We used to rely on our fossil-fuelled power station for ALL our electricity. Now the 60MW subsea cable connecting us to Europe is our primary source of electricity. This has delivered a 37.5% decrease in Guernsey's emissions from 1990 levels.
But we still have some way to go before Guernsey is net zero.
We used to rely on our fossil-fuelled power station for ALL our electricity. The 60MW subsea cable connecting us to Europe is now our primary source of electricity. When our demand exceeds 60MW, we have to make up the difference by using the fossil-fuelled power station. This comes with environmental and financial costs.
Phasing out petrol vehicles and fossil fuel heating, means the phasing in of electric-powered alternatives. At the moment, this would mean using the power station more. How should we meet this demand?
Whilst one of the more advanced technologies, the intermittent nature of solar energy (only generates in the day) limits the reliability. On very sunny days, Guernsey would generate too much, so we would need batteries or to ability to export via a subsea cable.
To provide 70 Megawatt (MW) of electricity from solar, 175,000 solar panels are required and each MW requires about 2.5 acres of space.
Wind energy is commercially viable, and research has shown a promising local resource for an offshore development. Consideration would be needed around impacts to the environment, fisheries and shipping for example. The fluctuation in wind would require battery storage or a second subsea cable to export energy.
Technology is still developing, and waves are an unreliable and unpredictable energy source.
Research has identified three potential locations but there are no technologies which are at a commercial scale.
Tidal energy is predictable, and we have one of the largest tidal ranges in the world which could be harnessed via tidal stream, barrage or lagoon. The local potential has been investigated but there are limited installation sites. It is expensive, there are environmental impacts and the power produced does not always match up with energy demand. Battery storage or a second subsea cable would be needed for when supply exceeds demand.
Generating from the power station is dependable, but significant upgrades are required imminently. As one of the most carbon emitting sources, it brings significant financial and environmental costs, threatening our ability to meet net zero.
A 100MW cable would provide enough electricity for the island and allow for the decabonisation of heating and transport in Guernsey, meaning the power station would no longer be required.
It would also provide the security to enable more local renewables and the ability to export and sell any excess energy.
The scale required to give security of supply for our Island is large and costly. For example, in the Winter, it would take around 10 days to recharge the batteries using solar and these would only provide enough electricity for 24 hours.
‘Guarantee of Origin’ certificates (GoO’s) are the current market mechanism for driving investment in renewables. We are using our market power to drive investment to the right places. By increasing the demand for renewable and sustainable electricity, we reduce the investment into fossil fuels. The more communities that make this same choice, creating more demand for energy from sustainable energy sources, the more generators will invest in these technologies.
Local renewables alone cannot provide the electricity we need today, let alone in the future. Using a mix of sources will offer reliability and security. This isn't a choice between subsea cable or local renewables.
The import cable alone does not meet the islands electricity needs when energy demand is at its greatest. The GJ1 cable can provide 100% of Guernsey’s energy needs in summer and around 75% in winter, so the power station is still required as both a top-up for the winter peak periods and as a back-up when the GJ1 interconnector requires to be switched off for maintenance.
Guernsey Electricity’s long-term strategy is for an energy system that supports renewables and reduces the reliance on fossil fuels to use the power station for emergency generation only.
This second cable would mean that the power station will no longer need to ‘top-up’ supplies and will act purely as a ‘back-up’ for emergencies.
This is becoming commercially viable, but at the moment it is not affordable for the island. The potential for exploiting Guernsey’s tidal range was investigated at Cobo Bay, Havelet Bay, Victoria and Beaucette marinas but the outputs and generation were initially too small to justify further investigation.
Over 80% of our streetlights are now LED or use energy efficient bulbs. Our systems automatically turn the lighting on and off at dusk and dawn in busy areas such as St Peter Port and main road junctions. Where safe to do so, lamps are turned off at midnight or 1am to save energy.
Smart street lighting systems are becoming more common around the world and we are keeping a close eye on developments to see if this technology could be used in Guernsey.