Related topics

Windfarm Britain means (very) expensive electricity

Renewable energy at normal prices 'is a myth'

Not just power cuts, but massive price rises too. Still want that electric car?

We're also, already, talking about very serious electricity price increases simply to make those wind farms happen: the only reason they ever get built is the government's Renewables Obligation Certificates (ROC) scheme. By cranking up the ROC system, the government can drive more wind into the market; this process is already underway, and set to continue for a long time. ROCs are often misleadingly described as a "subsidy", but they cost the Treasury nothing: their effect is to pay renewables plants a guaranteed minimum sum of extra money for every unit of power they put into the grid, on top of the market price, and pass the costs of this on to the consumer via the distributing companies.

This means that the seemingly-crazy idea of negative electricity prices actually becomes meaningful with ROCs and windfarms. At times of high wind and low demand the wind farms would have more electricity on hand than the grid wanted, and they would be competing to get their juice onto the grid: not so much for its price, but to obtain valuable ROCs.

It would become worth their while at such times, up to a certain point, for windfarmers to actually pay the distributing companies to take their electricity, in order to get ROCs. The spot electricity price could indeed go negative at times. Sadly this isn't good news for electricity bills; consumers pay for the ROCs too.

Obviously the thermal power stations would have been undercut off the grid well before the price reached zero, worsening their profitability. There wouldn't just be a few gas stations switching on and off on a fairly regular schedule as we see today: the entire thermal sector - perhaps even including nuclear - would be dropping in and out of play unpredictably, running their machinery perhaps for just a few hours at a time. This would not only result in lost revenue, but drive up maintenance and operating costs and increase breakdowns - so requiring more plants offline and under repair, at more expense. Again, prices would have to rise.

All in all, the whole thermal system - which would have to remain of a size to power the UK unaided by renewables - would be enormously more expensive for consumers than it is now. Added to the significant expense of the windfarms and other renewables, this would mean swingeing price rises.

Some have suggested that problems might be mitigated by "interconnector" power lines between national energy markets, bringing in power from places where the wind is blowing to places where it isn't and so smoothing out the troublesome surges. Pöyry are fairly blunt about this:

Interconnectors cannot be the 'golden bullet'... we note that if interconnectors remove price differentials between markets the commercial case for building them can be challenging.

"There's no such thing as cheap green power - that is a myth," Pöyry's Phil Hare told the BBC.

Sponsored: How to determine if cloud backup is right for your servers