Biogas – a healthy mixture of nature and the environment

At Terra Agrar AG, we want to play our part in the the energy transition and contribute to the energy mix.

As fossil fuel reserves dwindle, extracting them is becoming ever more expensive and harmful to the environment. For example, natural gas, oil and coal are extracted from underground reservoirs which are increasingly difficult to reach. The main problem, however, is that the use of fossil fuels leads to a very negative CO2 balance.

Production of electricity in cogeneration plants also releases CO2. The plants used for biogas need CO2 to grow, which means that CO2 from the atmosphere is naturally bound in them. In contrast to fossil fuels, there is no other waste that needs to be disposed of or pollutes the environment. Biogas is much better in terms of the environmental life cycle assessment, because the resulting CO2 is recycled.

Biogas is an environmentally friendly, renewable energy source

and unlike fossil fuels, it is not finite. We are fully aware that the production of raw materials for fuel can be in direct competition with food production. In Germany, however, we are sufficiently supplied with food, so we see it as an opportunity rather than a conflict.

We took up the challenge and built a biogas plant in 2007, which now supplies a flexible output of up to 1.9 MWel to the grid. We use the waste product – heat – for heating and for drying and preserving the agricultural products we harvest. Most of the renewable raw materials that feed the biogas plant, mainly alfalfa/grass and maize silage, come from our fields. The fermented residues are returned to our fields as valuable fertiliser to feed our crops. This creates a valuable circular economy.

Facts and figures about biogas and maize cultivation:

1. Together, Germany’s biogas plants produce electricity for 9 million households.

2. One hectare of maize supplies about 9,500 m³ of biogas, which generates about 19 megawatt hours of electricity. That is enough to supply around five three-person households with electricity for a whole year.

3. Together, these biogas plants reduce CO2 emissions by more than 21 million tons per year.

4. Biogas electricity stabilises the power grid and ensures a reliable basic supply.

5. Maize is a C4 plant, which means it can convert the CO2 that causes the greenhouse effect into biomass more effectively than other crops.

6. One hectare of maize can recycle the CO2 emissions produced by around 60,000 km travelled by car.

7. One hectare of maize generates the oxygen required for 50 to 60 people to breathe. The same area of woodland can only produce just under a third of this.

8. Fermented biogas slurry is an excellent fertiliser for plants.