According to Sven Lindstroem, co-founder and head of solar technology company Midsummer AB, building integrated photovoltaics (BIPV) offer the only feasible way of reaching the zero energy buildings goal in the EU. He believes the future of urban solar energy lies in integrating PV into roofing materials and facades already at the factory.
SOLAR ON HOUSES NEEDED FOR 2020 TARGET
In the last ten years, the installed global solar energy capacity has multiplied nearly 50 times. The cost of purchasing and installing a solar panel has decreased by 80% in five years and is still falling. The comparable cost of electricity generation has made solar energy the cheapest energy source today, from being the most expensive only six years ago. This is truly a green revolution.
So when politicians and activists set highly ambitious target for a ‘zero emission’ world, the success and potential of solar energy proves that they are attainable. It is clear that solar energy needs to play a very big role on the process of reducing CO2 emissions.
One of the most important targets, is the requirement set by the European Union that “all new buildings must be nearly zero-energy by the end of 2020, and all new public buildings must be nearly zero-energy by 2018”. The year 2018 is only two years away. The USA also has ambitious targets, on federal, state and county level, e.g. for federal buildings, and all in a matter of only a few years.
Zero-energy buildings are also called ‘passive houses’ (or zero net energy buildings in the US) since they require no or little energy for space heating or cooling. Needless to say, ventilation and insulation is important for a ‘climate smart’ house, but not sufficient – energy production is also almost always necessary. With solar energy these houses can even be turned into small power plants, producing more energy than they consume.
Millions of distributed small power plants
Having millions of these small power plants in a city or region is a dream for any urban planner (or Environment Minister). Luckily, the technology is already here. Builders need not experiment with new construction techniques or materials, just use existing building methods and apply solar panels.
Forget traditional heavy and rigid silicon solar panels on frames. They are suitable for large solar parks but not for urban purposes. Instead, thin film CIGS solar modules are ideal for BIPV since they are thin, lightweight, flexible, durable and highly efficient. They can easily be retrofitted to existing roofs and facades but the future of urban solar energy is to integrate photovoltaics into roofing materials and facades already at the factory where those building materials are manufactured.
With thin film solar panels on the roofs, virtually all buildings could become passive houses or even ’plus houses’, depending on roof area and location. Thin film CIGS solar cells (by Midsummer) produce 80-100 kWh/m2/year – more than enough for the house’s own consumption in almost any geographical location and climate (depending on whether it is a residential dwelling, an office or a factory).
New batteries potential disruptive force
Another strong disruptive force is improved batteries for storage of renewable energy. The price of battery storage has plummeted. Efficient storage of energy is essential for all renewable energy sources, as well as the electrical vehicle industry. Electric car maker Tesla’s (NASDAQ:TSLA) visionary founder Elon Musk is making a big play on solar energy and BIPV. Tesla recently opened its lithium-ion rechargeable battery ’gigafactory’ in Nevada. Research in even more advanced battery technology, like the promising lithium-air battery, may improve battery efficiency significantly.
It was recently announced that panel maker SolarCity (NASDAQ:SCTY), recently acquired by Tesla, plans to start developing and selling roofs integrated with solar panels. ”It’s not a thing on the roof, it is the roof”, said Mr. Musk, correctly identifying esthetics as one of the key selling points to the consumer market.
So in my view, roofs and facades on urban buildings will basically be made of thin film solar panels that will rapidly become both more efficient and nicer to look at. Owners of the buildings will smile ‘all the way to the bank’, or rather not having to go to the bank to pay electricity bills. The residents and office/factory workers will quickly get used to the look of the ‘solar houses’.
Building material suppliers slow to adapt
The future is to integrate PV into roofing materials and facades already at the factory where those building materials are manufactured. But most building material suppliers in Europe and US are reluctant and slow to step outside their core businesses. There is a huge opportunity for visionary companies not only to explore the European and US PV markets, but to enable a strong foothold into the multi-billion dollar building material market in EU and US.
The only feasible way of reaching the EU target of zero energy buildings by 2020 is through BIPV. The technology already exists and the panels are cheap – payback time of an installation is around seven years in most countries while the expected lifespan is at least 25 years. So what are we waiting for?
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