[experiment0]

We are already struggling to make low cost solar panels that have a high efficiency using light absorbed from the visible spectrum (which accounts for most of the sun's spectral irradiation [1]).

Furthermore, you can't just have solar cells that absorb a wide range of the solar spectrum, there is an optimum band gap for these materials of around 1.34 eV [2].

This means that the most popular solar cells in development, namely CIGS and CdTe are already occupying the niche for maximum efficiency. The challenge now is finding new materials that are cheaper to make and show greater efficiencies whilst not relying on the use of rare earth/toxic elements.

(Hint: the real development in this area at the moment is hybrid perovskites [3])

Basically, this is irrelevant cruft.

[1] http://zebu.uoregon.edu/~imamura/122/images/solar_spectrum.p...

[2] http://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limit

[3] http://www.nrel.gov/ncpv/images/efficiency_chart.jpg

(source: currently doing a PhD in a new photovoltaic materials)

[yxhuvud]

You can't make single cells that absorb a wide range, but you can layer cells that absorb different spectras to achieve a much higher absorbtion in aggregate.

[dpierce9]

This is a great point. We shouldn't ignore other efficiencies though. When used on the building envelope, light energy that would otherwise heat the building is converted into electricity instead. Assuming a reasonable efficiency for the conductors and inverters, this reduces the overall building demand. Even small reductions in demand can have huge price benefits for wholesale electricity buyers during expensive summer months (i.e. large commercial buildings). Hence, even if these panels are less efficient than opaque panels (and really how could they not be?) there may be other ways they can make sense from both energy savings and cost perspectives.

[yessql]

Now your window needs wiring. And an inverter. Would be more effective to coat it or tint it or put up some blinds.

[freehunter]

Why couldn't you collect the solar energy from the outside of the window and put up blinds to block the light from the inside of the window? Putting up blinds won't generate any electricity.

[larssorenson]

What if we could design a solar cell that could shift from transparent to opaque on demand? Instead of putting up blinds, simply move a slider or tap a button or what have you, and suddenly the amount of light coming in is dimmed, and the energy being captured is increased. Seems like a win-win to me, if it were possible.

[pbhjpbhj]

Solar-panel covered shuttering could do that.

[dpierce9]

Well blinds would presumably block the light you want in (visual spectrum). Furthermore, anything that isn't reflected back out serves to heat the building. Absorbing the energy in a PV material takes some fraction of energy that would otherwise become heat and turns it into something valuable.

Efficiency is very important but just one-big factor to consider in your application. Less efficient panels can have other benefits that justify their use. Crystalline silicon panels are more efficient than thin film but thin films are lighter and so can be used on roofs that don't support the heavier panels.

[freehunter]

Blinds would block the light after the light has already passed through the solar panels. You get the shade plus the electricity.

[higherpurpose]

As they say in the video, even if these are half as efficient as regular solar panels, you could still see them on other types of surfaces where current solar panels can't be used right now: think windows or smartphone screens.

We could also see them on large buildings or rich people's villas whose owners perhaps want to use energy from solar panels, but don't like the "look" of solar panels on those buildings. So then the choice becomes using this or using no other solar panels.

[experiment0]

We really don't have a shortage of space to put solar panels. The challenge is making solar panels that are cost effective (e.g. $ per Watt).

In response to your edit: That is a possibility, that yes they may find a niche in the fancy of the rich.

But the point I'm making is that the article is hyperbolic and misleading.

Transparent solar is not the future of utility scale power generation. It is not going to solve any of the problems currently holding back solar power from becoming ubiquitous.

[antr]

Volume is key. Volume to push price of silicon panels down to have electricity reach grid parity levels. An intesting project (which I think has been ditched or put on hold) is/was DESERTEC. Install thousands of PV pannels in the Sahara dessert, and connect this to energy-hungry Europe thorugh a new HVDC grid connection.

Source: http://en.wikipedia.org/wiki/Desertec

[ansible]

> The challenge is making solar panels that are cost effective (e.g. $ per Watt).

And the other key challenge is nighttime.

If we had relatively low-cost utility-scale electrical energy storage, we would see a much higher rate of solar energy adoption. More so in sunny places, but that would then drive down the cost for everyone.

I keep hoping something like a flow battery will turn out to be practical, where to size up the storage, you just need bigger storage tanks.

[jndetlefsen]

i get smartphone screens, but it's not that every other surface has been covered already or that you can't transport electricity from A to B.