Thanks to Luke Walker for alerting me to this:
ABC News: Solar takes off with US power supply deal
Extracts:
Two of America's biggest power utilities have unveiled plans for a multi-billion-dollar expansion of solar power supply, backing the argument that solar energy can indeed become a viable alternative to coal-fired electricity.
The company at the heart of the development is Ausra. It was started by Australian solar expert David Mills, who left this country for California earlier this year to pursue the further development of his ground-breaking work.
What makes the announcement more significant is that the utilities are confidently predicting that their solar power will soon be providing baseload electricity - that is, day and night - at prices competitive with coal.
Australian technology
The solar technology developed by Dr Mills already exists here in Australia, in the form of small pilot plants attached to the Liddell coal-fired power station in the New South Wales Hunter Valley.
A plant officer explains that the system's emphasis is on simplicity, with near-flat mirrors on giant hoops tracking the sun.
"Sunlight, on a clear day like this, strikes those mirrors and is gathered up onto the tower, and there's an absorber underneath that tower," he said.
Out comes steam, ready to drive a conventional power turbine. This is on a small scale; the new US company started by Dr Mills and Mr Khosla, Ausra, is now planning plants far bigger.
Dr Mills says the first plant size is more than two square kilometres in area and will generate 175 megawatts of power.
"But really we want to aim for gigawatt-style plants, and they're much bigger than that," he said.
Assumptions overturned
The coal and nuclear industries have long asserted that baseload power cannot be supplied by renewable energy. That mantra is oft repeated by Australian politicians like federal Environment Minister Malcolm Turnbull.
"You cannot run a modern economy on wind farms and solar powers. It's a pity that you can't, but you can't," he said.
Prime Minister John Howard says solar is "a nice, easy soft answer".
"There's this vague idea in the community that solar doesn't cost anything and it can solve the problem," he said.
"It can't. It can't replace baseload power generation by power stations."
But baseload power supply is just what Ausra is now being contracted to supply for the insatiable US market. It says that within two years it will be able to economically store its hot water for more than 16 hours.
Dr Mills says there is a convenient correlation between humans' power consumption and the sun's power supply.
"We get up in the morning everyday, we start using energy, we go to sleep at night," he said.
"And the presence of the sun, that's natural. And that correlation means that we can get away with a lot less storage than we might have thought."
Better than coal or nuclear
Dr Diesendorf says the huge US investment into solar will soon make talk of clean coal and nuclear as solutions to climate change redundant.
"Basically, the solar thermal technology will be on the ground, certainly in the United States and many other countries long before so-called clean coal and nuclear power," he said.
Mr Khosla says solar power is developing rapidly and will be cheaper than either nuclear power or 'clean' coal.
Ender,
I was sarcastic but the link that you provided was interesting but again they are aiming to be as baseload type plant as possible considering that would be a small network. They have increased their contribution to the network from 12% to 40% by diverting unused power to this flow battery system. King Island is a small network but my stance is still the same. The wind generators are capable of X amount of generation at optimal conditions, they divert power to the battery system to achieve a larger portion of the load or demand without increasing the to amount of windmills. The network is small and has larger variabilities than say the East cost network and as such a very small baseload if any and are able to charge their flow batteries when the wind blows and demand is lower.
So what after all this is your problem with my statement that the Ausra 1000Mw plant with the restrictions given in the article and had to operate day and night at a consistent output (using some form of storage)which is their aim that it would be approximately equivalent to 335Mw coal fired low cost plant baseload plant with an ACF of 85%. Remember most people if they were asked to tell you the output of a Hunter Valley Power Station they are more than likely to quote the maxium continuous rating. I was setting some common prespective getting away from the number of homes supplied or 50 million megawatt hours over 20 years which mean very little to the person who sees these large power stations but doesn't realise that the Ausra plant power output quoted is really only its "peak" output (I don't like the term, it would be getting confusing with peak load)and hence a smaller plant than the 660 Mw unit they see in the their "backyard" in total capacity.
It was not about network stabilistion, power mixes etc just a reasonable comparision to the average person.
Peter - "So Ender you are advocating fossil fuels. Why would you? I know. You want that consistent power supply for the load requirements part of which would be called baseload with wind only being approx 30% available (global) solar about the same."
No I am advocating a mix of power with fossil fuels reduced to less than 30% and absolutely no nuclear. I am not a renewable power zealot and I admit we will need a mix of power sources to power the future however the absolutely last thing we need is more baseload. We need more intermediate such as co-generation gas turbines burning either gasified coal, gasified waste biomass or natural gas. We need vastly more solar thermal, solar PV, wind, wave, tidal and geothermal. Coupled with large scale storage and new HVDC transmission lines with superconductor storage the requirement for fossil fuels will diminish as V2G cars and other storage take over the regulation and operational reserve.
One of the tasks that wind flow battery storage can do really profitably is grid regulation. The power converters that change the DC battery voltage to AC can also change phase, voltage and frequency instantly under automatic control to supply the extremely valuable ancillary services to the grid when wind farms with storage become more common. One is already installed at King Island.
http://www.metaefficient.com/archives/renewable-power/australian-island-using-flow-batteries-to-store-wind-power.html
Ender,
The definition you linked to for the Capity factor is Availabilty Capcity Factor (ACF). The ACF changes on power plant as it requires cleaning, runs out of fuel, mechanical and electrical problems etc. So no Ender I am not "absolutely and completely wrong here" or do you think that plant should not be able to run at its rated capcity at all or as I noted the Maxium Capcity Rating (MCR) which the ACF will be based on.
Ender.
Note it is the articles point that it could run day and night.
Your examples contain 2 fosill fuel plants and others that have either have to have storage facilities of some sort (which is Ausra's claim) or you only take them when they can supply (not pricing but when the sun is up or the wind blows). Geothermal is probably the only one that will work.
So Ender you are advocating fossil fuels. Why would you? I know. You want that consistent power supply for the load requirements part of which would be called baseload with wind only being approx 30% available (global) solar about the same. You must be in the pay of big coal.
Seriously though I know there are mixes hence the baseload, intermediate and peaking. I am only pointing out that to get to a baseload plant solar (photovoltaic or steam generator) would require a large storage system which would have to be filled if the supplier wants 24 hour production (Ausra will if they get it as cheap as coal plant i.e. profit hopefully 24 hours a day not just for 8 hours).
Peter - "f a thermal (coal or gas) power station was said to be a 500Mw unit it will if it is mechanically, electrically sound and inputs i.e. fuel, water etc are available it will produce 500Mw as a maxium continuous rating MCR"
Look you are absolutely and completely wrong here.
http://en.wikipedia.org/wiki/Capacity_factor
This is a good definition of capacity factor. There is no powerplant in the world that has a 100% capacity factor. For this it would have to run 24 X 7 X 365 with no maintenance and no failures. This is clearly impossible. There is also another term called availability. You cannot get power out of a coal plant that is down for maintenance. A wind farm with its drastically lower maintenance requirement has, given a good wind, a higher availability. A shut down coal plant even though there is coal in the bunker cannot deliver any power.
"solar heating system has to be over three times the size to feed the "heat sink" or the 1000Mw must be dropped to approx 335 Mw either way the solar farm has to be a multiple of over 3 to achieve this based on the figures in this article."
Only if the solar plant was the sole supplier of power as would be a standalone rooftop solar plant. In a future power supply system the solar plant would be a part of a network similar to today. You could not have a system that comprised 100% thermal coal or 100% nuclear power as these systems cannot do peaking loads. Our present coal plants are backed up with peaking plants. Also the system is already oversized to cope with the lower availability of thermal coal. Any solar thermal plant would also have wind, geothermal, IGCC coal plants, natural gas, tidal, wave etc power plants that will satisfy the current demand whatever the time of day or the season.
The thing that you are not allowing for is that power is more valuable depending on the time that it is available. For instance a roof top solar array cannot be relied on 24 X 7 without backup batteries. However connect it to the grid and it's value magnifies. One of the greatest recent demands is home airconditioning and it it threatening to overwhelm the grid. Grid-tie solar systems deliver power at precisely the times of greatest demand ie:when it is hot and sunny. Therefore the value of the power is much greater because it is delivered when it is needed. If the coal plants that delivered to grid power was more reactive it could be easily scaled up and down in response, saving greenhouse emissions. As it is now those coal plants are still running flat out however producing nothing and never able to change fast enough to make large savings. This is why renewables with coal do not deliver the emission savings that are predicted.
Ender,
If a thermal (coal or gas) power station was said to be a 500Mw unit it will if it is mechanically, electrically sound and inputs i.e. fuel, water etc are available it will produce 500Mw as a maxium continuous rating MCR (there are always slight caveats to this but they are usually close). This means that its availability capacity factor (ACF) is 100% if it can maintain the 500Mw 24/7. As factors such as fuel, temperatures, mechanical and electrical failures, outages for overhaul and cleans (note not demand or load) then affect the ACF reducing the factor to whatever but this thermal station is still a 500Mw unit.
On the other hand the Ausra plant is 1000Mw but I presume that this maxium would be for a certain period of the day but the "fuel" the sun degrades and then vanishes as the Earth rotates that means its ACF is reducing from 100% to if their figures are correct to 28.5% over the day/week/year. Not good in terms of control of the network i.e voltage and frequency. So to supply this generation as "baseload" (their claim i.e "predicting that their solar power will soon be providing baseload electricity - that is, day and night - at prices competitive with coal.") like a "baseload" thermal power station which is available 85% (the ACF) of the time the solar heating system has to be over three times the size to feed the "heat sink" or the 1000Mw must be dropped to approx 335 Mw either way the solar farm has to be a multiple of over 3 to achieve this based on the figures in this article.
Baseload plant is the lower cost, reliable power (closer to 100% ACF than discussed)suppliers compared to say the peak generation which will be high cost and/or unreliable i.e. its "fuel" water, sun etc but usually quick response.
Ender I will guarranttee that if you wished to rely on a solar cell at home (no mains or fossil fuel backup) that you would oversize the capicty install and add batteries to enable you to operate day and night. Your base load would be the fridge, the standby power on your aplliances, the light that one of the children has left on, the electric alarm clock anything that consumes electricty day and night even thogh you aren't at home. In a large network they also include buisinesses (the nightclub that runs all night), factories that run 24 hours a day and still be able for you to switch on the light at 2 in the morning to find out what the dog is barking at. This is some of the things that Nemmco has to allow for and they know to a fair degree what the minium power requirements are at certain times of the year hence the warnings about not having enough capacity in the system that they sometimes give and I am sure that you would not want to pay the maxium 10,000 dollars a Megawatt that could occur if the peaking plant has to be continually used.
Baseload will be here to stay but it is the definition/excepted wisdom of baseload plant that may change.
Davey - "Are you sure you don't work for a windmill company? You said you work for gummint. "
No sorry struck out on both there.
Peter - "Baseload and baseload power plant are to different things. Load is a demand on the system, generation is the response to the demand."
There is no such thing as baseload - it is an imaginary term that is misunderstood. True load is the amount of demand on a system and generation is the response however demand varies over the day and over the seasons and can be satisfied by any combination of whatever power generation capacity is available.
Demand never drops to zero and up until now the most efficient way of satisfying the minimum demand was with a power station that is more efficient running flat out than changing to meet demand. Up until recently only large power stations were economic however that is now not true. It is just as efficient to generate a kWhr from a 1kWhr solar panel or a 100kW microturbine as it is from a 1GW Coal Plant. Up until now this has not been the case and large power stations were the only way electricity could be generated efficiently and the old technology did not scale down at all.
Baseload power stations got their name from the fact that they were the best things for the largely unvarying base of the daily/yearly demand curve however it is not true today. Anything can deliver the base as long as it is despatchable. Coal operators desperately trying to remain valid in a changing world where they might have to actually pay for their greenhouse emissions they have invented the term baseload and invented the idea that coal plants are the only thing that can deliver it.
"If they wish to make this plant a baseload plant capable of producing a sizable output overnight they will have to restrict the output of the turb/generator hence my comment that the continuous output was more like 335 Mw."
Again you are fundamentally misunderstanding how power stations operate. Are you suggesting a thermal coal plant of 1GW be called and 850MW one because it has an 85% capacity factor? Or a nuclear power station that is down for 2 years because of defects be downrated from 1GW to 0GW. The rated output of a power plant is independant of the capacity factor.
"If they wish to make this plant a baseload plant"
It already is a baseload plant as it is a thermal steam turbine that I am pretty sure will not be able to be varied quickly so it would be classified as baseload at worst or intermediate at best.
Steve,
Are you sure you don't work for a windmill company? You said you work for gummint. Department of Windmills? Minister Don Quixote? CEO Sancho Panza? Windmills are a blot on the landscape. Now algae that produce hydrogen (Quantum last night) - I like it.
Steve,
Baseload and baseload power plant are to different things. Load is a demand on the system, generation is the response to the demand.
The point about the NSW system being capable of 12 gigawatts but usually only 8 gigawatts reminds me of Cain/Kirner/Kennet sell off of the SEC(V). They stated they had plenty of power available (I think they were claiming 10 gigawatts) but the reality was that there was a lack of reliable low cost power supply.
As for appearance it is misleading just as there has been claims that windpower had nearly 100% availability but the definition of availability had been changed though the Actual Capacity Factor was a lot lower than the thermal plant. This seems to apply to the Ausra plant. In this world of Nemmco there would be a willingness to chase the dollar and not look at system needs. If they wish to make this plant a baseload plant capable of producing a sizable output overnight they will have to restrict the output of the turb/generator hence my comment that the continuous output was more like 335 Mw.
All that being said I liked the Ausra concept when I first saw it because of its general robustness and what seems like current cheap (relatively) componets unlike the say the Solar Farm that is set to be built near Mildura. By the way does anyone what is happening with the Solar Tower that was suppose to be built out there.
Ender I usually equate it to the number of 2 Kw bar heaters it can supply and for how long but it is still big numbers.