Basics of biogas: Some interesting facts

By now, it is evident to all that we need a concrete long-term solution for the food waste management problem. Carbon emissions continue to rise, accelerating the path towards climate change beyond the point of no return.

In this regard, many have hailed biogas as the ideal alternative energy source, one that uses up organic waste and minimises carbon emissions.

Derived from plant and animal matter, biogas forms as a by-product of the anaerobic digestion process and can happen naturally or due to an industrial process.

Biogas has, in fact, been used as a fuel for centuries and has multiple innovative applications. Let us take a closer look at what makes it so interesting.

Biogas is a gas of many names

The most common name that biogas is also known by is biomethane. Other names include swamp gas, marsh gas, compost gas and sewer gas. However, biogas is not the name of natural gas — a common confusion. Natural gas is a non-renewable energy source. In contrast, biogas comes from the plant and animal materials and is thus renewable.

Biogas has been around for a while

The phenomenon by which organic matter decays and releases biogas has been happening for millions of years, well before humans came along.

It is the way nature recycles its resources, and today’s industry-level biogas production is simply accelerating that recycling process to benefit human needs.

The earliest recorded human use of biogas dates back to around 3000 BC, when the Assyrians used it to heat their baths.

In the 17th century, chemist Jan Baptist van Helmont first discovered that decaying organic material released flammable gas.

The application of anaerobic digestion as a way to treat municipal wastewater (before chemical treatments) and as an inexpensive fuel source for developing regions has long been acknowledged and put to good use. As far back as 1859, an anaerobic digestion plant was set up in a Mumbai leper colony.

Biogas versus biomass

Two others that get confused often are biogas and biomass. Both are biofuels, and both generate energy when burnt. Biomass, however, refers to the solid organic material itself, such as plant and animal remains.

Humans have been using it as a fuel source for thousands of years, and many power plants today use biomass in the form of compressed wood pellets as a renewable source of energy.

On the other hand, biogas is the gaseous matter formed when biomass is subjected to anaerobic digestion in a special digester or even when organic matter disintegrates on its own. Biogas, essentially, is the end product, while biomass is the raw material.

Biogas is mostly methane.

Yes, that is correct! Let us do the math:

About 97% of biogas is methane, a highly flammable gas that is ideal for energy production as well as household cooking and heating needs.

Biogas has its by-product, a methane-rich fertiliser, that can boost farmland yields or be sold for profit. The other 3% consists of trace amounts of other gases.

China leads in biogas production.

About 50 million Chinese households use biogas for their daily fuel needs, mostly in rural areas. Also, biogas was used to fuel the torch lit at the 2008 Beijing Olympics. There are 118 biogas plants currently in production in the UK.

The UK got its first biogas plant in 2011 under the Renewable Heat Incentive scheme, with the trend picking up in 2016 when 33 new plants were built, according to Anaerobic Digestion and Bioresources Association (ADBA).

A Somerset dairy farm took an interesting step in 2016 by plugging its biogas production directly into the national biogas transmission system. The US is further along in biogas production, with about 2200 biogas plants across 50 states.

Households generate most of the UK’s food waste. In 2020, they were responsible for 4.5 million tonnes of edible food waste in the UK.

Christmas food waste is enough to heat 25,000 homes with biogas.

According to WRAP, the UK generates about 10 million tonnes of food waste every year. And during Christmas alone, the volumes of roast vegetables, Christmas puddings and mince pies leftover amount to about 270,000 tonnes.

If subjected to anaerobic digestion, this food waste could generate about 300 GWh of biogas, powering around 25,000 homes and reducing carbon dioxide emissions by about 236,000 tonnes. And if all of the annual 10 million tonnes of food waste were turned into biogas, it could reduce emissions by about 8.8 million tonnes.

Realise the total value of biogas

Biogas has been gaining considerable attention as an alternative fuel source. You see, the primary use of the biogas is conversion-to-renewable energy through the integral CHP unit, which outputs electricity, heat, and hot water.

Equipped with a load buffer system sized to accommodate, our iD-R-5K compact AD system converts organic matter into biogas which can be deployed in several ways.

The post-process digestate is extracted from the system via a pasteurisation module, resulting in a PAS110-compliant organic fertiliser suitable for land application. This can be as a single component or as a two-component output (dry and liquid).

The whole process is automated and designed to operate continuously and be integrated with your existing infrastructure to maximise efficiencies and processes with minimal operator input. If you would like to know more about our systems, please email us at

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