“An Unprecedented Test for Europe’s Electricity System”

And we will not be able to contribute – by a hair. We have just ordered our photovoltaic generator, and installation is planned for April.

It is the (partial) Solar Eclipse on March 20 that made Europe’s Transmission System Operators (TSOs) release an announcement:

Under a clear morning sky on 20 March 2015, some 35000 MW of solar energy, which is the equivalent of nearly 80 medium size conventional generation units, will gradually fade from Europe’s electrical system before being gradually re-injected: all in the space of two hours.

Managing this event on the world’s largest interconnected grid is an unprecedented challenge for European TSOs. Solar eclipses have happened before but with the increase of installed photovoltaic energy generation, the risk of an incident could be serious without appropriate countermeasures

This paper shows the grid operators’ model and calculations.  20 GW would already correspond to a shift in frequency of 1 Hz – which is huge (from this German article on control mechanisms in the EU power grid). The TSOs’ benchmark is the speed of the  sunrise / sunset, and the solar eclipse’s shadow is faster.

I mentioned before on this blog that I think the power grid is a remarkable and most underestimated achievement in engineering as well as in the design of associated financial markets. In every single instant supply and demand of power have to be balanced exactly – so turning on and off an appliance immediately has to trigger a change in power provided by generators.

Grid operators today emerged from the split of monolithic power companies that integrated both power generation and distribution. Monopolies run by government, allegedly privileged and maybe as ‘popular’ as the stereotype ancient evil telephone company, emerged into a set of distinct players – operators of power plants and operators of the grid. They are now part of a complex market comprising also consumers, different kinds of traders, and agencies. Regulators needs to make sure that there is both fair competition and safe supply of electrical power to anyone in the long run.

For decades the grid had to deal with centralized, large generators only, and both the physical infrastructure  and the smartness of control systems needs to be continuously adapted to deal with a huge number of small, dispersed generators whose output is volatile. Commentators stated that unbundling of grid operations and power generation  caused players in the market to focus on their individual goals whereas ‘thinking holistic systems’ in not fostered anymore.

So TSOs might be concerned about the rapid increase of the number of generators of renewable energies as they are not the ones profiting most from energy sold anymore (their fees are regulated), but they need to care for safe and reliable distribution nonetheless. The development of the smart grid had been called the largest global IT infrastructure project ever – and this is perhaps not even doing the electrical engineering part justice. In Europe nearly all homes need to be equipped with smart meters until 2020 – which is a challenge given restrictive data protection laws and logistics.

It is  impressive that German TSOs can handle this today in such a reliable fashion:

Electrical power from different sources in Germany.At noon more than one third of power generated – about 20 GW  –  can come from photovoltaic generators, and some of that has to be exported to other countries. But this has to be compared to energy generated, that is power integrated over time: About 6% of all energy generated in a year is from solar generators – 32,8 TWh (Solar power in Germany, data for 2014).

Since a year has 8.760 hours, the average power is thus

32.800 GWh / 8.760 hours = 3,74 GW.

So the average solar power is only a fraction of peak solar power. And this is, unfortunately, why we should not over-hype record powers in solar energy generation. The challenge of the near future is storing, intelligent re-distribution, and management of consumption of electrical energy.