by Andrew Ward
Orkney, a sparsely-populated archipelago 10 miles off the northern tip of mainland Scotland, is not an obvious place to go looking for the future. Yet the windswept islands have become one of Britain’s foremost centres for innovation in renewable energy — including the use of hydrogen as a cleaner alternative to fossil fuels.
Orkney’s focus on hydrogen stems from its need for a way of storing energy from the islands’ prolific wind and tidal resources, which frequently generate more electricity than the local power grid can accept.
A range of public and community investors, from the EU to Orkney Council, have financed an electrolysis machine to turn surplus energy into hydrogen. The process works by splitting water into its component parts — hydrogen and oxygen — with an electric current.
The resulting hydrogen is stored as compressed gas to be used at a later date in fuel cells which reverse the electrolysis process to produce electricity. The power is used as a substitute for fossil fuels in ships docked in Kirkwall, capital of Orkney, reducing local pollution and carbon emissions.
“If we do not use [surplus wind and tidal power] it just blows or washes past so we may as well do something with it,” says Neil Kermode, managing director of the European Marine Energy Centre, based on Orkney.
“We’re trying to take energy out of the sea and use it for things like transport and heat.” The project is a small-scale example of the role which enthusiasts believe hydrogen can play in decarbonising the world economy. As wind and solar power generation rapidly grow as a share of global electricity generation, the problem of balancing intermittent output is becoming ever more acute.
Hydrogen has so far lagged behind battery technology in the race to become the dominant form of energy storage. Increasingly large batteries are being integrated into power grids to mitigate the volatility of renewable generation. The growing global fleet of battery-powered electric vehicles could also help balance supply and demand — if recharging is done when power is plentiful.
Yet, hydrogen has several advantages. Whereas batteries are heavy and require supplies of scarce lithium and cobalt, hydrogen is the lightest and most abundant known element in the universe. It produces nothing but water as a by-product when used to produce electricity.