Biomass

Energy from biomass is renewable if it comes from a sustainably managed source. This is where all the wood or other material is regularly replaced by new growth. 

This means that all the CO₂ released when the fuel burns is matched by the CO₂ absorbed by the new growth. Sustainable fuel should also be produced in a way that supports biodiversity and doesn’t contribute to other environmental or social problems. 

Most domestic wood fuel on sale in the UK does come from sustainable sources, but it’s important to check. 

Biomass is a lower carbon option than traditional fossil fuels. The CO₂ that’s released when you burn wood is the same amount that the tree absorbed while it was growing. The process is carbon neutral if new plants continue to grow in place of those used for fuel. 

There are also some CO₂ emissions caused by the cultivation, manufacture and transportation of the fuel. But if you choose sustainably produced fuel, these are lower than the emissions from fossil fuels. 

Burning wood at home can impact local air quality, potentially contributing to serious health problems. 

This is because burning wood releases certain gases and tiny particles of soot, known as particulate matter, into the air. 

The biggest concern is the use of open fires and traditional log stoves, especially if you use them inappropriately.

Possible risks include: 

• Emissions of particulate matter and nitrogen oxides from the flue. These can contribute to poor air quality in the local area, especially in built up areas where air quality is already a concern. 
• Emissions from a log stove going directly into your home whenever you open the stove door. This potentially creates unhealthy levels of indoor pollution. 

You can limit the pollution from log burners by:

• Choosing a modern, Ecodesign compliant appliance. 
• Using a registered, competent person to make sure your flue and installation are safe. 
• Using dry wood fuel only, to make sure it burns efficiently and completely. 
• Sweeping the flue regularly, to sure any pollutants are drawn out of the house. 

Emissions from pellet boilers, pellet stoves and log boilers are generally lower than log stoves. However, all wood burning systems will produce some pollution, so consider an alternative if you live in an area with existing air quality issues. 

If you live in a smoke control zone, you must use an appliance that your local authority has approved for use in these areas. Contact your local authority to check. For more information, read our guide to wood burner regulations. 

For biomass boilers, an automatically fed pellet boiler for an average home costs around £18,000, including installation.

Pellet costs depend mainly on: 

• how much you order 
• how you get them 

If you have room for a large fuel store that can take several tonnes of pellets at a time you can keep the cost around £400 per tonne. 

Logs can be cheaper than pellets, but costs depend on the wood suppliers in your local area, since logs can be expensive to transport. You can save money by buying unseasoned logs and letting them season (dry out) for at least a year. For this you’ll need to have room to store more than a year’s worth of logs. 

CO₂ emission savings are significant. When a biomass boiler replaces a coal fired system, you could save up to 11 tonnes of CO₂ emissions a year. 

However, financial savings are more variable.

If you currently have a modern condensing gas boiler, a biomass boiler is likely to cost you more to run than your current system. 

The Boiler Upgrade Scheme (BUS) pays a grant of £5,000 for biomass boilers in England and Wales. When you get a quote for a biomass boiler, the instlaler should deduct this amount should from the cost automatically.

Bear in mind there are other low carbon heating options such as heat pumps, which you may want to consider. Under the BUS, you can get £7,500 off the cost of a heat pump. 

For Scotland, the Home Energy Scotland Grant and Loan currently offers up to £15,000 (£7,500 grant plus up to £7,500 loan) for biomass boilers. To be eligible, you must have evidence that zero emission heating systems, including heat pumps and high heat retention storage heaters, aren’t suitable for your property. This can be either:

• A Home Renewables Selector Report.
• A Home Energy Improvement Report from a Home Energy Scotland specialist advisor.
• Written evidence from a certified installer.

If you live in Northern Ireland, contact NI Energy Advice to find out more about what funding might be available. 

If you’re thinking of installing biomass heating, here are a few things to consider: 

• Sweep your boiler or stove regularly. For biomass boilers, do this once a week. For log burners, you should do this before every use. 
• Use the heater’s self-cleaning function, if it has one. If not, you’ll need to shut down the boiler to clean ash from the combustion grate and heat exchanger tubes. 
• Sweep the chimney and flue at least twice a year, preferably just before and just after the heating season. 
• Conduct a maintenance check once a year. 
• If you’re using a log burner, make sure you only burn logs that have been air-dried for at least a year. 

Ready to take the next step? Here’s what you do: 

• Find out if a biomass system is right for you. Use our free online assessment tool Go Renewable to find out. 
• If you live in Scotland, read stories of homeowners who’ve installed a wood-fuelled heating system. 
• Get at least three quotes from different installers to make sure you’re getting a good deal. We recommend finding installers who have registered with MCS. If you live in Scotland, you can also find installers through our Renewables Installer Finder. 

If you’re looking for a heating system that saves you money on your bills and improves your carbon footprint, here are a few alternatives: 

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