Curtailment Impacts Large Power Users in the South

19.12.2023Orka

Curtailment Impacts Large Power Users in the South

Landsvirkjun has notified the large energy users in the Southwestern part of Iceland, i.e., Elkem, Norðurál, Rio Tinto, and district heating plants, that energy needed for their operations has to be curtailed. These large power users have not experienced any energy restrictions this winter. The curtailment will begin on January 19 and may last until April 30. However, water levels affect the duration of the curtailment.

The situation has deteriorated since last month, when restrictions of tertiary power to fishmeal factories, fish drying plants, and data centres that mine cryptocurrency were necessary.

Precipitation in the South has been deficient this December, and water levels at the Þórisvatn reservoir are severely low. The inlet at Þórisvatn this autumn is at its lowest 5% level. Estimates show that the surface of Þórisvatn reservoir could fall below 562 m above sea level this spring, which has only happened once when the reservoir levels dipped to 560.3 m above sea level in the spring of 2014.

The slow inlet means a curtailment of up to 200 GWh is necessary in addition to what was previously announced. Full utilisation of curtailment allowance is expected in the relevant power purchasing agreements, but the curtailment allowance varies according to agreements. In general, the contractual curtailment is approximately 10% per month, e.g., depending on how fast the companies can reduce their energy consumption.

Increased Transmission Capacity Would Prevent Curtailment

Large power users north of transmission bottleneck IIIB, will not experience curtailment. Bottleneck IIIB is currently the main transmission constraint in the energy system that has the most impact on energy and power utilisation of power stations. The bottleneck is defined by the power transmission line Blöndulína 1, to the west of Blanda Power Station, and the power transmission line Fljótsdalslína 2, to the west of the Fljótsdalur Power Station.

To indicate the impact of curtailment on the transmission system, 1600 GWh of energy flowed unused to the sea at the Fljótsdalur Power Station last summer. Increased transmission capacity through the transfer format would probably have prevented the curtailment now and, at the same time, ensured that the water levels at Þórisvatn reservoir would not have been as low as is the case.