Solar Cell Breakthrough - Over 40% efficiency!

[photon]

http://www.energy.gov/news/4503.htm

This is pretty awesome actually, it would be great to be able to put this on rooftops all over a city to suppliment the power grid.

[Table 5]

This is encouraging news. Solar panels in a sunny city like Calgary would be very welcome....especially with the weather you guy's have been having lately surely sucking up a lot of power.

[Bobblehead]

How would the power grind handle it if solar (or more wind, for that matter) caught on in a big way?

The power generation would still need to be capable to handle it when it was dark or there was no wind. Is there a point when it becomes too difficult for a utility to make up sudden shortages?

[photon]

True, though there are ways to store excess power (giant flywheels). Not a pure replacement yet.. Plus if you had a huge solar panel farm you have big distribution problems. I recall reading somewhere that a panel farm at 8% efficiency would need to be 280 miles per side to supply the power for North America or something.

EDIT: Hard to do but not out of the realm of possibility.

But combine it with good storage, or use it to get hydrogen to power the cars.. The end efficiency doesn't really matter if a) you're getting the power for free (from the sun) and b) it's economical to build the collection and distribution infrastructure.

[Bobblehead]

Originally Posted by photon

True, though there are ways to store excess power (giant flywheels). Not a pure replacement yet.. Plus if you had a huge solar panel farm you have big distribution problems. I recall reading somewhere that a panel farm at 8% efficiency would need to be 280 miles per side to supply the power for North America or something.

But combine it with good storage, or use it to get hydrogen to power the cars.. The end efficiency doesn't really matter if a) you're getting the power for free (from the sun) and b) it's economical to build the collection and distribution infrastructure.

For sure it is a storage issue, unless, as you mention, you use this power to replace other types of "non-immediate" power (like to produce hydrogen).

[ken0042]

Plus, most of the demand on our power grid occurs during the day; when offices and factories are working. Even on a cloudy day like today there is still power to be generated. And as Photon said, free electricity could be used to create hydrogen.

I only wonder; if we become so dependant on hydrogen; will we end up at some point being short on water? I know the hydrogen being burned will form water, but how much will be lost, and how much will be required to be stored?

[kevman]

Originally Posted by photon

a) you're getting the power for free (from the sun)

It's not entirely for free. The sun's energy heats the earth. The more energy we use the less energy reaches the earths surface and in turn heats it. I could just see it know...Global Cooling...

[Agamemnon]

Originally Posted by kevman

It's not entirely for free. The sun's energy heats the earth. The more energy we use the less energy reaches the earths surface and in turn heats it. I could just see it know...Global Cooling...

We've solved it!!

[photon]

Originally Posted by kevman

It's not entirely for free. The sun's energy heats the earth. The more energy we use the less energy reaches the earths surface and in turn heats it. I could just see it know...Global Cooling...

Yeah but if we use that energy where does it go? Unless we're trapping it in kinetic energy by launching stuff off the planet or storing it forever in some chemical bonds, it will eventually become heat. Burn the hydrogen, you get heat. Use it to move a car, all that energy becomes heat. Use it to heat a home.. you get the idea

[moncton golden flames]

It would be great to sell excess power ...but...as I understand it, Alberta has yet to allow "Net Metering" which allows selling excess power back to the grid. You would need some sort of battery to store extra energy, or it would go wasted.

[Burninator]

Originally Posted by moncton golden flames

It would be great to sell excess power ...but...as I understand it, Alberta has yet to allow "Net Metering" which allows selling excess power back to the grid. You would need some sort of battery to store extra energy, or it would go wasted.

When I went to SAIT they generated their own power for the campus, ACAD and Jubilie and sold the rest back to the city. They didn't use solar panels, they used cogeneration.

[Tron_fdc]

Originally Posted by Bobblehead

How would the power grind handle it if solar (or more wind, for that matter) caught on in a big way?

The power generation would still need to be capable to handle it when it was dark or there was no wind. Is there a point when it becomes too difficult for a utility to make up sudden shortages?

What do you mean by handle it? As in the transmission of new power? ie, is the grid capable of carrying all the excess being fed back in? My guess would be yes it is. Last time I checked the major transmission problems were in the Cal-Edm corridor, and small sites that were looking at producing wind gen down south.

There is enough generation now to handle most spikes (at least in Alberta) which mainly happpen throughout the day. It would take a major event to cause an electricity shortage at night, and in the words of the immortal Ralph Klein, if people woke up cold they could "get a better sweater". Nonetheless, there are probably a gazillion case studies that have seen done showing the benefits of self generation.

I'm not sure if Alberta's system is set up to do this however. I think Ontario is the only province in Canada where you can generate and fed back in (net metering), for a credit on your bill. It's not a major hardware problem here(from what I remember, anyways) but good luck convincing City owned Enmax that they're not going to be able to rape you as much as usual, after they replace their meters with ones that can record your solar panel.

Man, I hate deregulated electricity sometimes....

Edit: (thanks MGF, I forgot the term net metering)

[Tron_fdc]

Originally Posted by Burninator

When I went to SAIT they generated their own power for the campus, ACAD and Jubilie and sold the rest back to the city. They didn't use solar panels, they used cogeneration.

I do believe you needed a minimum capacity to feed back into the grid (1 megawatt in 2000, could have changed by now). You're only looking at a few kilowatts with solar gen on a house.

[Bobblehead]

Originally Posted by Tron_fdc

...stuff...

Actually, what I was thinking was more along the lines of everyone is happily generating say 40% of their own power. The power generating system only needs to maintain 60% of the work (but still must be able to pick up 100%). What happens if a dark weatherfront crosses teh province, or it is at night and the wind suddenly dies down, and the generating facilities need to now generate 90%.

How long does it take to get up to that capacity? What if the wind is gusting - does that cause the wind generation to fluctuate a lot?

I guess I'm thinking that since you can't store AC and most people/electrical systems require a fairly steady power source, that a power system were any significant portion of the power generation comes from a highly variable/unreliable source would hace unique and challenging issues.

[Phanuthier]

Originally Posted by Bobblehead

How would the power grind handle it if solar (or more wind, for that matter) caught on in a big way?

The power generation would still need to be capable to handle it when it was dark or there was no wind. Is there a point when it becomes too difficult for a utility to make up sudden shortages?

You would have to open the solar cells if the cells are not being illuminated, otherwise the cells would acts as a load.

40% to me isn't too big of a deal... just messing around with the thickness of your junction for the wavelength you want to absorb. Otherwise, the first layers that the light hits may absorb or reflect when you'd want it to transmit; the first layers may also be absorbing wavelengths of the specta that arn't exactly optimal, and not getting the sufficient power.

If you could control that, you'd be jumping to 90% efficiency, where your only loses (theoretically) is your quantum efficiency.

[Tron_fdc]

Originally Posted by Bobblehead

Actually, what I was thinking was more along the lines of everyone is happily generating say 40% of their own power. The power generating system only needs to maintain 60% of the work (but still must be able to pick up 100%). What happens if a dark weatherfront crosses teh province, or it is at night and the wind suddenly dies down, and the generating facilities need to now generate 90%.

How long does it take to get up to that capacity? What if the wind is gusting - does that cause the wind generation to fluctuate a lot?

I guess I'm thinking that since you can't store AC and most people/electrical systems require a fairly steady power source, that a power system were any significant portion of the power generation comes from a highly variable/unreliable source would hace unique and challenging issues.

You can actually bring up capacity quite quickly in Alberta. When I was involved in the industry there were a lot of gas generators that would sit idle, waiting for price spikes. As soon as there was one (which, in the first few years of deregulation there was a lot of) they would fire up and feed into the grid at market price. You were looking at a matter of minutes to bring them on. We would also monitor load throughout the night, and found that you would see the load at maybe 50%, so the chances of actually needing to bring on any generation was quite slim. With net metering, you would actually decrease price spikes as not only would people be feeding back into the grid with a solar panel or small wind turbine, but chances are they're not using a lot of power at that moment either. IMO it would greatly reduce spot price for power, and in the end reduce everyones power bills. It's a great idea, and I have no frickin idea why it hasn't been done in Alberta.....one of the only provinces/states in NA with a "true" deregulated electricity system.

There are also lines running East-West from Alberta, so in the event that we ran out of capacity we could purchase power from BC and Saskatchewan. I think that only once in the last 6 years did we ever hit 100% capacity, so it's not really a common occurence. The BC lines were used mainly to rape Alberta in the beginning of dereg, but that's a whole different story....

[Addick]

Being the sunniest city in Canada Calgary should really jump on this. I'd love to see more Plus Housing in Calgary! Hopefully if City Hall decides to push solar power on developers they do it better than they push smart growth on them... Like actually pushing it.

[Phanuthier]

Originally Posted by Addick

Being the sunniest city in Canada Calgary should really jump on this. I'd love to see more Plus Housing in Calgary! Hopefully if City Hall decides to push solar power on developers they do it better than they push smart growth on them... Like actually pushing it.

Initial fixed costs are very high... especially if you want to get these spectrolabs ones. These are concentrator cells, not an entire solar panal. They can get rather pricey.