Carbon dioxide emission intensity

Carbon dioxide emission intensity is defined as the level of emissions, relative to each operating unit, e.g. unit of produced energy, income, and other indicators relevant to the operation.

ON Power produces electricity for consumers, as well as hot water, which is sold wholesale to Veitur Utilities. Carbon emissions per unit of electricity and hot water at ON Power Plants have increased since 2016 and are now 7.6 g of CO₂ equivalents per kWh. Proportionate reinjection of carbon dioxide at the Hellisheidi Geothermal Power Plant was approximately 26% in 2022. Malfunctions in the air abatement unit, temporarily reduced the injection capacity by half or completely. An improvement process has been initiated to increase the unit's reliability and equipment has been purchased to reduce repair times, please see figure and table below. Operations at Hellisheidi and Nesjavellir Geothermal Power Plants are carried out under a scheme that aims for a zero-carbon footprint in 2025 and 2030, respectively. This means that 95% of the carbon dioxide emitted from the power plants, will either be captured and stored, or utilised, please see graph in chapter E1 Greenhouse Gass Emissions.

It should be noted that the emissions uncertainty is +/- 12% compared to the 95% uncertainty range.

Veitur Utilities distribute electricity and hot water to consumers, process and distribute potable water, as well as managing the sewerage systems. Veitur Utilities' water utility, district heating, electricity utility, and sewerage systems have increased their carbon emissions since 2016. The carbon footprint is primarily controlled by the need for investment, since the largest emission is caused by the fuel consumption of contractors. Veitur Utilities have prioritized projects to reduce these emissions, as well as supporting energy shift at construction sites and assessing and reducing the carbon footprint of utilities.

Reykjavik Fibre Network's data transmission has increased its carbon emissions per unit data transmission due to construction work 2022. Reykjavik Energy Group's activities do not emit any ozone depleting substances.

*Carbon footprint of low-temperature geothermal fields has been rated as approximately 0 g/kWh.

**According to the Environmental Agency's guidelines on emission factors (5th edition 2022) on the agency's website, the weighted average of greenhouse gas emissions per kWh of electricity produced with hydropower, geothermal and fossil fuels in Iceland in 2021 is 10.3 g. For hydropower, greenhouse gas emissions per kWh of electricity are 1.5 g and for geothermal 30.5 g. It should be noted that in the Environment Agency's calculations, all emissions from geothermal energy are transferred to electricity production, but none to hot water. However, OR allocates emissions to both media according to energy content allocation, which is a recognized method according to the GHG Protocol.

Hydrogen sulphide emission intensity

The hydrogen sulphide emission intensity from each produced kWh at the Hellisheidi Power Plant has been reduced since 2015, or from 6 g per kWh to approximately 0.6 g, and at the Nesjavellir Power Plant from 4 g per kWh to approximately 2 g.

The emissions of hydrogen sulphide from Nesjavellir and Hellisheidi Geothermal Power Plants amounted to 8.7 thousand tons in 2022. The concentration of hydrogen sulphide (H₂S) in populated areas exceed limits two times in 2022. Despite systematic cleaning and reinjection of hydrogen sulphide from the Hellisheidi Geothermal Power Plant in 2022 it was not possible to keep the concentration of hydrogen sulphide below the limits throughout the year. Proportionate reinjection of hydrogen sulphide from the plant was approximately 73%, which is a little less than previously planned, as the hydrogen sulphide abatement unit at the plant had to be adjourned for a prolonged period, due to unforeseen malfunctions, please see figure and table below.

Operation activities at the power plants at Hellisheidi and Nesjavellir are in accordance with the objective of a zero carbon footprint by 2025 and 2030, respectively. Thus, almost all hydrogen sulphide from the power plants will be captured and stored in basaltic rock.

It should be noted that the emissions uncertainty is +/- 12% compared to the 95% uncertainty range.