130 thoughts on “Energy storage getting real”

1. Looking at the SA government site I see that in Adelaide people apparently spend about 38% of their household electricity on heating and cooling. I cool my place in Adelaide in the summer, but I never heat it. This is Australia. It’s hot. What do you need to heat things for? The only time I heat my place is when my blind friend comes over and she needs warm fingers to feel things. Anyway, heating and cooling come to about 1,500 kilowatt-hours a year for the average Adelaide household. So let’s say double glazing works wonderfully and cuts the need for heating and cooling in half. That would save 750 kilowatt-hours a year. That’s about as much electricity as is produced by half a kilowatt of rooftop solar. And rooftop solar is now being installed in Australia for about $2 a watt before subsidy so half a kilowatt would cost about $1,000. As double glazing in a brand new home is supposed to increase costs by around $4,000 over single glazing, installing solar, or rather a larger rooftop solar system than one would otherwise, would clearly reduce far more emissions per dollar than double glazing and would give a higher return on the investment.

2. I should add that beyond what has been said above, personally, I don’t care if power costs a little more or even a lot more, provided the power is clean. If that’s what it costs and I need it, then as far as I’m concerned, we should just pay the price, and if needs be, curtail our expenditure somewhere else.

   There’s no doubt that I could save a lot of money if I sourced 80% of my protein and carbohydrates from bins behind restaurants and supermarkets. I choose not to because I put a value on hygiene and quality nutrient. I expect that food that meets food safety standards will cost more. I also pay extra to eat free range eggs and organic and grow veges in the back yard even though these also cost more.

   Energy supply is only one line item in the budget and all of us who want to reduce our footprint should be prepared to pay what it takes to have low footprint energy. Yes we should seek good value for money but you don’t have to be a chemical engineer to figure out why harvesting energy on the fly is going to be more expensive than raiding the capital stores of the carboniferous era. Expecting the wind and insolation collected today to compete with the results of millions of years of insolation and transformation under pressure and heat is naive — especially when no cost is put on the resultant pollution. As always, you get the service you pay for. If you’re relaxed about eating the future and polluting the world, then FHC cost competitiveness is a good marker. If you want not to debauch the ecosystem, that filth costs less is not relevant.

   I say we pay what it costs, go without what we must and look after those not as well off as we are with compensatory social support. Why wait? Just get on with it.

3. @Ikonoclast
   Re flywheels
   Thanks for the link. Actually, my impression was that short-term storage (albeit 2-3 days) was the idea there, with the purpose of the flywheel being to even out load demands but I may be reading more into the article than is actually there.

4. @Fran Barlow

   There’s no doubt that I could save a lot of money if I sourced 80% of my protein and carbohydrates from bins behind restaurants and supermarkets. I choose not to because I put a value on hygiene and quality nutrient.

   Tsk, tsk, See ww.amazon.com/dp/B005DI9PH8 for a veritable paen for dumpster-diving (not sure of the Australian term).

5. @jrkrideau

   My impression from another article I read is that sophisticated flywheels (housed in a near vacuum and mounted on near frictionless permenant magnetic bearings) can be used for load-levelling on a grid. This load levelling occurs over time spans of minutes, seconds and even fractions of a second. These flywheels are connected to electric motor/generators amd can absorb or deliver power at need, reacting in fractions of a second. Another use is for UPS supplies, where the flywheel might deliver power for up to several minutes until a diesel generator is started and kicks in. Another use, which you no doubt read about, is to provide a huge short term energy supply for laser experiments in labs.

   I am not aware of flywheel systems that can store power for days or even hours of grid use when baseload is down. I don’t think flywheel systems are suitable for that. However, it always possible that windfarms could be combined with flywheel systems (one per wind generator) and this along with geographical distribution could greatly smooth windfarm contribution to the grid.

6. Footnote: Flywheels to power vehicles (like the Swiss bus experiment) suffer from the effects gyroscopic forces when the vehicle turns. The flywheel might have to be on gimbals. I can’t see that ever being a go-er now anyway. Batteries and power lines for electrified transport work much better.

7. > I can’t see that ever being a go-er now anyway.

   http://en.wikipedia.org/wiki/Audi_R18#R18_e-tron_quattro
   http://www.parrypeoplemovers.com

8. @Ronald Brak
   As usual Ronald you make excellent points. Double glazing with glass is out of the question for us anyway but for using those extra solar panels while they are generating power and retaining the heat or cooling longer into the evening, I plan to install acrylic sheets to the inside of the living areas using magnetic strips. This I can do for around $1,500 as opposed to over $20,000 for a double glass retrofit.

9. Watkin Tench :
   You raise an important point, Salient Green.
   I’ve had a look at energy saving options for my own oversized poorly built house but most of them are very expensive (at least 25-30 grand) but I have no way of accurately calculating whether they are worth it.
   If you don’t have sliding windows (unfortunately I do), there are cheap double glaze retrofit options availavble.
   Ultimately building standards need to be raised so that homes are properly insulated.

   Indeed and they have been to some degree. My house was built with loads of halogen downlights – all the high use areas have them. I’ve held off replacing them because (1) they look good and (2) the energy efficient replacements were never bright enough to substitute as a direct replacement… Well until now 🙂 Just tried some I sourced on EBay and yippy!

10. @Ronald Brak

    This is Australia. It’s hot. What do you need to heat things for?

    Obviously you have never lived in Canberra. Or Hobart. Or indeed anywhere a long way from the coast but not in the tropics.

    But of course heating is nowhere the big electricity user. Peaks for cooling are almost everywhere – even in most of Canada – more important.

11. Oh, I did the Canberra thing. One morning I woke up and discovered someone had spread salt or something all over the ground.

12. @Watkin Tench
    All good points on the economics of reducing the need for energy use through retro fitting. But discuss the building standards with any “solar architect” for want of a better description – and they will tell you the standards encourage the building of a house sized esky. Perfect for keeping the energy costs of heating and cooling to a minimum. Not targeted at removing, as much as possible, the need for heating and cooling through design. You can get them VERY agitated about the type of design that the “rules” promote!!

13. @Will Boisvert

    Even if you and Hermit are right on the relative costs of nuclear and renewables, Will, what’s the point of banging this drum any longer? There are only a handful of new nuclear plants on the way anywhere in the developed world, and no prospect of any new large scale program starting for a decade or more. Even if that happened, we’d be looking well after 2030 before there was any significant contribution to electricity supply.

    If you want to go to China and push nuclear there, feel free. But in the developed world context, bashing renewables as both of you do continuously is as bad as outright denialism. There is, literally, no alternative.

14. 1 million rooftops with PVs, and counting…and what’s the EROEI? No one is counting closely (certainly not on this forum anyway) — but “very pitiful” is the only clear, likely, answer.

15. @iain
    I take it from your precise estimate that you’re not exactly counting the EROEI closely yourself.

    Given that the vast majority of PV in Australia has been installed in the last 3 years, based on the range of figures in most studies done on PV solar in the last few years, the EROEI figues for rooftop PV in Australia would likely range from (using your rating system) “good enough” in the southern mainland capitals to “pretty good” in northern Australia.

16. Iain, a watt of solar PV now costs 50 cents. In a mediocre installation in Australia it will produce over 40 kilowatt-hours of electricity in its lifetime. The Czochralski process for silicon ingots uses electricity due to the need to precisely control the temperature gradient. So even if the only cost of making solar PV in China was electricity and nothing else, that would give a return of eight times as much electricity as was put in. Now if you want to seriously make the argument that China is spending more than 50 cents worth of electricity on making something that they sell to us for 50 cents, go ahead and make that arguement. Let’s see what you’ve got.

17. @ John Quiggin 13,

    Even leaving aside the comparison with nuclear, battery storage is still pretty dubious from a standpoint of comparative renewables policy. As the Stafford Hill example shows, batteries provide very little storage and reliability at very high costs. (Pumped hydro is much more economical, but geographically limited.) Utility-scale electricity storage in any form is so difficult and expensive that some academic “all-renewables” modeling studies are concluding it’s better to ignore it and just pile up the wind and solar and then rely on hydro, geo, biomass and natural gas for backup and stability. (Unfortunately, those solutions also have major drawbacks.) If a renewables future does come to pass, utility-scale battery storage like Stafford Hill’s will probably play no significant role—and certainly not by 2030.

    As for nuclear—yes, it faces strong headwinds in the West, but you might be too pessimistic about its prospects. 7 reactors building, 6 more planned in Finland and Britain, many more if you count South Korea and United Arab Emirates as “developed.” Britain’s program is quite significant: the new nuclear they are planning, due online before 2030, should provide at least 20 percent of their electricity and perhaps much more. The US EPA’s new carbon emissions rules have provoked new interest in nuclear with possible announcements this year. The politics of nuclear are fairly positive in Britain, America, Canada and Eastern Europe, but costs must come down before a major buildout will happen; there’s hope for that as the global industry and supply chain gains economies of series. (If China can start exporting nuclear parts to the West the way it exports solar panels, that alone could substantially reduce costs.) There’s also the crucial issue of preserving the West’s current reactor fleet. The US NRC is gearing up to start relicensing Gen II reactors out to 80-year life spans; if that can be done throughout the West it will make an enormous contribution to low-carbon generation in the coming decades. So I feel that discussions of nuclear energy are still relevant to decarbonization policy in the developed world.

    I think renewables enthusiasts often let wishful thinking get in the way of sober analysis of costs, logistics and feasibility. That can’t be a good basis for policy or for advancing the debate about it, which is why I go on banging the drum.

18. @Will Boisvert

    I’ve got no problem with keeping the existing nuclear fleet, or completing the 13 projects you mention. But even allowing for a 4:1 availability factor, the new projects would add about the same as one year’s developed country renewables (around 25 GW each of wind and solar PV). And of course, we need several times that rate if we are going to decarbonize electricity and power electric vehicles. So, to repeat, nuclear in developed countries is not going to be a significant part of the solution.

    Renewables (and efficiency) are the only solutions on offer. If you think current cost estimates are too low, you should be trying to do something positive about it, for example looking at better pricing structures, or ways to promote energy efficiency, not banging on about nuclear.

19. @Ronald Brak

    We can get a bit more precision than this. The polysilicon content of a cell is about 10g/w, so at $20/kg, that’s about 20c/w. As you say, that’s an upper bound if you suppose electricity is the only cost.

    Going a step further, if the price paid by poly producers is 10c/kwh (a pretty good price even for industrial users), the energy in is no more than 2Kwh, so the payback time is about a year, and the EROEI is the life of the panel in years, say 15-20.

20. @Will Boisvert

    Re your last paragraph. If it’s “sober analysis of costs, logistics and feasibility” that you’re after, then lots of posters and commenters on Clean Technica can do that for you.

    For example, Vogtle nuclear plant should come in with an LCOE of US11c/kwh. New PPAs for wind farms are being signed at US2.5c/kwh. That’s sober.

21. Thanks for that, John. And looking it up I see that by the end of this year it the average silicon per watt is expected to have fallen to five grams. And it’s predicted that 49 gigawatts of solar PV will be produced this year. That’s enough to produce about three times the electricity the three Chinese reactors brought online this year will. And of course PV production capacity is still expanding.

22. @John Quiggin 18,

    “If you think current cost estimates are too low, [high?] you should be trying to do something positive about it, for example looking at better pricing structures.”

    I don’t think “pricing structures” can really solve the problem of solar economics, even with storage.

    The basic problem is low capacity factors and chaotic surge-and-slump production, which make it impossible to size intermittent supply to fit demand in an economical way. You have to vastly overbuild solar megawatts to get high grid penetration. But that means that in the brief periods when solar produces, it vastly overproduces and drives down the price of solar electricity, making recovery of costs impossible—solar puts itself out of business before it bankrupts fossil generators. And since solar can’t produce under night or cloud, you have to have other fleets of generators to pick up the slack; not only wind turbines but dispatchable plants for when wind and solar both fail. All of that just adds to the glut while raising real costs. So the hallmark of an intermittents grid is huge overcapacity and ballooning real costs, coupled with low nominal prices that make cost recovery from the market impossible. That’s precisely the dynamic in Germany, for example.

    Can storage rescue the situation? I don’t think so. Solar produces in the daytime when electricity demand is high, so regularly generating a surplus to store, over immediate demand, would require even more overbuild and glut—even higher costs with even lower prices. Will storage facilities that buy the electricity restore the finances of solar? No. Remember, they are storing that electricity to sell at night, when demand falls along with prices. They will be competing in that market with overbuilt wind and dispatchible generators which will sell at very low prices; coal, which will bound the price, can sell at 4-5 cents per kwh. So even if batteries store surplus solar electricity for free in the daytime, the highest buy-sell spread they can expect to see is maybe 5 cents per kwh. Obviously that’s nowhere near enough of a spread to sustain the solar-plus-storage electricity supply chain, which, to judge by Stafford Hills, costs 25-33 cents per kwh LCOE, as we’ve seen above. Pumped hydro would be cheaper but not all that cheaper, and it’s in limited supply.

    The only “pricing structure” I can think of that will allow solar to weather these grotesque market distortions is plain old state subsidy and preferment. That’s okay by me; I’m a social democrat and I’m comfortable with state subsidies. But if we go that route, I think it’s proper to ask which low-carbon technologies need the least subsidy when we scale them to run the whole grid.

    As it happens, nuclear comports very well with storage, especially pumped hydro. It can reliably store a surplus at night when demand and price are low, then sell the stored power into daytime peak demand when prices are high. The stored electricity is still expensive, but cheaper than power from gas peakers. So the reactor can run flat out in baseload, the PH makes a profit buying low at night and selling high in the daytime, and the grid meets peak demand at a lower cost and without building expensive new generating capacity. That’s the way a rational electricity storage system should work. As was mentioned above, many pumped hydro stations are built to complement nuclear plants—and that makes sense.

23. @ David Jago,

    Do you happen to have a ref on wind PPA at 2.5 cents per kwh? Is that subsidized or unsubsidized? Are there state as well as federal subsidies? Does that price include any RECs? Is it typical of prices in places with bad wind resources, like Georgia, where the Vogtle reactors are going up? Does the PPA include the costs of integrating the wind into the grid, extra transmission costs and costs of backing up the wind farm when the wind stops? Will that backup power need to burn fossil fuels, and if so, how does that affect the climate? How might the capacity factor of wind turbines change at high penetrations when much wind generation has to be spilled, and how would that effect the LCOE? Does your Vogtle price factor in the big drop in cost of Vogtle power during the 30 to 50 years of service after the capital costs, which are most of the LCOE, are paid off? Vogtle’s reactors will have a capacity factor of 90 percent and can run a year and a half nonstop at nameplate power; the average US wind farm has a capacity factor of 31 percent, will almost always be running at less than nameplate, and will likely not be running at all for days on end many times each year. Do you think a nuclear plant like Vogtle has advantages in reliability that might justify a price premium over a wind farm? Can we generate all the low-carbon electricity we need just with wind? How about with nuclear? If we can’t do it all with wind, what will the total system costs be for all the other components we have to add in to assist wind? Are those costs fully represented in wind’s LCOE figures?

    John’s post and my comment was about the Stafford Hill solar-with-storage project, costing 25 cents per kwh. Do you feel that Vogtle electricity at 11 cents per kwh is more economical than Stafford Hill, and if so, do you think it should be built in preference to Stafford Hill?

    @ Ronald Brak,

    Four Chinese reactors so far this year–Fuqing 1 went on line on Wednesday.

24. @Will Boisvert

    I can’t find the actual article which I was remembering re the wind PPA, which is annoying.

    However, a quick search finds a couple of hits. This first one references in turn the US Department of Energy:

    http://robertscribbler.wordpress.com/2014/08/19/us-wind-hits-record-low-price-of-2-5-cents-per-kilowatt-hour-9-12-gigawatts-of-renewable-energy-additions-ramp-up-for-2014/

25. @Will Boisvert

    Ha! So my first reference is in moderation. The second wind PPA reference is from a Mike Barnard article on CleanTechnica back in May. You’ll need to look it up.

    The Vogtle LCOE is from Citigroup.

    In any event, nuclear here in Australia is currently a complete non-starter for public opinion and political reasons. Therefore the economics are irrelevant. All the calculations will just return a divide by zero error.

26. Will, thanks for catching me on the number of Chinese reactors. Boy, is my face red. Now let me help you out in return:

    I just recently paid for rooftop solar in Queensland. It cost under $2 US a watt before subsidy. With a 5% discount rate it will generate electricity for under 10 cents a kilowatt-hour. The cost of grid electricity in that area is 33 cents a kilowatt-hour which is not a great deal higher than the Queensland average. There was nothing particularly special about the deal. Other people are getting solar installed for less.

    The cost of rooftop solar is continuing to decline.

    In Australia neither grid generators nor distributors currently have a property right to the contents of my trouser pockets.

    I’ll let you arrive at what this obviously means for grid generation yourself.

27. @ Dave Rajo,

    Thanks for the reference. The ultimate source is the DOE’s Wind Technologies Market Report for 2013, which does indeed report an average Power Purchase Agreement of 2.5 cents per kwh for all US wind farms coming on line in 2013. But once you read the fine print you find that price is not representative of the actual costs of wind power.

    For one thing, the PPAs are reduced because of government subsidies. All these projects would have gotten either the Federal Production Tax Credit of 2.3 cents per kwh, or the Federal Investment Tax Credit of 30 percent of capital costs, which is generally reckoned to be even more lucrative on a per kwh basis. The report also mentions additional Federal subsidies like accelerated depreciation, and state subsidies, none of which are accounted for in the PPAs. So to get closer to the true cost of the wind projects you would have to add all these subsidies back into the PPAs. DOE also notes that the PPAs don’t reflect the costs of extra transmission capacity for wind, of integrating wind into the grid, backup, etc.

    Also, the sample of projects DOE looked at was extremely skewed, by its own admission, almost all of them being in Great Plains locations where construction costs are lowest and capacity factors highest. It’s not DOE’s fault: it just so happens that that’s where virtually all the wind farms were built in 2013. The reason is that wind installations collapsed almost completely in 2013, down from 13 gigawatts in 2012 to just 1 GW in 2013. Why the collapse? It’s because the Federal tax credits expired at the end of 2012; developers didn’t want to build wind farms in 2013 because they would be unprofitable without the subsidies. As a result, only the handful of projects with the very best locations, performance, financials, RPS preferments and state subsidies went ahead in 2013. So the 2013 crop of PPAs is a very unrepresentative sample of wind farm costs. As it happens, the Federal tax credits were reinstated for one year in January 2013, so all the 2013 projects got them anyway, enabling them to sign dirt-cheap PPAs. (This episode casts doubt on starry-eyed claims that wind power can compete in the market-place on its own; it shows that without government subsidies the industry would almost completely dry up.)

    You’re right that Vogtle nuclear electricity will probably cost 10-11 cents per kwh during the 30 years or so that it’s paying off its mortgage. After that, for the remaining 30-50 years of its service life the cost will drop to maybe 3 cents per kwh in O and M. Averaged over the whole service life the cost will be about 6-8 cents per kwh. Vogtle is towards the high end; the VC Summer reactors under construction next door in South Carolina will cost about 25 percent less.

    So yeah, some wind power on the great plains could well be cheaper than some nuclear on a narrow LCOE basis. And if utilities think it serves their needs, no reason they shouldn’t buy it in preference to nuclear. But that comparison isn’t as stark as it looks at first blush, and it isn’t going to hold up in every location, over every time period, and for every purpose that we need power. If we need steady, reliable electricity, which we sure do, then wind alone just isn’t going to do it. (In Texas, for example, wind power in the summer almost perfectly anti-correlates demand, reliably flatlining during afternoon peaks when electricity is most needed.) That means we have to construct a system with extra components that compensate for the unreliability of wind, and then reckon the extra costs of that system.

    One of the components that is talked up by renewables advocates is electricity storage, which is the subject of John’s post. He’s looking at a system designed to make solar more reliable by adding a storage component. But as we’ve seen, the storage component actually provides very little extra reliability while adding outlandishly high costs. Will wind-plus-storage be better and cheaper? Maybe, but it has to be drastically better and cheaper if it’s to be a feasible solution to the problem of unreliability. More likely, any system that manages to make wind power as reliable as, say, nuclear power will also make it dramatically more expensive than nuclear power.

    Which is why it may make a lot of sense for a utility to buy a nuclear plant in preference to a wind farm, even if the wind farm has a lower LCOE. Nuclear provides a much better and more useful quality of power that accommodates a grid with much lower system costs. It could therefore earn its price premium (and generally does).

28. @ David Jago, 25

    “In any event, nuclear here in Australia is currently a complete non-starter for public opinion and political reasons. Therefore the economics are irrelevant.”

    Well, that doesn’t sound good. I think economic considerations should be central to clean-energy policy. Maybe a vigorous public debate could get people to open their minds.

29. @ Ronald Brak 26,

    It’s wonderful that you bought solar panels.

    It would be interesting if you could keep us apprised of the details of their performance, maybe over the next year or so. Here are some of the things I would like to know:

    1. How much exactly did you pay for the whole system–panels, inverter, everything, with and without subsidy? Do you have an itemized budget?

    2. Do you have any battery storage? If so, how much, what kind and how much did it cost? Charging and discharging times? Expected battery lifetime and number of cycles?

    3. What are the maintenance costs over a year (actual recorded figures rather than estimates)?

    4. How many kilowatt-hours of electricity does the system produce during the course of a year (actual production figures, not estimates)?

    5. Did your household use all the electricity you generated during the year? Did you export some of it to the grid? How much? Did you get a feed-in tariff and if so, how much in total and at what rate? If you have batteries, how much did you store? Were any of the kwhs spilled? (Again, actual records are more useful than estimates).

    6. Have you gone completely off the grid, literally severed the grid connection so that you are generating all your own electricity?

    7. If you did go completely off grid, do you have a backup generator? What does the generator cost, how many kwhs did you draw from it during the year, and what was the cost of maintenance and fuel for it?

    8. If you have not gone completely off grid, how many kwh of grid power did you use during the year, and what fraction of your total electricity usage is that? How much do you reckon it costs the grid to maintain service to your house? How much does the grid save if you go off-grid? What fraction of those costs do you think you should be charged for grid services?

    (As always, actual data are better than estimates.)

30. 27, David Jago, not David Rajo–deepest apologies!

31. Some thoughts. If people with PV + batteries in the suburbs disconnected from the grid I would be appalled if they bought a backup petrol generator to cover rainy weeks. It’s a) cheating if the aim is low carbon and b) bloody annoying to those within earshot. I know this from living next to a rural shed sometimes used for parties. IMO batteries have a fair way to go before making sense for suburban PV owners.

    A public opinion poll in SA found 58% support for nuclear. Evidently the opponents have more political leverage since nuclear power remains prohibited via sections of the federal biodiversity and radiation protection acts.

    No disputing electricity from sunny daytime PV will be as cheap as from a new coal fired powers station. Therefore there must be some reason why PV generates ~2% of our electricity while coal generates 64%. Can those percentages be reversed without subsidies? Some say coal is due for a comeback with higher gas prices, a possible El Nino and no carbon penalties.

32. Will, you asked: What fraction of costs do I think I should be charged for grid services? The answer is less than the 30 cents or so a kilowatt-hour brokerage fee many Queenslanders are currently charged to sell electricity to their neighbour. What should the fee be? It’s not possible to give a precise answer, but it should approximate what it would be if all generators competed on an equal basis with no artifical distinction between rooftop solar and Tarong Power Station.

33. @Will Boisvert

    Google, “The nuclear renaissance is stone cold dead.” Even oligarchic capitalism is not interested in nuclear power if they can’t get massive subsidies to run it. These are the facts on the ground. Each year, those who keep on derping about nuclear power will look more and more foolish and irrelevant. By all means keep it up, I enjoy the amusement. 🙂

34. And the wholesale electricity price at around noon here in South Australia, the state with the most rooftop solar capacity per capita, was half a cent a kilowatt-hour. Now it doesn’t usually go that low. This may even be the first time it’s been that low at noon. But it does show how things have changed and are changing. And it does show that any new generating capacity is going to have to be able to compete in an environment with low daytime electricity prices. Today’s peak grid demand, well tomorrow’s peak actually, is predicted to come just after midnight when our off peak hot water systems all switch on at once.

35. @RB by your reasoning gas and coal must be even better
    http://www.wattclarity.com.au/2014/08/negative-spot-prices-in-queensland/
    I reckon later this year Adelaide and Melbourne will have a still humid evening when it is 35C at local 9 pm. I wonder what spot prices will be then? Example $1+ per kwh.

36. @Hermit
    Hermit, go to the AEMO site and you will see that demand dropped in South Australia. At around noon grid demand was as low as it was at four o’clock in the morning.

37. Right now, 14:36 Adelaide time, we are at a little under one cent a kilowatt-hour.

38. There are growing signs that PV on the users premises will be use-it-or-lose-it. We have feed-in tariffs of 44c per kwh in some places but in other places new PV connections get 5.5c. Large commercial premises in Qld will pay a fixed daily $537 connection fee regardless so there is little point in reducing consumption with rooftop solar. Poland and the Czech Republic have installed phase shifting transformers to block solar power surges from Germany on sunny days. In some suburbs of some Australian cities you can’t install more than 5kw per roof in case of local power overload.

    If sufficiently smart smart meters become standard there may also be the possibility of export curtailment. The grid operator will decline to accept more PV input and send a signal to your meter to stop exporting power. On the other hand we don’t want pensioners in fibro homes dropping like flies in hot weather. This will all take the wisdom of Solomon to sort out.

39. @Hermit
    Careful, Hermit. If anyone tells you rooftop solar can cause a local power overload they are lying to you. And I’m sure you wouldn’t want to be deceived into spreading lies.

40. @ RB it’s not just in SA but several states
    http://www.theaustralian.com.au/news/rooftop-solar-panels-overloading-electricity-grid/story-e6frg6n6-1226165360822
    I’m not saying it’s a serious problem just one of a number of difficulties that may prevent PV achieving the level some want.

41. @ Ronald Brak

    “the wholesale electricity price at around noon here in South Australia…was half a cent a kilowatt-hour….Any new generating capacity is going to have to be able to compete in an environment with low daytime electricity prices.”

    OK, but does that stricture apply to new solar generating capacity as well? When new rooftop solar rigs export electricity into the grid at noon, should they be paid a half-cent per kwh feed-in tariff, in line with the wholesale spot price? If they are paid any more than that, doesn’t that constitute a subsidy to rooftop PV? And if they are paid only that very low wholesale spot price, what does that do to the financials of owning rooftop PV?

42. @Will Boisvert

    Right on cue, another CleanTechnica article yesterday discussing your exact questions. All sober, realistic, analytical stuff – trolls don’t count.

43. @Will Boisvert

    Will, judging by your comments, you seem to be a passionate advocate who is into lots of detail. This is generally a good thing in terms of evidence based policy dialogue.

    Unfortunately, here in Australia, the policy dialogue has largely been captured by the fossil fuel lobby. They are no more interested in nuclear than renewables: it’s all competition to be stamped out at every opportunity.

44. @Hermit
    And the same article from three years ago crops up again. The Australian really should print a few new ones of these. Funny how South Australia has vastly more solar per capita than the states mentioned in the article that were supposedly having problems back in 2011 and South Australia has no problem. Anyway, unless you made your solar inverter at home out of an old microwave, when the voltage on the grid rises too high the inverter cuts off the power. That might be personally annoying, but it doesn’t damage the grid.

45. @Will Boisvert
    Will, as I mentioned, using a 5% discount rate, my parents’ rooftop solar produces electricity for under 10 cents a kilowatt-hour and their cost of grid electricity is 33 cents a kilowatt-hour. So clearly the feed-in tariff would have to be negative to prevent people from installing rooftop solar. And a negative tariff could be easily circumvented by not exporting electricity to the grid.

46. @Ronald Brak
    Well I know from personal communication it has been a problem around Victor Harbor. I looked at the council’s solar webpage and their optimism over future developments surpasses yours. On the bigger scale whole countries are taking action; Poland saying to Germany for example we don’t want your solar power surge.

    It may make sense to a bean counter to purchase new PV with no expectation of a generous feed in tariff. Most people with meagre cash reserves however want quick and obvious returns. That is probably why 2011/2012 will remain the peak for PV installation rates in Australia.

47. What has been a problem in Victor Harbor, Hermit? People’s inverters tripping? Or are you saying that voltage levels in the grid there have risen above Australian standards? Really, there’s have to be quite a few faulty inverters there to happen, even on a sunny day in the off season. Maybe Pigdog and Spider have been installing ex-microwave oven inverters? But don’t you think it’s more likely to be another expression of wind turbine syndrome? Just because the refrigerator burned out doesn’t mean solar power is to blame.

48. @Hermit
    Hermit, my bank will give me a home loan at 4.49% and the standard variable rate for a home equity loan is 5.64%. They also say I can get a credit card at 11.8%. Even at 11.8% people can still save money installing solar. Solar leasing is also an option that people without money on hand can use.

49. First go at a Solar Baseload equation:

    4 hrs a day solar = 1460 hrs per year

    20 hrs a day batteries = 7300 hrs per year

    Stafford purchased 3.4MWh of battery capacity for $4 million.

    We assume they’re lithium iron phosphate, set battery cycle around 60% to 10%, and should see well over 10,000 cycles within that range.

    Gives us 50% effective battery capacity = 1.7MWh

    1.7MWh / 20 hrs a day = 85kW

    That figure becomes our system size.

    To match it, we need enough panels to generate 85kW, plus charge 1.7MWh of battery capacity, for 4 hours a day.

    85kW + (1.7MWh / 4) = 510kW

    Stafford purchased 2.5MW of solar panels for $5 million

    We only need 510kW = $1 million

    $4 million storage + $1 million of solar panels = $5 million capital cost

    35 years = 306,600 hrs

    306,600 hrs * 85kW = 26,061,000 kWh

    $5 million / 26,061,000 kWH

    = 19 c/kWh

50. Or – to go over the top, and completely account for any number of cloudy days:

    To match it, we need enough panels to generate 85kW, plus charge 1.7MWh of battery capacity, for 1.5 hours a day.

    85kW + (1.7MWh / 1.5) = 1.25MW

    Stafford purchased 2.5MW of solar panels for $5 millon

    We only need 1.25Mw = $2.5 million

    $4 million storage + $2.5 million panels = $6.5 million capital cost

    35 years = 306,600 hrs

    306,600 hrs * 85kW = 26,061,000 kWh

    $6.5 million / 26,061,000 kWH

    = 25 c/kWh