The first industrial power-to-gas plant is ready-made

BERN – Switzerland’s first industrial power-to-gas plant opened today in Dietikon (ZH). It will be operational in mid-May and will be able to provide about 18,000 megawatt-hours annually of synthetic gas produced from renewable energies in addition to savings in CO2 emissions of up to 5,000 tons.

Energy to Gas technology allows surplus electricity produced by solar, wind or hydraulic plants to be stored in the form of methane (synthetic natural gas) or hydrogen. When more electricity is produced than is being consumed, it is possible to store the surplus for the long term through methane production. This makes it possible to transfer large amounts of energy from renewable sources from the electricity grid to the gas grid for greater flexibility in terms of time and space.

The Ditikon plant, which costs 14 million francs, produces gas from waste and waste water. It is managed by the inter-municipal corporation Limeco, which has a sewage treatment plant, a waste recycling plant and a local heating network in the Limmat Valley. Excess electricity from burning waste and carbon dioxide (CO2) from sewage gases is used to produce methane.

With the process of electrolysis, through the passage of electric current in water, hydrogen (H) is obtained. This is in turn converted to methane (CH4) in a bioreactor which combines it with carbon dioxide from wastewater treatment. The obtained “green” gas, which has the same chemical composition as natural gas, is then fed into the supply network.

Gas is easier to store than electricity. With a so-called power-to-gas (power-to-gas) plant, electricity can be stored as gas in the summer for use in the winter, when demand is higher, Limeco’s managing director explains. Patrick Al Fossi was quoted in a press release issued today on the occasion of the opening.

If there is an oversupply in the summer, when power grid operator Swissgrid asks market participants to reduce energy input, it is currently still “burned out” in the Limeco cooling towers.

Feusi then points out that Limeco doesn’t want to make anything of gas production. It is sold at cost so as not to artificially inflate the price. The goal is to show that the technology works and that it can be profitable from an industrial point of view, that is, the costs are covered without subsidies.

Limeco launched the project in 2020 in partnership with eight energy suppliers, who have pledged to purchase gas for 15 years. The other partner is Swisspower, an association of dozens of municipal and regional companies, of which Limeco itself is a part. At the end of March, the gas was first introduced into the network for testing.

There is no comparable plant in Switzerland that is based on the principle of energy to gas and is as large as the Dietikon plant. According to Thomas Baer, ​​a consultant to Swisspower, it is unlikely that the idea will be copied from other waste incinerators in the near future. He points out that in a market where electricity prices are skyrocketing, converting electricity to gas is not the obvious thing to do. But if the extension of solar power plants in Switzerland continues as planned, and there is a regular excess of supply in very sunny periods, especially in the summer, this could change.

Switzerland already imports electricity from neighboring countries in the winter. And by 2025, according to regulator Elcom, there may be a shortage of cold season. The Federal Council’s 2050 Energy Strategy plans to replace nuclear electricity with solar, hydroelectric and wind energy.

Electricity prices had already risen significantly last year, and exploded to unprecedented levels in the aftermath of the war in Ukraine. Now gas prices have skyrocketed.

keystone-sda.ch / STF (ENNIO LEANZA)