New type of extremely powerful solar cell

[Mariner]

Storing solar energy in molten salt then generating electricity using the heat is certainly an option. The question is whether the cost and efficiency of this sort of system is better or worse than a concentrator -> solar PV cell -> energy storage medium system. The devil, as they say, lies in the details.

If you see the Sunrgi and Morgan Solar devices linked above, these do rely on tracking but aren't by any means 'giant', both being pretty small devices and relatively cheap to produce.

Using pumped water for energy storage could prove troublesome where land is as flat as a pancake! Other storage approaches include the molten salts you mention, as well as flywheels and compressed air though I doubt how efficient some of these approaches can be.

We just need somebody to invent a cheap, reliable Ultracapacitor to help us with the energy storage. Unfortunately, EEstor are still keeping quiet and nobody really seems to believe their claims - if something seems too good to be true, it usually is.

 

[soylent]

I recommend the free, downloadable book: Sustainable Energy – without the hot air as an introduction; it's decently sourced and doesn't take a grating ideological stance.

I meant some kind of smaller solar cell with high power in general, not specifically this thingy.

It's inherently a diffuse source. The average annual solar insolation on a flat, vertical facing surface is 100-200 W/m^2 for most of Europe an the US. Cost-effective solar cells are in the 10-20% efficiency range; but lets assume a miracle happens and the 30-40% efficient multi-junction solar cells become cost-effective for more than just satellites and concentrating solar. That gives you something like 30-80 W/m^2. Much of the time you'll be in shade so it's even less.

They're not going to extend the range of your average driver by anything more than a piddly amount. But the need for air conditioning neatly overlaps the availability of sunshine; that might be a worthwhile option for sunny climates.

 

[_xxx_]

I don't think that would be enough to keep the battery filled all the time, but it would certainly contribute a lot overall. Just leaving your car outside during the summer days while at work instead of having to plug it in would be useful and comfortable and after all whatever amount of energy you get out of it, it's 100% free and doesn't affect the environment in any way. So even if that would make say 10%, it's free and thus nice.

 

[KimB]

You're not displacing coal and nuclear; they can't respond that quickly(smaller coal or nuclear plants could load-follow, but that's not the kind of plants that have been built).

You're displacing a bit of hydropower and a bit of natural gas(and you have to pay them for that privilege; why would they decide to forgo profits?) all the while becomming more dependent on natural gas being there in the future.

That seems, to me, to be a matter of plant design. They could, for instance, have large capacitors that allow a time lag so that they can adjust the fuel usage of the plants quickly enough. And one way of dealing with the issue of still burning fossil fuels that would be comparatively low-impact on infrastructure would be to instead use efficient biofuels to take up the slack for power generation.

 

[soylent]

Storing solar energy in molten salt then generating electricity using the heat is certainly an option. The question is whether the cost and efficiency of this sort of system is better or worse than a concentrator -> solar PV cell -> energy storage medium system. The devil, as they say, lies in the details.

Storing thermal energy is easy and efficient(it reduces the size of the required heat engine and may even be a net cost decrease over not storing the heat).

Storing electricity is difficult. Rarely do good solar insolation coincide spatially with good opportunities for pumped hydro and the amount of land you need to flood for the scale you will to make a dent in the power supply is going to attract a lot of flak from both NIMBYs and BANANAs.

Batteries are singificantly more expensive but might make sense if there's a large installed base of battery electric vehicles and you are able to compel them to charge opportunistically to soak up intermittent energy or even to sell energy back to the grid.

The only two large scale CAES plants in existance uses electric power to compress air and then use the compressed air in a natural gas turbine to avoid having to use part of the turbine's output to compress the air it takes in; McIntosh, the newer and far more efficient of the two consumes 0.69 kWh of intermittent electricity and 1.17 kWh of natural gas to produce 1 kWh of dispatchable electricity(A decent combined cycle gas turbine can generate 1 kWh of electricity from 1.8 kWh of gas).

Hydrogen fuel cells aren't terribly efficient and never can be; hydrogen is difficult to store, difficult to transport and has a fairly low energy density(due to the massive tank required to store compressed hydrogen). Might be a way to use fossil fuels more effectively but that doesn't help the storage problem.

If you could cost effectively store large amounts of grid power there'd easily be a nobel peace price in it; or at least, there should be.

The only advantage that I can see for the PV system is in the efficiency of the conversion to electric power, which can be higher in the best multi-junction cells; but a concentrating PV system does not need to be huge to accomplish this.

If you see the Sunrgi and Morgan Solar devices linked above, these do rely on tracking but aren't by any means 'giant', both being pretty small devices and relatively cheap to produce.

Remains to be seen how reliable they are and what they'll actually cost(I've seen claims of <1$/W since the 80's but they never seem to materialize).

Using pumped water for energy storage could prove troublesome where land is as flat as a pancake! Other storage approaches include the molten salts you mention, as well as flywheels and compressed air though I doubt how efficient some of these approaches can be.

Flywheels and SMES is not for bulk storage; it's for power conditioning.

We just need somebody to invent a cheap, reliable Ultracapacitor to help us with the energy storage. Unfortunately, EEstor are still keeping quiet and nobody really seems to believe their claims - if something seems too good to be true, it usually is.

I agree; if their claims are even remotely true it will be huge.

 

[soylent]

That seems, to me, to be a matter of plant design. They could, for instance, have large capacitors that allow a time lag so that they can adjust the fuel usage of the plants quickly enough.

No, they can't. It takes about a day to fully start or stop a coal plant. Capacitors have a craptacular energy density(up to about 10 Wh/kg for the best commerical ultra-capacitors); it would take 100 000 metric tonnes of ultra-capacitor to store as much energy as a single 1 GW coal plant produces in an hour.

Capacitors have excellent power density; that's why they're interesting, not energy density. 10 kW/kg is not uncommon; this would give a 1 GWh ultra-capacitor as above a maximum power output of 1 TW, or about 1000 1 GW coal plants.

The only way in which coal plants can quickly adjust is unplugging their generator from the grid and keeping the turbine spinning and synchronized with the grid; but they'll still consume a lot of fuel acting as spinning reserve and the solar people will need to slip the coal people some cash for providing the service.

And one way of dealing with the issue of still burning fossil fuels that would be comparatively low-impact on infrastructure would be to instead use efficient biofuels to take up the slack for power generation.

Even the best land-based biomass produces less than 1 W/m^2 of average power; waste can only take you so far until you need to set aside massive amounts of land. Unless emissions have a cost I suspect it's more economical to use biofuels to replace expensive natural gas or liquid fuels rather than replacing cheap coal.

 

[Sxotty]

I have to agree with Xxx I know that the PV won't do much for the car, but having a roof made out of solar cells would be cool in and of itself even if it took a day to charge enough to drive only 10 miles.

I guess I could not use a roof mount bike rack then though

 

[RudeCurve]

Whats up with those guys that claim they can use a printer and print out solar cells ?

I would think something like that printed onto shingles for houses could work very well. Here in jersey during the summer you can power all those air conditioners and in the winter when they make less power (or are covered in snow making none) they can be used to light up a few engery efficent light bulbs taking any strain away from the power plants. In the winter we don't use as much power here.

I def like the distribuited solar plant ideas better than huge solar farms though. If i could shingle my house with solar panels for 2k or 3k more than it would currently cost to single my house but the solar cells would last 15+ years and lower my electrical bills i'd go for that and i'm sure many people would also .

Well there's actually a better solar solution to cooling buildings.

Pretty amazing isn't it?

Edit: It could also be used during the cold months to heat buildings too.

 

[KimB]

Well there's actually a better solar solution to cooling buildings.

Pretty amazing isn't it?

Edit: It could also be used during the cold months to heat buildings too.

Doesn't sound like a very useful piece of technology. And it still requires input energy (in this case, the solar panels). There are other ideas as well for using similar designs, such as using the fact that the ground temperature a few feet down is very stable, and having a heat pump that exchanges heat with water that travels through pipes a few feet underground. This makes for very efficient heating/cooling, as not only are you using a more efficient heat pump, but you're using as a heat exchanger water that is closer to the temperature you want to be at, as opposed to the temperature of the external air.

 

[Mintmaster]

Thin film needs something to put it on. That is where the cost will come from. BOS will cost a lot even if the thin film was free.

Not really. You could put it down in places like the Utah salt flats, or use a mesh to support the film. Even if you did need a glass substrate, that's still so much better than large, angled structures that need to move while tracking the sun.

Well, perhaps the benefit of the approach of focusing the sunlight onto a smaller area is that if the reflector is much, much cheaper than the solar panel, then it's an overall cost savings from using panels.

Of course it's cheaper, which is why the technology has been around for many decades, but my point is that it's not cheap enough.

Even just considering the material production leads to mind-boggling quantities. 12 freakin' square kilometers of glass and steel/aluminum for a 1000 MW plant?

I don't think that would be enough to keep the battery filled all the time, but it would certainly contribute a lot overall. Just leaving your car outside during the summer days while at work instead of having to plug it in would be useful and comfortable and after all whatever amount of energy you get out of it, it's 100% free and doesn't affect the environment in any way. So even if that would make say 10%, it's free and thus nice.

Unfortunately most people would rather have their car parked in the shade to keep it cool, and they'd think a big solar panel would be rather ugly, too. In sunny areas, though, you could probably get 10-20 miles worth of energy during the day, which isn't bad.

 

[Mariner]

Ground source heat pumps are a very good idea but I understand they cost a small fortune to install. It would seem to me to be a good idea to install them around new housing as it is being built but there doesn't seem much inclination for people to do so despite the large energy savings available.

From what I can tell, it seems to be mainly the wealthy with large gardens who install them here in UK. I certainly doubt I could have one installed in my house - my garden/property just isn't anywhere near large enough.

 

[Ty]

Well, for the time being it'll just supplement current power production, easing the stress on the grid and allowing other plants to power down during sunny days.

Which happily enough, is when much of the grids are strained due to A/C units going full bore.

 

[Sxotty]

Not really. You could put it down in places like the Utah salt flats, or use a mesh to support the film. Even if you did need a glass substrate, that's still so much better than large, angled structures that need to move while tracking the sun.

...

Unfortunately most people would rather have their car parked in the shade to keep it cool, and they'd think a big solar panel would be rather ugly, too. In sunny areas, though, you could probably get 10-20 miles worth of energy during the day, which isn't bad.

When the wind blows the thin film breaks unless you have something decent to hold it.


On the other front.

PHEV + PV = power to your house if you park it outside Though most people will want their phev in the garage probably.

 

[Mintmaster]

When the wind blows the thin film breaks unless you have something decent to hold it.

True, but you don't need anywhere near as much structural rigidity as large, moving mirrors. Wind can generate a lot of stress at the joints and on the panels there.

For something flat on the ground, though, I still think glue, screen material ($0.10 / sq. ft at Home Depot after markup), and a wire mesh (~6 inch spacing) could work if you anchor every few feet. It'll be at least one order of magnitude less material, if not two.

 

[KimB]

True, but you don't need anywhere near as much structural rigidity as large, moving mirrors. Wind can generate a lot of stress at the joints and on the panels there.

For something flat on the ground, though, I still think glue, screen material ($0.10 / sq. ft at Home Depot after markup), and a wire mesh (~6 inch spacing) could work if you anchor every few feet. It'll be at least one order of magnitude less material, if not two.

Just don't forget the costs of periodically cleaning dust off of the surface.

 

[Mintmaster]

Just don't forget the costs of periodically cleaning dust off of the surface.

Don't worry, I know. I'm just saying that construction costs and materials were always the biggest problem with solar simply due to the large area needed. Thin film reduces that by an order of magnitude at least, even considering lower conversion efficiency.

Interestingly, I remember reading a book in the 90's discrediting the idea of solar panels on rooftops even from a safety perspective. People dying from accidents during cleaning would be many orders of magnitude bigger than the risk from nuclear power plants and even coal mining.

 

[Arwin]

Well, that's the 90s. A few years ago I was offered a solar panel that I could simply and safely construct so that it more or less hangs out of my window, and I simply plug it into the mains. Excess power would flow back into the main grid and cause my meter to run backwards. I didn't take it back then because I didn't have any money (debt, more like), which is a shame because it only cost 500 euros (subsidised obviously), and these days you'd have made that back in a few years.

What I also think is interesting is that back in the 80s, me and my sister had handheld video-games that ran on solar power. Mine (called Amazone) still works, as far as I know (it's not in my possession anymore, but I came across it a few years ago either at my mother's or my sisters, can't remember, or maybe I have it myself somewhere). There's definitely something more that could be done with them. For instance these ebooks should be able to run off them. A reading light should in most cases offer enough energy.

 

[Davros]

what we really need is a device that converts my awesomeness into electricity
that would solve the worlds energy problems

 

[_xxx_]

what we really need is a device that converts my awesomeness into electricity
that would solve the worlds energy problems

We couldn't store that much energy and thus the universe would explode

 

[Mariner]

There is an interesting series of articles about CPV over at Greentech media. Quite a bit of information about various CPV companies/approaches etc.

The blog entry for Sunrgi is quite amusing. Safe to say that the author is less than impressed with their scientific and business credentials!