At a technical level, solar photovoltaics (PV) are booming. Almost very month there are reports of some new breakthrough. While there are many high hurdles still to be jumped, solar electricity works today and is being fast tracked for even greater efficiency and lower cost.
Solar electricity comes with an obvious upfront cost. As Peter Erling of PV Solar noted, with the global financial crisis in full swing, “there is not much interest in adding more dollars to the value of a building”.
Yet it is government policy that really shapes the solar market. Jo Bradley, manager at Going Solar, provides one example. In 2006, when government rebates for solar photovolatics were $4,000, Going Solar was arranging around 50 installations a year. But for the past two years since the rebate doubled, its volume of installations has quadrupled.
Market research firm Solarbuzz reports that the global industry saw a 2008 growth rate of 110 per cent, with Europe accounting for 82 per cent of demand. Just two countries, Spain and Germany, now account for 73 per cent of the world’s installed PV energy capacity. One reason is because their governments established favourable conditions for the industry to prosper.
The situation at home is not so rosy. In our Department of Resources, Energy and Tourism report Energy in Australia 2008, it said renewable energy accounts for less than 5 per cent of Australia’s total energy consumption. But 92 per cent of that tiny amount comes from a combination of wood, wood waste and sugar cane waste, as well as hydroelectricity. Solar energy currently makes up only 1 per cent of renewable energy used in the residential sector, and the vast bulk of this is accounted for by solar hot water systems.
So what can architects and building designers do to arrest Australia’s decline in this game? For one thing, they can lobby industry associations to hold all levels of government accountable for the ever moving mishmash of legislation and incentives. As Dan Farrell of SkyPanel says, “You can’t even get a decent business plan together, it’s too risky, everything keeps changing”.
Secondly, have faith in the client. In the ACT, demand for solar photovoltaics over the past year was equal to the previous five. Even after the Federal Government applied a means test to its solar panel rebate, applications were being received at the rate of over 500 per week. Even in the face of worldwide economic meltdown, 17 per cent more households signed up for GreenPower in NSW in the last three months of 2008 than did for the same period in 2007. 10,300 NSW businesses are also on board.
Thirdly, building professionals can stay abreast of the types of solar PV they can encourage clients to consider, in particular, building integrated photovoltaics (BiPVs).
Going Solar have deployed panels using technology from Schott, notably its ASI Glass panels, in several projects, which integrate semi- transparent thin film amorphous solar cells. Panels like these were installed into 200 sqm of the north facing window façade at Ballarat University. The windows allow 10 per cent light to pass through, whilst generating 7.3 MWh of energy annually. And being double glazed, they limit solar radiation from entering the building. Other uses of the Schott Glass panels include a noise barrier near Melbourne’s Essendon Airport, where 500m of the panels produce 24 kW of peak power output.
Working with steel instead of glass, Skypanel laminate Uni-Solar thin film amorphous solar cells to a modified zincalume or Colorbond roof profile, the combination of which it calls SolarDEK. It can be directly walked on, or even pierced, and still continue operating. Farrell of Skypanel says the system is best suited to large-scale applications because the roof profile is mostly laminated on demand, and commercial sized projects are better placed to achieve a more cost effective economy of scale. One example of such an application is the Kogarah Town Square in Sydney. The complete roof of the library and accompanying redevelopment was clad in SolarDEK, with EnergyAustralia exporting all of the captured electricity to the grid.
PV Solar has long been proponents of integrated roof tile systems for residential and commercial applications. These are solar modules in a frame designed to comply with Australian roof construction standards. Erling of PV Solar recently discovered another benefit of integrating PV systems flush with the roof profile. Whilst inspecting an above-roof retrofit he discovered that possums had built a nest of pine needle debris under the raised solar panel frame and chewed attached cabling. Subsequently, a fire started, igniting the accumulated pine needles.
Although a key advocate of integrated systems for many reasons, including their improved aesthetics and ability to be coupled with solar heater systems, Erling acknowledges that integrated units can have their own foibles, such as shared responsibility between tradespersons.
Spark Solar has a technology it calls angled buried contact, which increases the cell area by offsetting electrical contacts away from sunlit surfaces. Spark recently received an Australian government endorsement to establish a $60 million high-tech solar cell factory, producing screen- printed solar cells on silicon wafers.
Plenty of systems are already out of the lab claiming high performance. Sunpower, which earlier this year completed the largest roof mounted solar power system in Australia (305- kilowatt) on the Crowne Plaza Hotel in Alice Springs, says its solar panels, roof tiles and tracking systems deliver up to 50 per cent more power per unit area than competing systems.
Sanyo has also been rolling out its HIT (Heterojunction with Intrinsic Thin-layer) cells. These are a hybrid construction with thin mono crystalline silicon surrounded by an ultra-thin film of amorphous silicon, which Sanyo claims results in a 30 per cent efficiency increase and produce a smaller module size. Sanyo say its HIT cells also perform better in high temperatures. Clean Up Australia’s Ian Kiernan recently installed 10 HIT panels on his farmhouse at Bathurst, NSW.
In the US, Veranda Solar is a prototype plug- and-play solar module that homeowners and renters self-install on their window sills. Also in the US, researchers have developed cells that, in the lab at least, attain 40.5 per cent efficiency.
Across the Pacific they’ve also been developing solar cells from ‘hairy’ nanowires. Also, cells that mimic the light catching patterns on butterfly wings, and special window glass with solar cells imbedded in the frame, as well as Prism Solar’s modules that employ laminated laser scribed holograms to diffract or concentrate light, with the stated intention of reducing costs by 75 per cent. There are certainly many out there chasing the new Holy Grail — a cost effective solar cell.
Though, as Rob Largent, manager of design assistance at the University of NSW’s School of Photovoltaic and Renewable Energy Engineering explained, such innovations, in many cases, struggle to be commercialised due to manufacturing roadblocks. He pointed out that developing processes to profitably produce these new cells on mass can be as technically challenging as designing the cells themselves.
Analogous with that idiom that ‘a bird in the hand is worth two in the bush’, Largent says we shouldn’t wait around for the labs and factories to potentially realise their technological visions. Instead, we should be busy installing the high quality systems readily available today. This is what will ensure the solar industry grows and our carbon emissions shrink.
