Spain suffered several power glitches and industry officials sounded repeated warnings about the instability of its power grid in the build up to its catastrophic blackout on Monday.
The government has ordered several investigations into the blackout. Industry experts say that whatever the cause, the mass outage and earlier smaller incidents indicate the Spanish power grid faces challenges amid the boom of renewables.
A surplus of energy supply can disrupt power grids in the same way as a deficit, and grid operators must maintain balance.
Solar is generated as a DC current which has to be converted to AC and the grid voltage (so, 220V in Spain) in order to supply it to the energy grid, so all that it takes to control the flow of energy from solar generation into the grid is to be able to remotely tell the DC-AC converters of the solar farms to stop sending power to the AC side. When the converters are in that state, energy is not flowing down to the energy grid and all that happens on the other side is that the solar cells get a bit more warm.
Of course that means it has to mandatory for any solar supplier to the mains network to have a converter which can be switched off remotely by the grid management company.
Similarly, wind generation can be reduced and even stopped by changing the pitch of the blades and similarly it must be possible for the grid management company to do so remotely.
Switching on and off power sources (for example, switching on or off power turbines in dams or gas power stations) has long been how the grid management company balances production with consumption in order to avoid blackouts.
The problem is not an inherent inability of the new forms of renewable generation to be reduced or stopped when needed, it’s that if not forced the businesses generating that energy won’t pay the extra money to have systems in placed to do so which can be remotely activated by the electric grid management company: the flow of renewable energy is not controllable because the power supply operators won’t spend the money into making it controllable unless forced and at least until now there was no political will to force them to do so.
It’s a political (and Capitalism) problem, not a technical problem.