A Düsseldorf, Germany-based energy company called Uniper announced last week that it sent methane made from renewable hydrogen into the local natural gas pipeline.

The methanation plant in Falkenhagen that made the synthetic methane opened in May 2018 (PDF), and the plant's operators began testing the process to combine renewable hydrogen with carbon dioxide from a nearby bioethanol plant.

The synthetic methane is sent into the local natural gas pipeline, where it's used along with traditional natural gas. "Today, the plant produces up to 1,400 cubic meters of synthetic methane (SNG) per day, which corresponds to approximately 14,500 kWh [kilowatt hours] of energy," a Uniper press release noted.

The methanation plant receives renewable hydrogen (H 2 ) from a nearby plant that has harnessed excess wind and solar power for electrolysis-based hydrogen synthesis since 2013. The renewable-hydrogen project is run with help from Store & Go, a European Union-funded research program that recently partnered with CO 2 -capturing startup Climeworks to build a synthetic methane plant in Troia, Italy.

Uniper's Falkenhagen-based methanation plant combines the renewable H 2 from Store & Go's nearby electrolysis plant with captured CO 2 from the nearby bioethanol plant, combining the two molecules to create methane (CH 4 ), the primary ingredient in natural gas. That process also creates heat as a byproduct, which is used at a nearby veneering plant.

A big advantage of this methanation project is that it can leverage existing natural gas infrastructure, allowing vehicles, residences, and other customers to indirectly use renewable energy for fuel and heat.

The problem with methanation is generally cost. Uniper didn't state how much its synthetic methane costs to make, but it is likely not competitive with the price of natural gas, even in Europe, where natural gas is not as plentiful as it is here in the United States. In the US, a methanation project such as this would undoubtedly be much more expensive than using traditional natural gas, at least in the absence of policy or a tax on carbon emissions.

An Austrian pilot plant

Austria's largest electricity supplier, Verbund, announced this week that it intends to build a pilot hydrogen-electrolysis plant next to the country's largest natural gas plant. Sunfire, a European low-carbon technology specialist firm that is helping Verbund build its pilot project, said in a press release that the project will test "the partial substitution of natural gas with hydrogen produced in a climate-neutral way."

As Austria plans a continued expansion of wind and solar power, the country is looking for ways to store excess intermittent energy for times when the Sun isn't shining and the wind isn't blowing. The Verbund pilot plant, called "Hotflex," will use electricity to drive a high-temperature electrolysis process to create H 2 gas. It's unclear if renewable energy from a specific source will be used in this process or if the pilot plant is simply taking electricity from an increasingly renewable-heavy grid.

However, the resulting H 2 "will be mixed with natural gas to drive the two gas turbines [at the natural gas plant] in a more climate-neutral manner," Sunfire wrote.

Hydrogen-enriched natural gas has been studied in recent years as a way to cut the carbon emissions associated with home heating and cooking. In 2018, a study in Sustainable Energy and Fuels suggested that, in the United Kingdom, natural gas could be enriched with up to 30 percent hydrogen without seriously increasing the risk of damaging burner phenomena called "flashback" and "blow-off."