The RES expansion headache

For the first time ever, the Greek grid last Sunday recorded an electricity price of zero euros for six consecutive hours, being reminiscent of grids in northern European countries with a high penetration of renewable energy.

Also for the first time, the Independent Power Transmission Operator (ADMIE) last weekend resorted to cuts of "green" energy that went beyond any precedent so as to maintain the stability of the system. For 12 consecutive hours on Saturday and another 11 hours on Sunday, with a three-hour interval, ADMIE continuously threw out of the system "green" megawatts to keep it functioning and prevent an overload that would lead to a blackout.

Renewable energy source (RES) output on Sunday reached the very high levels of 80% of the total domestic production, though that was not the highest ever recorded: On October 7 last year and for five consecutive...