Grid operators and developers: utilize reserve capacity of electricity grid
UTRECHT - The development of new solar parks in the Netherlands is facing significant delays due to a lack of grid capacity. Because grid expansion can take years, short term creative solutions are needed like utilizing the reserve capacity of the grid, the use of inverters to manage grid voltage and building solar parks and wind farms side by side.
That is what grid operators, developers and other experts say in the run-up to the 11th edition of The Solar Future NL conference, on June 13 in Utrecht.
With the installation of 4.6 million new solar panels, the Dutch PV market increased by 46 percent from 2.9 to 4.2 gigawatts (GWp) last year. In addition, there are 6.1 gigawatt peak of SDE+-subsidised projects under development. According to Dutch grid operators, this increase causes major capacity problems on the electricity grid. Especially in thinly populated provinces such as Groningen, Friesland and Drenthe, the grid is not designed for the connection of so many large solar parks. Billions are needed for the necessary modifications and expansion, which will take years.
“Only in Friesland we expect a twenty-fold increase in the amount of solar energy in the long term.”Jelle Willis - Liander
“Only in Friesland we expect a twenty-fold increase in the amount of solar energy in the long term. This requires necessary extensions of cables and substations. In addition, smart solutions are important, because only adding extra copper wires is not a viable solution. We don’t even have enough technicians for that in the Netherlands,” says Jelle Wills from Dutch DSO Liander.
Chint Solar/Astronergy Netherlands, which is working on the development of over 15 solar parks, particularly in the northern provinces, has been affected by the grid congestion. “The capacity problems are a roadblock that slows down the entire development of solar energy in the Netherlands,” says Head of Business Development Europe Bernardo Silvestre. “In the past we only had to focus on a suitable location, an SDE+-subsidy and a permit, but since the past six months the grid capacity has become an increasing problem.”
This has already delayed four of Chint’s projects. The problem forces the developer to search for suitable locations in other provinces, such as Noord-Holland and Gelderland, where there is still enough grid capacity. According to Silvestre, the government must pass new legislation, allowing DSO’s en TSO’s to expand the grid more quickly.
In the meantime, grid operators should be able to use the reserve capacity of the grid, so say all parties. This so-called emergency lane consists of extra cables that guarantee grid-security but are only used when a cable breaks. “A very smart solution if you get all parties to agree on this,” says researcher Marcel Eijgelaar of independent energy expert DNV GL. Silvestre of Chint: “You could use this reserve capacity temporarily as a buffer until the expansion of the grid is completed. I do not think this will jeopardize grid-security, especially because solar parks do not generate power continuously 24/7, such as coal and gas plants.”
DSO Liander also sees this as the most promising solution for the short term. “With this we can rapidly create extra capacity. However, this requires amending laws and regulations. As grid operators, we are discussing this with the Ministry of Economic Affairs,” says Wils.
During The Solar Future NL, DNV GL will present another smart solution to increase the capacity of the grid. Eijgelaar shows the results of the ‘Power Quality in Control’ project, which DNV GL executed with Synergy Consulting, Liander, TU Eindhoven and Kenter. This involves programming solar park inverters to prevent the voltage in the grid from becoming too high if the power current is increased. They do so by absorbing or injecting non-usable reactive current. This is called autonomous power regulation. “A pilot project at a solar park in Friesland showed that by implementing this you could build double the amount of megawatts of solar energy in this specific part of the grid,” says Eijgelaar.
Solar parks next to wind farms
Other solutions that parties suggest are temporary storage of electricity in batteries or hydrogen or building wind and solar parks side by side. “Liander has discovered that the sun usually does not shine when the wind blows and vice versa. That is why we say: develop solar parks next to wind farms and use the same cable. That saves construction and costs,” says Wils. Chint is eager to do so. “We can partner up with wind farm developers, but then the grid operators have to tell us where that development can take place,” says Silvestre.
“We can partner up with wind farm developers, but then the grid operators have to tell us where that development can take place.”Bernardo Silvestre - Chint Solar/Astronergy
The developer notices that grid operators lack the personnel and engineers to handle all applications, which also leads to delays. That is why the RVO should grant extensions if a project with SDE+-subsidy has not been completed within the three-year deadline. Chint is prepared to install the infrastructure and connections to the high-voltage grid itself, if by doing so a number of parks can be connected to the grid at the same time.
“We can take over this task and related costs from the grid operator if there is a high confidence on not losing the SDE+ subsidies due to delays in the realization phase,” says Silvestre. “This is precisely what we have done with project Midden-Groningen (103 MW), now in construction, which we are connecting to TenneT’s high voltage grid (110 kV).”
All parties agree that good long-term plans must be made to expand the grid. “Although we think that expansion is not always the only solution,” says Wils of Liander. “It costs a lot of tax payer’s money and, moreover, cannot be realized because of the limited number of technicians. It is better to develop smart solutions like this.”