China may not have a strong reputation as a sustainable economy. In fact, the manufacturing giant is the world’s largest emitter of CO2 and accounts for almost 27% the greenhouse gases being released into the atmosphere globally. However, the government is now taking steps towards a more sustainable footing and at least when it comes to manufacturing the latest technology in the world of renewable energy China is the world’s leader. Around 75% of all solar panels are produced in China and it is also one of the top wind turbine manufacturers.
And it’s not just as a manufacturer that China is taking a lead. There is also plenty of research and development going on around new solar and other renewable energy technology. One of the most promising avenues currently being explored is that of solar roads. A major drawback of renewable energy generation installations, especially with regard to solar and wind, is the amount of space they fill. This results in the unwelcome drawback of landscapes sometimes becoming dominated by rows upon rows of solar panels or wind turbines.
One potential solution to installing the volume of solar panels required for them to make a serious contribution to the power supply is for them to be integrated into existing structures. We are already familiar with the sight of sections of roofs being covered in solar panels. However, while efficient use of space there are aesthetic drawbacks, especially when the rest of a building doesn’t have a matching modern design. But what better combination of existing structures offering vast surface area and not involving an aesthetic compromise than roads? If it were possible to create a safe, practical, and affordable road surface that integrated solar panels it would no longer be necessary to fill fields and hillsides with panels. Roads also run through and around the built-up areas where most energy is needed, adding further efficiencies.
Solar road technology and installations is exactly China is now starting to experiment with. Shandong Province is the epicentre of solar road development due to a partnership between solar panel manufacturer Pavenergy and Qilu, a government-owned road construction and management operation. The specialist panels being made by Pavenergy for solar roads are made of a ‘complex polymer that resembles plastic’. The level of friction they offer resembles that of the asphalt traditionally used in roads and can be adjusted for specific conditions.
Pavenergy and Qilu hope that in the near future wireless charging technology will even mean that their solar roads will allow for the upcoming generations of electric vehicles to be charged while driving along them. However, there are still obstacles to overcome. Though the price of producing solar panels has fallen to a tenth of what it was a decade ago building a solar road is still much more expensive than using asphalt. An asphalt road comes with a resurfacing and repair cost of around $120 per m2 a decade. The most ambitious current cost projections from Pavenergy and Qilu for solar roads are $310 per m2. However, they are expected to last for longer than asphalt equivalents and with each m2 expected to produce $15 of electricity a year, over a 15-year lifespan the value of the power produced would close the price gap with asphalt.
Another issue is complications with roads that are built from more asphalt with less concrete underneath. The solar panels’ silicon cells can take the pressure of heavy trucks when there is a solid concrete base underneath a layer of asphalt. However, when there is not, the asphalt compresses very slightly under the weight of the biggest trucks. The paper-thin solar cells snap when bent which is obviously a problem for road systems built using less concrete. This is typical in, for example, the USA. A further issue is the prospect of the panels being stolen and this is one that may have more serious repercussions on the large scale roll-out of solar roads.
However, considering the very early stage the technology is currently in it can be presumed that both costs and technical specifications will see considerable progress. The problem of theft will also hopefully not prove to be insurmountable. Solar panel roads will not, after all, be the first time public infrastructure has included potentially valuable components that could be attractive to thieves. The potential of the new technology is certainly exciting for the future of renewable energy.