Biomass Energy: Does it Have a Place in a Net-zero Future?
Biomass energy often falls behind heat pumps, solar and wind farms in discussions about a net-zero UK, but there is a growing school of thought that biomass energy could play a big role in future energy and heat generation systems.
Here we explore biomass energy as a potentially sustainable fuel and how you could incorporate it into your home heating.
What is biomass energy?
Biomass energy is generated from burning organic (natural) matter like plants, wood, grass, manure and household waste. If the organic matter is produced and sourced sustainably, i.e. the matter being burned is replaced, biomass is a renewable source of energy.
Biomass energy does produce some carbon emissions when burned, but significantly less than fossil fuels. In the case of plants and wood, the burning process will only release as much carbon as was originally absorbed as the plant or tree grew. This is described as being a carbon neutral process.
Biomass energy is also referred to as biofuels or biogas, depending on the form the fuel takes.
Types of biomass fuel
- Wood and agricultural products such as logs, chips, sawdust and bark
- Biodiesel made from recycled grease, animal fats and vegetable oils
- Heat energy generated from burning solid waste or rubbish
- Bioethanol is produced by fermenting plants and is an alcohol-based biofuel
- Biogas generated from burning sewage and agricultural waste
How is biomass energy being used?
Humans have been using biomass energy since we first discovered fire and started burning wood and plants. There is also evidence that in China in the 13th century they were generating biogas from covered sewage tanks. In the late 1800s before petroleum-based diesel became widely available, Rudolf Diesel invented an engine which could be fueled by vegetable oil.
Biomass can be used to generate heat or electricity, in combined heat and power units (CHP) or as a liquid fuel. One of the most important ways in which biofuels could reduce our carbon footprint is in the transport industry. Our cars, buses and aeroplanes are largely fueled by fossil fuels and produce huge amounts of greenhouse gases. Switching to biofuels could be a significant step on the path to net-zero.
Today, in domestic settings, biomass commonly refers to the wood we burn in wood burning stoves or the wood pellets burned in biomass boilers.
In industry, biomass is being used as a replacement for coal in energy generation. Currently, biomass is only generating approximately 4% of the UK's electricity while solar and wind account for 11 and 12% respectively. However, according to the Renewable Energy Association's report from June 2019, bioenergy could account for as much as 16% of our energy generation by 2032 helping the UK to reach its carbon reduction targets. Another report from the International Renewable Energy Agency (IRENA) has suggested that biomass could provide 60% of global renewable energy by 2030.
For example, the Drax Power Station in North Yorkshire has come under a lot of criticism in recent years as the largest producer of carbon dioxide in the UK. Now the power station uses biomass imported from the US, Canada and Brazil to generate electricity. There are several other biomass energy projects in the UK, as well as future plants in the planning process, including:
- Blackburn Meadows Cogeneration Plant in South Yorkshire harnesses excess heat from combustion to provide heating to nearby businesses via a district heating system.
- Templeborough Biomass Plant opened in August 2017 and provides enough energy for 78,000 homes saving up to 150,000 tonnes of carbon dioxide annually.
- Kent Biomass power station has been meeting the energy demands of up to 50,000 homes since summer 2018.
- Tees Renewable Energy Plant (due to be finished in 2020). This will be the largest biomass plant in the world saving 1.2 million tonnes of carbon emissions per year while producing enough electricity for 600,000 homes.
To ensure a large power plant which runs on biomass is sustainable, there are many factors to consider including where the fuel is coming from, how it was produced and transported and how much carbon was emitted during all of those processes.
How efficient is biomass energy?
Energy is measured in joules or megajoules (MJ). There are 1 million joules in every megajoule. Wood, the most common form of biomass which many people use in their biomass boiler or wood burner, emits around 15 MJ per kilogram (MJ/kg). However, if the wood is dried before it's burned, this increases up to 18 MJ/kg. When you compare this to coal which generates between 25-30 MJ/kg and crude oil which generates 42 MJ/kg, it's obvious that biomass energy isn't as efficient.
Burning biomass in the home
While burning biomass for heating and electricity on a wide scale is not a realistic prospect at the moment, homeowners who wish to reduce their carbon emissions by getting rid of a fossil fuel boiler (which burns gas or oil) may want to consider a biomass boiler in their home.
A biomass boiler burns wood pellets, logs or chips to generate heat for your hot water supply. A modern biomass boiler has a fuel storage compartment which will automatically feed the wood chips/pellets into the combustion area to be set alight by a probe. As the fuel burns it heats the water via a heat exchanger.
While gas boilers have a constant fuel supply from the gas network and an oil boiler is supplied by a large tanker, a biomass boiler's fuel needs to be topped up either by hand or by an automatic mechanism called a hopper. A hopper stores a greater volume of fuel and will automatically refuel the boiler as needed, reducing your workload. As it burns solid fuel, a biomass boiler needs to be manually emptied of ash and cleaned every now and again. Depending on the type of boiler you have and the technology involved this could be once a week or once a year.
Renewable Heat Incentive
Biomass boilers which are MCS accredited and installed by an MCS accredited engineer are eligible for the Renewable Heat Incentive (RHI). This means that the government will pay you for every kilowatt-hour of heating that your system produces. This figure is estimated based on the Energy Performance Certificate (EPC) which your property should already have. You would receive quarterly payments every year for 7 years.
Is a biomass boiler right for your home?
A biomass boiler is likely to take up more space in your home than a gas, oil or electric boiler and you'll not only need space for the appliance, but somewhere to store the fuel too. You will need plenty of storage space and may even require easy access for delivery trucks. Your home will also need to have a high chimney that's suitable for wood burning. You may be able to convert an existing chimney by adding the right flue materials but this is likely to add to the initial costs. For more information on biomass boilers including pros, cons and costs, click here.
Many parts of the UK are smoke control areas where you can't emit smoke from a chimney unless you're burning an authorised fuel or using 'exempt appliances'.
It is important to remember that a biomass boiler is only a renewable heating system if its fuel comes from a sustainable source, i.e. the trees which are chopped down are being replaced, there has been no negative impact through the production process such as the loss of ecosystems like rainforests and the fuel is being transported with sustainable practices. Make sure that any fuel you buy is from a sustainable local source and that your supplier is registered. The Biomass Suppliers List contains details of approved suppliers.
If you would like to speak to a professional engineer in your area about installing a biomass boiler in your home, get in touch with us today. We can get you with up to 3 free quotes for a biomass boiler to help you find and compare the best deals around.