The cost of producing hydrogen from renewables must be reduced if the gas is to fulfil its potential as the fuel of future mobility. Academics from the Centre for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) have been working hard with industry partners to find out how this can be achieved through a power-to-gas (PtG) plant in southern Germany. Much has therefore been riding on the first quarter results of the megawatt plant in Grenzach-Wyhlen, which opened in December 2019.

After four months of operation, the plant (which has an electrical connection capacity of 1 MW) has proven highly efficient in producing high grade green hydrogen, using electricity from the Rhine hydroelectric power plant. There are several advantages of producing hydrogen in this way: it is available around the clock (unlike solar or wind power), there are no grid fees and it is exempt from the EEG levy. The savings mean that the price of the green hydrogen comes down significantly.

In terms of output, over a period of 1,800 operating hours 60 trailers were filled with high grade, fuel cell compatible hydrogen (each containing around 300 kilograms). The plant is capable of producing 500 kilograms of the gas per day – enough to power the average daily use of 1,000 fuel cell passenger cars. Furthermore, the overall efficiency of converting electricity to hydrogen is currently up to 66 percent in relation to the calorific value of the gas.

There are other innovations taking place at the PtG in a research capacity. For example, electrolysis blocks are being developed with a maximum output of 300 KW which will further reduce the cost of hydrogen. The team at ZSW’s ultimate goal is to halve the cost of producing green hydrogen through this and other projects. The state of Baden-Württemberg is funding the PtG plant with a total of EUR 4.5 million.