Potentially Available Capacity : what you have to know

The available capacity: a slightly outdated notion


Till the end of June 2009, RTE gave the available capacity per substation for connecting new installations of generation. This capacity was defined as the the additional power that can be accepted on the grid in any case. In other words, as long as the output power of a generation installation was lower than the capacity, the electricity generator was almost sure that, after connection, his installation could inject without any limitation in any case. However if the output power was greater than the capacity, the installation could be connected but would have to limit its output power in some cases, of which the probability of occurrence would not be negligeable every year.

In the framework of the Renewable Energy Sources development, many projets have realized since the beginning of 2000 and the network capacities are nowadays inexistant in many locations. The information given on RTE website was finally useless for electricity producers who should contact RTE to get information on how critical was the lack of capacity.


The Potentially Available Capacity


From now on, RTE gives information on the potentially available capacity. It is defined as the maximum additional power that can be injected in the network. However, the output power may be reduced in some cases, which are identified in the offer of connection and must be agreed by the generator. If required, an automatic control device will be installed.
The injection of more power than this potential capacity would certainly lead to regularly overload some equipment even if all equipments are available in the grid and this could not be accepted until the grid has been reinforced


Grid development


Very weak potentially available capacity urged RTE to find grid solutions to allow the connection of new generation. These solutions are difficult to justify externally for lack of certainty on the magnitude and the location of generation projects. This difficulty should be overcome given the provisions in the project of the “Grenelle of environment ” Act on the planning of a grid dedicated to Renewable Energy Sources. In order to give information to electrical producers on the progress status of RTE projects it has been agreed to organize a consultation within the CURTE during the second semester of 2009


Some practical information

  • Potentially Available Capacity for new generation: this value is calculated assuming that all installation is available
  • Queued request: this information as well as the same information on the other substations in the vicinity gives an idea of the attractivity of the area for new projects, on one hand, and on the possibility that some projects withdraw, on the other hand
  • Theoretical HV/MV transformer capacity: this information is dedicated to projects to be connected in MV. The remaining available transformer capacity in the substation is calculated according to connected installation in MV and minimum consumption load. It shows whether or not it is necessary to upgrade the capacity of the HV/MV transformers in a substation in order to connect a new installation.