The noticeable easing of the energy supply and grid situation since Christmas 2015 and in January 2016 has continued in February. Although energy reserves still remain low as a result of the low water levels in the reservoirs, the measures initiated by Swissgrid in cooperation with the energy industry and European transmission system operators have proved effective, leading to a positive forecast for the energy supply and grid situation in March and April 2016.
The energy supply and grid situation, which has been tense since December 2015, has eased gradually in recent months due to the impact of various technical and market-oriented measures.
In terms of the energy supply situation, there is a positive trend in terms of reservoir levels. The current level of the reservoirs (32.3% as of 15.2.2016) has once again reached the minimum fill level of the last twenty years and is continuously approaching the long-term median.
Mild winter weather and solutions in cooperation with the energy industry
Various factors and measures have contributed to the improved situation:
- Joint problem-solving by the energy industry: Since December 2015, a working group from the Swiss energy industry (power plant operators, distribution system operators and traders) has been developing solutions to ease the situation. Swissgrid has also introduced and implemented additional technical and market-oriented measures in close coordination with European transmission system operators.
- Mild temperatures: The unusually mild temperatures this winter have resulted in reductions in grid load and in overall consumption, which has had a positive effect on the energy supply and grid situation. Thanks to frequent rainfall since mid-January, electricity production from run-of-river production has also been higher than normal for this time of the year.
- Restarting of Beznau 2: Since the restarting of Block 2 of the Beznau nuclear power plant on 23 December 2015, a proportion (360 MW) of the unavailable base load is once again supplied into the 220-kV grid.
Measures prove effective
One of the most effective measures since the end of December has been the gradual increase in net transfer capacity (NTC) at the borders with France, Germany and Austria. The market participants largely exploited this net import capacity resulting in improved coverage of Swiss energy consumption.
In coordination with the neighbouring transmission system operators, Swissgrid has decided not to offer any monthly products for export in the months from January to March 2016 in order to avoid frequent cuts to already-allocated awarded capacity rights in the event of a possible restriction of exports. The available cross-border capacity has instead been made available to the market in the form of daily products. This measure has had a dampening effect on exports, as a result of which more imported energy has been available in Switzerland.
Swissgrid has also purchased ancillary services in advance for the months of February to April 2016, as well as reserving minimum amounts of energy in selected power plants for intervention in the deployment of power plants (redispatch).
On the technical side, the situation has also been eased by the development of various topological measures to be employed for preventing bottlenecks in the grid. Swissgrid has implemented alternate substations and lines configurations leading to permanent or temporary improvements in the load flow situation.
Swissgrid also has also taken various measures at relevant 380/220 kV transformers to increase overall capacity. For example, a transformer which is intended as backup for the Linth-Limmern power plant has been put into normal operation to increase the 380/220 kV transformer capacity.
Further trends in the energy supply and grid situation indicate a sustained easing
As a result of the mild weather and temperature forecasts up to the start of March, the energy supply and grid situation is expected to be favourable until the beginning of March 2016.
It is nonetheless still too early to sound the all clear. The failure of a critical asset would reduce net import capacity and possibly production at the 220 kV level. An unexpected lengthy cold spell could also lead to increased hydro power generation as a result of higher grid load, and to an even faster drop in reservoir water levels, which are already well below average.
Swissgrid will therefore continue to implement the measures that have been introduced. Furthermore, as immediate measure for the coming winter of 2016/2017, the accelerated procurement of the transformer for the Beznau substation has been set in motion.
Swissgrid is monitoring the energy and grid situation continuously and providing information about further developments at planning for winter.
The Swiss transmission grid is composed of a 380-kV level, over which some 90 percent of the imports and exports are transported, and a 220-kV level, which mainly services national and regional supply. The capacity of the transformers that reduce the energy from 380 to 220 kV determine how much of the imports can be used to supply Swiss consumers.
Redispatch is an essential real-time measure for reducing transformer overloads for which Swissgrid is responsible. To ensure that power plants are able to deliver this, it must be guaranteed that sufficient energy is available. Through the reservation it has implemented, Swissgrid is ensuring that it can access sufficient energy in the relevant power plants at any time throughout the entire winter so that transformers can be relieved via redispatch measures.
NTC (Net Transfer Capacity)
The NTC is the maximum exchange programme between two areas which is consistent with the security standards of both areas.Tthis allows market players to carry out their energy trading without jeopardising the interconnected grid. Along with the neighbouring TSOs, Swissgrid determines the NTC values on all four Swiss borders on an annual, monthly and daily (d-2) basis.