Sparko, John Reece: solar power not good enough! I: psss!

[lilpixieofterror]

Sure, but it's mistaken to say they can't do it at all. Off grid applications, including homes, do use them successfully and the tech has greatly improved.

In some respects, the tech has caught up to conventional but only in the niches where cords are bad things (tools, for example). It's not to where you can run a house on it without compromise, however.

I will agree that the they have improved over the past decade and they do work better and likely will get better in time, but the key I am finding is these battery banks have a very difficult time providing peak output levels for very long (about 15 minutes is the capacity of the bank in Alaska). My laptop can stay charged for days if it is on sleep or stand by mode and the same is true for the rest of my electrical devices too. How long do they last though when they are actively being used? It depends on usage and the power requirements of the device, but they are measured in hours, not days. The big limits for a battery is its capacity to provide peak output levels for a long period of time. For low power applications, solar and battery systems are great (Cali has been running those side call boxes on this sort of set up since I was a kid). When you need to provide high output for long periods of time, they are not so great. You would need lots and lots of batteries, with banks being switched on and off, for these systems to work in such a way people might put up with it.

As to waste issues, yes they must be addressed but that's gonna happen anyway - too many applications need long battery life and the demand for it will grow. From that the massive batteries will also improve and will have to be disposed of. It's already happening so it's not a compelling argument here.

It is for those who talk about clean energy. If you can cleanly collect your power, but the stuff needed to run it puts out hazardous waste. You kind of have an issue. Especially at the industrial quantities you would need to run such a system.

[Truthseeker]

Though I had already mentioned Hawaii's recent electricity development, it looks like I should do a
longer post item on its import for the future of solar PV technology. In the rest of this post, please
bear in mind that I am discussing the combination of energy storage (batteries and fuel cells,
e.g.), inverters (for conversion of dc to sinusoidal ac) and solar pv.
http://en.wikipedia.org/wiki/Solar_power_in_Hawaii
For years the most economical way to generate electricity in Hawaii was to import low-sulfur fuel oil and
coal and use them in generators. If solar PV technology was used, it was for special situations.
That is no longer true. S PV t is now generally a good alternative to the conventional regime in Hawaii.
In just 2 to 3 years more the S PV way will be obviously superior.
By then more areas of the world than now will also find s pv t to be preferable to the other ways of
generating electricity. You might find the wikipedia article "Grid Parity" interesting
http://en.wikipedia.org/wiki/Grid_parity
[The numbers in the next 3 unbracketed sentences are not verified. I am afraid they are wild. I have been fruitlesslly searching for data on overall lifetime cost (20 years?) divided by total kilowatt-hours generated in the lifetime, but I may have information in a few days. The cost should include that for energy storage and for conversion from dc to ac or conditioning, repair and maintenance, etc. Meanwhile feel free to get the data yourself and post it here. Historical data, especially.] By 2020, s pv energy prices might be 1/2 today's s pv energy price. In five more years, 1/4. 5 yet more years, 1/8. By then we might have 80% of the world's energy output coming from s pv t.

[Sparko]

If they found a cheap non-polluting way to generate a lot of hydrogen, then fuel cells would be a great source of electrical power.

[Truthseeker]

If they found a cheap non-polluting way to generate a lot of hydrogen, then fuel cells would be a great source of electrical power.

Not only can solar power be used to purify sea water, it can be used to dissociate water to generate hydrogen and oxygen. Eventually in oh, say, fifteen years, that may become a major use of solar power.

[lilpixieofterror]

Not only can solar power be used to purify sea water, it can be used to dissociate water to generate hydrogen and oxygen. Eventually in oh, say, fifteen years, that may become a major use of solar power.

Sure, if you ignore the fact that desalination of water creates a rather toxic byproduct and takes a lot of energy to do. Once you could figure those problems out, you'd be set.

[Leonhard]

I agree with people's assessment about solar thermal power. Its not a viable candidate. However solar photovoltaics will eventually outcompete both coal and gas this century, even with the most optimistic estimates of new discoveries of deposits.

[Leonhard]

Not only can solar power be used to purify sea water, it can be used to dissociate water to generate hydrogen and oxygen. Eventually in oh, say, fifteen years, that may become a major use of solar power.

That's a very inefficient way to store energy, and with all the difficulties lilpixie mentioned. If you're going to do on on-site storage, it will likely be with batteries.

[Leonhard]

If they found a cheap non-polluting way to generate a lot of hydrogen, then fuel cells would be a great source of electrical power.

Fuel cells have no advantage at all over batteries, not even over lithium-ion batteries. They manage to simultaniously take up more space, weigh more and are more expensive to build and maintain than lithium-ion batteries. Come next paradigm of batteries such as the lithium-silicon, or the more ambitious sodium-sulphur or lithium-sulpher, it won't be any competition at all.

[Sparko]

Not only can solar power be used to purify sea water, it can be used to dissociate water to generate hydrogen and oxygen. Eventually in oh, say, fifteen years, that may become a major use of solar power.

Perhaps one day. It has to be a LOT more efficient though. You really seem set on solar power. Why? there are lots of other and better sources of renewable power. Solar is one of the least efficient ones out there and may never get good enough.

[Sparko]

I agree with people's assessment about solar thermal power. Its not a viable candidate. However solar photovoltaics will eventually outcompete both coal and gas this century, even with the most optimistic estimates of new discoveries of deposits.

I disagree. Solar PV rely on rare earth elements and unless they find a way to make them a lot more efficient, the sheer quantity of material needed for PV will limit its usage.

[Sparko]

Fuel cells have no advantage at all over batteries, not even over lithium-ion batteries. They manage to simultaniously take up more space, weigh more and are more expensive to build and maintain than lithium-ion batteries. Come next paradigm of batteries such as the lithium-silicon, or the more ambitious sodium-sulphur or lithium-sulpher, it won't be any competition at all.

Did you read my PM to you about creating graphene capacitors that could be used as power storage? That sounded pretty neat.

But the advantage of fuel cells over batteries is that fuel cells generate electricity. Lithium batteries only store electricity. It has to be generated somewhere else. So if we had a cheap and plentiful source of hydrogen, fuel cells would be a good way to generate electricity. Not nearly there though.

[Leonhard]

Perhaps one day. It has to be a LOT more efficient though. You really seem set on solar power. Why? there are lots of other and better sources of renewable power. Solar is one of the least efficient ones out there and may never get good enough.

I think Truthseeker's excitement about solar power is mainly driven by the popular articles popping up as that's what he's primarily linking to. That doesn't mean that he's wrong, it just means that he might not know the best arguments for why solar power will likely become th king of the energy industry.

If you're asking which alternative energy is the cheapest in general is right now, then that's land based windmills, which is competitive with coal power in most places. However in some places like Arizona its solar power.

By itself solar power already is 'good enough' in terms of the power produced. You might be looking at the conversion efficiencies and see numbers such as 20% for thin-film solar cellls and think to yourself "That's not much." Its true that its far away from fully extracting it, to say nothing of the record breaking (and super expensive) 43% cells they put on some satellites, but you really don't need to extract much because the sun puts out quite a lot of power per square foot. I've seen conservative estimates that in an alternative energy society you wouldn't need to cover much more than around 5% of USA to more than fully cover for all its energy needs.

What's hampering it isn't the power per square foot, its the price. The solar photovoltaic cells themselves are fairly cheap, today they will last for they cost about as much as dry wall. Its less than a third of the Total Cost of Ownership. Even if they were free, solar power wouldn't be significantly cheaper. Why? That's because of the two parts which is the cost of manually installing the panels, and for the electrical systems they need to be hooked up to, especially the power inverters.

Things are changing on that front though. There's been a smorgasbord of companies in the US trying out various solar power models in states with favourable amounts of sun. Many of these have failed, but a few have succeeded and are now growing exponentially. The business model of Solar City is very good and they've had running growth for the past six years, albeit with this year being fairly slow.

The cost of installation can be brought down with standardised solutions and ways to make installing these things less of a custom job and more akin to applying well tried solutions out in each case. The cost of inverters and the other stuff can be brought down by the economies of scales, atleast a 15% to 25% on that side of the cost can be gained by scaling production by a factor of ten.

So right now you have this exciting new development where solar power is already price competitive with coal in places like Arizona. Right now. If the price can be brought down by 50% it would be price competitive with coal even in Denmark where I live.

And as soon as this is the cheapest way to generate power, it will happen. All the green world campaigns can't force this change to happen, but when the price per kilowatt-hour crosses a certain threshold, the change will happen. Either the current reigning champions in the energy market will be moved over by these early shakers, or - which might be more likely - the companies like Exxon will start developing solar power as if its been their goal from the start.

Its a nice change of paradigm. Its new companies competing about what technical solution will be the. Its new technologies and lots of technical wizardry.

I think that's kinda exciting to watch. Plus I kinda like the idea of generating some of my own energy for home use one day.

[Leonhard]

I disagree. Solar PV rely on rare earth elements and unless they find a way to make them a lot more efficient, the sheer quantity of material needed for PV will limit its usage.

This is certainly true for CdTe photovoltaic cells. Tellurium is kinda of rare in the crust, and about three times more expensive than gold. Its mainly produced as a byproduct of copper extraction currently. Solar City, the company I'm kinda fanboying over, is opening its own mine to get a better control of the prices there. However with the current production you don't have a significant ceiling for a growing solar power industry.

I can't remember how many square miles of CdTe cells you could make for one ton of tellurium. Which I feel kinda embarrassed about, this must be what it feels like for a football fanatic who loses track of a bit of interesting trivia. I'll get back to you on that one.

CdTe cells are easy to recycle. The heavy metals are sandwiched between two layers of glass, more than 95% can easily be extracted.

Better paradigms are definitely worth seeking, but this will more than suffice to really kick off this industry.

[Leonhard]

Did you read my PM to you about creating graphene capacitors that could be used as power storage? That sounded pretty neat.

Capacitors might have be a breakthrough. Lithium-ion energy density or more, and charging faster than it takes to fill a car on gas... and with nearly no degradation with use? It could change everything.

So if we had a cheap and plentiful source of hydrogen, fuel cells would be a good way to generate electricity. Not nearly there though.

There are only two sources of hydrogen currently: Cracking natural gas with high temperature steam and by hydrolyses of water with electrical power (not done very much at all). There are no natural sources of pure hydrogen gas out there.

Once that's factored in you're looking at filling a car with something more expensive than gas, and up to eight times more expensive than charging a car on electrical power.

[Teallaura]

I will agree that the they have improved over the past decade and they do work better and likely will get better in time, but the key I am finding is these battery banks have a very difficult time providing peak output levels for very long (about 15 minutes is the capacity of the bank in Alaska). My laptop can stay charged for days if it is on sleep or stand by mode and the same is true for the rest of my electrical devices too. How long do they last though when they are actively being used? It depends on usage and the power requirements of the device, but they are measured in hours, not days. The big limits for a battery is its capacity to provide peak output levels for a long period of time. For low power applications, solar and battery systems are great (Cali has been running those side call boxes on this sort of set up since I was a kid). When you need to provide high output for long periods of time, they are not so great. You would need lots and lots of batteries, with banks being switched on and off, for these systems to work in such a way people might put up with it.



It is for those who talk about clean energy. If you can cleanly collect your power, but the stuff needed to run it puts out hazardous waste. You kind of have an issue. Especially at the industrial quantities you would need to run such a system.

1) No argument. My point was merely that they can actually run a house - with compromises.

2) Nope, I don't have a problem at all. I want cheap energy - I'm not deluded enough to believe that any source will ever be perfectly 'clean' - and as long as we clean up after ourselves, I'm not sure it's a worthwhile goal, anyway.