One of the most rewarding aspects of being a 100% green energy supplier is knowing that we are supporting independent businesses around the UK. Many of our generators have an inspirational story to tell and we are proud to be part of it.

We visited dairy farmer Stephen at his farm in Norfolk to find out what inspired him to invest in an anaerobic digester (AD) and why his zero-waste approach to farming is so important.

What is biogas?

Biogas is a green and renewable energy source. It can be used to generate electricity, fuel vehicles and also injected into the gas grid in the same way as fossil-fuel generated gas.

How is biogas made?

Biogas is made from natural, organic matter such as plants, food scraps, manure and other agricultural waste.

The first stage of producing biogas is for the waste to be broken down into a slushy mix called ‘feedstock’.

Anaerobic digestion is a process similar to what happens inside the stomach of a cow when digesting food. The biowaste is heated to a similar natural body temperature of 37 °C. In the case of Stephen’s AD, he uses the waste heat from his electricity generator to maintain the correct temperature.

An anaerobic digester is a sealed tank that starves the feedstock of oxygen. This allows the right bacteria to exist and breakdown the waste into simple chemicals and carbon dioxide, which another type of microbe, the Archaea, then turn into methane. This happens over the course of around 8 weeks.

Biogas is produced from renewable, natural organic material, which creates a mixture of methane and carbon dioxide. This gas is prevented from being released into the atmosphere so even the process of creating it is environmentally friendly.

The biogas is fed into an engine where it is burnt - this process drives a generator which produces renewable electricity. This does produce some CO2 but because it has been captured from the atmosphere recently, it is just being recycled, unlike fossil fuel CO2 which adds to the load in the atmosphere. This means that it is far kinder to our planet than fossil-fuel generated electricity.

Can biogas be put into the gas grid?

Biogas can be upgraded to become biomethane which can be used to heat our homes in the same way that natural gas can be. The process involves removing the carbon dioxide, hydrogen sulphide and any moisture.

At 100Green we only supply gas created in this way. We do not supply fossil fuel generated gas.

Biogas comes from natural waste that was created recently and will be replaced – after all humans and animals will always create waste. The whole process of anaerobic digestion takes approximately 3 weeks. Whereas using fossil fuel generated energy causes damage to our planet because we are extracting material and gas made millions of years ago – which can’t be replaced.