The Norwegian power system is vulnerable as the production can fluctuate greatly from year to year due to variations in weather conditions. While the normal annual production in the Norwegian hydropower system is around 120 TWh, an extremely dry year may result in around 90 TWh. This causes some challenges for the security of supply for electrical energy.
As the system operator of the Norwegian power system, Statnett is responsible for ensuring an instantaneous balance between production and consumption of power at all times.
Central Norway is a region that is unable to produce enough energy in relation to own consumption. During a normal year, meaning years with normal precipitation levels, the region has an energy deficit of 8-9 terawatt hours. This deficit equals a consumption of 20 000 KWh for 400 000 households.
Due to the energy situation, Central Norway is dependent on electricity imports from other regions as well as Sweden. This makes the region more vulnerable in terms of reliable electricity supplies.
According to the lisence conditions, the reserve power plants can only be started during a highly strained power situation (SAKS). A SAKS situation occurs when the risk of electricity rationing is greater than 50 per cent. To start the reserve power plants during a SAKS situation, the Norwegian Water Resources and Energy Directorate (NVE) has to approve the start-up of the power plants.
Statnett’s most important task is to ensure that everyone has access to electricity. The energy situation in Central Norway puts a major strain on the grid, and as a result, the risk of fault is increased. Based on this situation, Statnett has applied for, and received, dispensation from the licence conditions for use of reserve power plants to prevent causing power outages for customers.
Statnett also got a dispensation from the license conditions to start the reserve power plant at Nyhamna to supply the gas plant Ormen Lange with electricity, if a prolonged outage of the 420 kV power line between Viklandet and Fræna should occur.
With the dispensation from the licence conditions, Statnett is able to decide when to start the reserve power plants over the course of a few hours if a fault should arise, causing outages in large areas.
The reserve power plants will not be started due to prices.
Facts about the reserve power plants
- Cost: NOK 2.1 bn
- Capacity: 150 MW for each reserve power plant, total 300 MW
- Time for start-up at full preparedness: Nyhamna approx. 4 hours. Tjeldbergodden approx. 48 hours
- Time for start-up under the licence conditions: approx. 2 weeks
The gas turbines are the same for both facilities, and thus, the emissions are the same. The output of the facilities is approx. 36 per cent, compared with 58-60 per cent of combined cycle power plants with both gas and steam turbines. This is because the facilities are easier to install and more mobile than combined cycle power plants. Currently approx. 3000 MW have been installed on oil platforms on the Norwegian Shelf using similar gas turbines.
A single reserve power plant will, during operations, emit 2450 tonnes of CO2 per day (0.68 tonnes/MWh), with total emissions of 367 000 tonnes during a maximum SAKS period of five months. In comparison, the CO2 emissions from a coal-fired power plant is 0.79 tonnes/MWh.
Large amounts of water is injected into the gas turbines, thus reducing the NOx emissions from 175 ppm to 25 ppm, equivalent to approx. 78 kilos per hour and 281 tonnes for five months of operation.