Will the solar roof tile ever crack the mainstream market?

A Canada-based company called Ergosun caught One Step’s eye this week with a pitch to the Spanish market for its “ready to install” Integrated Solar Roof Tile – a product engineered in the UK and so far rolled out to the US, Canada, the United Kingdom, Sweden, South Africa, and Jamaica.

Ergosun, it appears, is expanding its presence in the relatively niche market of residential solar roof tiles, with an integrated PV product it says has a “harmonious” appearance, an easy ”click & play” installation process, and is “respectful with the environment.”

The tiles are designed to be installed on a section, or sections, of a roof, and then integrated with similar-looking regular roofing tiles. Ergosun says each tile can produce 15W of energy of peak power and can perform as an individual solar PV panel, each having a module, junction box and integrated MC4 connectors, allowing for “click & play” installation. (The system on the house above is said to be able to produce up to 8kWh of energy.)

In the Spanish market, Ergosun will be competing with another company called Tejas Borja, which has manufacturing rooftop tiles in Valencia for over a century, but has recently started producing a solar version, the Solar Flat-5XL, which comprises a slim-line ceramic tile overlaid with PV panel. And there are bound to be many more contenders in Europe.

In the US, of course, Elon Musk’s electric vehicle and battery juggernaut, Tesla, has its own plans for world domination with its sleek solar glass shingles, dubbed the Solar Roof, a residential PV product that Musk in 2019 predicted would achieve market growth “like kelp on steroids.”

This has not happened. At least, not yet.

Certainly, in Australia, Tesla’s Solar Roof is nowhere to be seen, despite having opened to orders – with a $1000 deposit – almost exactly a year ago. In response to an inquiry through the Tesla Australia website, One Step was told that the Solar Roof could still be 12 to 24 months away from being available.

Elsewhere on the Australian market, we have seen the Flat SOLARtile, which was launched with some fanfare in April of 2019 by Chinese thin-film solar specialist Hanergy in partnership with local industrial giant CSR.

As reported at the time, the two companies had agreed to begin pre-sales of the Thin Film Flat SOLARtile in Australia, New Zealand, South East Asia, Japan and United States markets, ahead of an official global launch later the same year.

But the SOLARtiles, which were to be marketed through CSR roofing subsidiary Monier, are still “coming soon” according to the website. (Monier does also offer an InlineSOLAR option, too, which can be “elegantly recess-mounted” within most Monier rooflines.)

On the more promising side, an all-Australian BIPV roofing product, the Tractile, appears to be ticking along nicely, five years after parent company Trac Group geared up to fund its commercialisation.

So what are the pros and cons of solar roof tiles? And will they ever, as Musk believes, go off like kelp on steroids?

According to a research team from Western Sydney University, which is developing its own BIPV roofing product, solar tiles are the logical next step for residential solar. And not just because they look better.

“[Solar roof] tiles have a range of advantages, such as low maintenance, attractive look, easy replaceability, and no extra load on the roof compared with conventional roof-mounted solar arrays,” the team says.

But one of the key benefits of solar tiles, compared to panels, is that they have been shown to generate power more efficiently, largely because they are less susceptible to overheating.

According to the WSU team, preliminary results from its own solar roof tiles showed they could generate 19% more electricity than conventional solar panels.

“This is because the tiles can absorb heat energy more effectively than solar panels, meaning that the tiles’ surface heats up more slowly in sustained sunshine, allowing the solar cells more time to work at lower temperatures,” the researchers said in The Conversation.

Tractile says its integrated solar tiles are rated up to 55% efficient (per square metre) in converting the sun’s energy into usable electricity – “up to 3 times more efficient than regular solar panels.”

Solar tiles are also advertised as being generally more robust, not just compared to solar panels but to regular roofing tiles. (Videos of hammers bouncing off undamaged solar tiles, while smashing through their ceramic counterparts, can be viewed on both the Tesla website and on Tractile’s).

This is said to make the solar roofing tiles more resistant to damage from extreme weather events like cyclones or hail storms and able to be trod on with impunity by installers or maintenance workers.

In Tractile’s case, the website says its product is rated for ‘H8 destructive,’ which covers hailstones from 60-90mm; can withstand winds up to 280kph; can withstand the weight equivalent of two tradies and their toolboxes on one tile; and – added bonus! – will resist damage from golf balls, so, great for those who live next to a golf course.

Tractile also claims that its solar roof offers “natural insulation with an R-value of 0.05, while the Tractile Eclipse solar tile provides seven times greater insulation than concrete tiles with an R-value of 2.00.”

Finally, of course, (some) PV-integrated roof tiles look good. This is less of an issue for the vast majority of the population which – I’m guessing, here – are mostly ok with the way solar panels look on their roof, perhaps even proud to have them on display.

For architect-designed homes, or rooftops limited by heritage overlays or other council restrictions, the integrated solar tile comes into its own. You can see some impressive examples on both Tesla’s and Tractile’s web pages (and above).

As for the cons, price would have to be the number one. As the headline of the WSU article puts it: “We can make roof tiles with built-in solar cells – now the challenge is to make them cheaper.”

Currently, the article says, (and currently being late 2019) the installation cost of commercial solar tiles could be as high as $A600 per square metre, including the inverter.

This would be a particularly hard cost to swallow in comparison to rooftop solar panels, which continue to come further and further down in cost, while also continually raising the bar on efficiency – and even aesthetics.

Which brings us to the other major road blocks for solar roof tiles, which are: poor consumer awareness, and lack of industrial-scale manufacturing process.

The latter has been speculated on as one of the key speed-humps for the Tesla Solar Roof. A Company Tweet in March 2020 claimed its New York gigafactory, in Buffalo, had “built 4MW of solar roof” in one week – enough for up to 1000 homes. But installations – at least, those reported in the media – remain sporadic in the US.

To be fair, Tesla has a lot going on with its battery and electric vehicle production lines and there has been a little old global pandemic to contend with since the March tweet. But Musk remains confident the product will take off – and if anyone can do it …