Good Energy’s information on biomass

Biomass refers to biological materials that can be used to make electricity through bio generation. Just as coal is burned in traditional power stations, biomass is burned to heat water and generate steam to turn a turbine. The vital differences are that biomass is renewable, and that it does not unleash the high levels of CO2 that coal does. Good biomass can come from waste products, or be grown quickly with minimal energy consumption.

How does biomass work?

When plant life grows it absorbs carbon dioxide (CO2) from the atmosphere. When a plant stops living, it decomposes and eventually it returns the same amount of CO2 to the atmosphere as it absorbed during its life. In this sense, biomass materials are carbon neutral.

This plant life or organic matter can be processed to create fuels that can be used to generate heat and power. This is known as biogeneration. When biomass is burned to create energy, they return the same amount of CO2 to the atmosphere as if they decompose naturally. This means that properly managed biomass does not disturb what is known as the carbon balance and does not contribute to climate change.

Materials such as waste wood, straw and other crop residues and crops grown specifically for energy production such as willow and miscanthus grass are used as fuel in biomass systems. Having been harvested and dried, the biomass is burned at high temperatures. The heat produced is used to turn water into steam. This steam turns a turbine which generates electricity.

Biomass from CHP

The most efficient biomass systems are Combined Heat and Power (CHP) systems. CHP takes the residual heat from the electricity generation process and puts it to good use. The Centre for Alternative Technology (CAT) is installing a CHP system that will be fuelled by waste wood and will provide electricity and heat for the site. The surplus electricity they generate will be sold to Good Energy.

Potential for biomass and biogeneration

In the US, Biomass provides nearly 2,000MW (about the same amount as an average sized coal burning power station) of electricity, preventing 11 million tonnes of CO2 entering the atmosphere. Over in the UK, we are on our way to matching this with new biomass generators upwards of 350MW each, such as the plant at Port Talbot.

Biogeneration has a lot of potential to provide consistent, base load electricity at with high output, as Port Talbot biomass plant demonstrates. This potential is far from being realised in the UK.

To see some examples of where Good Energy purchases Biomass from see our case studies here.

Critics of biomass

The idea of growing matter to produce fuel has been controversial over the last few years. In the worst cases, inappropriate crops have been grown that are energy intensive and have even forced the local market price of food up. Biomass energy has to be managed very carefully to make sure it is beneficial and sustainable, and does not create social issues in an attempt to fix environmental ones. For example, growing food crops, transporting biomass over long distances to feed power stations can undo much of the good that the plants create. With the right management however, biomass can be a sustainable and people friendly fuel.

This is why we have developed a biogeneration procurement policy. Our policy defines what we believe is sustainable when it comes to sourcing and transporting biofuels and producing biogeneration. To assess a biogenerators sustainability, we require them to complete an application and based on the information they provide, we decide if we can work with them.

Because of the issues of material demand, biomass energy is well suited to small scale projects that can feed on waste from a local community.  Waste is the second largest source of biomass energy.

Biogas

Biogas is produced through a process called Anaerobic Digestion (AD). This is a natural biological process carried out by bacteria in the absence of air, by which organic material is broken down into stable fertiliser and useful biogas. These anaerobic bacteria are an integral component of nature’s waste management and are commonly found in soils and deep waters, as well as in landfill sites.

How does Anaerobic digestion work?

The break down of organic compounds is achieved in a soup of many types of bacteria including those that generate carbon dioxide and methane.

The organic waste is broken down into sugars and amino acids by enzymes similar to those found in our mouths that help digest our food. These sugars are then fermented to produce volatile fatty acids and then converted by various types of bacteria into biogas, a mixture of carbon dioxide (40%) and methane (60%) and other trace elements.

While there are many ways of building anaerobic digesters (AD) the basic principle takes a feedstock that is fed into a completely enclosed tank, which is heated and regularly mixed.

What do you need to make Biogas?

You need feedstocks. Organic feedstocks are very flexible, ranging from farm manures and sewage sludge to catering and food wastes comprising uncooked and cooked food, meat and bone. The feedstock then goes through the process of anaerobic digestion. This is the process of creating optimum conditions for bacteria growth. As time goes by the feedstock is digested (eaten) by these bacteria that in turn generate two byproducts - digestate and biogas.

The biogas is then ready to be burned in a combined heat and power unit to produce electricity and heat. Normally a biogas engine can gain an electrical conversion efficiency of up to 35% with the remainder being available as heat.

Help grow the biomass industry by switching to Good Energy

Switching your home or business from your standard electricity supplier to Good Energy means that all the electricity you use will be supporting independent renewables around the UK, including the biomass power schemes we buy from. We are the UK’s only 100% renewable electricity supplier and fight for renewable energy every day.

Switching to Good Energy is the first step in supporting biomass power.