Solar roads: A shining idea with a big price tag

Solar panel roads are a wonderful idea, but one that might be a bit premature. Photo / Youtube

Take the vast, network of roads across our country and the sun that beats down on them and turn them into energy-creating super highways.

The idea of solar panel roads is still in the early stages of development but it's one that has been gaining traction in a number of countries around the world.

It's about to get a real life trial on one of the world's most iconic roads - Route 66 - known as the "main street of America".

A husband and wife start-up company out of Idaho called Solar Roadways are behind the idea to replace traditional asphalt roads with glass based "solar panels that you can drive on" in a bid to turn roads into sources of renewable energy.

Scott and Julie Brusaw have raised nearly $3 million through an online fundraising campaign in order to pursue their ambitious goal. The company is set to launch a trial of its product on a small section of the iconic highway in hopes that it can generate enough energy to power a rest station.

The French government recently announced plans to cover 1000km of road with solar panels in the next five years.

The country's National Institute of Solar Energy has teamed up with a French road building company to develop solar panels that are less than a centimetre thick to lay over the top of roads.

It's an initiative they hope will be able to generate renewable energy for five million people.

Holland has also been experimenting with the idea and built the world's first solar bike path in 2014. After six months of the trial Dutch researchers said it proved more successful than expected, producing enough electricity to power a single-person household for a year.

WHAT IS THE DOWN SIDE?
It sounds exciting but there are road blocks on the idea with some renewable energy experts questioning the idea, believing it is inefficient and overly expensive.

Andrew Thomson, a solar researcher at the Australian National University, admits the idea is attractive but warns at this stage it's a somewhat misguided one.

"It's a really attractive looking idea," Dr Thomson said. But while "it's technically feasible, it's very expensive. I don't really think there's a market for it, the opportunity cost is very much against it".

However others, such as famed science personality Karl Kruszelnicki, known mainly as Dr Karl, are more optimistic about its potential use.

"It's an interesting concept. I like the idea," Dr Karl told news.com.au.

"The advantage of using roads as solar cells is that it's not a part of the world that people are in love with, so they're happy for you to put stuff there, like solar cells," he said.

Dr Karl believes such projects could help pave the way for solar roads to be built in Australia.

"I see solar roads as a small part of the overall package of renewable beautifulness. I don't see it as the only solution," he said.

It's an incredibly attractive idea but plenty of solar researchers are not entirely on board.
Their concerns revolve around the prohibitive expense, the comparatively poorer performance of road solar to other options such as roof installations and potential safety issues.

Price
Building roads out of thick slabs of toughened glass costs about four to five times the amount of typical bitumen/asphalt roads - a disparity that is unlikely to change.

If solar panels are made out of recycled glass, the solar panel can suffer a dramatic performance hit of more than 50 per cent.

Supporters claim the energy produced by the roads will recoup costs but such claims makes little sense if there is a more efficient alternative.
"I don't see how they're ever going to make an economic case for it," Dr Thomson told news.com.au.

Performance
If the solar cell is partially shaded, it dramatically reduces the energy creation of the panel. Given that roads are not orientated towards the sun and can be shaded by buildings as well as the cars driving on them, the performance of the solar panel is significantly reduced.

The technology of Idaho's Solar Roadways boasts a number of nifty features such as self-heating to ensure roads remain free of snow and ice and the panels can alert drivers to animals crossing the road via panels that light up. But for some solar researchers, such potential benefits are not enough to trump the "relative inefficiency" of the road technology.

It does have its place, but ultimately it's a niche market, Dr Thomson said. "When the world runs out of rooftop and other spare places."

However as Dr Karl points out; "as solar cell manufacturing gets cheaper, it's not going to matter that it's not generating the maximum amount of energy."

Safety
There is also safety concerns over the long term wearability of the solar glass.

Asphalt roads wear away to simply expose more layers of rough asphalt with the same consistency and grip. While solar glass will be made with surface topography to increase traction, over time the homogenous material will wear smooth.

"It's a good PR exercise but I think if you actually rolled it out you'd have a potentially bad PR exercise when people started crashing," Dr Thomson said.

A step in the right direction

Dr Thomson is not the only critic about the idea of solar roadways.

Referring to the French government's plan to pave roads with solar panels, Craig Morris of Renew Economy said "it's enough to make you despair".

"Would someone please tell French leaders that putting stuff on solar is a bad idea in terms of power generation," he wrote.

Meanwhile equities.com referred to the plan as "a costly, inefficient boondoggle".

A scathing critique by senior editor Joel Anderson said the idea amounted to "putting government funds into an inefficient and expensive form of solar power, despite readily available options that are clearly and obviously superior."

The fact that the idea continues to gain support in different parts of the world remains somewhat of a curious phenomena.

For Dr Thomson, he thinks there are subtle psychological factors at play and it has something to do with a good-natured compulsion to improve what is ultimately a very environmentally unfriendly activity that gets people so excited about the idea.
"I think that's where it comes from," he said.

However he believes it can detract from the project at hand of moving towards a much more energy efficient world and would rather see resources directed towards more viable projects.

"We need to not be looking for that silver bullet and back something that has a real chance of being successful in reducing the cost of electricity," he said.