The remote and exposed Scottish islands are a potential source of abundant wind power as well as other resources such as solar and marine energy.
With the ability to generate more power than can be accommodated into the network, alternatives such as storage are needed to limit curtailment and optimise both the generation and economic potential. Another related option gaining increasing support in these islands is hydrogen. Orkney is most advanced with a strategy and several projects under way and the Western Isles and Hebrides also are investigating various options including hydrogen power for ferries.
Now the Shetland Islands are planning to tap the hydrogen economy, with the recently completed 4.5MW Garth windfarm on the island of Yell having the potential to generate enough energy to make the concept viable.
Commenting that Shetland experiences curtailment levels of 20-25%, Shetland Islands Council local heat Officer Sean Haughey told Engerati that while the hydrogen production potential can’t be divulged due to the status of project development, “if we went full scale, I can tell you it would be the largest renewable hydrogen producer in the UK.”
The initiative, a combined venture between the Shetland Islands Council and North Yell Development Council, is anticipated to start with a small test electrolyser to produce the hydrogen and oxygen as the other by-product but at a level of only a fraction of the total capability of the turbines.
“We are currently evaluating a number of loads that could be met with the produced hydrogen,” Haughey says. “Providing heat to schools and care homes as well as providing shore power to our ferry fleet are two of the more promising areas we are investigating.”
Ferries are key for contact between the islands and the mainland and issues that need to be addressed include the storage and handling of hydrogen at ferry piers.
Haughey comments that tenders are expected to be released within the next few months. He also is positive in the expectation of receiving support for the initiative through a UK government ‘islands deal’, saying that a “large pot” is expected which is intended to benefit all the islands rather than any one island group and that some is likely to go towards hydrogen development.
The role of hydrogen in decarbonisation is an open question at this stage and it tends to get overshadowed in the energy sector by the traditional renewables and in transportation by battery power.
However, the International Renewable Energy Agency (IRENA) believes that hydrogen could hold the key to a low carbon future, providing a viable option to reduce the carbon emissions produced by around one-third of the energy sector which is currently not economically feasible and supporting higher shares of wind and solar energy with the excesses directed to its production. Hydrogen also offers the possibility of tapping high quality renewables, which often are located far from end users as it can be transported unconstrained by grid connections. In addition, it can take advantage of existing infrastructure by being injected into the gas grid.
A study from Northern Gas Networks found that converting the UK gas grid to hydrogen has the potential to provide “deep decarbonisation of heat as well as transportation and power generation” corresponding to around 80% of the country’s remaining 2050 reduction target. Under Northern Gas Networks’ proposal, over 3.7m homes and 40,000 businesses and industries in the north of England that are currently heated by natural gas could be converted to hydrogen by 2034 with a further 12m homes following by 2050.
The UK Committee on Climate Change also has highlighted hydrogen as a credible option to help decarbonise the UK’s energy system. However, it believes that hydrogen heating as well as heat pumps face significant challenges to ensure public acceptability.