On the French road to nowhere

One year into the two-year project for the disposal of French taxpayers' money (5 million EUR) involving the creation of a solar road called the 'Wattway' in Normandy, the director of the project submits a half-time report.

The one kilometre of solar road with its 2,800 square metres of solar panels was expected to produce 280 MWh of electricity during the year. In its first year, however, it produced 149.4 MWh (the number after the decimal is very important). That's only 53 percent of its planned output ('half' in everyday language).

Looking on the bright side, which is the only way to look at solar energy, the press release tells us that this quantity of energy would be enough to power an electric car (type unspecified – Scalextric?) for 87,000 km, helpfully translating that into 400 times the journey between Paris and Alençon in Normandy (190 km).

Putting these figures in terms a normal human being can comprehend, an output of 150 MWh in a year will power 183 kettles like mine (2240 W) for one hour a day for the year. That's a year's daily tea-making for a small village. We recall that when the project was opened we were told that the power generated would be 'sufficient to power the public lighting of a village of 5,000 inhabitants'.

Looking on the even brighter side, the Wattway engineers tell us that if the PV tiles that didn't work had worked, the output would have been over 85 percent. Some of the tiles, for example, were 'disconnected' by a storm.

Now looking directly into the sun, eyes wide open, the Wattway people tell us proudly of one of the greatest success of the project: the 'solidity' of the PV tiles. 'Only' 5 percent of the tiles have been damaged and have had to be replaced. We deduce from this that in the course of twenty years a solar road will have to be replaced bit-by-bit in its entirety. Bad enough once every twenty years, but this maintenance effort and its concomitant disruption will be required at frequent intervals during that period in order to keep the output up.

In all this breezy positivism there must be a negative somewhere, surely. Yes, indeed – noise. Noise both for anyone near the road and anyone in a vehicle. In the latter case the experience has been compared to that of driving fast down a cobbled street (a Gallic hobby, if ever there were one!). To pacify those living near the road the speed limit has been reduced from 90 to 70 km/h.

The ribbed effect on the top of the PV tiles was seen as one of the great design triumphs of the project. These triumphs will now be replaced with tiles with much flatter ribbing, holding out hopes of a lot more fun in snow, ice and rain. In the right conditions it might be possible to press your foot on the brake at the start of the solar road and reach its end without having used any fuel at all.

Whilst it is replacing tiles, the company that produces them is going to make further improvements. Apparently the tiles get dirty very quickly and produce less electricity at low sun angles. Quelle surprise!

The director of the project tells a waiting world that he is 'very satisfied' with the results of the project. We doubters only recall Dr Pangloss in Voltaire's Candide, ou l'Optimisme, for whom everything is for the best in the best of all possible worlds. It certainly is for the director: he got 5 million EUR to spend and a fat salary while he was doing it.

Speaking of fat salaries, Ségolène Royal, the French Environment Minister who promoted and ceremonially opened the Wattway project, where is she now?

Well, she lasted only four months after she was pictured walking along the Wattway at its opening in December 2016. Lover boy Hollande returned to the outer darkness and the new president, Emmanuel Macron, turfed her out at the beginning of May 2017. The pain of rejection didn't last long though: she was made an 'ambassador charged with international negotiations about the Arctic and Antarctic poles'.

Voltaire! thou shouldst be living at this hour.

Update 30.07.2019

It was only a mattter of time – and time has run out for Wattway's solar road.

In brief, the reasons for the failure of the project are those we forcast at the time of its launch three long, expensive years ago and in our second look in the present article in 2018: the power produced is only a fraction of that expected – not worth the effort, in fact; the road surface is unacceptably noisy; the solar panels cannot take the pounding meted out by normal traffic – the road is now irreparably damaged.

The country road was intended to produce 790-kilowatt-hours per day.

The surface created so much noise that a 70km/h speed limit was imposed. The meagre output of the road matches challenges faced by less-high-profile experiments in “solar highways” elsewhere.

The Normandy road was forecast to produce 790kWh per day, but the first year’s energy production was 50 per cent per day of what was expected, with less than 150,000kWh produced that year. In the first half of this year, the road generated only 37,900kWh.

It was supposed to raise €10,500 a year in sales but it only yielded €3,100 last year.

Energy Reporters.

Rather late in the day, even the Greens in France are criticising the waste of money. Now the taxpayer (we presume) is going to have to pay to dig it all up and put back a proper road in its place.

We recall with some amusement (the French are paying!) the excited calculations by those involved in the project of just how much electricity could be produced if all the many roads in France could be surfaced with solar panels.