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Australia Engineers Set New Solar Energy World Record With 34.5% Sunlight To Energy Efficiency (unsw.edu.au)
An anonymous reader writes: Australian engineers have edged closer to the theoretical limits of sunlight-to-electricity conversion by photovoltaic cells with a device that sets a new world efficiency record. A new solar cell configuration developed by engineers at the University of New South Wales has pushed sunlight-to-electricity conversion efficiency to 34.5% -- establishing a new world record for unfocused sunlight and nudging closer to the theoretical limits for such a device. The record was set using a 28-cm2 four-junction mini-module -- embedded in a prism -- that extracts the maximum energy from sunlight. It does this by splitting the incoming rays into four bands, using a hybrid four-junction receiver to squeeze even more electricity from each beam of sunlight.
That is correct, but watt/m^2 is highly correlated with watt/$, because installation and maintenance costs already dominate the cost of the panels, and those costs are correlated with the total area of the panels. Higher efficiency panels are cheaper to install and keep clean. As the cost of panels drops further, you might naively think that efficiency doesn't matter: With panels so cheap, you'll just buy more. In reality efficiency becomes more important as the cost of the panels becomes irrelevant.
The important criteria is no longer watts/$. It is storage.
While progress on efficiency is nice, the important criteria is watts/$, not watts/m^2. We have plenty of space on rooftops, over parking lots, and in deserts. But we need to continue to bring down the cost.
You obviously do not live in the Bay Area.
You can't lie the solar panels flat (they have to be angled), and if you have a flat roof, that means building up at least framing. Much of the roof space in the San Francisco Bay Area is flat.
More framing means more $/watt, so an improvement in watts/m^2 is an area squared improvement in cost.
In my personal area, mid-peninsula, I don't have enough usable roof area to hit break-even with the current panels SolarCity is trying to get people to buy for them so they can sell the property owners their electricity. A more efficient panel and two "power walls" would solve this break-even problem for me, but it turns out that once you are locked into a contract, they will not replace the panels, other than as a result of maintenance, for the next 20 years.
A more efficient panel would be a godsend, but until it happens, I'm either buying my electricity from both SolarCity and PG&E, or just from PG&E, and the up front cost amortized over 20 years of time value of money actually makes PG&E the cheaper option (for now).
Note that for rental properties, you might be talking 3 families in a 3 story building, and you have to fit the panels for everyone on the roof area that's pretty narrow, and pretty built upward already. I know of a large number of properties in the Inner Sunset and up towards the Outer Richmond, Sea Cliff, and Richmond districts that literally *can't* install solar panels without a zoning variance. It would make the building too tall to build the angle racks, or roof over the flat roofs with angled roofs, instead -- since the Solar providers won't guarantee against roof leaks, with an angled panel install, anyway.
No, solar is far from a solved problem, and increased energy density helps a lot more in dense areas than putting a lot of panels *everywhere* in a relatively limited area.