As market inconveniences go, the moon is rather a large one.
On 20 March, all eyes will turn to the sky for a rare solar eclipse that will plunge Europe into temporary gloom. But ahead of that, all energy geeks have turned their attention to the effect that this might have on solar panels.
In the UK this is a pretty marginal concern. But in renewables-rich countries such as Germany, grid operators will be scrambling to keep up as solar output diminishes at almost three times the rate of your average sunset, only to return just as speedily.
Already, traders note that the price of near-term power on the German wholesale power market is 8 per cent higher on Friday than for delivery a few days before – despite the fact that Friday typically brings lazier pre-weekend demand levels.
The price premium is unsurprising. Experts at energy management firm Opower estimate that the eclipse could force the German power grid into a supply-demand scenario equivalent to turning off a medium-sized power plant every minute for an hour.
The German grid operators’ 75-minute astronomical rollercoaster is complicated further by the fact that while the timing of an eclipse can be perfectly forecast, predicting cloud cover is trickier. An already dull day would mean a less dramatic experience for sky-watchers but perhaps a calmer day at the office for the transmission system operator.
It certainly puts the UK’s current wind intermittency woes into perspective.