Green gas is a promising renewable energy form produced from organic material (biomass). The development of its generative processes along with its integration in energy systems will, no doubt, be vital for decarbonising the UK and reaching net-zero emissions. Here we take a look at what green gas is, which energy providers offer green gas plans and how it is produced.
UK net-zero emissions targetIn June 2019 the UK became the first G7 country to set a legally binding net-zero emissions target. The 2050 Target Amendment to The Climate Change Act 2008 commits the UK to reduce all greenhouse gas emissions by 100% of 1990 levels (net-zero) by 2050.
What is green gas?
Green gas refers to biofuel products sourced from decomposing biodegradable materials such as human waste, manure, crops and other organic matter - all of which are generally subsumed under the term biomass in the context of energy production.
The primary green gas biofuel released from the decomposition of organic matter is known as biogas, which is harvested in large quantities in biogas plants. A derivative biofuel called biomethane is also produced in these plants by concentrating and refining the methane present in biogas.
Both biogas and biomethane can be used for generating energy in the same way as fossil fuels, although each has a distinct application in the energy system.
Biogas is a naturally occurring by-product of decaying organic matter, readily found in landfills, compost heaps and swamps. It is made up primarily of methane and carbon dioxide - with trace levels of other contaminants, making it highly combustible and, as such, apt for energy production.
Raw biogas extracted in biogas plants can be burned near the point of production to generate electricity and heat to be consumed locally, stored for future consumption or exported.
Green gas in this form cannot, however, be integrated into the gas grid and used interchangeably with extant natural gas. The latter is predominantly methane and has been treated to meet gas quality and safety requirements; moreover, it has distinct thermal qualities. Biogas, on the other hand, is rather unpolished by comparison. This is to say, it is not pipeline quality. Indeed, its injection into the gas grid would be harmful to both the grid and the end-user.
Biomethane is produced in a treatment plant where the methane present in biogas is purified, ‘scrubbed’ and concentrated to levels equal to or greater than 95%. The resultant biofuel (biomethane) thus acquires the same properties and quality certification conditions as natural gas.
Following the treatment process, Biomethane can be injected into the gas network and used in domestic and industrial gas appliances. Of course, in our current energy context, it is used in conjunction with natural gas, though it has been touted, along with other forms of eco gases - namely, green hydrogen - as the green alternative.
How does green gas differ from natural gas?
Natural gas is a fossil fuel. Much like oil and coal, it is a product of natural processes that convert plant and animal matter into gaseous hydrocarbons over millions of years. These hydrocarbons rise close to the earth’s surface over time and are extracted through such means as vertical drilling, fracking, and as by-products of other fossil fuel extraction processes.
Crucially, fossil fuels are finite resources and carbon-intensive from extraction to end-use. The former means that fossil fuels diminish over time; the latter contributes to the climate crisis by emitting more greenhouse gases into the atmosphere than are being removed (surplus emissions).
Green gas biofuels differ from natural gas on these two points. Not only are they sourced from renewable organic materials, they also have the potential to achieve carbon-neutrality and, therefore, reduce surplus emissions.
Is Green Gas renewable?
Yes. Green gas is a renewable energy source. Organic materials like food, animal and agricultural waste, used in the production of green gas biofuels, are easily renewed, and at a faster rate than fossil fuels.
Other materials like grass and wheat crops, algae, wood and straw require careful management but are also relatively easy to replace.
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Is Green Gas bad for the environment?
This is a more complex matter than the question suggests. Green gas puts to use greenhouse gases - namely, methane, which is far more potent than carbon dioxide - that would have otherwise been released into the atmosphere by the natural decay of the organic matter used to produce it.
And although the burning of green gas for the generation of energy does release carbon dioxide into the atmosphere, studies have shown that it is quantifiably less than the amount of CO2 released from burning fossil fuels, thus making it comparatively better for the environment.
What about carbon neutrality?
While often proclaimed as such, green gas is by no means inherently carbon neutral. Rather, it requires an emissions mitigation network to ensure that our carbon balance and cycle is equilibrated. This includes:
- Low carbon green gas infrastructure
- Sustained reforestation
- Careful management of energy crops
- Carbon capture and storage
- The integration of renewables in energy systems
- The phase out of fossil fuels
Consumers should be aware that, currently, energy suppliers offering ‘carbon-neutral’ gas options apportion a miniscule percentage of green gas in their gas mixes. The majority rely heavily on natural gas which they offset with carbon credits.
Green Gas & Greenhouse GasesDon't get green gas mixed up with greenhouse gases. Green gas is a renewable energy source that releases greenhouse gases when burned, although not as much as fossil fuels. Greenhouse gases trap heat in the atmosphere and, in our production of surplus emissions, have contributed to global warming.
Green gas suppliers in the UK
Do you think green gas is the future? There is a growing number of UK electricity and gas providers that focus on integrating green gas in their tariffs. Here are a few of them:
Good Energy sources 6% of its gas supply from green sources. Like other green energy companies, it compensates for the use of natural gas by investing in carbon offsetting initiatives. Good energy has committed to biogas and forest conservation efforts abroad.
Tonik Energy is a fast growing green energy provider that is handily outperforming the Big Six on customer service. Tonik's goal is to halve its members’ energy costs over the next four years while focussing on green gas and electricity. The provider offers tariff options that use 10% of green gas and offset the environmental impact of the remaining supply through investments in carbon emission reduction initiatives elsewhere.
Ovo Energy is an independent energy provider known not just for its focus on renewable gas and electricity but also for its topnotch customer service. For a monthly £5 charge, Ovo Energy pledges to make 15% of your gas supply green no matter how much you use. The remaining supply is made up of regular natural gas but Ovo pledges to fund environmental projects that offset equivalent amounts carbon emissions.
Ecotricity was the first energy supplier to make green gas available. It is currently aiming to supply 12% of heating demand from renewable sources. It is important to note that the provider is investing in green gas power stations to reach its long-term 100% green gas goal. In the meantime, Ecotricity is committed to ensuring that none of its current gas comes from fracking.
Bulb Energy is one of the largest green gas supplier in the UK. Its gas mix is made up of 10% green gas, all of which is produced from energy crops and food and farm waste. The rest is natural gas which is offset by support for and investment in carbon reduction projects. Bulb purchases 40% of all green gas in the UK green gas market.
Bristol Energy, owned by Bristol City Council, uses 15% green gas in its supply. The provider uses “poo power”, that is, from local sewage waste to provide Bristol residents with cleaner gas. The provider aims at carbon neutrality by 2030 and offsets its current carbon use by supporting lower carbon initiatives that benefit the environment.
The British energy market is full of independent energy providers that charge a variety of energy prices. Here at Selectra, we can give you impartial advice and help you find the cheapest and best residential green gas supplier for your needs. We can advise you on how to switch (it's much easier than you think!) and how to bring down bills. Get in touch using the info below! Contuct us using the info below. Get an beforehand so that we can give you an accurate quote.
How do they make green gas?
There are four types of energy plants that can produce green gas: three biogas plants, each employing different methods to break down and collect organic materials, and one biomethane treatment plant.
Below are descriptions of the processes used in each biogas production plant:
- Anaerobic digestion (AD):
Anaerobic digestion (AD) plants remove oxygen from sealed tanks in which organic materials such as agricultural waste, manure, sewage, grass crops and other ‘energy crops’ are left to decay. Microorganisms break down and digest these organic materials, in the process releasing methane-rich gas (biogas). The absence of oxygen is crucial as it allows for a higher concentration of methane.
The Biogas produced is either stored for generating energy or moved on for treatment in a purification plant. The residual waste from the organic material is used for fertilisation.
- Thermal Gasification:
Thermal Gasification plants primarily use wood chips, straw, and seaweed or other marine algae. These materials are hermetically sealed in tanks and heated to very high temperatures. Oxygen or steam is injected to induce gasification reactions that produce biogas, which is collected and either stored for consumption or treated in a purification plant. Residual waste can also be used for fertilisation.
- Landfill biogas collection:
Landfill plants collect biogas that has been produced passively by waste products in landfills. Although not quite as productive as AD or gasification, these plants can still play a crucial role in cutting emissions by putting to use greenhouse gases that would have otherwise been released into the atmosphere. The biogas collected is used in the same way as biogas from AD and Thermal Gasification plants
Biomethane production plants
Biogas extracted from the methods outlined in the preceding section can be treated in a purification plant to produce biomethane. This production process includes concentrating methane to levels equal to that of natural gas (95% or over) and removing carbon dioxide along with other toxic gases and water vapour. Propane may be added to increase biomethane’s heating power (Calorific Value), and odorant applied to eliminate unpleasant smells.
Decarbonising the UK
Britain has more than doubled the number of biogas plants in operation since 2015. Currently, there are more than 640 AD biogas plants, 583 of which produce, use or export electricity; 42 of them produce and use heat; and 102 are used for producing biomethane for the national gas grid.
On the way to net-zero emissions, biomethane is of particular importance, as natural gas accounts for almost two thirds of domestic energy demand. According to a report commissioned by the Energy Networks Association, £109-122bn of investment is required to decarbonise Britain’s gas network by 2050.
Did you know?Surplus electricity generated by wind power that would otherwise go to waste can be turned into green gas through electrolysis. That gas can be stored so when there isn't enough wind to power the turbines it can be sent to a gas-fired electricity plant to keep lights on.
Green gas around Europe
Other European countries are investing in green gas production for their national energy mixes and in some cases for their export markets too. Learning and partnering with them may hold the key to improving Britain's energy independence and renewable energy production over the next decade.
- Germany relies on its green gas capacity to generate 1.7% of its renewable electricity. Additionally, 20% of fuel used by gas-powered green buses and lorries comes exclusively from sustainable green gas. Germany has the largest amount of green methane gas facilities in Europe, with almost 200 plants so far. This allows them to export green gas.
- Sweden has built several large-scale green gas facilities that use forestry residues, dung, wastewater and food waste as biomass for biomethane production. The biomethane produced in these facilities will be sent directly to Sweden's national gas grid for use in heating, electricity production and transport. Sweden is looking to green gas as a way to meet stringent air quality and emission reduction deadlines as part of its energy policy.