There are a wide range of potential solar technologies some requiring rare earth minerals and some not. It is not correct to write off solar technology due to such resource limitations.
For example see our article on Concentrating Solar Power which doesn’t need anything fancy, just large amounts of direct sunlight as is found in the US’s southern deserts or North Africa.
New solar technologies use lots of rare earth minerals that soon will be gone. Gone.
I think this would be a great story theme to be followed up here.
I have been listening to all the "gush" about thin film solar, but from my almost completly uniformed position it really seems unlikly to me that some of these technologies can scale up to utility sized projects that are sustainable.
The wide scale deployment of LCD monitors has driven up the price of Indium > an order of magnitude in only a few years, its about as common in nature as Silver, and the best efficiency seems to be with Tellurium compounds, the rarest solid element on the planet (except for some radioactive things that decay). Its price has risen, I belive from $US4 per pound in 2000 to over $100 now.
Does anyone know how much deployment it would take before we could expect the current price gap between these designs and the silicon based technologies to be erased?
Also Palladium, Platinum, and Gold cost more than 400$USD a kg
A reduction in the quanitity of junction materials, as well as directed production of PV targeted cell materials will likely have huge economy of scale effects, lowering the $/Watt price down. This in turn will allow for the economy to grow in a more sustainable fashion.
To address rarity, Wiki says 0.001ppm on average (1e-9) concentration, so going by typical concentrations required from the NREL website (http://www.nrel.gov/pv/cdte/) which states less than 0.1% by mass is required(about 7g/m^2 from the NREL pdf on the same page.).
Therefore a meter square of panel will require 7E9 g of marginal mining (7e6 kg, or 7000 Tons). This is the marginal requirement, obviously currently exploited ores are much easier, considering that the Tellurium for 1 sq m of PV only costs 400$USD*7/1000 = 2.80$USD
Pretty cheap for something which will produce 200W of power for 30-40 years. (200W*35*365*24*60*60= 2.2E11Joules)
Current module prices for silicon based modules are at www.solarbuzz.com, and it would seem these modules cannot ever close the gap(simply based upon the price of Te), unless concentrators are used.
WOW! You just invented a solar panel that produces power at night! Now if you divide your result by 10 you may get a better picture of what you'll get.
2.2E10J = 6111 kwth. * 10c/kwth = $611
So you pay as a minimum $1000 for a 200W panel only to get $611 worth of electricity in 35 years. Impressive!
Average insolation is what the sun puts out onto the panels on average, year after year. It is mainly affected by latitude, yearly cloud cover, and panel angle.
Sooo, at 21.39 c/kwth (average) we get a nice return in 35 years of ~1307$USD at 4.84 a watt the initial investment would have been 968 bucks. For an ROI of >1% in monetary terms.
please don't move the goal posts here. May I suggest working from average numbers rather than your cherry picked ones. (however you did estimate the cost of a 200 Watt installation very well.) Good Job.
It is also prudent to add that with larger installations the cost will fall due to purchasing power and economies of scale, it is unlikely that PV will see diseconomies of scale for quite some time or volume of manufacture.
Gil.
(note: I seem unable to remove all the dumb space above the table, my apologies)
In California, obviously a large PV market, average residential cost to customer is 16.3 c/kwh (ranges depending on use from 11.4 to 36.4 c/kwh). Average for commercial use is 16.7 c/kwh.
Clearly, for a residential customer paying at the high end over 30 c/kwh, the PV systems can pay off pretty rapidly.
We have a 2.5 kw system on our roof, but rarely or never paid over baseline to start with, so it is a slow payback. However, our cost is now paid, while I am pretty confident electrical rates will be climbing significantly. Our system will provide for our entire annual usage for 20-30 yrs or more. Part of a retirement plan.
California has been blessed with deregulation and Enron. It is a shame that the most affluent state in the country does not get affordable and reliable electricity service.
But also CA subsidizes PV panels to the tune of 2/3s of the cost. This is still payed by the customers but is just split between all of them so it is not as visible. The 3000MW program will raise prices even further so you were right - for you personally you made the correct decision in the right time. But you have to admit that most of your costs were covered by the other consumers. In addition you are not paying for the use of the grid as a backup; this is also a subsidy payed by the other users.
Looking at the bigger picture, contribution from PV in CA is negligible - just 0.2% in 2006
Actually, the subsidy was a little less than half the cost and has been declining. That said, it is still a big chunk. We do pay a $4 monthly meter fee for being grid-connected, and any oversupply goes to pge at the end of the year without reimbursemnt to us. We will probably wind up giving 300-500 kwh to pge this year. I know it doesn't apply to all. Of course the contibution is low, but growing. And what is put in is additive through time without further money for fuel or maintenance, etc. It does reduce the need for new generation but has a long ways to go and isn't for everyone. The subsidies - well I think they are necessary right now. People without schools subsidize schools for others, same goes for roads, health & mental health services, etc. It's not a question of PV saving society, there is no single answer and reducing consumption is far more important overall. But I believe, with my experience, that PV has a lot to offer as a portion of the solution. What alternatives are you proposing that have no negatives? As your link shows, natl gas is the largest contributor - but what happens as that goes away?
peakearl... your fee of $4 x 12 plus 300-500 kwth would amount to ~$100 / annum. With these $100 your utility has to be able to sustain all the fixed costs of the enormous transmission and generation infrastructure that serves you as a backup. If you needed to use a battery pack instead it would have costed you almost as much as the PV system, maybe to the tune of $2-3000 a year (considering you would have to replace the batteries in several years).
Having said that I am all for PV and what the CA is doing about it. I just think it is a bit premature to try to push starting it on a larger scale that the technology is ready to. Having taken look at the numbers, the 3000MW program is a bit too much of taxpayers money thrown for a too small benefit. In the end of the day these PV panels will produce as much energy as an average NG generator.
I suspect that a single person living alone in an apartment without A/C is not paying much more than $100/yr in infrastructure costs either. Is that a subsidy? What is a reasonable amount to pay? PG&E isn't supplying much more than infastructure these days, they buy all of their power.
If PG&E buys its power they are paying industry prices for it, adding some costs to maintain their infrastructure plus profit and reselling it to you at retail price. Their problem is that they are buying from you retail prices - foregoing any fixed costs and profits they would have otherwise taken. Here is a small calculation:
Spot electricity prices are usualy in the 50-70$/Mwth, if we take the higher end this is 7c/kwth, and the difference to 16c is 9c.
9c times 12000 kwth (annual consumption) is $1080. So you end up tricking the utility by $980. Of course the utility managers are not stupid and it is certain that they pass these costs to the other consumers.
Actually, no. The utilities are finding that they can get more out of existing infrastructure and do not need to spend so much on upgrades, so net metering is saving them money. The problem they face is they lose some customer base. So far it looks like net income stays neutral, especially since they get power at a lower price than wholesale at peak, but going to a much higher fraction of net generation provided by solar could pose a problem as the spinning reserve kept for peak becomes less needed and so less expensive. But, if they won't net meter, folks will start getting off the grid and then their infrastructure won't even get supported with the connection fee.
Don't worry though. Uilities are very very good at making the stranded cost argument, so they'll make money one way or another.
The utilities are finding that they can get more out of existing infrastructure and do not need to spend so much on upgrades, so net metering is saving them money
Frankly I think you are making this up. If a house has 2.5kW solar panels and its peak power it uses is 10kw, the line to this house, the transformers that serve it etc.etc. must be calculated for... 10kW. There will be times of the day that PV does not produce anything and the infrastructure is calculated based on the maximum load, not the average one. It's a common sense.
There might be some benefits in reduced average load and wear, but with 0.2% of electricity produced I would suspect these to be hardly noticable if any. Power equipment hardly gets damaged by normal use, it is sudden surges/drops of power that usually cause problems.
You are not thinking like a utility. Consider a development large enough to require a substation. If the development were built with solar, much of the energy use will be produced within the development and so it can be larger with the same size substation. Put another way, you need fewer substations for the same number of customers. A growing town that grows with solar does not need a new transmission line as soon as one that grows without solar. The last half mile does not change much, but everything getting there does.
Again you are not making sense - like I said there are times of the day solar will produce nothing over the whole area served, and the whole country actually. The transmission infrastructure and the number of substations and transmission lines would have to cover for that time period - as though solar does not exist.
The effect you described may have some credibility in the scenario when solar reduces the midday load peak in summer. Well, guess what - there is a secondary peak between 6 and 7pm (when people go back from work) and at that time solar panels will be producing virtually zero. And what about winter, when solar is producing almost nothing while more and more people go to resistive heating and heat pumps?
Anyway if there are some savings I expect them to be minuscule compared to the revenues foregone by utilities. You need to link some industry report to prove your point, otherwise your assertions are largely theoretical.
Now you are beginning to think like a utility a little. Take the delta between the main peak and the secondary and there is your savings.
You have forgotten that non-time-of-use rate net metering customers are providing power to the utilities when the wholesale power price is above the retail price.
It was your point that solar makes some savings and I agreed there might be some small savings. It's up to you to show how large are they and do they cover the subsidy to PV customers. If we are talking a $1 of savings per $100 costs for PV panels we are obviously not doing anything meaningful.
For these $100 every house could be equipped with CFC bulbs and more efficient A/Cs - potentially saving hundreds of MWs of peak load. One very cheap but not present everywhere appliance - a scheduler for the A/C would likely save more than all the PV combined at a small fraction of the price.
"It's up to you to show how large are they and do they cover the subsidy to PV customers."
It's always helpful for boths sides of a debate to offer data, sources & calculations, rather than for either (or both) to just ask for the other side to bear the burden of the proof.
"For these $100 every house could be equipped with CFC bulbs and more efficient A/Cs - potentially saving hundreds of MWs of peak load. One very cheap but not present everywhere appliance - a scheduler for the A/C would likely save more than all the PV combined at a small fraction of the price."
I think we all agree that efficiency and demand management are the cheapest alternatives and should be given a very high priority, but at any level of demand we'll still need some generation, and non-carbon emitting forms should be developed ASAP.
It's worth mentioning that demand management will also help reduce that seconday peak you mentioned earlier, when people arrive home.
It was mdsolar's point that PV is bringing some savings in utility costs, my point was that any savings would be insignificant compared to PV costs, and asked him what he has to prove his point.
If we both can not find any numbers I guess the question will remain open.
In fact, no, you objected that utilities get nothing out of net metering but they do. If you shift ground now and say that what they get should cover the state subsidy you are mischaracterizing the discussion. The utilities don't own the PV, they only get to take advantage of the generation. One wants to look at the benefit to the owner and the state rather than the utility to examine the benefits of the subsidy.
"By your logic each time I switch off my A/C I should get a subsidy for not loading the grid."
And a lot of utilities do that, with peak demand management, and they consider it quite cost effective. Of course, that's for selected maximum peaks, but the principle is there.
DOE, for example says the same thing. You can probably find a few things here.
I have to say that you a quite rude as you hold untenable positions. Words like ridiculous do not describe what I have been saying and certainly do not do so in a polite manner. If you look at net metering from the utilities' point of view it is beneficial up to a certain capacity, probably about 25% depending on demand growth. Higher if they need RECs and can get them at a low cost from the net meterers. Industrial and commercial customers are more likely to sell their RECs at market price. We are certainly considering plans to give connected utilities discounts. Perhaps the best benefit of net metering is the sense of working together to make things better. When there is an outage, and someone goes outside to flip the switch to disconnect from the grid, they'll be thinking of the linesmen they are protecting by keeping power out of the mains. That kind of thing makes a difference even if you can't count it in money. To paraphrase MLK, net metering is going to really happen in the TVA first.
BTW, if you have tiered rates, you do get a subsidy by turning off your AC.
PG&E has a cap of 0.1% for net metering. Obviously they don't share your view that up to 25% it will not hurt them. Both articles talk about theoretical benefits to utilities, but none are calculating them. I think it is self-evident that the grid operators can not benefit from net metering. They still have to maintain the transmission lines and substations to the houses despite them being with a lower load. But at least their losses could be offset partially by what you said.
IMO the fair thing to in this case would be to charge PV customers higher fixed fees for using the grid as a backup while keeping their electricity (up to the produced by PV) for free.
And please don't consider me rude - you are the one who made the claim and you were supposed to back it up. Otherwise it was just a hollow argument.
"PG&E has a cap of 0.1% for net metering. Obviously they don't share your view that up to 25% it will not hurt them. "
It is in PG&E's interest to maximize production, consumption & revenue. This isn't in the community's best interest.
Sure there's a subsidy here, but as we've agreed in the past, it's perfectly reasonable to consider this a countervailing subsidy to those enjoyed by fossil fuels. Is this perfect? No. Would a carbon tax, and an end to all other subsidies be a perfect world? Sure, but this isn't too bad, and it's better than no net-metering.
And to answer your question - yes, it is a subsidy, paid by non-solar consumer. No operators in their right minds would made such contracts with their customers if they were not forced to by the state legislation. In effect the state is forcing non PV-customers to subsidize PV customers.
It would have been realtively OK if the PV share was kept small, but it is obviously set to rise. Prepare for price hikes.
"yes, it is a subsidy, paid by non-solar consumer."
Sure, you can think of it that way. OTOH, coal is heavily subsidized by the right to emit (CO2, pollutants) without cost. This can be thought of levelling the playing field.
Fair enough. But what has to happen in this case is either price the carbon or force CPPs to eliminate the polution.
This should truly level the playing field and then the competition should determine which one is the best.
My guess is that the winner would still be nuclear as it is almost on par with coal. But if solar brings down costs a some more it maybe the ultimate winner. Personally I'd be happy see nukes providing baseload and PV and NG providing for the peaks... but unfortunately with PV we are not there yet.
"what has to happen in this case is either price the carbon or force CPPs to eliminate the polution. "
That would be best. We seem to be doomed to spread around additional subsidies forever, rather than reduce them. Easier politically, it seems.
"My guess is that the winner would still be nuclear "
If nuclear can move fast enough. Wind & solar are likely to move much faster, and cut off nuclear's window of opportunity. Wind was 20% of new generation last year, is doubling every 2 years, and could easily provide all new generation in 5 years. Solar is about 8 years behind, and growing just as fast.
Something is very weird with the CA PV number. I looked at your link and the previous reports to see how PV has changed, here's what you find:
Year Gwh
2006 616
2005 660
2004 741
2003 758
2002 864
According to these numbers, PV has been shrinking in CA in recent years when we know it has actually been taking off rapidly. I'll have to try to figure this out!
Their figure did not include residential PV systems, just commercial scale ones. It could be that some of the commercial systems installed in the 80s are retiring or reducing output as they age... just a guess.
If you take a look at the small script below, they are estimating residential PV contribution to ~200GWh for 2006.
It still makes no sense. Even added together you don't get an increase -- when all reports I have seen report multiple large and small new installations during that period. Very little was put in in the 80's, so I can't imagine that accounting for it. I don't have time now but may try to track this down this weekend. I know several very busy people in the PV industry. I read the report script below and also don't understand it. They don't actually reference home vs commercial, e.g., our small installation is actually treated as though it were commercial. I thought they meant off-the-grid vs grid-tied installations. There are many of these in the hills, for well pumping operations and other uses large and small.
We can get 21.5% efficiency from silicon, see http://www.sunpowercorp.com/pdf/SPR-210-WHT.pdf
Sunpower have achieved 23% with silicon using a fine diffused pattern of back connectors but this technique is too expensive for domestic use.
Silicon the second most abundant element on the planet. It is not lack of materials that will prevent us making all the solar cells the world needs.
Nor is silicon at the end of the road in development. The thickness of silicon in single crystal cells has been falling with no loss in performance. It will soon be under 100µm and the difference between material usage in single crystal and thin film silicon is becoming less.
Edge defined crystal growth can reduce the wastage in slicing cylindrical Czochralski grown crystals. Polysilicon raw material produced expressly for photovoltaic use could be much cheaper and use less energy to produce than the electronic grades that are used now.
Other more efficient materials may overtake silicon if they are competitive but it will depend on the costs of rare materials. The Spectrolab triple junction cells have achieved 40.7% efficiency at concentration factors of several hundred. http://www.spectrolab.com/com/news/news-detail.asp?id=172
The great advantage being able to operate at such high concentration factors is the enormous reduction in the area of semiconductor needed. Working at 400 times concentration and twice the efficiency of silicon 50 cells 5mm x 5mm, each behind a 100m x 100mm Fresnel lens, a total of 0.00125 m² will produce the same as 1m² of best silicon. This reduction in area of semiconductors at present compensates for the use of exotic materials, Aluminium Gallium Indium Phosphide, Gallium Arsenide and Germanium.
These technologies may, or may not become victims of their own success if they push up the cost of rare materials but we will always have silicon to fall back on and it is sufficient if fossil fuel prices rise a lot.
As Chris Vernon points out there are other, thermal ways of converting solar energy, the troughs he mentions, the Stiling engine dishes, the solar towers and the solar chimney idea. Ground sourced heat pumps are also getting the energy gain over the electrical input from solar energy re-heating the cooled ground.
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“No civilization can survive the physical destruction of its resource base.”
Solar Power is good!
Big Problem that greenies never tell you: We can't make enough solar cells to save us.
New solar technologies use lots of rare earth minerals that soon will be gone. Gone.
So this is just another pipe dream, although the rich will certainly get the benefit from it.
There are a wide range of potential solar technologies some requiring rare earth minerals and some not. It is not correct to write off solar technology due to such resource limitations.
For example see our article on Concentrating Solar Power which doesn’t need anything fancy, just large amounts of direct sunlight as is found in the US’s southern deserts or North Africa.
I think this would be a great story theme to be followed up here.
I have been listening to all the "gush" about thin film solar, but from my almost completly uniformed position it really seems unlikly to me that some of these technologies can scale up to utility sized projects that are sustainable.
The wide scale deployment of LCD monitors has driven up the price of Indium > an order of magnitude in only a few years, its about as common in nature as Silver, and the best efficiency seems to be with Tellurium compounds, the rarest solid element on the planet (except for some radioactive things that decay). Its price has risen, I belive from $US4 per pound in 2000 to over $100 now.
Does anyone know how much deployment it would take before we could expect the current price gap between these designs and the silicon based technologies to be erased?
This is blatantly uninformative.
Also Palladium, Platinum, and Gold cost more than 400$USD a kg
A reduction in the quanitity of junction materials, as well as directed production of PV targeted cell materials will likely have huge economy of scale effects, lowering the $/Watt price down. This in turn will allow for the economy to grow in a more sustainable fashion.
To address rarity, Wiki says 0.001ppm on average (1e-9) concentration, so going by typical concentrations required from the NREL website (http://www.nrel.gov/pv/cdte/) which states less than 0.1% by mass is required(about 7g/m^2 from the NREL pdf on the same page.).
Therefore a meter square of panel will require 7E9 g of marginal mining (7e6 kg, or 7000 Tons). This is the marginal requirement, obviously currently exploited ores are much easier, considering that the Tellurium for 1 sq m of PV only costs 400$USD*7/1000 = 2.80$USD
Pretty cheap for something which will produce 200W of power for 30-40 years. (200W*35*365*24*60*60= 2.2E11Joules)
Current module prices for silicon based modules are at www.solarbuzz.com, and it would seem these modules cannot ever close the gap(simply based upon the price of Te), unless concentrators are used.
more to come.
WOW! You just invented a solar panel that produces power at night! Now if you divide your result by 10 you may get a better picture of what you'll get.
2.2E10J = 6111 kwth. * 10c/kwth = $611
So you pay as a minimum $1000 for a 200W panel only to get $611 worth of electricity in 35 years. Impressive!
Average insolation is what the sun puts out onto the panels on average, year after year. It is mainly affected by latitude, yearly cloud cover, and panel angle.
Sooo, at 21.39 c/kwth (average) we get a nice return in 35 years of ~1307$USD at 4.84 a watt the initial investment would have been 968 bucks. For an ROI of >1% in monetary terms.
please don't move the goal posts here. May I suggest working from average numbers rather than your cherry picked ones. (however you did estimate the cost of a 200 Watt installation very well.) Good Job.
It is also prudent to add that with larger installations the cost will fall due to purchasing power and economies of scale, it is unlikely that PV will see diseconomies of scale for quite some time or volume of manufacture.
Gil.
(note: I seem unable to remove all the dumb space above the table, my apologies)
OK, I apologize - it is not 5-6$/Wp but $4.87-$6.5/Wp (4.78 euro).
I also apologize for thinking that the average electricity price is ~10c instead of your 21.39 c/kwth:
Source:
http://www.eia.doe.gov/neic/brochure/electricity/electricity.html
I'm sorry, next time I promise I'll trust you, not my eyes. So, who did you say has goal posts?
In California, obviously a large PV market, average residential cost to customer is 16.3 c/kwh (ranges depending on use from 11.4 to 36.4 c/kwh). Average for commercial use is 16.7 c/kwh.
Clearly, for a residential customer paying at the high end over 30 c/kwh, the PV systems can pay off pretty rapidly.
We have a 2.5 kw system on our roof, but rarely or never paid over baseline to start with, so it is a slow payback. However, our cost is now paid, while I am pretty confident electrical rates will be climbing significantly. Our system will provide for our entire annual usage for 20-30 yrs or more. Part of a retirement plan.
California has been blessed with deregulation and Enron. It is a shame that the most affluent state in the country does not get affordable and reliable electricity service.
But also CA subsidizes PV panels to the tune of 2/3s of the cost. This is still payed by the customers but is just split between all of them so it is not as visible. The 3000MW program will raise prices even further so you were right - for you personally you made the correct decision in the right time. But you have to admit that most of your costs were covered by the other consumers. In addition you are not paying for the use of the grid as a backup; this is also a subsidy payed by the other users.
Looking at the bigger picture, contribution from PV in CA is negligible - just 0.2% in 2006
Source:
http://www.energy.ca.gov/electricity/gross_system_power.html
Actually, the subsidy was a little less than half the cost and has been declining. That said, it is still a big chunk. We do pay a $4 monthly meter fee for being grid-connected, and any oversupply goes to pge at the end of the year without reimbursemnt to us. We will probably wind up giving 300-500 kwh to pge this year. I know it doesn't apply to all. Of course the contibution is low, but growing. And what is put in is additive through time without further money for fuel or maintenance, etc. It does reduce the need for new generation but has a long ways to go and isn't for everyone. The subsidies - well I think they are necessary right now. People without schools subsidize schools for others, same goes for roads, health & mental health services, etc. It's not a question of PV saving society, there is no single answer and reducing consumption is far more important overall. But I believe, with my experience, that PV has a lot to offer as a portion of the solution. What alternatives are you proposing that have no negatives? As your link shows, natl gas is the largest contributor - but what happens as that goes away?
peakearl... your fee of $4 x 12 plus 300-500 kwth would amount to ~$100 / annum. With these $100 your utility has to be able to sustain all the fixed costs of the enormous transmission and generation infrastructure that serves you as a backup. If you needed to use a battery pack instead it would have costed you almost as much as the PV system, maybe to the tune of $2-3000 a year (considering you would have to replace the batteries in several years).
Having said that I am all for PV and what the CA is doing about it. I just think it is a bit premature to try to push starting it on a larger scale that the technology is ready to. Having taken look at the numbers, the 3000MW program is a bit too much of taxpayers money thrown for a too small benefit. In the end of the day these PV panels will produce as much energy as an average NG generator.
I suspect that a single person living alone in an apartment without A/C is not paying much more than $100/yr in infrastructure costs either. Is that a subsidy? What is a reasonable amount to pay? PG&E isn't supplying much more than infastructure these days, they buy all of their power.
Well, that makes it even easier to figure out.
If PG&E buys its power they are paying industry prices for it, adding some costs to maintain their infrastructure plus profit and reselling it to you at retail price. Their problem is that they are buying from you retail prices - foregoing any fixed costs and profits they would have otherwise taken. Here is a small calculation:
Spot electricity prices are usualy in the 50-70$/Mwth, if we take the higher end this is 7c/kwth, and the difference to 16c is 9c.
9c times 12000 kwth (annual consumption) is $1080. So you end up tricking the utility by $980. Of course the utility managers are not stupid and it is certain that they pass these costs to the other consumers.
Actually, no. The utilities are finding that they can get more out of existing infrastructure and do not need to spend so much on upgrades, so net metering is saving them money. The problem they face is they lose some customer base. So far it looks like net income stays neutral, especially since they get power at a lower price than wholesale at peak, but going to a much higher fraction of net generation provided by solar could pose a problem as the spinning reserve kept for peak becomes less needed and so less expensive. But, if they won't net meter, folks will start getting off the grid and then their infrastructure won't even get supported with the connection fee.
Don't worry though. Uilities are very very good at making the stranded cost argument, so they'll make money one way or another.
Chris
The utilities are finding that they can get more out of existing infrastructure and do not need to spend so much on upgrades, so net metering is saving them money
Frankly I think you are making this up. If a house has 2.5kW solar panels and its peak power it uses is 10kw, the line to this house, the transformers that serve it etc.etc. must be calculated for... 10kW. There will be times of the day that PV does not produce anything and the infrastructure is calculated based on the maximum load, not the average one. It's a common sense.
There might be some benefits in reduced average load and wear, but with 0.2% of electricity produced I would suspect these to be hardly noticable if any. Power equipment hardly gets damaged by normal use, it is sudden surges/drops of power that usually cause problems.
You are not thinking like a utility. Consider a development large enough to require a substation. If the development were built with solar, much of the energy use will be produced within the development and so it can be larger with the same size substation. Put another way, you need fewer substations for the same number of customers. A growing town that grows with solar does not need a new transmission line as soon as one that grows without solar. The last half mile does not change much, but everything getting there does.
Chris
Again you are not making sense - like I said there are times of the day solar will produce nothing over the whole area served, and the whole country actually. The transmission infrastructure and the number of substations and transmission lines would have to cover for that time period - as though solar does not exist.
The effect you described may have some credibility in the scenario when solar reduces the midday load peak in summer. Well, guess what - there is a secondary peak between 6 and 7pm (when people go back from work) and at that time solar panels will be producing virtually zero. And what about winter, when solar is producing almost nothing while more and more people go to resistive heating and heat pumps?
Anyway if there are some savings I expect them to be minuscule compared to the revenues foregone by utilities. You need to link some industry report to prove your point, otherwise your assertions are largely theoretical.
Now you are beginning to think like a utility a little. Take the delta between the main peak and the secondary and there is your savings.
You have forgotten that non-time-of-use rate net metering customers are providing power to the utilities when the wholesale power price is above the retail price.
Chris
It was your point that solar makes some savings and I agreed there might be some small savings. It's up to you to show how large are they and do they cover the subsidy to PV customers. If we are talking a $1 of savings per $100 costs for PV panels we are obviously not doing anything meaningful.
For these $100 every house could be equipped with CFC bulbs and more efficient A/Cs - potentially saving hundreds of MWs of peak load. One very cheap but not present everywhere appliance - a scheduler for the A/C would likely save more than all the PV combined at a small fraction of the price.
"It's up to you to show how large are they and do they cover the subsidy to PV customers."
It's always helpful for boths sides of a debate to offer data, sources & calculations, rather than for either (or both) to just ask for the other side to bear the burden of the proof.
"For these $100 every house could be equipped with CFC bulbs and more efficient A/Cs - potentially saving hundreds of MWs of peak load. One very cheap but not present everywhere appliance - a scheduler for the A/C would likely save more than all the PV combined at a small fraction of the price."
I think we all agree that efficiency and demand management are the cheapest alternatives and should be given a very high priority, but at any level of demand we'll still need some generation, and non-carbon emitting forms should be developed ASAP.
It's worth mentioning that demand management will also help reduce that seconday peak you mentioned earlier, when people arrive home.
It was mdsolar's point that PV is bringing some savings in utility costs, my point was that any savings would be insignificant compared to PV costs, and asked him what he has to prove his point.
If we both can not find any numbers I guess the question will remain open.
In fact, no, you objected that utilities get nothing out of net metering but they do. If you shift ground now and say that what they get should cover the state subsidy you are mischaracterizing the discussion. The utilities don't own the PV, they only get to take advantage of the generation. One wants to look at the benefit to the owner and the state rather than the utility to examine the benefits of the subsidy.
Chris
By your logic each time I switch off my A/C I should get a subsidy for not loading the grid.
Your point was ridiculous from the very begining and I'm expecting you to provide your sources proving it.
"By your logic each time I switch off my A/C I should get a subsidy for not loading the grid."
And a lot of utilities do that, with peak demand management, and they consider it quite cost effective. Of course, that's for selected maximum peaks, but the principle is there.
DOE, for example says the same thing. You can probably find a few things here.
I have to say that you a quite rude as you hold untenable positions. Words like ridiculous do not describe what I have been saying and certainly do not do so in a polite manner. If you look at net metering from the utilities' point of view it is beneficial up to a certain capacity, probably about 25% depending on demand growth. Higher if they need RECs and can get them at a low cost from the net meterers. Industrial and commercial customers are more likely to sell their RECs at market price. We are certainly considering plans to give connected utilities discounts. Perhaps the best benefit of net metering is the sense of working together to make things better. When there is an outage, and someone goes outside to flip the switch to disconnect from the grid, they'll be thinking of the linesmen they are protecting by keeping power out of the mains. That kind of thing makes a difference even if you can't count it in money. To paraphrase MLK, net metering is going to really happen in the TVA first.
BTW, if you have tiered rates, you do get a subsidy by turning off your AC.
Chris
PG&E has a cap of 0.1% for net metering. Obviously they don't share your view that up to 25% it will not hurt them. Both articles talk about theoretical benefits to utilities, but none are calculating them. I think it is self-evident that the grid operators can not benefit from net metering. They still have to maintain the transmission lines and substations to the houses despite them being with a lower load. But at least their losses could be offset partially by what you said.
IMO the fair thing to in this case would be to charge PV customers higher fixed fees for using the grid as a backup while keeping their electricity (up to the produced by PV) for free.
And please don't consider me rude - you are the one who made the claim and you were supposed to back it up. Otherwise it was just a hollow argument.
Better note the age of the study. California's cap is 2.5% now. This one I think you can look up yourself. It will be raised again.
Chris
"PG&E has a cap of 0.1% for net metering. Obviously they don't share your view that up to 25% it will not hurt them. "
It is in PG&E's interest to maximize production, consumption & revenue. This isn't in the community's best interest.
Sure there's a subsidy here, but as we've agreed in the past, it's perfectly reasonable to consider this a countervailing subsidy to those enjoyed by fossil fuels. Is this perfect? No. Would a carbon tax, and an end to all other subsidies be a perfect world? Sure, but this isn't too bad, and it's better than no net-metering.
And to answer your question - yes, it is a subsidy, paid by non-solar consumer. No operators in their right minds would made such contracts with their customers if they were not forced to by the state legislation. In effect the state is forcing non PV-customers to subsidize PV customers.
It would have been realtively OK if the PV share was kept small, but it is obviously set to rise. Prepare for price hikes.
"yes, it is a subsidy, paid by non-solar consumer."
Sure, you can think of it that way. OTOH, coal is heavily subsidized by the right to emit (CO2, pollutants) without cost. This can be thought of levelling the playing field.
Fair enough. But what has to happen in this case is either price the carbon or force CPPs to eliminate the polution.
This should truly level the playing field and then the competition should determine which one is the best.
My guess is that the winner would still be nuclear as it is almost on par with coal. But if solar brings down costs a some more it maybe the ultimate winner. Personally I'd be happy see nukes providing baseload and PV and NG providing for the peaks... but unfortunately with PV we are not there yet.
"what has to happen in this case is either price the carbon or force CPPs to eliminate the polution. "
That would be best. We seem to be doomed to spread around additional subsidies forever, rather than reduce them. Easier politically, it seems.
"My guess is that the winner would still be nuclear "
If nuclear can move fast enough. Wind & solar are likely to move much faster, and cut off nuclear's window of opportunity. Wind was 20% of new generation last year, is doubling every 2 years, and could easily provide all new generation in 5 years. Solar is about 8 years behind, and growing just as fast.
Oh, and multiply that subsidy by millions of potential users and see how quickly california is bankrupt.
Something is very weird with the CA PV number. I looked at your link and the previous reports to see how PV has changed, here's what you find:
Year Gwh
2006 616
2005 660
2004 741
2003 758
2002 864
According to these numbers, PV has been shrinking in CA in recent years when we know it has actually been taking off rapidly. I'll have to try to figure this out!
Their figure did not include residential PV systems, just commercial scale ones. It could be that some of the commercial systems installed in the 80s are retiring or reducing output as they age... just a guess.
If you take a look at the small script below, they are estimating residential PV contribution to ~200GWh for 2006.
It still makes no sense. Even added together you don't get an increase -- when all reports I have seen report multiple large and small new installations during that period. Very little was put in in the 80's, so I can't imagine that accounting for it. I don't have time now but may try to track this down this weekend. I know several very busy people in the PV industry. I read the report script below and also don't understand it. They don't actually reference home vs commercial, e.g., our small installation is actually treated as though it were commercial. I thought they meant off-the-grid vs grid-tied installations. There are many of these in the hills, for well pumping operations and other uses large and small.
We can get 21.5% efficiency from silicon, see http://www.sunpowercorp.com/pdf/SPR-210-WHT.pdf
Sunpower have achieved 23% with silicon using a fine diffused pattern of back connectors but this technique is too expensive for domestic use.
Silicon the second most abundant element on the planet. It is not lack of materials that will prevent us making all the solar cells the world needs.
Nor is silicon at the end of the road in development. The thickness of silicon in single crystal cells has been falling with no loss in performance. It will soon be under 100µm and the difference between material usage in single crystal and thin film silicon is becoming less.
Edge defined crystal growth can reduce the wastage in slicing cylindrical Czochralski grown crystals. Polysilicon raw material produced expressly for photovoltaic use could be much cheaper and use less energy to produce than the electronic grades that are used now.
Other more efficient materials may overtake silicon if they are competitive but it will depend on the costs of rare materials. The Spectrolab triple junction cells have achieved 40.7% efficiency at concentration factors of several hundred. http://www.spectrolab.com/com/news/news-detail.asp?id=172
The great advantage being able to operate at such high concentration factors is the enormous reduction in the area of semiconductor needed. Working at 400 times concentration and twice the efficiency of silicon 50 cells 5mm x 5mm, each behind a 100m x 100mm Fresnel lens, a total of 0.00125 m² will produce the same as 1m² of best silicon. This reduction in area of semiconductors at present compensates for the use of exotic materials, Aluminium Gallium Indium Phosphide, Gallium Arsenide and Germanium.
These technologies may, or may not become victims of their own success if they push up the cost of rare materials but we will always have silicon to fall back on and it is sufficient if fossil fuel prices rise a lot.
As Chris Vernon points out there are other, thermal ways of converting solar energy, the troughs he mentions, the Stiling engine dishes, the solar towers and the solar chimney idea. Ground sourced heat pumps are also getting the energy gain over the electrical input from solar energy re-heating the cooled ground.