Energy costs fuel interest in biomass boilers
Nigel Blandford draws on 25 years’ experience in the biomass sector to offer practical advice on getting the best from biomass boilers. He is currently managing a £750 000 project to increase the uptake of biomass energy systems in the north west of England.
The combination of rising energy prices and the current economic climate is ‘fuelling’ interest in biomass since it is substantially cheaper than traditional fossil fuels. This has increased interest amongst businesses to investigate installing a biomass heating system.
Although the term ‘biomass’ literally means anything organic, it generally refers to materials based on woody plants. Pelletised fuel is readily available throughout the UK in significant quantities. Chipped fuel is very well developed in places such as the North West of England.
There are several immediate advantages of biomass systems.
• They can reduce long-term fuel costs in an increasingly volatile energy market.
• They can help to meet planning commitments to install a percentage of renewable energy in new developments.
• The Climate Change Agreement or the EU Emission Trading Scheme may stipulate biomass as a requirement.
• The Government is actively promoting the technology, so there are a range of financial packages available to businesses — both regionally and nationally.
Biomass will often be the cheapest option in terms of cost per installed kilowatt of renewable energy capacity. There are, however, several issues which should be considered at the early planning stages.
Planning and legislation: If the development is in a Smoke Control Area (SCA) an ‘Exempt appliance’ will be required. Boilers under 400 kW will require little further attention from the regulatory authorities as they fall below the threshold of Pollution Prevention & Control Regulations 2000. Further technical details may be required by the local authority or SEPA in Scotland for larger boilers fuelled with recycled wood.
Building Regulations also apply. Part J (Combustion Appliances & Fuel Storage Systems) must be adhered to for installations under 50 kW. The regulations also provide useful pointers for larger installations. Just as approved gas installers are accredited by Gas Safe Register, the solid-fuel registration body is HETAS.
Fuel stores: Fuel store size is dependent on how often refuelling will be required. Generally, the storage area should be as large as possible to ensure sufficient reserves. This is obviously linked to the size of boiler but also the size of the delivery vehicle. If fuel is delivered in 10 m3 loads, at least 12.5 m3 of storage will be required if fuel is reordered when the store is a quarter full.
There is a variety of options for receiving and storing fuels. Some suppliers of pellets and reprocessed fuels can blow fuels through pipes some distance into elevated silos.
The best option, particularly where space is constrained, is below-ground storage — although this is the most costly. It allows for the easy tipping of fuels from a variety of vehicle types. Many novel solutions exist to get round most constraints, and you should establish contact with fuel suppliers at an early stage.
Fuel supply and quality: Pellets are dense, consistent and can be blown through a pipe to above-ground storage. They are however the most expensive fuel at between 4 to 6 p/ kWh.
Chips are considerably less expensive at 0.5 to 3 p/ kWh, but they are bulkier and less consistent than pellets.
If an automated boiler under 40 kW is being installed, strongly consider pellets. Above that size, chips come into their own.
Practical differences: In the vast majority of cases a biomass boiler cannot merely be substituted for a gas boiler. This is most marked where there is a modern building-management system (BMS). To get the best from systems, it is now accepted that they have an insulated accumulator tank or thermal store. The BMS can then draw heat from store, and the boiler recharges it by running at high output. This mode of operation enables biomass boilers to be undersized.
Maintenance: Maintenance requirements are greater than for gas appliances but are not onerous. They will, however, need to be built in to any existing contracts with building/heating maintenance providers, who will need to have the correct training and allocate sufficient time for the work. Some of this work can be undertaken by having a remote diagnostic link back to the installer supplier.
Conclusions – The top 3 issues
1 Biomass is a solid fuel. Issues of delivery, reception and storage need to be considered at a very early stage.
2 Modern biomass heating systems are efficient and reliable. There are some key differences which mean a biomass system cannot be simply substituted for a gas boiler. The contracted mechanical or heating engineer needs to understand and plan for these.
3 The business’s usual energy contractor or maintenance staff may not have experience of biomass systems. They will need to be properly trained by the installer or will need to contact the installer about an energy supply or long-term fuel and maintenance contract.
Nigel Blandford is the senior sector development manager for biomass at Envirolink Northwest. www.envirolinknorthwest.co.uk
Further advice and guidance
Biomass heating – a developers advice guide.
This can be downloaded from www.envirolinknorthwest.co.uk by clicking ‘Publications’ then ‘Envirolink publications’ and selecting the guide for downloading.
Biomass heating — an introductory guide for potential users.
Download from www.carbontrust.co.uk. You can locate it by typing CTG016 into the search field.
Biomass Energy Centrewww.biomassenergycentre.org.uk
