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Is Tesla’s Solar Roof the Future of Home-Generated Renewable Energy?

Solar energy – especially relating to domestic systems – is at the absolute cutting edge of scientific innovation at the moment and, at Harrisons Energy, we are hungry to make the most of new technologies and products.

On our blog, we enjoy bringing you the latest research and information on what’s available so you can make fully informed decisions on what’s best for your home and family and how you can turn PV solar systems into a way to save you money.

But with innovation – especially in regards to renewable energy – comes a wide range of opinions and commentary on whether specific products are quite as groundbreaking and game-changing as their inventors claim.

The key areas that solar energy systems have to fulfil are:

  • Cost-effectiveness
  • Utility (does it do what it claims – especially in New Zealand’s unique environment)
  • Practicality (both in terms of installation and maintenance)
  • Longevity (to pay back set up costs and also remain useful in a rapidly evolving environment)

So when Elon Musk revealed Tesla’s new solar roof tiles and caused the inevitable global stir that Tesla announcements usually achieve (few other companies can rival their Tesla Gigafactory in Nevada, Model S P85D supercar and EV supercharger stations for press release impact!), we thought we’d do some asking around as to whether they’re really going to start popping up on roofs in New Zealand any time soon.

We talked to Markus Lambert, National Manager, Solar Sales, for LG Electronics Australia Pty Ltd who said the combination of the new solar roof tiles and the newer version of the Tesla Powerwall home battery storage was “very cool” although “some people are sceptical about the roof tile specifically”.

Over the ditch in Australia, Natural Solar’s Sydney-based Chris Williams has said that a solar roof combined with the Powerwall 2, takes Australian homeowners closer than ever before to off-the-grid electricity independence. Chris says that although a large roof with multiple Powerwall 2s to store energy is already possible, a solar roof that is a complete replacement to traditional solar rooftop PVs would allow solar panels to face the sun for every hour of daylight.

On the other hand, there are those – like Eric Wesoff, the editor-in-chief of Greentech Media – who have reservations and say a number of companies involved in creating solar roofing, solar windows and flexible roll-on solar panels have failed to fly.

According to Wessof, roofing and PV panels have different roles and combining the two compromise both roles at a very premium cost. He also wrote in his article that it’s one of those ideas like the solar roadways that attracts imagination and seems inspiring but has no practical benefit.

The fact is, too, that solar roof tiles have been available in Australia and New Zealand for a number of years via Australian roof tile manufacturer Monier but haven’t really taken off.

Markus has come up with eight hurdles he feels Tesla’s solar roof needs to overcome.

  1. A solar roof tile is more expensive than a normal tile or metal roof. Solar PVs installed on existing roofs are still more affordable than solar roofs. Investment returns will take longer as compared to rooftop solar PVs. Solar Panels usually take 5-6 years to pay back while solar tiles will take about 12 years or more.
  2. Solar tiles do not have the same efficiency as the conventional high efficient solar panels. Therefore, one gets less electricity per square metre than some of the high efficient panels available today. For example LG currently has a 320W 60 cell NeON2 range and will release a new NeON R panel in January, which will produce a competition beating 360W 60 cell panel.
  3. Metal roofing sheets and roof tiles are made to last 50 to 60 years, while present-day solar power systems are already proven effective and still evolving fast. Solar technology keeps changing and producing more electricity out of the same 1.62m2/panel area and will require more solar generation as batteries and electric car charging will double the electricity requirements in future years. It would be a brave home owner who is prepared to change his or her entire roof in a short span of say 10 years just to keep up with technological improvements.
  4. Solar installers have pointed out three key reasons why solar systems fail – inverter failures, panel failures due to water damage and de-lamination and connection failures on connectors or isolators. A solar roof tile system has thousands more of connection points than a conventional solar system.
  5. In terms of solar repair, one big advantage of micro converters is that they offer panel level monitoring. Anyone can easily check if a solar panel is not performing well or it has completely stopped working thus repair and replacement will be exact and fast. It is not clear if the solar roof will offer that technology.
  6. Roofers, electricians and system installers have special training and certifications/accreditation before they can do their job. If a solar roof tile gets broken, who will you call? The roofer, the electrician or the solar installer?
  7. How durable are these solar roof tiles to walk on just in case the roof needs repairs, cleaning or maintenance? If micro cracks or solar cell damage happens, this will be a big issue.
  8. The battle of roofing is to improve its insulation properties, not counter it. Elon Musk held up a tile during the product launch and showed the transparent look. A Green house in the roof space may not assist with any cooling effect we desire during our hot summers. Maybe the higher cost of insulating will be required to counter this.
Undoubtedly solar roof tiles are an exciting step in our search for practical and cost-effective ways to reap renewable energy from the sun and many industry experts agree that in theory, they are an excellent idea. But when the technology has been already around for a while, it’s clear that Tesla’s announcement is just the first part of having to convince consumers and the rest of the solar industry that their tiles can overcome a number of practical challenges.