Film Turns Windows Into Solar Panels 186
itwbennett writes "At the Ceatec electronics conference in Japan this week, 3M is showing film that turns windows into solar panels. Although the product only generates about 20% of the electricity of a traditional solar panel, it will cost about half as much, is much easier to install, and takes up no additional space. 'An average person could go to the store, buy some of this, and then bring it home and install it themselves,' said Yasuhiro Aoyagi, a senior manager in the company's construction markets division."
Re:Average person rewiring their house? (Score:4, Informative)
Actually it is dead easy these days. You buy an inverter which plugs into any socket. It doesn't support "island mode", so if the grid power fails, the solar power goes out too.
They are not universally legal, so check the local laws. They are about as safe as anything gets when electricity is involved.
Re:Return on investment (Score:3, Informative)
You're right though, fossil fuels (for example) are an actual energy source when compared to typical current photovoltaic solar panels which use more energy to produce than they'll generate over their lifetime (and that's before the conversion losses). The typical solar panel you see on a rooftop is really more a coal burning panel.
Now you're making things up. According to NREL, back in 2004, the time needed to generate the amount of energy used to produce solar panels was about 3-5 years or less, depending on the type of panels ( http://www.nrel.gov/docs/fy04osti/35489.pdf [nrel.gov] ). The financial payback time (time to recover the dollar cost through savings on your bill) without subsidies is longer because you're paying for more than manufacturing energy, and because the competing technologies are both subsidized and are also larger, more established industries.
According to Murphy & Hall ( http://dx.doi.org/10.1111%2Fj.1749-6632.2009.05282.x [doi.org] ), the EROI for PV is 6.8. That means it takes one unit of energy from somewhere else to result in 6.8 units of electricity from the panels. Compare that to natural gas, which has an EROI of 10, which means it takes 1 unit of energy from other sources to get enough gas out of the ground to burn for 10 units of energy. This comparison doesn't take into account that the "energy returned" is in the form of a finite resource you have to burn in the case of gas. In other words, with 1 unit of natural gas, you can generate 6.8 units of electricity by using it to build PV, or you can get around 0.4 units of electricity by burning it in a turbine, after deducting the amount needed to get another unit of gas out of the ground. For comparison, the same source says that nuclear power has an EROI of 5-15, and coal is higher at 80. Again, this doesn't take into account that you're using the fuel itself.
Nothing against research into solar energy, just when you find people deploying with current technology onto their rooftops (or window panes) and announcing their "helping the environment" or that they have a "carbon neutral" energy source or that what they're doing makes economic sense is laughable.
In terms of environmental impact, grid-tied solar power makes sense with today's technology (or 10-year old technology for that matter). In terms of dollar cost for putting it on residential roofs, maybe you don't save money without the subsidies. For the window film, who knows.
Solar panels are not carbon-neutral, but they generate about 90% less greenhouse gas emissions than the conventional plants they displace, which are primarily coal- and gas-fired.