Power to Gas - Overview
The share of electricity from renewable sources in the European electricity mix is increasing. As the power generation from wind and solar fluctuates, the match between renewable power supply and demand is becoming more challenging. At the same time, there are additional challenges to transmit the increasing volumes of renewable power from wind or solar farms to end users. The gas infrastructure can accommodate large volumes of electricity converted into gas in case that the supply of renewable power is larger than the grid capacity or than the electricity demand. As a result, power-to-gas (P2G) enables the share of renewables in the energy mix to increase, making this innovation an important topic in achieving a carbon-neutral gas supply in 2050.
Power-to-gas is the functional description of the conversion of electrical power into a gaseous energy carrier like e.g. hydrogen or methane. This technological concept is considered to be an interesting option for enhancing the energy transition.
P2G is of particular interest for the Europe as its on- and off-shore natural gas infrastructure is well developed. In addition, the combined generating capacity of offshore wind farms could reach around 100 GW by the year 2030, while the PV capacity installed is expected to increase from 35 GW in 2012 to almost 60 GW in 2020.
Power-to-gas could give substance to this.
1. Utilizing the excess power from intermittent sources (like solar and wind energy)
When the supply of power exceeds the demand alternative utilization of power is needed. In 2009 strong winds in Germany caused 71 hours of wind curtailment which resulted in economic damage in the order of a 100 million euro’s. Also UK grid operators paid millions of euros for shutting off wind power in the autumn of 2011.
2. Energy storage (both short term and seasonal)
Power-to-gas in combination with gas-to-power technology (like gas turbines, fuel cells, etc) enables storage of energy, either by a dedicated storage facility or by the gas grid. Power-to-gas in combination with electrification results in significant efficiency losses. Therefore, the energy that is captured in times of low economic value (excess / curtailment) should rather be utilized for heating in winter times or as feedstock for industry.
3. Long distance energy transport when the power transmission grid is inadequate
For the transportation of energy over long distances, for example in remote areas or cross country, the gas infrastructure can sometimes be better accessible than the power infrastructure. For instance, the North Sea has an existing gas infrastructure, which connects the offshore gas fields to the shore. These existing gas pipes could be used to accommodate gas from wind power.
Germany in particular is a showcase for power-to-gas for transportation distances. Since the energy turnaround in Germany the need for long distance energy transport arises. The existing power infrastructure might be unable to transport the energy from the northern area (large wind potential), to the southern, industrial area (where energy is needed). Since there is an existing gas infrastructure between these two regions with sufficient capacity, power-to-gas is considered.
4. Production of gas or chemicals from renewable sources as feedstock for industry and mobility.
A valuable synergy can be found between the integration of renewables and the chemical industry and mobility sector. When imbalance issues in the power infrastructure are solved by applying power-to-gas, the chemical industry and mobility sector can be fed by renewable hydrogen. In this way a win-win is created between the intermittent effects of renewables and that need for decarbonisation in the industry or mobility. Also dedicated installation of wind and solar parks for the production of a ‘green’ feedstock can be enabled by power-to-gas.