The myth of baseload power demand

Today’s Fin has a leader arguing that we should be laying the ground for a move to nuclear power. It’s commendably realistic about the long time lags involved, and argues we should get started on preparations now. My view is that it would be better to wait and see if the US makes progress on its (currently faltering) attempts to revive the industry there. But the thing that really got me going was the repetition of the claim that alternative energy sources are problematic because they can’t meet “baseload power demand”.

I’ve said before that this claim is wrong, but I think it’s time to sharpen my position, and state two claims:

*There is no relevant sense in which baseload power demand is a meaningful concept in our current electricity supply system.

*Any electricity supply system likely to exist in the next 40 years and capable of meeting peak power demand will have no problems meeting baseload demand.

The first point may seem paradoxical, but the reasoning is quite straightforward. Our current electricity system is based primarily on coal-fired power stations which cannot be turned on and off at short notice. So, generating power during times of peak demand (daytime) entails generating power during off-peak times, even if there is no demand for that power at a price that covers average costs. That is, we have a baseload supply, which easily exceeds the demand for off-peak power at average cost, and sometimes even at fuel cost. The result, as we observe, is that off-peak power must be heavily discounted, and even so, demand is barely enough to keep the turbines turning.

To consider any meaningful notion of baseload demand, we could do a bottom-up analysis, and consider how much of electricity demand corresponds to the notion of a continuous, stable 24/7 demand. In the average household, for example, this would include the fridge and those ‘vampire’ appliances that are left on standby all the time. In addition, of course, lots of households have off-peak hot water, but this is only because of the price incentives designed to get rid of the excess baseload supply. The same points apply to offices and a most industrial uses (including some that operate at night to take advantage of cheap power, even though other costs are higher). There are only a few continuous processes like aluminium smelting that really constitute baseload demand in the strict sense. Of course, there are off-peak demands that don’t constitute baseload in the strict sense, like people watching TV at 3am, but there’s no reason to think that such demands are large.

To get a quantitative handle, we can use the following analysis: currently off peak prices are about half of daytime prices, and offpeak demand is about half of daytime demand (illustrative numbers only, will fix). If we didn’t discount offpeak electricity, it seems likely that offpeak demand would be around a quarter of daytime demand.

So, as long as 25 per cent of supply is generated by baseload suppliers like coal, oil, geothermal and nuclear, our main problem will be one of excess baseload supply, as at present. We’re unlikely to reach that point for some decades. But even then, the offpeak demand could be met by reliable sources that are independent of time of day, most obviously gas and hydro. In that case, standard principles of marginal cost pricing would suggest that there should be no off-peak discount. In such a system, the baseload sources would be used optimally, rather than generating excess low-value electricity as at present.

A baseload demand problem would only emerge in a system reliant almost entirely (more than 75 per cent) on solar electricity. And, even if such a problem emerged, it could be dealt with exactly as we deal with our current problem of excess baseload supply, by changing relative prices.

I haven’t dealt with the separate problem of supply variability from solar and wind (hint: the answer has to do with prices, as before). But, in our current circumstances, and as regards marginal increments to the system, the far bigger problem is that of supply invariability. It is a positive disadvantage for nuclear that it generates power 24 hours a day rather than solely during the daytime. Much of that power, and the fuel used to generate it, is effectively wasted.

134 thoughts on “The myth of baseload power demand

  1. Fran, this one sets it all out.

    Penny Wong was asked about the Govt’s positon on nuclear power this morning on ABC 891. She said we are blessed with tides, wind, solar and geothermal and the government is committed to developing them.

    I have posted several times on what a nonsense CC&S is, including one with many facts and figures which easily showed how silly it is to waste money on it’s research. I would have thought Michael would have read them.

  2. Salient Green, the problem is not the science but the will to go green.

  3. I heard Kym Beasley on AM Agenda this morning saying that although the scientists were saying it’s real tricky we need to press ahead with carbon Captcha-n-StoreIt, because coal won’t go away overnight. Boy oh boy. Wouldn’t it be great if it was a snap to make this work – but scientists are saying it’s pretty tricky – so we’ll just politely ignore their judgment and indulge in some p*ssing uphill against the wind. Rather than chuck a $100 million or so into Captcha-n-StoreIt blow it on something that works now and just needs some encouragement. The Coal Crew would no doubt start pouring some serious money into Captcha-n-StoreIt if they felt the heat of various carbon markets upon their industry.

  4. There’s no point selling me on the idea of nuclear as part of the solution. I’m already on board, especially with thorium and LFTRs but the reality is that no party will push it and there is no timeline on which you could introduce at scale to make a difference when we need the difference to be made.

    Simple as that really, SG

  5. Fran, I got a problem with nuclear energy especially after Chernobyl and the many associated problems such as ie recently when the Swedish-German utility Vattenfall had no idea as to why the Kruemmel nuclear plant in Germany malfunctioned. No thanks.

  6. Do you also have a problem, Michael, with flying in aircraft because of all those plane crashes? Will you stay away from cars because the Trabi is a pretty ordinary piece of equipment? You know, you should stay away from ocean liners — remember the Titanic?

    We humans try stuff out. If it doesn’t work we figure out why and either improve the design or do it a different way. These days, nuclear plants have containment structures. There are safety standards. We can run sub-critical plants. We don’t monkey about with the controls to see what would happen.

    An you’re the one who wants coal plants … sheesh … what are the morbidity and health impactis associated with them again?

  7. No Fran, the Kruemmel nuclear power plant incident was recently.

  8. Kruemel was built in 1983

    It was shut as a precaution when a fire broke out *near* the plant but if didn’t fail and no person was injured. What was your point?

  9. Fran, the Kruemmel incident is but one in a long long long long list of nuclear power plant accidents around the world. No thanks, the future lies in solar energy and in harnessing sunlight similar to what the Europeans are now focused upon; the $560 Billion DESERTEC project.

  10. I have a problem with nuclear accidents. A big problem. A plane crash is usually contained relatively to the potential for spread from nuclear accidents (and then there is the spread that you dont find out about…the leaks, the contamination of water supplies, the leaks of material into the black arms and weapons markets. Its an ugly filthy business.

  11. There is no need for nuclear. Period. I dont care how damn efficient it is – efficiency and cost isnt the be all and end all.

  12. Alice

    All technologies carry risk. The only rational way to copmapre them is to realte cost and risk to benefit. By this standard, nuclear is way ahead of coal. I happen to prefer soalr thermal and geothermal and wind and biomass, and tidal where these can work, but where they can’t, nuclear is preferable to coal.

    Waste from thorium plants is not weaponisable. Thorium plants can be used to burn and degrade weaponizable materials, reducing the risks that we all would want to reduce.

  13. To change tack a bit, I think the Australian Labor Government’s, and the Coalition are the same on this, only real goal is to milk every dollar they can out of coal and uranium. To do this, they are prepared to push and manipulate public opinion to it’s limits by token expenditure on anything which obfuscates this purpose.

    The clue to this is in the link I posted above. “Australian electricity prices are almost the lowest in the world. Residential prices are 36% of those in Japan and a little over half of those in most of Europe. Industrial prices are 30% of Japan’s and 60% of most European prices.”
    Average Victoria 2.8 c/kWh
    Average NSW 3.9 c/kWh
    Average Qld & SA 3.2 c/kWh

    Carbon Capture and Storage is a callous waste of money. Grants to geothermal projects are token only. What Geodynamics or Petratherm could do with the money being spent on CC&S and other coal subsidies would be truly exciting for most Australians. Everyone knows that the solar power rebates would have returned many times the KW/hrs if directed towards large commercial arrays of PV or Solar thermal.

    Much of our best research into renewable energy has gone overseas, safely unthreatening to our cheap, coal based power. Any mention of nuclear power is off the agenda, not because it is proliferating or waste producing or dangerous, but because the looming 4th gen reactors threaten income from uranium mining.

    Anyone with vision and integrity can make renewable energy 100% of Australia’s electricity source. I believe the Greens can do this. But, in the absence of the Greens in power, 4th gen nuclear is preferable to coal and is needed, somewhere in the world, to use a large part of the waste generated from older nuclear technologies.

    Our politicians are unable to make plans or set goals that are meaningfull. I admit we are in an uncertain phase of development in so many technologies but this fixation on the current economic system of population, consumption and economic growth takes priority, with most of our politicians, over handing a better world over to our children.

  14. Here’s an interesting link on Nuclear waste in the US but more interesting to me was one of the comments on the economic value of the waste-

    “There’s $35,000,000,000 worth of rhodium in those spent fuel rods.
    There’s $500,000,000 worth of palladium in them.
    There’s enough plutonium and uranium in them to provide all our electricity for a century or more.
    And that’s not even starting to talk about the ability of Gen IV reactors to use the rest of the waste as fuel and fission it until it’s not a problem anymore.”

  15. From memory rhodium is even better than platinum in cat converters. There’s some talk of it being used in CO2 sequestration as well. Apparently it’s about 6 times as valuable as gold.

    It’s not surprising that palladium is there too as this is the decay product after rhodium.

  16. Tell me Salient Green, where are the so-called generation IV reactors you claim are in service?

  17. Michael, I don’t claim any 4th gen reactors are in service but I do know that the technology is proven. India is committed to the LFTR as they have oodles of thorium. Visit and read what Barry Brook has to say on the IFR. Please don’t misjudge me on this Michael. I am not a fan of nuclear power at all but I believe the 4th gen technology is better than using coal. There are much worse effects on the planet from coal than the CO2 it produces.

    I truly despair at the damage we have done to the natural world. This is not what I would have liked to be handing over to my kids. We need to be working now on a world population of about one billion by the end of this century. This process alone would solve many of our problems but especially energy.

  18. No Salient Green, the so-called generation IV reactors you speak of is still a pipedream, even after 3,000 plus scientists have worked countless hours on the project since 2001. At best the first of these so-called generation IV reactors will be rolled out in two or three decades, if ever.

  19. Michael, you really needed to have visited Brave New Climate before that post. This is from The Science Show interview with Barry Brook.

    “Robyn Williams: How much do they cost and how long does it take to put them up?

    Barry Brook: That’s a question that can only really be answered by building a commercial scale demonstration. The Russians are building a reactor called the BN-800 right now, which is a sodium cooled fast reactor, it’s one of these generation four reactors, currently under construction. The Chinese are looking at building one too. The Indians are building a fast breeder reactor. So we’ll know within the next couple of years about how much they cost and about how quickly they can be built.

    General Electric Hitachi, one of the major world producers of nuclear power stations, has got a model blueprint called the S-PRISM which is one of these integral fast reactors that they say can be built for about $1,500 per kilowatt installed, which is extremely competitive.”

  20. Salient Green, unless I am totally wrong sodium-cooled fast breeder reactors are not safe and can lead to a Chernobyl ie the Indian nuclear power industry still rely on plutonium as a driver fuel. No thanks.

  21. SG — 1 billion by 2100?

    Surely you jest. We are going to have 9 billion by 2050, and if we do well we might stabilise and decline to about 7 billion by 2100. Where do the other 6 billion go?

  22. Salient Green, I will end up by saying the nuclear industry is riddled with problems and provide a sample of what is happening in the real world. During 2002 two workers were exposed to a small amount of radiation and suffered minor burns when a fire broke out at the Onagawa Nuclear Power Station Miyagi Prefecture, Japan. And during 2005 at Dounreay, UK the site’s cementation plant was closed when 266 litres of radioactive reprocessing residues were spilled inside containment & in October another of the site’s reprocessing laboratories was closed down after nose-blow tests of eight workers tested positive for trace radioactivity. In 2007 at the Hunterston B nuclear power station the plant was shut down due to “problems with controls that keep the delicate process at exactly the right temperature”. During 2008 100 employees were exposed to low level radiation during maintenance on the 4th reactor at the Tricastin Nuclear Power Center. Still think nuclear power is safe?

  23. Please post here deaths and harms associated with the normal operation of coal plants and their feedstock, Michael

  24. @Alice

    That’s pretty much hitting it on the head: if a nuclear accident contaminates a large scale area, and that area is surburban, the cost of clean up and compensation would be enormous. And I’m not forgetting the health impacts upon those in the affected area. While Chernobyl was an unlikely set of events, it happened, exposing all and sundry.

    Two conditions must be met before I am likely to accept nuclear power in Australia.
    The first condition is that the reactor and plant technology are robust enough to limit the impact of any adverse event to a small, localised zone around the reactor and plant. None of this Chernobyl malarky, none of this construction along a known faultline, next to population water supply, etc.
    The second condition is that the reactor and plant, and all of its waste, are located a Hell of a long way from any populated regions, known aquifers, and from arable land. The reason for stipulating this is that it is tempting to get the cost down by placing them near the customers and near a good water supply, often competing with customers for that very water supply. Legislation that actively prevents reactor, plant, and any waste from being anywhere near people – other than the employees – is essential, otherwise due to cost the kit will be put right next to the bigger cities.

    There are a whole range of other things I’d like to see too, but those two conditions are primary. Personally, in Australia, I see little need for nuclear when that same capex would massively boost other alternative energy solutions readily available in Australia, now.

  25. Fran, world populaton will not get to 9b. Resource shortages will constrain population growth well before this. There is a groundswell of awareness of overpopulation and ecological overshoot. Our business and political leaders will be dragged kicking and screaming to their senses well before 9b. I also said we need to work on 1b, it wasn’t a prediction.

    Michael, some of the adverse environmental effects of coal mining and burning.

    Release of carbon dioxide and methane, both of which are greenhouse gases, which are causing climate change and global warming according to the IPCC. Coal is the largest contributor to the human-made increase of CO2 in the air.
    Generation of hundred of millions of tons of waste products, including fly ash, bottom ash, flue gas desulfurization sludge, that contain mercury, uranium, thorium, arsenic, and other heavy metals
    acid rain
    Interference with groundwater and water table levels
    Impact of water use on flows of rivers and consequential impact on other land-uses
    dust nuisance
    Subsidence above tunnels, sometimes damaging infrastructure
    rendering land unfit for other uses
    Coal-fired power plants without effective fly ash capture are one of the largest sources of human-caused background radiation exposure
    Coal-fired power plants shorten nearly 24,000 lives a year, including 2,800 from lung cancer.
    Coal-fired power plant releases emissions including mercury, selenium, and arsenic which are harmful to human health and the environment.
    Mountain top removal is an environmental disaster.

  26. Fran, I’ll answer your question by saying the “true cost” of coal-based electricity is much higher than the current “market price” depending upon how one values human life but until more money is poured into renewables we are stuck with clean coal technology.

  27. Donald

    I don’t have any basic issue with your constraints on nuclear power plants — the containment is always met these days. Having it away from large population centres is not really going to help though because safety really isn’t altered either way.

    It’s possible to use molten salt as the coolant rather than water.

    I see no pressing need for nuclear in Australia, and in most places I doubt it can play a role for reasons that are largely political or economic, though it might well do so in Japan or China as the less nasty alternative to coal.

  28. I broadly agree with Salient Green on the population problem. It has already doubled in my lifetime and I’m only at the 50% mark (touch wood). Another doubling would put it at 12-14 billion before I pop my clogs. Of course, the odds aren’t entirely favourable on water, food and resource sufficiency, and that implies war and stuff. While it is difficult to forsee technological changes that may make it possible for 14 billion consumers to squat on this block, extinction rates for anything larger than a squirrel will most probably climb – until the naturally imposed limit is reached, of course. To say nothing of land prices…

  29. Michael – what clean coal technology?!! There’s more CO2 produced than the coal burned. CO2 is much more difficult get hold of, to transport and store than coal is. You can’t load it in open trucks. You can’t just dump it, it’s got to go deep, in the right kind of geology, where it won’t resurface. Gigatons of it. Renewables, expensive as they are, are already cheaper than what coal would cost with CCS. Nuclear, when it can come in on budget, looks cheaper than both. On that basis it’s going to be attractive.

    Sorry, but if ever there was greenwash it’s CCS. It’s Federal Labour’s way to ‘look’ serious about the new climate reality whilst presiding over the continuing expansion of the mining and export of coal and entrenching domestic reliance on coal powered electricity.

    With the current ‘negotiations’ over the ETS, the intent of the Opposition seems to be to commit Australia to no more than the least our trading partners do. Wow. Such is the ‘leadership’ on climate change! It’ll take a changing of the guard before we see more than greenwash from Opposition – or from Government.

    Even so, I think the sense of urgency needed will come to permeate politics. The coal industry’s calls for concessions will come to arouse the ire of middle Australia. The 3D’ers, the doubt, deny, delay crowd, want us to face the greatest challenge of their times with eyes closed and ears blocked! I don’t believe Australia will ignore the great challenge we are facing.

  30. And one may add, Ken, that at least with nuclear (unlike with CC&S), the waste need not be sequestered forever.

  31. Tell me Ken, which political party has nuclear energy on its books for the last time I read the papers Australia was stuck with clean coal technology. But then I maybe be totally wrong.

  32. The “Better Place” electric car batteries will give a large amount of electricity storage capacity. Many renewables harvest “heat” which is turned into electricity. You store heat. Electricity from water turbines is easily adjusted and so you can pump water uphill when you have too much power. Smart grids can turn off your beer fridge if there is not enough power.

    There are dozens of ways of evening out the load in a grid.

    Base Load Power requirement always was and still is a “non problem”

  33. This analysis is false. It is not the average amount of electricity delivered by renewables that matters, but whether they can handle all peak loads.

    Any electricity system must be able to deliver near-peak load at many times during the day, including after dark (wintertime when everyone is home from work watching TV, keeping their houses warm, etc), and when the wind is not blowing. Even if solar and wind could cover 95% of the peak-load times (which they clearly cannot), we would still require a parallel system capable of delivering peak load the remaining 5% of the time. That is, we would still require essentially twice the generating infrastructure as we do at present.

  34. @Newsman #33

    Not at all. Hydro/pumped storage could easily cover the slew, and before these ran out we could bring NG or small waste biomass plants online, do demand management etc.

  35. Hydro/pumped storage could easily cover the slew

    Australian governments are so captured by green interests they won’t even approve new dams for essential drinking water. What makes you think they’ll allow them for hydro/pumped storage?

    And you can’t do demand management at peak load times. All “demand management” means in that case is “demand reduction”, which is fine, but still doesn’t change the fact that you need a parallel system to deliver the peak load when the renewables cannot.

  36. Michael, if clean coal is all we’ve got we’ve got nothing. Seriously, capture and storage of CO2, on that scale … there’s more than 3 times as much CO2 produced as coal burned to make it and it either has to be bound chemically by as much of something else again to become a stable solid or forever be pumped deep underground… Seriously it makes more sense to use the deep drilling capabilities needed to develop geothermal energy as our baseload and underground cavern systems are better used for very large scale compressed air storage than used up first in a quest for places to put CO2.

    I think nothing much has happened on large scale energy storage because there’s not much current need for it by electricity providers. They haven’t changed much of anything about how they produce electricity in response to climate concerns. Pumped hydro gets used but it’s not something Australia is likely to be able to boost capacity of much although grid upgrades could make what there is more widely usable.

    CAES or molten salt or whatever storage will be more expensive than coal fired baseload electricity. What will be more expensive than all including coal and nuclear is losses in agricultural production and increased security costs of climate change.

  37. Ken, it has been estimated that Australia could reduce its current energy consumption by some 20-30% and Labor is exploiting this one area. And whether we like it or not we are stuck with clean coal technology until governments have the ‘will’ to go truly green and pump more money into renewables.

  38. @Newsman

    Who said anything about new dams?

    There is enormous scope for building pumped storage into city based water and water treatment facilities and saving power in the process, for example.

  39. “There is enormous scope for building pumped storage into city based water and water treatment facilities and saving power in the process, for example.”

    How exactly?

    For example, peak NSW power consumption is around 15GW. Assume for safety you need to store at least 12 hours of power for those windless, freezing nights when everyone runs their heaters. So that’s around 200GW hours. 1 cubic meter of water at 100M elevation is about 1MJ of energy or 0.27 KW hours.

    So to store 200GW hours you’d need around 700 million cubic meters of water at 100M elevation, or 700 million kilolitres (you’re not going to get much more than 100M elevation change within the city system). An average household consumes around 200 kilolitres per year (from memory it’s something like that), so you’d need to pump the equivalent of 3.5 million household’s annual water consumption in 12 hours.

    Even assuming there are 3.5 million households in NSW (an overestimate), to handle that level of pumping using city-based facilities you’d have to increase the capacity by a factor of 730 (= 365 * 2 – ie pump a year’s worth of water in 12 hours). So I think your “enormous scope” claim is rather overstating things. You’re not going to get that kind of pumped storage capacity without huge new reservoirs or dams.

  40. Michael I think it’s not merely a matter of waiting for Labour to really go green, it’s a matter of LibNats accepting the real danger to prosperity and security that is climate change. It will take serious bipartisan efforts to get more than greenwash. That’s all ‘clean coal’ is – greenwash.
    Fran, I have to agree with Jonathan – pumped storage in a water and geographically contrained Australia is not going to be sufficient.

  41. Jonathan, I very much doubt that even on cold nights, power demand is anywhere near the peak. The problem is more likely to emerge on cold, cloudy, windless days. But there are solutions less drastic or technologically demanding than pumped storage – warm clothes, for example. Given the right prices, I’m sure these tried and true energy conservation measures will go a long way towards solving scarcity problems.

  42. Jonathon

    There are several problems with the way you went about specifying the problem which ought to be addressed before I respond in some detail, as I will when I have more than a couple of minutes to compose an outline of what I had in mind.

    1. The window we need to protect is the minimum time between the onset of a negative slew and the bringin on line of new generating capacity. Natural gas can be bought to capacity within about 30 minutes — and so can diesel generators — and depending on the specific locality either of these might be plausible

    2. You’re assuming that the entire generating capacity were lost — i.e. all 15GW at peak, but this in practice has never happened. What can happen is a loss of 5-10% of the capacity normnally online to service the load. Current redundant capacity is not set up to stand in for 100% of peak load or anything like it. What happens is the largest installed capacity or 5% is covered. More would be prohibitively expensive.

    3. Much of the standard load in major urban areas is used to pump water to supply points. This work is scheduled around the existing load shape, but delaying it for 12-24 hours really has no major implications for public access to water. In short, this basic pice of demand management can be used to brdige slews fairly easily. Moreover, was we know, significant portions of residential demand are of doubtful marginal utility. Smart metering devices can cut power to non-essential devices — electronic devices on standby, off-peak water heaters etc as needed. During the rolling blackouts during the California heatwave a few years back (2005?) as much as 6% of demand was in standby devices, many in homes where people qwere on holidays away from their residence — more than the shortfall in supply.

    I believe my comments about the scope to use pumped storage to manage slews was reasonable with all this in mind, though I wish to comment in some detail later.

    I would also note that nobody claimed that baseload capacity could be discarded entirely and indeed, if much of it were NG or waste biomass derived feedstock rather than coal then slews should not pose the magnitude of problem you suggest.

  43. 2. You’re assuming that the entire generating capacity were lost — i.e. all 15GW at peak, but this in practice has never happened.

    That’s because we currently use fossil fuels which are available regardless of the weather. It will happen if we generate most of our power through wind and solar.

    “I would also note that nobody claimed that baseload capacity could be discarded entirely and indeed, if much of it were NG or waste biomass derived feedstock rather than coal then slews should not pose the magnitude of problem you suggest.”

    If your main generating capacity can disappear altogether, which it can (and will) if you are relying on solar/wind, then you need a parallel supply of equal generating capacity. It doesn’t matter what that parallel supply is. Maybe you could get 5% storage out of the city water but then you’d still need 95% in NG. Which begs the question: why not just build NG plants and be done with it?

  44. “If your main generating capacity can disappear altogether, which it can (and will) if you are relying on solar/wind, then you need a parallel supply of equal generating capacity.”

    This claim is wrong, as the post shows. The whole idea that there is a fixed demand that must be met is an artifact of a system which needs to produce a fixed supply. As pointed out at length in the post, the existing system needs to use price signals to get any kind of night-time demand. A solar-wind-gas system would need different price signals, but would still work fine.

  45. @Jonathan Baxter

    That loss of all baseload has never happened does not derive from fossil fuel usage. It derives from the fact that the systems are stable and about 85% available with some redundant capacity built in.

    If, as JQ suggested about 25% were baseload — possibly geothermal, NG from either fossil or waste biomass; biomass or petroleum-derived diesel then the slews asociated with negative volatility in demand and supply could easily be covered from demand management and pumped storage, and a range of others sources. I believe I’ve quoted these above in the thread.

    In practice though a properly designed system of reticulated wind solar and tidal will always be producing most of its power since the wind and the tide is always going to be supplying energy somewhere, and the sun’s patterns of insolation are highly predictable. Molten salt and other storage is also possible as is using the East west axis to extend the hours of daylight available.

    When was the last time that there was simultaneously an unpredicted and zero notice outage of insolation, tidal pressure and wind everywhere in the continent and its immediate waters?

    You assert 100% redundancy is necessary but you don’t show why one should foresee losing 100% of installed renewable capacity.

  46. @Jonathan Baxter
    Some assumptions about specs I am taking into the calculations

    1. The aim of pumped storage would be to provide on-demand capacity for a slew of about 5% for two hours (or the likely slew in any intermittent capacity, whichever was the greater) i.e. enough time to allow thermal capacity such as NG to be brought online and/r demand management to be implemented.

    Taking your figure of 15GW*0.05 = 150MW *2 hours = 300MwH

    2. The Sydney area, for example comprises about 1600Km2. Assuming the creation of five pumped storage facilities each supplying treated water and/or power to the grid as required implies servicing an area each of about 320Km2 — an area covered roughly by a circle of with a 10km radius. Given average population densities of about 30 persons per Ha each area would service somewhere between 800,000 and 1 million people. Note: These densities are much lower than ideal. While Hong Kong is much too densely populated at about 300 persons per Ha to be desirable, somewhere between 75 and 100 would probably be viable for low cost infrastructure … but I digress.

    3. Although you would, ideally choose locations as high as possible on stable gvround in the releavnt locality, given that you are going to need a low reservoir, one could simply achieve the difference in height one wanted by excavation. Assuming a 100 metre differential you’d need about 1.2 Gl of water stored or about 240ML capacity in each of the five locations. Each reservoir (upper and lower) would have to have a capacity of around 240,000m3. You could store a little more than that amount of water in a cylindrical vessel with a diameter of 86 metres and a height of 43 metres. Assuming the lower band of 800,000 people in a district and 2.4 per household that’s 333,000 households. Assuming your 200Kl each per annum that’s 66,600,000kl or 66.6Gl per annum or 182.4Ml per day — which would be about 75% of the capacity of the reservoir to be pumped in a day. Given the elevation and the nature of the sites, it would prbably make sense to locate wind turbines at these points. Given the likely strong winds, VAWT might well be apt.

    I should add that IMO the system should not merely or even mainly be reliant on the outflux of sub-potable water from households that have ultimately sourced that water from places like Warragamba. Instead, what I’d prwefer to see is localised water collection from the rooves of residential, commercial and industrial buildings. At the moment, every serious rainstorm causes water to flood stormwater drains with debris and other plastic waste that either winds up in creeks or causes road hazards. Collecting this on rooves, doing basic primary filtration for PM locally, and then pumping that water to the local reservoir would not only massively reduce the call on the major dams, and abate environmental nuisance and road haazrds but reduce the distance every cubic metre of supplied water was pumped, both at input to consumers and at outflow. We could radically cut effluent at ocean outfalls and save power and make it part of a system of localised power supply and storage that could lower the emissions intensity of our power grid. And of course, at higher densities and higher relative elevations, it would work even better.

    What’s not to like about that?

  47. PS … and I didn’t even mention the possibility of similar facilities to Sydney’s north at Peats Ridge and the Central Coast, the west at Blaxland and the south around Bulli all of which have excellent topography for this sort of thing

  48. jquiggin As pointed out at length in the post, the existing system needs to use price signals to get any kind of night-time demand. A solar-wind-gas system would need different price signals, but would still work fine.

    You don’t need price-signals to generate night-time demand after dark. You may need them at 2AM, but look at your electricity bill: you are not paying cheap rates for evening consumption.

    Peak load in NSW occurs on cold winter evenings when people turn their heaters on. So imagine there’s a cold, windless evening. The frost crunches underfoot, your breath condenses, and the trees glow with the moon’s silvery light in the frigid, still air.

    The only power you have available is gas (no sun, no wind). And absent a countervailing price signal you have demand for peak load. Your “price signals” will have to be so large that people would rather shiver under blankets than turn their heaters on. Sure, it’s doable ($10/KWh would do it), but political suicide. It would not “work fine” as you claim.

    Therefore, you either have to store enough energy to get you through the night, or have peak load capacity in your gas system, which begs the question: why bother with solar/wind?

  49. @ Fran Barlow
    “In practice though a properly designed system of reticulated wind solar and tidal will always be producing most of its power since the wind and the tide is always going to be supplying energy somewhere, and the sun’s patterns of insolation are highly predictable.”

    The sun’s patterns of insolation are very predictable after sunset.

    Even throwing tide into the mix you’ll still have times of peak load with little generating capacity. That’s what the “baseload” concept addresses. You can get around that either by storage, or by having a parallel system capable of picking up the slack. My point is that a parallel system is going to need nearly enough capacity to handle the peak-load, which negates the need for the renewable solution.

    Of course if you can come up with a storage system to handle sustained periods of peak load, then that’s your “baseload” solution. But I don’t think we’re even close to that yet.

    Frankly, if we want to get rid of fossil fuels, lets just go Nuclear. Barry Brooks has a great series on his blog discussing the new generation reactors.

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