Biogas: an alternative to natural gas?

Dusseldorf Every newly installed heating system should be operated with at least 65 percent renewable energy from 2024, according to the federal government. Oil and gas heating systems still account for the majority of systems in German households. In the future, heat pumps operated with green electricity will replace boilers fired with fossil fuels.

But there is another option that, according to energy experts, promises great potential and could represent an alternative to fossil natural gas: biogas. We answer the most important questions about the energy source.

Biogas is an energy source that is obtained from renewable raw materials. This can be crop residues, leftover food, liquid manure and other agricultural products. The gas is created from the fermentation of these substances by breaking them down in an airtight reactor with the help of bacteria.

Maize is also suitable as an energy crop. However, this is controversial: In recent years, more and more areas have been planted exclusively with corn. These monocultures damage the ecological balance in the soil. They also take up land for the cultivation of other food and fodder crops.

>>> Read here: Sewage sludge, chip fat, liquid manure – How green fuels are made from waste

The majority of biogas plants are used to generate electricity and thus only reach a small proportion of consumers in the energy sector. “This is a good first step, but it is not enough to use biogas as a climate-neutral energy source on a large scale,” says Frank Gröschl, Head of Technology and Innovation Management at the German Association of Gas and Water.

Can you heat with biogas?

Conventional gas heaters cannot be operated with biogas because the methane content is too low. However, if the biogas is refined into biomethane, it can be fed into the gas network and used in conventional heating systems. A conversion is not necessary.

Technologies for upgrading biogas into biomethane are known and available. However, there are not enough of such systems in Germany, says Gröschl. “That’s wasted potential.” So far, only around 250 of the nearly 10,000 systems are connected to the natural gas grid.

How much does a kilowatt hour of biomethane cost?

In order to determine the costs, the prices for biomethane must be used.

The biomethane trader Agriportance shows the price development of biomethane on its website, broken down by source material. The data is based on information from biomethane traders, such as operators of biogas feed-in plants or bio-LNG liquefaction plants.

Farm with a silo in a yellow rapeseed field

According to Greenpeace, around 80 percent of the biogas is produced by energy crops such as maize, rapeseed and silphie.

(Photo: IMAGO/penofoto)

Assuming a seven-year supply contract starting in January this year, the market price for biomethane from manure such as manure in April was between 14 and 17 cents per kilowatt hour. That’s less than a year ago. In April 2022, a kilowatt hour cost between 18 and 22 cents.

Under the same conditions, the prices for biomethane from residues such as harvest waste are nine to eleven cents. Biomethane from renewable raw materials such as corn was cheaper in April at around eight cents per kilowatt hour.

Why are biomethane prices rising?

The price increase for biomethane is due, among other things, to the renewable energy directives RED II and III. They contain clear and narrow criteria as to which basic products are permitted to produce biomethane. Large-scale use of biogas plants such as corn is only possible to a very limited extent. Accordingly, the raw materials are limited to residues such as harvest waste and liquid manure.

At the same time, however, the demand for biomethane is increasing, not only in the field of building heating, but above all in the mobility sector. As a result, rising prices can be expected.

How much does a kilowatt hour of natural gas cost compared to biomethane?

Natural gas prices have fallen since January. The comparison portal Check24 measures 109 cases of gas price reductions in the basic supply, from which around 1.9 million households benefit. Compared to January 1, 2023, the saving is an average of 253 euros with a consumption of 20,000 kilowatt hours.

A family of four with a consumption of 20,000 kilowatt hours pays an average of 13.4 cents per kilowatt hour and 2680 euros per year in the basic supply, in an alternative supply around 10.4 cents per kilowatt hour and 2077 euros per year. The model household saves 603 euros a year when switching to the cheaper alternative. This means that the prices of biomethane and natural gas are similar on average under current conditions.

How is the demand for biogas and biomethane developing?

The almost 10,000 biogas plants in Germany currently supply almost ten million households. The Federal Association of Energy and Water Industries (BDEW) calculates that by 2030, 100 terawatt hours of biomethane could be generated in Germany and fed into the gas grid. This corresponds to about a fifth of the amount of natural gas that Germany consumed in Russian natural gas last year.

Due to the energy crisis and the ambitious goals of the federal government to operate newly installed heating systems primarily with renewable energy, the demand for biogas heat has increased in recent months, says Ingram Täschner from the Federal Association of Energy and Water Industries. The EU’s plans to further promote biomethane production have also boosted energy production from biogas.

How do you find a suitable biogas tariff?

The Biogas Association lists biomethane traders in Germany. Here you will find the current status of April 2023. The tariffs can either be requested by email or can be found on the websites of the companies.

More: Associations call for more biogas – “to replace Russian natural gas”

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