RTE estimates installed wind capacity will reach 5000 MW in 2010 and 7000 MW in 2012, compared to a current total of 3262 MW. The Renewable Energy Syndicate (SER), a trade association, believes that around 1000 MW of new capacity each year over the next two years is achievable, as long as there are no hiccups.
Given these figures, RTE notes that "wind speed is a new meteorological parameter that must now be taken into account when forecasting balance between supply and demand." It adds: "The parameter is short term: the variability is strong and a lot less easy to forecast than temperature or cloud cover."
Other difficulties identified by RTE, alongside the rapid pace of wind power's growth, are dealing with a variety of wind turbine concepts that are mostly connected at the level of the distribution grid. Despite its concerns about how to manage a variable power supply, RTE acknowledges that "wind power helps balance supply and demand." As long as plant are geographically dispersed, it estimates that 20,000 MW of wind can displace 4000 MW of thermal output.
As to how large amounts of wind power can be accommodated on the network, RTE admits that "the capacity to accept wind power onto the grid remains limited." It estimates that around 6000-7000 MW can be connected "as things stand at present." This can only be achieved by "optimising the geographic spread of the output." Wind plant, however, are usually located according to the resource potential, coupled with social and environmental factors, RTE points out.
The operator also notes that the grid is already under strain in some wind-rich areas, where up to now the system only had to deliver a limited amount of power to a scattered rural population.
Looking forward, RTE stresses the importance of long term planning and calls on developers and the authorities to involve it from the earliest possible stage. It takes two to three years on average to complete a wind plant in France, but it can take as long as six years to get new lines built, largely because of the time consuming authorisation process.
In this respect, RTE welcomes the introduction of wind power development zones (ZDEs), which require communal authorities to identify areas that are suitable for development. The existence of these should help RTE plan any necessary extensions or upgrades. As of July 2007, only wind plant built within a ZDE are eligible for the guaranteed purchase price set by government.
RTE also reports that regulations will be introduced requiring that all wind turbines in France ride through faults on the grid rather than dropping off line. In this way they can help support momentary voltage collapses on the grid and contribute to ensuring secure supplies of electricity.
In addition, RTE is working with wind power producers to develop a system of central dispatch control, which requires that the grid operator is provided with a stream of real-time output data. By the end of this year, around 80% of turbines should be connected to the system, which will allow RTE to give precise and detailed estimates of output up to one day ahead based on historic data. The operator is also studying the possibility of controlling wind installations remotely from dispatch centres and is working with the national meteorological agency, Météo France, to improve its forecasting of wind strength and direction.
Wind power generated 4 TWh of electricity in 2007, according to RTE, 79.4% more than in 2006 and amounting to 0.8% of national consumption. The average annual capacity factor over the last three years was a healthy 24%, varying from 10% to 35%, with a winter peak. The maximum production at any one moment was 1659 MW.