ENTSOG TYNDP 2017 - Main Report

7.4.2 POWER TO GAS

Power to gas (P2G) is the name for technology and process that converts electrical power into a gaseous energy. Through this process, the excess production of renew- able electricity which would normally be curtailed can be used to produce hydrogen by electrolysis. This technology is considered an important element in turning sys- tem and sector coupling into a reality  1) . This could offer a solution to the challenges of balancing electricity production and consumption, especially in a world of increased intermittent renewable generation, and offers a highly flexible means of renewable energy storage. Although using this hydrogen to generate electricity involves further efficiency losses, there are other uses which avoid this, such as the use of hydrogen as fuel for transport. P2G does not only offer the possibility to store renewable energy but also to trans- port it over long distances by using the gas transmission network, saving costs to the European energy system by utilising the existing infrastructure.

Hydrogen generation

CURRENT

CURRENT

Power grid

Wind energy plants

HYDROGEN

CURRENT

VARIABLE MIXING

HYDROGEN

Mixing valves

combined heat and power units

Hydrogen storage

HYDROGEN

WARMTH

BIOGAS

District heating

Biogas storage

Fuels

Figure 7.2: Example of P2G filling station installation (Berlin 2011) (Source: Enertag 2013)

As Hydrogen changes the quality of natural gas and has an impact on the heating value, there are currently doubts and restrictions on the hydrogen percentage that can be injected into the gas grids. However, there has been intense research  2) aim- ing at defining optimum injection rates and identifying measures to make current gas infrastructure fit for hydrogen. On top of this, there is the option to combine the hydrogen in a second step with CO ² by a methanation process, producing synthetic methane that can be injected easily into the natural gas grids, and used in any gas application e. g. as heating energy in modern hybrid systems or as a fuel for trans- port. As CO ² is also retained from other sources, the synthetic methane is carbon neutral. P2G as a green energy storage could make an important contribution to the energy transition.

2010 2011 201

 1) http://etogas.com/fileadmin/documents/news/2015_Fraunhofer_ISE_Study_PtG.pdf  2) http://www.dbi-gruppe.de/hips-net.html

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