Australia has begun a $15m trial to convert solar and wind power into hydrogen gas. It is one of a number of trials launched or being considered around the world to transform renewable energy into hydrogen.
Wind turbines and solar panels can generate more electricity power than the grid can take. One solution is to convert the electricity to hydrogen gas, which can then be stored for use across a natural gas network. The Aussie hydrogen project, developed by energy company Jemena and co-funded by the Australian Renewable Energy Agency, uses existing gas pipeline technology to store excess renewable energy as hydrogen gas for weeks and months, making it more efficient than batteries.
Jemena says the H2GO project will involve a 500kW electrolyser, which will generate enough hydrogen to power 250 homes. Jemena’s New South Wales gas network delivers gas to 1.3m customers. ‘Electrolysers are more expensive per unit of power than batteries. That makes hydrogen more expensive to make than putting electricity into a battery,’ says John Barton, renewable energy expert at Loughborough University. ‘However, once made, it is cheaper to store hydrogen than to store electricity in a battery. Batteries are quickly full, but lots of hydrogen can be put into storage in a high-pressure tank at lower cost.’
The main hurdles with hydrogen power today are the limited infrastructure and expense. ‘The biggest cost is the electrolysers, which are currently produced in small numbers and high cost [which] has to fall for hydrogen to be really affordable,’ says Barton. Most household equipment is not yet set up to utilise 100% hydrogen, he points out. ‘If a small percentage of hydrogen is injected into the natural gas grid, typically up to 3%, the gas network can cope well with no modification. Up to about 15% of hydrogen, small modifications are required. Beyond that, the modifications get more expensive.’
Germany has been researching power-to-gas for some time, he continues, with the city of Hamburg using some electrolytic hydrogen in its gas grid since 2015. Germany also hosts an electrolyser supplying hydrogen to Shell’s Rhineland refinery, which was announced as the largest of its kind in the world in January 2018. The refinery usually uses hydrogen produced from steam reforming from natural gas.
‘The UK is considering converting its gas grid to hydrogen, but the plan is to make hydrogen from natural gas while burying carbon dioxide,’ Barton notes. ‘The city of Leeds was used as a case study, but the plan is not yet implemented.’