The revelation by National Grid that Britain’s energy margins are being squeezed to the limit has caused widespread discussion of energy policy, with renewables advocates scrabbling to assure the public that solar and wind power can meet the demand. But are the cold hard facts being defenestrated in the process?

Breitbart London decided to fact check one claim – that variable outputs by solar and wind plants could be smoothed using energy storage facilities.

In an exchange on Nicky Campbell’s Radio Five Live show, Sally Uren, the CEO of Forum for the Future accepted that sun and wind aren’t always on hand, but said “…that’s not a worry when we’re thinking about security of supply from renewables because we have these things called “storage units” and so we have this grid that allows us to store energy and deal with peaks and troughs in demand and so this notion that when the sun stops shining and the wind stops blowing so does our energy, it’s just not true.”

Her comments drew criticism almost immediately, not least from energy blogger Bishop Hill, who wrote “This, not to put too fine a point on it, is about as far from the truth as it’s possible to get.”

Breitbart London talked to Dr Benny Peiser, director of the Global Warming Policy Foundation to see if we could get closer to the facts of the matter.

“I’m afraid Sally Uren is rather economical with the truth,” he told us.

“While there are some small-sized prototypes for domestic households, large-scale energy storage for the UK’s renewable energy production simply does not exist.

“There are both technological and economic barriers to grid storage that are nowhere near to being solved any time soon.”

Earlier this year an American company, AES, revealed plans to build a battery facility to store energy produced by wind farms, at the site of the Kilroot and Ballylumford power stations in Northern Ireland. According to the BBC, the company, which claims it already runs a 64MW facility in West Virginia, has submitted an application for connection to System Operator Northern Ireland, which runs the Northern Irish electrical grid.

“Storage arrays have the unique ability to participate as active power system support with no emissions and to provide both supply and load to help manage the variability of renewables,” John Zahurancik, vice president of AES Energy Storage said.

However, the planned facility will only have a capacity of 100 MW, or about 0.3 percent of the average demand for electricity in the UK. It also appears to be the only such facility planned in the UK.

“Germany provides the best example of what happens to renewable energy when it stops generating electricity and in the absence of grid energy storage,” commented Dr Peiser.

“More than half of the world’s solar panels are installed in Germany. On a very sunny summer day, Germany’s solar power production can generate more than 20 gigawatts of energy, meeting almost 40 per cent of the country’s entire peak electricity demand. But to understand that this peak is quite meaningless, consider the grid’s growing problems during winter.

“For many weeks in December and January, Germany’s 1.1 million solar power systems generated almost no electricity during those overcast months. To prevent blackouts, grid operators have to import nuclear energy from France and the Czech Republic and power up an old oil-fired power plant in Austria.”

Verdict: it looks as though the technology required for us to rely on wind power keeping our lights on still has a long way to go.