The ‘carbon footprint’ is a measure of GHG’s released into the atmosphere, either directly or indirectly as a result of anthropogenic activities.
Landsvirkjun’s carbon footprint is defined as net annual GHG emissions from Landsvirkjun’s operations after including estimated carbon sequestration and carbon neutralising measures. Landsvirkjun’s total GHG emissions in 2015 were approx. 52, 000 tonnes CO2-eq and have decreased by 1% between years.
Landsvirkjun has been involved in the extensive land reclamation and re-forestation of the areas surrounding their power stations for over forty years. Landsvirkjun has worked in cooperation with the Iceland Forest service and the Soil Conservation Society of Iceland on carbon sequestration projects since 2011. The annual carbon capture measures carried out by or for Landsvirkjun are estimated to be 22,000 tonnes CO2 eq per year.
Origin of greenhouse gas emissions
The largest source of greenhouse gas (GHG) emissions can be traced to Landsvirkjun’s geothermal power stations which account for 68% of emissions. The reservoirs at the Company’s hydropower stations account for 29% and less than 3% is caused by the burning of fossil fuels, waste disposal and SF6 emissions from electrical equipment.
Greenhouse gas emissions can vary substantially when hydropower and geothermal power stations are compared. The carbon footprint for every GWh generated by geothermal stations was 65.2 tonnes CO2-eq/GWh whereas the carbon footprint for every GWh generated by hydropower stations was -0.445 tonnes of CO2-eq/GWh. Landsvirkjun has therefore carried out carbon removal measures beyond the emissions produced by hydropower.
Conceptual model for the source and flow of carbon dioxide from active, high temperature volcanic areas
Geothermal fluid is extracted from wells, at a depth of 2000 metres, in high temperature geothermal areas during the utilisation process. Geothermal fluid is composed of steam, water and various gases within the steam. Geothermal gas is mostly composed of carbon dioxide (approx. 80-95% by weight), hydrogen sulphide (5-20% by weight) and other gases (less than 1%), including the greenhouse gas methane. It is a matter of opinion whether the GHG emissions from geothermal power stations are manmade or in fact natural emissions from the geothermal area. There is no combustion involved in the geothermal utilisation process. The inclusion of these emissions in national emissions inventories for the United Nations Framework Convention on Climate Change (UNFCCC) varies between countries but Iceland includes this information in its accounts. More information can be accessed in Landsvirkjun’s Green Accounts (pdf).
The Life Cycle Assessment (LCA) methodology
The Life Cycle Assessment (LCA) methodology can be used to assess the environmental impact of electricity generation over the entire "life cycle" of the station from the procurement of raw materials for construction and maintenance, operation and the disposal of materials and waste during the expected lifetime of structures.
The objective of LCA is to demonstrate where the greatest environmental impact will be in the process and how to adjust the design and operation to minimise this impact. An example of this includes the division of total greenhouse gases emissions between the construction phase and operational phase for each 1 kWh generated.
Electricity generation from renewable sources usually causes much less environmental impact than energy production from fossil fuels such as oil and coal. However, the requirements for companies generating electricity from renewable sources with regard to the reduction of environmental impacts are no less.
The Life Cycle Assessment (LCA) methodology was used to evaluate the environmental impact of two research wind turbines operated by Landsvirkjun in the Hafið area above Búrfell. The results showed that the raw materials used for the manufacture of wind turbines as well as their installation cause the greatest environmental impact.
The carbon footprint of the two wind turbines is 5.3 g CO2- equivalents/kWh over a period of 25 years of operation and 43% efficiency.
The analysis showed that there is a considerable benefit to recycling the remaining metals when wind turbines are dismantled and decommissioned. Recycling can decrease the gross carbon footprint by at least 11% based on the assumptions made on recycling.
The environmental impact of a wind turbine per produced kWh depends on its total output which is determined by factors such as the estimated lifetime of the wind turbine, installed capacity and efficiency. The efficiency of the wind turbines in the Hafið area is higher than that of wind turbines in other areas on land. When compared with other wind power projects and other energy resources used internationally, the two turbines perform well with regard to their carbon footprint and energy return on investment (EROI).