In the period between 01.12.2020 until 31.12.2023 the need for reductions may vary between 0-200 MW for both export and import. The reduction will vary based on the expected constraint and flow. Before the end of 2023, it is expected that the new 420kV line between Lyse-Fagrafjell will be in operation.

The reductions will be placed on the corridor with the lowest expected socio-economic cost as described in the last chapter below.

The reductions can be expected when there is an unbalanced flow on the existing corridors leading to and from the HVDC-cables. For export capacities, this can be expected at high consumption in combination with low production from hydro power plants and low wind infeed in the Southern NO2 area. For import capacities, this can be expected at low consumption in combination with high production from hydro power plants and high wind infeed in the Southern NO2 area.

The capacities given to the market may also be reduced due to reductions made by the counterparty TSOs. Known reductions from the counterpart will affect on which HVDC-cable the reduction will be placed.

For updates related to these reductions, please refer to any updated NUCS messages at NUCS.net

 

Reduction on HVDC-cables due to planned outages in the Norwegian grid in 2021

Statnett has received plans for outage coordination for 2021. Some of the outages will have an impact on the available transfer capacity for the HVDC-cables. This market message is to inform market participants on which average capacity can be expected based on the planned outages for 2021. Each of the different combination of outages will be informed to the market by a separate market message. The expected need for reduction due to outages in 2021 is limited to certain periods within the period from 25.02.2021 until 08.10.2021.

The indicated capacities in this message is a prognosis based on the expected grid situations and normal flow patterns. Due to high uncertainty of this prognosis, the capacities are indicated with a range. In normal situations, it is expected that capacity can be given in the high end of the range. For certain unfavorable load or production flows, the capacities may be given in the lower end of the range. 

The needed reductions will be placed on the cable with lowest socio-economic cost, based on an analysis of Day-Ahead prices and the effectiveness on the grid issues as described in the last chapter. In this prognosis, the socio-economic cost is based on effectiveness only. The capacities calculated by Statnett and given to the market may differ from this prognosis based on updated parameters closer to real-time and will be informed to the market in advance by separate market messages. The capacities given to the market may also be reduced due to reductions made by the counterparty TSOs. Known reductions from the counterpart will affect on which HVDC-cable the reduction will be placed.

Based on the prognosed capacities the expected average capacity for 2021 given by Statnett per interconnector is (values referring to receiving end):

  • NO2>DK1 1605-1624 MW
  • DK1>NO2 625-878 MW
  • NO2>NL 560-605 MW
  • NL>NO2 649-656 MW
  • NO2>DE 917-1140 MW
  • DE>NO2 1363-1377 MW

For updates related to these reductions, please refer to any updated NUCS messages at NUCS.net

 

Statnett methodology for reducing capacities on HVDC-cables

The methodology for reducing capacities on HVDC-cables when expecting internal grid problems is based on a socio-economic principle. The reduction will be placed on the cable/cables with expected lowest socio-economic cost. The parameters used in this methodology are Day-Ahead prices and the expected effectiveness on the grid problem the reduction will have.

Statnett simulates each coming grid situation and in cases where bottlenecks caused by high HVDC-flows are expected, there will be a need for reducing the capacities on HVDC.

The three HVDC-cables are located in different nodal points in the Norwegian grid. Depending on the expected congestion overload, reduction on any of the three cables will affect the bottleneck differently. Reduction on a cable with high effectiveness on relieving the bottleneck will have a lower socio-economic cost than reducing capacity for a cable with low effectiveness.

Statnett has HVDC-connections to Denmark, Netherlands and Germany, which are located in different European price areas. Prices in the different areas may vary, depending on congestions between the areas. As input to the capacity calculation, Statnett will use prices in the three regions. The prices are compared to the prices in the South West of Norway (price area NO2). When the price differences are high, reducing the capacity in direction low price to high price, results in an increased socio-economic cost.

To minimize the socio-economic costs of reducing capacities, the reduction will be placed on the cable/cables with the lowest cost, combining the analyzed inputs for price differences and effectiveness on the expected congestion. When there are no (or small) differences expected on several cables, the reduction will be reduced by a pro-rata principle, based on installed capacity.

Other actions will also be considered as an alternative to reducing the HVDC-capacities. This may include;

  • Internal counter trading in NO2. If the internal grid issues effectively can be solved by internal counter trading in NO2, this will be considered in order to maintain a higher HVDC-capacity. This action can be limited by the location of the grid problem and availability of reserves available for counter trading.
  • Use of system protection schemes. On NorNed and Skagerrak, system protection schemes with emergency power are installed and may be activated in situations where there is an expected critical grid situation, such as overload on lines or components. These system protections are included in the capacity calculation and will thus reduce the need for capacity reductions. For NorNed, a reduction of export capacity from NO2 to NL below 500MW will reduce the effectiveness of the system protection, due to its technical implementation.

Other system protections schemes, internally in NO2, will be used before reducing capacities. Such system protections are typically connected to hydro power stations in NO2 and will be included in capacity calculations based on probability of its availability.

  • Changing grid configurations. In order to avoid internal bottlenecks, it is possible to change grid configuration by opening or closing specific circuit breakers. This is done to reduce the flow on critical network components before and/or after a fault.
  • Reducing market capacities internally between Norwegian areas, primarily between NO1-NO2 and NO2-NO5. This will be done if it is considered to solve the grid issues with the same or increased effectiveness as reducing the HVDC-capacities. This will be applied when the expected grid issues are closer to the internal borders than to the HVDC-borders.