Updates: last update's detail
RTE is updating its national temperature reference base, with help from Météo-France
Source: RTE - DICAP 27/05/2011
From June 2011, RTE is updating both the panel of stations used to calculate its national temperature index and the reference temperatures used to adjust demand for temperature contingencies.
A temperature reference system for analyzing and forecasting electricity demand
Electricity demand is heavily dependent on temperature. This influence is especially marked in winter due to the use of electric heating, and in summer as a result of increased use of cooling equipment (air-conditioning, refrigeration, etc.) or irrigation, for example.
In order to quantify this relationship, RTE uses a national temperature index based on data from a panel of meteorological stations spread optimally across the country, to give the most accurate picture possible of national electricity demand.
Reference temperatures (which are climate change-corrected normal temperatures) are used to adjust past demand values for temperature contingencies or to establish forecasts looking ahead from two weeks to around thirty years, for which no reliable meteorological forecasts are available.
The term "reference temperature" is now preferred to the term "normal temperature" used in climatology, which according to the World Meteorological Organization's definition, does not properly take into account the effects of climate change.
Reference temperatures available for the entire energy sector
Since early 2011, Météo-France has made a new commercial offer for a set of reference temperatures for the energy sector. They include annual series of values defined at three-hourly intervals at a selection of weather stations in mainland France, and intended to allow optimum monitoring of electricity or gas demand, for example. In addition to the need for updated figures to take account of climate change, the adoption of these reference values by RTE, from June 2011, reflects the operator's commitment to transparency for other players in the energy industry. In March 2011, RTE formally presented the new references to the French energy regulator CRE, in conjunction with GRDF and Météo-France.
The new reference temperatures, obtained from a statistical analysis of the 1980-2010 series, are considered to be representative of the 2011-2020 decade. They replace the current reference values, which RTE had been using since 2003. Météo-France recommends that these data should be updated every ten years, with relevance checks to be carried out every five years.
National temperature index update
RTE has also revised the panel used to calculate the national temperature index, based on a series of statistical studies. The panel now consists of 32 stations (*), compared with 29 previously.
Changes with little impact on electricity demand analyses
The combined effects of the changes to reference temperatures and the national temperature index have little impact on the national mean annual temperature, which falls from 12.70°C to 12,65°C.
The new reference temperatures are a little higher in the morning, and a little lower in the afternoon: the daily amplitude is slightly reduced, better reflecting what has been observed over the last ten years.
In terms of electricity demand, the change to the reference base (reference temperatures and national index) signifies an increase in annual demand adjusted for reference temperatures of approximately 1.5 TWh, out of a total of around 490 TWh. This deviation is largely due to an upward revision in the thermosensitive share of demand attributable to heating; the impact of the rise in thermosensitive demand in summer on overall demand remains marginal.
For more information, please contact firstname.lastname@example.org (RTE) or email@example.com (Météo-France).
(*) Table showing the 32 meteorological stations selected by RTE and the associated weightings applied to calculate the national temperature index:
|Meteorological station||Associated weightings||Meteorological station||Associated weightings|