A Couple of Bad Ideas in Renewable Energy
My good friend Henry asked me to check out these two companies: SolarWindow and LiquidSolar.
Henry: Thanks for thinking of me.
Companies like Solar Window make me nervous. First of all, its predecessor MotionPower (extracting energy from speed bumps) sounds like a bad idea right out of the chute in terms of levelized cost of energy. As they claim, it’s akin to generative breaking, the device which travels along with the car for use at any moment when the car’s forward motion needs to be retarded. Here you have a device buried in the ground which extracts some small combination of the car’s forward kinetic energy and the potential energy that was gained when the car drove up on the speedbump. In the latter mode, it’s like “WattShocks,” a deliciously bad idea that would convert some of the energy from the vertical motion of a car driving along into a tiny amount of electricity. How do I know it’s “tiny?” Because right now it’s being converted into heat. OK, so how hot do your shock absorbers get? Not very.
Keep in mind that even garden-variety regenerative breaking is controversial in terms of its ROI to the driver; postal trucks that stop every 100 feet or so get great returns, but most drivers don’t; the devices are heavy and expensive, and most drivers use their brakes in such as way that this system barely pays for itself over the lifetime of the vehicle.
As far as solar windows are concerned, there are many attempts at this subset of BIPV (building integrated solar photovoltaics). Do these folks have the most cost-effective approach? It’s possible, but there’s no reason to think so based on what I can see here.
Re: the second link, you need to know that I stop reading when I come across something preposterous. Here, I encountered this at the beginning: “Its makers said it’s engineered to out perform rooftop panels by 50-fold.” The efficiency of solar PV is already over 20%. Even if its makers claimed a five-fold increase (rather than 50-fold) they’d still be charlatans.
I love the license plate pictured above. But let’s keep this in perspective. Good ideas help us laugh at ExxonMobil; bad ideas help them laugh at us.
These windows are using organic photovoltaic technology. This technology is still not mature and the versions I am aware of have a poor product life.
There may well be a fast payback as these buildings use laminated glass windows anyway, and the OPV technology is in effect just another coating in between two panes of glass laminated together.
It would probably make more sense to use cadmium telluride, micro-morph thin film silicon (tandem junction), or CIGS with 80% coverage and 20% transmission, or even conventional silicon wafers spaced out with clear glass. Such an approach would give a durable glass glass panel incorporated into a double glazed unit suitable for glazing tower blocks. The approach would also give cost savings as compared to rooftop solar as laminated glass double glazing units and frames would in any case need to be incorporated into the building – so much of the hardware cost would be incurred anyway, With new buildings, there would be minimal soft costs as permission would be sought as part of the initial planning application, and significant savings would also be made on the labour of installation costs.