Four years ago, the promise of a viral campaign to fight climate change and jump attracted the world.
Start the economy by replacing the tarmac on the world's roads with solar panels.
This bold idea has gone through some road testing since then.
The first results of the preliminary study have come out recently, and they are a bit uninteresting.
Solar panels located under roads have many disadvantages.
Since it is not at the best tilt angle, it produces less power and is easier to color, which is a problem because only 5% of the shadow on the surface of the panel can reduce the power generation by 50%.
Panels may also be covered with dirt and dust, and require much thicker glass than conventional panels to withstand the weight of traffic, which will further limit the light they absorb.
Read more: Solar roads?
Why the future of this technology may not be so bright that it will not benefit from the air circulation, and it is inevitable that these panels will also be heated more than the roof solar panels.
At the optimum temperature, loss of 0 per 1 °c.
Energy efficiency is 5%.
Therefore, the performance of the solar road has dropped significantly compared to the roof solar panels, which must be expected.
The question is what is the economic cost?
Road test results are one of the first solar roads installed in the Tourau-Perche, France.
It has a maximum power of 420 KW, covers an area of 2,800 m² square meters and costs 5 euros for installation.
This means a fee of 11,905 euros (£10,624)
KW per installation.
Although the road should produce 800 KW hours a day (kWh/day)
Some recently released data show that the yield is close to 409 KW hours/day, that is, 150,000 KW hours/year.
Wondering how much this is, British families use about 10 KW hours a day on average.
The capacity factor of the road-measuring the efficiency of the technology by dividing the average power output by the potential maximum power output-is only 4%.
In contrast, the Cestas solar plant near Bordeaux has a row of solar panels carefully tilted towards the sun with a maximum power output of 300,000 KW and a capacity factor of 14%.
Cost 360 euros (£321m), or €1,200 (£1,070)
KW per installation, 1-
The cost of solar power generation is ten times that of our solar power generation.
In the United States, a company called "solar roads" has developed a smart highway with solar panels, including sensors and LED lights, to show any imminent danger such as deer traffic
It also has heating pads to melt snow in winter.
Several of their SR3 panels have been installed on a small portion of the road surface in Sandypoint, Idaho. This is 13.
Area of 9 m² square meters, installed capacity 1. 529 KW.
Installation costs $48,734 (about £37,482)
, Which means that the cost per installation kW is 27,500 euros (£24,542)
More than 20 times higher than Cestas power plant.
Solar Roadway's own estimate is that the LED lights will consume 106 MW per lane mile and the panel will generate 415 MW, so the LED will consume more than 25% of useful power.
This will further reduce performance.
The heating plate is also quoted as Figure 2.
Miles 28 MW per lane, so running for only six days will offset any net income from solar panels.
This is before we look at the actual data for the Sandypoint installation that generates 52.
6 months at 397 KW, or 104.
8 KW a year.
From this, we can estimate that the capacity factor is only 0.
782%, 20 times less efficient than Cestas power plant.
Nevertheless, it should be noted that the group is on a city square.
If there is one thing we can conclude that in the snowy northern town, a section of the sidewalk surrounded by buildings is not the best place to find solar installations.
However, it may not be a good idea to have a larger solar road on the city streets.
The road is no longer as large as we think.
The Department of Transport has broken down the length of different road types in the UK.
Let's say we can cover these with solar panels, with four lanes per highway, two lanes on A & B, and half of the C & U (
A lot is a one way street, just not suitable)
We propose a surface area of 2 billion.
Before you realize that buildings in urban areas of the UK occupy 17 areas, it sounds like it is. 6 billion m².
Therefore, just using solar panels to cover a small part of the UK's roof will immediately generate more power than putting them on the road.
This is very different from the benefits that higher locations will bring to larger power generation.
All of this suggests that it is actually appropriate to have only a small portion of the road network.
Moreover, given the relatively small size of the road network, solar roads can only become a niche energy source and will never be a shortcut to our energy supply in the future.
This article was re-published from the conversation based on the creative sharing authorization.
Read the original text.
Dylan Ryan does not work, consult, own shares or obtain funds for any company or organization that benefits from this article, and does not disclose any relevant contacts other than academic appointments.