TenneT prepares grid system for renewable energy growth

The increase in electricity from renewable source like wind and solar will, in time, lead to a decline in the reserve capacity offered by conventional generation, like coal- and gas-fired power plants.

Consequently, the growing share of green electricity in the overall supply demands new solutions to cope with fluctuations in the electricity grid. For that reason, TenneT, together with four other suppliers, will start a pilot for providing primary reserve capacity using “new” technologies.

Earlier this year, TenneT already started another pilot together with The New Motion, involving the use of charging stations for electric cars as primary reserve capacity.

Ben Voorhorst, COO, TenneT: ‘These new pilots fit in with the wider strategy TenneT is pursuing to prepare the electricity system for the larger share of renewably produced energy. Over the coming years, the production of renewable energy will soar, and there will be times when practically all of the large power plants are switched off. It’s at those times in particular that we need to be able to cushion any fluctuations.’

Pilot project

TenneT will use the pilot to assess whether other parties, i.e. apart from conventional power plants, can play a part in providing primary reserve capacity. The four parties, besides The New Motion, participating in the pilot are ENGIE, KPN, Peeeks and Senfal. They intend to do so using methods including (control of) combinations of water pumping stations, cooling installations, CHP plants, (used) batteries, thermal boilers, solar panels and wind turbines.

Always balanced

Grid stability is essential to prevent power disruptions or outages. Similar to other TSOs in Europe, TenneT’s job is to ensure a stable frequency of the interconnected power grid. To maintain a stable frequency there needs to be an exact match between the supply of electricity and the demand. At any given time, TSOs must be able to ensure – in real time – that potential surpluses or shortages are minimised. This is referred to as power balance maintenance. Any imbalance between demand and supply will result in a disturbance of the grid frequency. Such frequency disturbances must be minimised as much as possible. The current method to achieve this is to have conventional power plants increase or decrease their output, which is the so-called primary reserve capacity TenneT purchases. By means of this pilot, TenneT wants to look at whether smaller suppliers are also able to provide primary reserve capacity, either without or in concert with alternative power plants, to compensate for any disturbances in the European grid frequency.

Selection criteria

Earlier this year, TenneT issued an appeal to any parties able to supply a product that meets the required ramp rate specifications, but who face obstacles that prevent them from participating in regular auctions. Based on selection criteria including scale, delivery timeline, product portfolio and data transmission options, TenneT was eventually able to select four parties. Its aim was to select the widest possible variety in technologies for creating the primary reserve capacity. This will ensure the best possible insight into the obstacles parties face when attempting to enter this market.

The pilot participants are set to start delivering primary reserve capacity to TenneT from January 2017. For TenneT, the purpose of this pilot is to gain insight into the restrictions that current requirements create for small enterprises and how systems can be future-proofed in terms of the delivery of primary reserve capacity. The aim of these pilots is that the experience gained should enable all market parties to use the new and improved mechanisms. In the new situation, regular competitive principles (in the form of e.g. bid ladders and auctions) will determine which offers are implemented in our operational processes.

Regulating and reserve capacity pilot

In the near future, TenneT will also examine options for contracting new parties for regulation and reserve capacity. In view of the large capacities involved in regulation and reserve capacity, current suppliers are all large-scale producers. For parties with a direct grid connection and parties producing more than 60 MW, supplying regulation and reserve power is even mandatory. The increase in renewable energy production means the availability of sufficient regulation and reserve capacity is no longer self-evident. For that reason, TenneT wants to find new parties (operating independently or as a partnership) that would be interested in participating in the pilot using new production capacity or smaller capacities. That will enable TenneT to identify what its options are in order to adequately prepare for a future with more and more renewable power generation. This autumn, TenneT expects to start the first exploratory meetings. Following those, a pilot aimed at contracting regulation and reserve capacity is expected to start in the course of 2017.