Deep re-injection of separated water supports the efficient utilisation of the geothermal system
In 2016, the energy generation process produced 6,516 thousand tonnes of condensate and separated water of which 4,640 thousand tonnes were re-injected back into the geothermal reservoir. The re-injection of separated water supports the efficient utilisation of the geothermal system and reduces the impact of geothermal utilisation at the surface. Surface disposal has been reduced significantly in recent years whereas re-injection measures have been increased even further this year. However, surface disposal increased again this year as a result of the utilisation of an older water-rich well.
Annual groundwater monitoring has been conducted on solutes in springs by Mývatn since 1997 to assess the impact of brine discharge from Krafla and Bjarnarflag
Monitoring is based on natural tracers such as arsenic which are at a much higher concentration in discharge water from the power stations than that found in groundwater. Monitoring in the Mývatn area shows that the concentration of arsenic has not increased and it can therefore be assumed that the water has not been affected by geothermal water from the power stations.
Emissions of hydrogen sulphide into the atmosphere
Hydrogen sulphide emissions have so far been an unavoidable part of geothermal energy utilisation in Iceland. Hydrogen sulphide (H2S) can have a negative impact on humans and the ecosystem. Natural emissions from geothermal areas also affect the concentration of hydrogen sulphide in the atmosphere.
Landsvirkjun monitors the concentration of hydrogen sulphide in the atmosphere as a result of geothermal utilisation in the northeast of Iceland. Real-time results and annual reports can be accessed on Landsvirkjun’s webpage.
The monitoring station at the Reykjahlíð School is closest to the energy utilisation areas at Krafla and Bjarnarflag.
The yearly average for hydrogen sulphide concentrations in 2016 were within set environmental limits 5 µg/m³ (±3 µg/m³), at all of Landsvirkjun’s monitoring stations. The results from monitoring at the Reykjahlíð School showed that the rolling average concentration of hydrogen sulphide, over a 24-hour period, never exceeded environmental limits (50 µg/m³). The results can be seen below where the yearly average for hydrogen sulphide concentrations for 2016 was 4.6 µg/ m³.
The monitoring results for 2016 show that the rolling average concentration of hydrogen sulphide, over a 24-hour period, never exceeded environmental limits at Landsvirkjun’s monitoring stations.
Landsvirkjun’s total consumption of fossil fuels has decreased in recent years
Landsvirkjun uses fossil fuels to operate vehicles, machinery and equipment and to operate stand-by generators. Fossil fuel consumption levels as a result of employee air travel are also recorded.
Landsvirkjun’s total consumption of fossil fuels in 2016 was 231 thousand litres, most of which was diesel consumption.
The consumption of fossil fuels has been reduced in Company operations by 13% in the last five years. The greatest decrease is in vehicle consumption which has been reduced by 20% during this period. This decrease can mostly be attributed to biodiesel use in vehicles in the Þjórsá area where the fuel is either used on its own or is mixed with fossil fuel.
Carbon footprint decreased by 13%
Landsvirkjun’s carbon footprint in 2016 was approx. 48,000 tonnes CO2 –eq which can mostly be traced to Landsvirkjun’s geothermal power stations, which account for 67% of emissions, as well as the reservoirs at the Company’s hydropower stations, which account for 31%.
Landsvirkjun is still involved in extensive land reclamation and re-forestation projects based on an older estimate where the total amount of carbon sequestered is 22,000 tonnes CO2 –eq per year as well as 1000 tonnes in carbon neutralisation measures via the Kolviður Fund.
Landsvirkjun’s carbon footprint in 2016 was subsequently over 25,000 tonnes CO2 –eq, a decrease of 13% when compared to the previous year. The decrease can be attributed to increased steam utilisation efficiency for every GWh produced by the geothermal power stations.
Landsvirkjun’s carbon footprint = total GHG emissions – carbon offsetting
More effective inspection and incident registration during construction
There were 13 environmental incidents in 2016. All these incidents occurred during construction projects carried out by Landsvirkjun, i.e. drilling at Krafla, the Þeistareykir project and the expansion of Búrfell. Landsvirkjun’s objective is to operate without environmental incident and there have been few or no incidents in recent years. This decrease can be attributed to increased awareness amongst employees, contractors and their willingness to support environmental matters.
Most of the incidents reported during the year were related to oil or hydraulic fluid leaks. Other incidents included land damage due to off-road driving, material extraction, detour areas which were not defined in project plans and leakages from drainage tanks for tunnel excavation.
Oil spills were reported to the public health authority and the appropriate action was taken. Meetings were also held with safety and environmental officers from the contractors to review work procedures. Several cases are still in progress.
Landsvirkjun’s Green accounts for 2016 can be accessed here (in Icelandic only).