-managed UK woodlands by 2020 – that’s around half of the available, currently unharvested, material in English woodlands.
The Carbon Trust reports that sufficient UK woodfuel resources exist to supply a large number of new biomass heating systems. It is worth noting that, under the RHI, biomass installations of 1MWh capacity and above will be required to report quarterly on the sustainability of their biomass feedstock.
Fuel can be stored in various ways, such as dedicated storage facilities (either above or below ground), integrated facilities within existing buildings, or in removable storage containers. A well-designed system for delivering, storing and transferring solid biomass fuel is essential to ensure a smooth-running biomass heating system. Obviously, these factors are far more onerous than would be the case with a gas-fired boiler.
One of the main differences between a biomass heating system and a conventional fossil fuel heating system is that the biomass boiler is best suited to being operated relatively continuously (between around 30% and 100% of its rated output). This means that a fossil fuel system is often specified alongside the biomass boiler to manage peak demands. Also, a biomass heating plant will be considerably larger in volume than an equivalently rated fossil-fuel plant due, in part, to the inherent combustion characteristics of solid, organic materials. They also require sufficient free space around the unit for maintenance and cleaning.
Buildings where the heating system is used for long periods during the year, such as swimming pools, hospitals etc offer conditions more suited to biomass boilers than general occupancy buildings such as offices, for example.
Periodic removal of ash and cleaning of heat exchanger surfaces will be no different to the operation and maintenance (O&M) requirements of other solid fuel systems. Look for a manufacturer that offers automated de-ashing and heat exchanger cleaning mechanisms. Even with the best equipment, it should be recognised that biomass systems do require more looking after than oil or gas-fired systems. For a typical biomass installation, the time needed for on-site staff may be around 0.5 to 1.5 days per month but this can often be reduced as experience of the system is gained.
Certainly, biomass has a bright future. By 2020 the government estimates that the renewable heat sector will have grown to include around 110,000 installations in the commercial and public sectors, supplying 25 per cent of the heat demand in these markets, alongside 13,000 installations in industry.
Remeha Commercial is well versed in all aspects of supplying biomass boilers, often in conjunction with our eco-friendly, low NOx commercial gas boiler ranges. Whatever your requirements, Remeha Commercial has the perfect solution to match.
Related Industry News