In France, one of Europe's most powerful solar farms marries innovation with scale

Over several decades, France has come to rely heavily on nuclear power. According to the World Nuclear Association, around 75 percent of the country's electricity comes from nuclear.

The country is undergoing something of an energy transition, however. In 2015, France introduced an "energy transition for green growth" act, which set six medium and long term-objectives. These include cutting fossil fuel consumption by 30 percent by 2030 and reducing nuclear energy's share of electricity production to 50 percent by 2025.

In the south west of France, one solar farm is looking to marry innovation and scale. "The Cestas solar farm site covers 250 hectares with a power output of 300 megawatts from one million solar panels," Guilhem de Tyssandier, site manager at the Cestas solar PV plant, told CNBC's Sustainable Energy.

"The plant provides, on average, power for 300,000 people per annum," de Tyssandier added.

De Tyssandier went on to state that the solar farm, which has been in operation since November 2015, was innovative for a range of reasons.

"The panels on this plant are oriented east and west," he explained. "This technique allows the panels to be around three times as productive per hectare as on other sites."

What's more, the technique used to assemble the farm enabled it to be completed in just one year, which de Tyssandier said was "extremely short" for a project of such magnitude.

Turning to the costs involved, de Tyssandier said that the site produced energy which sold for 105 euros per megawatt hour. "To give you an idea, it's cheaper electricity than the one produced by the new generation nuclear reactor," he said.

Commenting on the cost of solar power in general, the International Energy Agency's Simon Müller noted how times have changed. "Many people think solar energy is very expensive, and this was super true 10 years ago, it was true five years ago, but today it's simply not true anymore," he said.

"Solar energy is becoming cost competitive," Müller added. "We see some auction results where the price of solar is coming in at a level which is actually cheaper than the price of gas to burn in the power station, so we're really going into a cost effective era of renewable energy."

Correction: A previous version of this story included figures relating to the cost of energy produced at the Cestas solar farm. One of these was incorrect and has been removed.