Solar roof tiles, or roof tiles with solar cells. They seem like the perfect solution for those who are not much of a fan of conventional solar panels. Solar roof tiles are a lot more unobtrusive, but are they also a good investment?
WHAT IS A SOLAR ROOF TILE?
Solar roof tiles or solar roof tiles are ordinary roof tiles with a solar cell on top. This solar cell works the same as the solar cells in a solar panel. So you don’t need any other inverter for solar roof tiles than for solar panels. Solar roof tiles have only been on the market for a few years. The first house in the Netherlands with a sunroof was completed in 2015. Since May 2017, Tesla has also been selling solar roof tiles in the United States. As with any new innovation, it is expected that solar roof tiles will develop further in the coming years.
A MATTER OF TASTE
A roof with solar roof tiles is an aesthetic choice. Because the solar cells are incorporated in regular roof tiles, you do not have to place large panels on your roof. This looks calmer, especially on roofs with many obstacles. Solar roof tiles are ideal for owners of listed buildings who are not allowed to install solar panels by the municipality. Solar tiles are allowed in many cases. For owners of ‘normal’ homes, it is mainly a question of whether the appearance of the solar roof tile is worth the large price difference.
HIGHER PRICE, LOWER YIELD
The higher costs are also the reason why you don’t see solar roof tiles everywhere. Solar roof tiles are about 2.5 times as expensive as solar panels per kWh; With regular panels you come to an average amount of 4000-5000 euros, solar roof tiles quickly go towards 11,500 euros. This also makes the payback period a lot longer; 15 to 20 years. Solar panels have an average payback period of about 7 years. The longer payback period is partly because the installation of solar roof tiles is a lot more complicated. All tiles have to be replaced, while solar panels can simply be placed on the existing roof. You do save on the costs of new tiles, but this is only relevant if the old roof has to be replaced anyway, or on new construction.
The yield per m2 of solar roof tiles is much lower than with solar panels: 80-90 Wp per m2 compared to 180-225 Wp per m2 for traditional solar panels. This is mainly because 25% of the solar roof tile cannot be used to generate solar power. A solar roof tile, just like a normal roof tile, has a bulge, so that no solar cell can be processed in it. Furthermore, there is no ventilation under the roof tile. This makes solar roof tiles hotter than solar panels. The hotter the solar cell, the less energy it generates. The lower yield of solar roof tiles is offset by the fact that you can place them on parts of your roof where larger panels do not fit. This way you generate about the same amount of solar power.
THE BEST RETURN? GO FOR SOLAR PANELS
Technological developments are fast, also in solar power. So who knows, solar roof tiles may eventually knock traditional solar panels off their throne. It’s just not that far yet. Due to the lower yield per m2 and higher costs, the efficiency of solar roof tiles is a lot lower than that of solar panels. You will eventually earn back your investment in solar roof tiles, but the chance is small that you will also make a profit. While with traditional solar panels you can enjoy free electricity for at least 15 years after the payback period. It is financially more interesting to invest in solar panels. So only choose solar roof tiles if the appearance is very important.