‘Large-scale energy storage could be used early as 2030’
GUERNSEY could be using large grid-scale batteries to store energy as early as 2030 – despite the island’s draft electricity strategy stating they would not be ‘cost optimal’.
Alan Bates, chief executive of Guernsey Electricity, told the Guernsey Press there were two reasons why he thought they would need to play a role in the island’s energy transition.
‘When we produce too much from renewables, we might want to store it. Also, in the short term, it could stop us starting up the power station for very small increases in load, which we currently have to do,’ he said.
Mr Bates said that by the end of the decade Guernsey Electricity would need to change some of the large turbines at its North Side power station. But the replacement generators to be installed would depend on the final directions in the States’ electricity strategy.
Deputies will debate options presented in a policy letter from the Environment & Infrastructure committee when the Assembly next meets on 5 July.
Mr Bates said that if the States backed the option recommended by E&I – which includes a 60MW wind farm, expansion of solar power and an underwater cable link direct to France – the next generation of generators at the power station could require investment in battery technology.
‘The issue with storage is that it’s quite an inefficient process – taking it from being a kilowatt and then putting it into a very expensive battery and taking it back out,’ he said.
‘So if you create a kilowatt hour of wind, you want to try and use it immediately. Balancing that supply and demand is the optimal solution.
‘If it’s windy overnight, and we’re not using it, we can then store it. Then you could use it for when the peak comes the next day, where we want to try and augment that import capacity, and the local renewable capacity, with a little bit of local generation as well.’
A study by the German technology company Siemens, which underpins much of the draft electricity strategy presented by E&I, advised that energy drawn from a battery would cost approximately £200 per mega watt hour, whereas it is estimated that electricity generated from offshore wind would cost £86/MWh at today’s prices.
The Siemens report also highlights how hydrogen could play a part in energy production in the future, possibly even replacing diesel generators at the power station as technology develops.
It suggested that 47MW of electricity could be produced this way by 2040 – about a third of the generating capacity at the power station.
Mr Bates said the production of hydrogen from renewable resources could be considered as another form of battery, with excess electricity potentially used to extract gas from seawater before storing it in tanks until it is needed.
But he suggested that hydrogen was more likely to be produced from offshore wind rather than solar power.
