Power-to-gas: gas from wind and sun

Germany’s energy transition has almost doubled the share of renewables such as wind, biomass, solar and hydro in power generation in only five years between 2010 and 2015 from 17 percent to 32 percent. But, when it comes to providing a country with a safe and reliable electricity supply, there is more to it than generation alone. Electricity generated from renewable sources still has to be transported to the consumer and has to be stored in sufficient quantities to ensure a constant supply on still, foggy February days as well as on windy or sunny July days. Current battery storage technology is not yet capable of reliably storing large quantities of electricity over long periods.

One solution for storing large quantities of electricity over long periods is the idea of using the gas infrastructure, that is to say the gas pipeline system and underground storage facilities, for this purpose. This technology is known as power-to-gas. The process initially involves using electricity in an electrolysis process to break water down into its constituent parts of oxygen and hydrogen. While the oxygen is released into the atmosphere or used in industrial applications, for example, the hydrogen can be used in many different ways to act as a source of energy. It can, for example, be used as fuel for cars and trains, in which the combustion engine has been replaced by fuel cells, or limited quantities can be fed into the gas pipeline network. If, after electrolysis, carbon dioxide is added in a second step to convert the hydrogen into synthetic methane, the main component of natural gas, there is no limit to the amount that can be transported and stored in the gas infrastructure. The synthetic methane produced in this way has the same properties as conventional natural gas. It can therefore completely replace natural gas in all applications, from electricity generation and industrial processes right through to domestic heating.

The existing German gas pipeline network is already equipped for transporting and storing large quantities of energy. Its 500,000 km of pipelines already transport nearly 1,000 billion kilowatt hours of energy. Compared with the 540 billion kilowatt hours transported by the German electricity network every year, that is nearly double the transport potential, which we cannot afford to ignore. The gas infrastructure is also greatly superior to the electricity infrastructure in terms of its storage capability. While the theoretical storage range of the electricity grid is 0.6 hours, that of the gas storage facilities is 2,000 hours, which is nearly three months.

Open Grid Europe is ready for new tasks

So the gas pipeline system holds the answers to the most pressing questions of the energy transition. As an infrastructure operator, Open Grid Europe is prepared to become actively involved in helping to find these answers. However, at the same time politicians have a duty to further develop the existing legal framework in a way that will make power-to-gas economically viable by exempting this technology from the levies currently imposed by legislation. What is also needed are policies that enable infrastructure operators to realise the visions they already have and in this way maximise the potential benefit of the energy transition.

[April 2017]