Remember the hype a few years ago about “solar roads”? These were roads with embedded solar panels that would generate enough power to save the planet. It seems that, as any engineer can tell you, the real world is a much tougher place than a lab. Things get dirty and wear out so that you $6 million dollars investment in 1 km of road in a cloudy part of France might not be terribly effective.

From Jo Nova

Solar road is $6m epic disaster — 4% capacity, broken and so noisy speed-limits were cut

Solar Road, Normandy, France   |  Credit: KumKum

Would you like to drive slower, add to noise pollution and waste money? Then solar roads are for you:

The world’s first solar road has turned out to be a colossal failure…

Ruqayyah Moynihan and Lidia Montes, Business Insider

• Two years after the world’s first solar road — the Normandy road in France — was set up, it’s turned out to be a colossal failure, according to a report by Le Monde.
• The road has deteriorated to a terrible state, it isn’t producing anywhere near the amount of energy it had previously pledged to, and the traffic it has brought with it is causing noise problems.

The original aim was to produce 790 kWh each day, a quantity that could illuminate a population of between 3,000 and 5,000 inhabitants. But the rate produced stands at only about 50% of the original predicted estimates.

Even rotting leaves and thunderstorms appear to pose a risk in terms of damage to the surface of the road. What’s more, the road is very noisy, which is why the traffic limit had to be lowered to 70 kmh.

Despite costing up to roughly $6.1 million, the solar road became operational in 2016.

The 1km road is in Tourouvre-au-Perch, Normandy, France made by Colas.

Leaves fall on the road, then cars grind the leaves on the beautiful polymer surface. The road isn’t angled towards the sun, gets brutally hot, and both reduce efficiency. If the top polymer layer was thicker and tougher, less solar energy would get through. Planting trees beside the road would cool it, but the shade…

Who likes trees anyhow? Not the Greens.

 Getting 50% worse than expected every year:

Anna Versai, Technowize, Aug 19th, 2019

The stretch of the road in Tourouvre-au-Perch, Normandy, France was meant to produce about 150,000 kWh a year, which is enough to provide light to up to 5,000 people, every day. Instead, it made less than 80,000 in 2018, and fewer than 40,000 by July 2019.

Meant to power lights for a city of 5000 people:

Translating the Le Monde article, for €5 million in public funds they now generate € 1,450 worth of electricity per year and falling.

Financed by public funds of € 5 million and supported by Colas (Bouygues Group), the subsidiary Wattway aimed to provide the equivalent of the annual consumption of public lighting in a city. of 5,000 inhabitants.

The general director of services of the departmental council of the Orne made his accounts: “The revenue from the sale of electricity produced by the road should bring us 10 500 euros per year, details Gilles Morvan. In 2017, we received 4,550 euros. In 2018, 3,100 euros, and for the first quarter of 2019, we are at 1,450 euros. “

Not much sun there to start with? From Science Alert:

There proved to be several problems with this goal. The first was that Normandy is not historically known as a sunny area. At the time, the region’s capital city of Caen only got 44 days of strong sunshine a year, and not much has changed since. Storms have wrecked havoc with the systems, blowing circuits. But even if the weather was in order, it appears the panels weren’t built to capture them efficiently.

There’s 40 smaller roads like this?

For its part, Colas has admitted the project is a bust. “Our system is not mature for inter-urban traffic,” Etienne Gaudin, Colas’ chief executive of Wattway, told Le Monde. The company also operates 40 similar solar roads, smaller than the one in Normandy.

A solar bike path in the Netherlands works better:

In the Netherlands, a solar bike path has been declared a success. Dubbed the SolaRoad, the bike path is exactly what its name suggests. The electricity generated by SolaRoad is used for various purposes such as traffic management systems, public lighting, households, and electric mobility.

At the beginning of the trial, an energy yield of between 50 and 70 kWh/m²/year was expected. SolaRoad exceeded expectations by yielding 73  kWh/m2/year (first version, built in 2014) and 93 kWh/m2/year (second, improved version, built in 2016).

There were hiccups despite its impressive results. Due to poor weather conditions, a top layer of the solar bike path came off, and a major path had to be shut down.

The French solar road has a capacity factor of 4%

And this was a year ago. Probably that capacity factor is now 2%.

Dylan Ryan, The Conversion, Sept 2018

One of the first solar roads to be installed is in Tourouvre-au-Perche, France. This has a maximum power output of 420 kW, covers 2,800 m² and cost €5m to install. This implies a cost of €11,905 (£10,624) per installed kW.

While the road is supposed to generate 800 kilowatt hours per day (kWh/day), some recently released data indicates a yield closer to 409 kWh/day, or 150,000 kWh/yr. For an idea of how much this is, the average UK home uses around 10 kWh/day. The road’s capacity factor – which measures the efficiency of the technology by dividing its average power output by its potential maximum power output – is just 4%.

In contrast, the Cestas solar plant near Bordeaux, which features rows of solar panels carefully angled towards the sun, has a maximum power output of 300,000 kW and a capacity factor of 14%. And at a cost of €360m (£321m), or €1,200 (£1,070) per installed kW, one-tenth the cost of our solar roadway, it generates three times more power.

Dylan Ryan is a lecturer in Mechanical & Energy Engineering at Edinburgh Napier University.

In Idaho a solar road had an 83% failure rate:

Andrew Follet, Daily Caller, October 2016

Despite massive internet hype, the prototype of the solar “road” can’t be driven on, hasn’t generate any electricity and 75 percent of the panels were broken before they were even installed. Of the panels installed to make a “solar footpath,” 18 of the 30 were dead on arrival due to a manufacturing failure. A short rain shower caused another four panels to fail, and only five panels appear to be presently functional. The prototype appears to be plagued by drainage issues, poor manufacturing controls and fundamental design flaws.

Can’t power a whole microwave oven, April 2017

The Solar FREAKIN’ Roadways project generated an average of 0.62 kilowatt hours (kWh) of electricity per day since it began publicly posting power data in late March. To put that in perspective, the average microwave or blow drier consumes about 1 kWh per day.