20th March solar eclipse: a real challenge for the electric grids?

The transmission system operators’ challenge

The 20^th March solar eclipse and its consequences on the European electric grids are on every lips. Indeed, the share of renewable energies has much progressed since the last similar phenomenon which took place in the summer of 1999. Back then, the solar installations were not so much widespread, and the energy production associated with them was too insignificant to unbalance the grid. Today, however, things have greatly evolved. In Europe, photovoltaics (PV) now cover 3% of the electricity demand and 6% of the peak electricity demand according to EPIA’s (European Photovoltaic Industry Association) “Global Market Output” report.

On the 20^th March 2015, in the space of two hours, 35,000 MW of solar energy – the equivalent of 80 medium size conventional generation units – will progressively disappear from the European electric grid, before being gradually reinserted into it.

The ENTSOE (European network of transmission system operators – TSOs – for electricity) describes this event as an unprecedented challenge for TSOs. To the extent that a Solar Eclipse Impact Analysis has been carried out and published one month before the eclipse, on the 19^th February. Even though the different TSOs and electrical systems won’t be affected in the same way depending on their location, it is crucial that a coordination be put in place. It is the best way to answer the sudden electricity demand that will take place during the eclipse.

An anticipated phenomenon

Admittedly, March’s solar eclipse presents a hitherto unseen challenge, but it mostly consists in an anticipated phenomenon for which the TSOs have been preparing for several months, if not years. The PV production’s variation will therefore be handled without trouble.

As for the daily production drops due to solar energy’s intermittent nature, their impact is naturally lesser, but the meteorological hazards make them more difficult to predict. Soleka, Reuniwatt’s decision making tool, has been especially developed to supply solar power production forecasts. Soleka is intended in particular for transmission system operators. Using Soleka enables them to more efficiently manage solar power production’s variations on a daily basis. Taking into account the swelling number of PV installations across Europe, this consists in a more recurrent and increasing challenge than the solar eclipse to come.

To go further

An FAQ on the impacts of the solar eclipse on the electrical system is available on the ENTSOE’s website.