ULiege: ‘Belgium should store green electricity in gas’
A study from the Liege University proves the important potential of power-to-gas for Belgium. The technology transforms surplus green electricity into hydrogen or methane gas, which is easier to store and lasts longer than batteries. For the optimum CO2 reduction, that solution could store more than 100 GWh of renewable electricity by 2025.
“We’ve been working with Fluxys (gas network operator in Belgium e.n.) for almost a year now and most of the energy transition studies focus on electricity, while gas, which offers real storage possibilities, is neglected”, says ULiege scientist and professor, Damier Ernst.
The study, which is still going on, aims at creating a theoretical framework to develop the best tool for the optimal energy planning for 2025, both in terms of types of energy and storage.
The basic principle of that technology is simple. Surplus electricity produced by renewable energy is used to produce hydrogen (H2) through electrolysis of water (H2O). This gas can either be stored on its own – or be used in fuel-cell cars or fuel-cell plants to produce electricity – or it can be injected with CO2 to create methane (CH4).
That methane can be stored much more easily than hydrogen and it can power gas power plants, CNG cars or even be injected in the city gas network.
Audi is already producing what they call e-Gas in Werlte, Germany. This synthetic gas is used to power cars running on compressed natural gas (CNG), such as the g-tron range of Audi vehicles. The German plant has a production capacity of 6 MW.
+100 GWh storage capacity
The ULiege study took two basic cases. In the first one, the 2025 CO2 emissions stay at the same level as today’s emissions, representing a 40% reduction compared to 1990. The energy storage is therefore unnecessary and gas power stations can compensate the holes in renewable electricity production. The total cost is estimated at 4,62 billion euro per year or 51,5 euro per MWh.
In the second case, goal is to reduce CO2 emissions by 80% compared to 1990. Wind and solar power are being massively developed to a total capacity of 49 GW. Power-to-gas starts to show its advantages for Belgium.
93,9 GWh can be stored in hydrogen and 10,3 GWh in methane. When necessary, those gases are transformed back into electricity. Batteries also come into play with a storage capacity of 10,7 GWh. The total cost is estimated at 5,07 billion euro per year or 56,52 euro per MWh.
‘Important role in Belgium’
“To give perspective, the Coo turbine pump station can store 5 GWh of electricity, which is little compared to the potential of power-to-gas”, explains Fluxys spokesperson, Laurent Remy.
“Hydrogen can also be used in the industry to produce fertilizer and it can be injected at 2 or 5% in our gas network.” Although the transformation technology is rather costly – hydrogen production is estimated at 100 to 150 euro per MWh – it is still cheaper to store energy in gas than with batteries.
Off-shore wind farm
Fluxys is currently working with the Colruyt Group on an industrial plant that would transform off-shore wind farm electricity into hydrogen. “It is still in the study phase but we’re talking about a 25 MW plant that should be operational by 2020. It’s still too soon to promote it but we really believe in that technology”, ends the Fluxys spokesperson.
In Germany, TenneT, Thyssengas and Gasunie Deutschland have announced this month the construction of a 100 MW power-to-gas plant in the Ruhr region to be operational by 2022. Duch gas network, Gasunie, in partnership with French Engie will built a 100 MW hydrogen power plant in the north of Holland.