Verification
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Electric HeatingRead the studyHeating powered using electricity in Guernsey produces over 70% less carbon than oil heating and over 60% less than LPG gas liquified petroleum gas. This takes into account the entire lifecycle of each heating type, and for electricity this includes electricity generated using diesel generators at the Vale power station.
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Air Source Heat PumpsRead the studyAir source heat pumps are the cheapest and cleanest form of central heating system due to their high efficiency. They can produce around 90% less carbon emissions than oil or gas heating, and nearly 70% less than a traditional electric heating system. This refers to the entire lifecycle of each heating type, and for electricity includes electricity generated using diesel generators at the Vale power station.
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Electric vehiclesRead the studyIn Guernsey, most electric vehicles will produce around 73% less carbon emissions than a petrol vehicle and around 68% less than a diesel vehicle. These figures are calculated across the vehicle's entire lifecycle, and for electricity it includes production of the lithium-ion battery, top-up diesel generation at the Vale power station, and final disposal. Charging between 11pm and 5am will reduce an EV's carbon impact further.
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Appliance Carbon EmissionsRead the studyUsing some electrical appliances between 11pm and 5am could reduce your appliance carbon emissions by around 90%. This is because during quiet periods on the grid, we can rely 100% on our imported electricity which translates into a significant reduction in your carbon footprint simply by changing when you run certain appliances such as washing machines, dishwashers and tumble dryers.
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Power station peak timesRead MoreThe best time to use electricity in Guernsey is between 23:00 and 05:00. During this period, demand is low and the power station is not required to top up our electricity demand. When demand exceeds the 60MW renewable importation capacity, Guernsey Electricity will start a diesel generator at the power station. When demand exceeds around 70MW, a second diesel generator is required to meet demand.
We will do our best to ensure our marketing communications are in line with the Competition and Marketing Authority's Green Claims Code. If you believe any of our advertised material does not adhere to the key points mentioned, please let us know.
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The 'GEL Mix'Electricity in Guernsey is made up of a mix of sources. Annually this consists of over 90% imported hydro, wind and solar power, with the rest topped up by on-island community solar power and diesel-generated electricity from the Vale power station. -
Lower-Carbon ElectricityGuernsey imports 60MW of lower-carbon electricity from the European grid. -
Fossil-Fuel GenerationWhen islander's demand exceeds 60MW, the power station is required to start up a diesel generator to supply the electricity required. At times when demand exceeds 70MW, a second generator start-up is required. -
Peak DemandElectricity demand follows human behaviour and peaks at certain times. The common peak times are 8am, 2pm and notably 6pm, when most stress is placed on the power station. During a typical summer, demand remains below 60MW and the power station is not required to top up our electricity demand.
Electric Heating
Cleaner, greener heating that doesn't cost the earth
Carbon intensity of heat sources available in Guernsey as of 31 December 2021
This table reflects the grams of carbon dioxide present per kWh in the fuel ('Fuel'), and the quantity after use in a property's central heating system ('Usage') based on an assumed efficiency for a new boiler or heating system.
Why are there two figures?
1. The figures in column 1 represent the grams of carbon dioxide equivalent present in the fuel source before it is used in the home.
2. Column 2 demonstrates the impact boiler efficiency has on the carbon intensity of each fuel type and for the purposes of comparison, this table assumes each heating system is new.
Efficiency
Gas, oil and HVO boilers will always be less than 100% efficient and this efficiency will be reduced as the boiler ages. As efficiency decreases, the carbon intensity increases because more fuel needs to be burnt to produce the same level of heat.
Electric boilers are practically 100% efficient and remain so throughout the heating system's lifetime as the 'fuel' (electricity) arrives ready to use
Air source heat pumps are powered using electricity, however the mechanism within the system converts cold outside air into heat. As the refrigerant gas inside the system boils at a very low temperature, air source heat pumps can achieve a 300% efficiency provided the property is well insulated.
Electricity Mix
This consists of diesel-generated electricity at the Vale power station, on-island community solar power and imported renewable energy.
Lifetime Intensity
These carbon calculations for heating consider the entire energy production chain.
This includes exploration, extraction, processing, storage, transport, transformation into secondary fuels, final use, and disposal.
The Guernsey Electricity's mix for the emissions intensity of GEL's electricity includes an assumption based on the proportion of electricity generated by each energy source (oil and renewable imports).
*References: GEL sought independent advice from UK Carbon Emissions Specialists, WSP, in identifying the IPCC figures used in this note.
This is short for carbon dioxide equivalent.
CO₂e is a way to describe the overall contribution to global warming when taking into account the carbon dioxide (CO₂) as well as other greenhouse gas emissions, such as methane and nitrous oxide.
Air source heat pumps
The cheapest and cleanest way to heat a home in Guernsey
Carbon intensity of heat sources available in Guernsey as of 31 December 2021
This table reflects the grams of carbon dioxide present per kWh in the fuel ('Fuel'), and the quantity after use in a property's central heating system ('Usage') based on an assumed efficiency for a new boiler or heating system.
The air source heat pump system is powered using electricity
are powered using electricity, however the mechanism within the system converts cold outside air into heat. As the refrigerant gas inside the system boils at a very low temperature, air source heat pumps can achieve a 300% efficiency provided the property is well insulated.
Why are there two figures?
1. The figures in column 1 represent the grams of carbon dioxide equivalent present in the fuel source before it is used in the home.
2. Column 2 demonstrates the impact boiler efficiency has on the carbon intensity of each fuel type and for the purposes of comparison, this table assumes each heating system is new.
Efficiency
Gas, oil and HVO boilers will always be less than 100% efficient and this efficiency will be reduced as the boiler ages. As efficiency decreases, the carbon intensity increases because more fuel needs to be burnt to produce the same level of heat.
Electric boilers are practically 100% efficient and remain so throughout the heating system's lifetime as the 'fuel' (electricity) arrives ready to use
Electricity Mix
This consists of diesel-generated electricity at the Vale power station, on-island community solar power and imported renewable energy.
Lifetime Intensity
These carbon calculations for heating consider the entire energy production chain.
This includes exploration, extraction, processing, storage, transport, transformation into secondary fuels, final use, and disposal.
The Guernsey Electricity's mix for the emissions intensity of GEL's electricity includes an assumption based on the proportion of electricity generated by each energy source (oil and renewable imports).
*References: GEL sought independent advice from UK Carbon Emissions Specialists, WSP, in identifying the IPCC figures used in this note.
Electric Vehicles
Driving forward a cleaner future, today
Carbon intensity of vehicle sources available in Guernsey as of 31 December 2022
This table reflects the grams of carbon dioxide present per kilometre in the fuel ('Fuel').
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Cost to driveVehicle cost calculator
How much does my vehicle cost to run?
We've provided our customers with an online calculator to help them understand the cost of driving a vehicle in Guernsey. True cost should be considered in both in monetary terms and carbon impact.
These calculations are based on a number of assumptions and should be used as a guideline only.
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Why charge between 11pm and 5am?Off-Peak UsageWhy charge an EV between 11pm and 5am?
Where possible, the best option is to set the electric vehicle's on-board timer to start charging the vehicle between 11pm and 5am as this is the cheapest* and cleanest time to use electricity.
Even during winter, the power station is not required to top up demand on the network and means the carbon footprint of EV drivers can be significantly reduced simply by changing when the vehicle is charged.
*Cheaper for customers on the Super Economy 12 Tariff
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Vehicle Study DefinitionsRead the study
Vehicle Lifetime
184,000 km was assumed as an average lifetime usage of a car, based on estimates from literature available for the study.
Electricity Mix
This consists of diesel-generated electricity at the Vale power station, on-island community solar power and imported renewable energy.
Lifetime Intensity
These carbon calculations consider the emissions generated across the entire energy production chain.
The Guernsey Electricity's mix for the emissions intensity of GEL's electricity includes an assumption based on the proportion of electricity generated by each energy source (oil and renewable imports).
*References: GEL sought independent advice from UK Carbon Emissions Specialists, WSP, in identifying the IPCC figures used in this note.
What stages were used in the vehicle study?
Production
Emissions generated during the production of all 3 types of vehicle. This includes producing the lithium-ion battery, together with raw material extraction and processing.
Operation
This includes exhaust pipe emissions from the combustion of petrol/diesel, emissions produced from generating electricity*, vehicle maintenance and well-to-tank (WTT) emissions.
*this includes electricity generated at the Vale power station. Electricity in Guernsey is made up of over 90% imported renewable energy – a mix of solar, wind and hydro power – with the remaining demand topped up by electricity from the power station.
Maintenance
The carbons emissions generated from maintenance work to keep the vehicle in good working order.
End-of-life
This is when the vehicle, its part and components become waste and needs to be dismantled and disposed of.
This EOL figure is an average of several studies which also take into account battery recycling aspects.
Well-to-tank (WTT)
WTT specifically refers to the journey of the fuel used in the vehicle, from extraction (well) to final use in the petrol or diesel vehicle (tank).
Our study used data taken from a scientific publication which reviewed and consolidated the results from many lifecycle emission assessments on different vehicle types.
As the battery reclaim process develops, and when there is a stable supply of used batteries to reclaim, it is likely that the End-of-Life (EOL) impact of electric vehicles will significantly decrease in the coming years and further reduce the full lifecycle impacts of electric vehicles.
EOL emissions were discerned from the review paper Review and Meta-Analysis of EVs: Embodied Emissions and Environmental Breakeven (Dillman et al 2020). The review highlights inconsistency in data regarding emissions from the end-of-life stage and battery replacement; it asserted that this was because of a lack of available data on recycling technologies and their success as EVs have only relatively recently entered the mass market and many are yet to reach end of life. The EV EOL emissions factor is the mean average of the meta-analysis of a range of EV lifecycle assessments, of which a few of these studies included recycling aspects.
Advertising campaigns
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Work it 9 to 5Verification Letter
This is an advertising campaign run by our sub-brand Electric Living to encourage electricity customers to consider switching some of their electricity usage to between 9pm and 5am while the power station is still being used during early 2022.
Frequently asked questions
We've answered some of the questions asked about electricity in Guernsey
We need to have a secure supply and 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 for a sustainable supply.
Importing electricity today is the bridge to tomorrow's technology and will enable more local renewables. A second cable also opens up the opportunity to sell electricity to Europe.
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.
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.