Chile approves 260MW 'baseload' solar plant with storage | RenewEconomy

Chile approves 260MW ‘baseload’ solar plant with storage

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SolarReserve says solar tower and storage plant will compete with coal on reliability and cost to power Chile’s huge mining sector.

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The Chile government has given environmental approval for a solar tower and storage plant that would deliver 260MW of base load power to the country’s grid.
US company SolarReserve, which is putting the finishing touches to its first 110MW solar tower and storage plant in Nevada, expects the new plant at the Copiapó Solar Project will begin commercial operation in 2019.
“It will deliver 260 megawatts (MW) of reliable, clean, non-intermittent baseload power 24 hours a day to consumers of the central interconnected system (SIC),” the company said.
The project technology is based on SolarReserve’s successful Crescent Dunes project in the U.S., which is complete with construction and is currently in final commissioning.
However, the Copiapó project, located in the sun-rich Atacama Region, will add solar PV to the concentrating solar power (CSP) tower technology with molten salt thermal energy storage.
The hybrid concept will deliver more than 1,800 gigawatt hours annually, while providing a highly competitive price of power, mostly to mining companies that operate in the region.
CEO Kevin Smith said the plant would operate at a capacity factor and availability percentage equal to that of a coal fired power plant.
“No other proven renewable energy technology can provide this cost competitive energy solution to meet the needs of Chile’s largest and most important industries,” he said in a statement.
“Our proprietary solar energy storage technology provides a viable and cost competitive alternative to fossil-based electricity generation, with the potential to meaningfully reduce reliance on fossil fuels and associated carbon pollution that is contributing to climate change.
“This technology realistically has the potential to power the entire country of Chile using two phenomenal Chilean resources, salt and sun.”
SolarReserve’s 110MW Crescent Dunes Solar Energy Plant in Nevada is the world’s first utility-scale solar thermal facility to feature advanced molten salt power tower energy storage capabilities.  It includes 10 hours of full-load energy storage and will supply power to Las Vegas until midnight to meet peak demand needs.
It is also building the 100MW Redstone project in South ASfrica, which will have 12 hours of full-load energy storage will be able to reliably deliver a stable electricity supply to more than 200,000 South African homes during peak demand periods, even well after the sun has set.
SolarReserve has also made a submission to the ACT government’s next generation storage tender in Australia. The ACT government is looking to commission up to 50MW of solar plus storage capacity, but has been inundated with offers from a variety of technologies and project developers.
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  1. onesecond 5 years ago

    Is there any information about the costs per kWh? And is the water for the turbines used in a closed cycle? I would think water should be a problem in the Atacama desert.

    • JonathanMaddox 5 years ago

      The water for the steam cycle and the turbine working fluid is (almost) always used in a closed cycle, even in coal- and nuclear-fired power stations. Cooling water is a separate stream that doesn’t need to be clean and distilled. Some power stations use river, lake or ocean water directly, while others evaporate water from a river or reservoir in cooling towers.

      At Crescent Dunes, SolarReserve uses “hybrid” cooling — apparently it’s able to avoid water consumption and do dry cooling most of the time, while allowing the use of some to keep output up during peak production periods.

      “The power plant employs a hybrid cooling system designed to enhance performance during peak electricity demand periods while reducing water consumption relative to wet-cooling systems. The facility will use less than 600 acre-feet/year of water, a significant savings over traditional wet-cooled plants.”

      “Like its competitors, SolarReserve has incorporated the newest dry cooling methods into its facilities to reduce water consumption. The Saguache project will be built on private agricultural land, which, according to SolarReserve, currently draws 8,800 acre-feet (2.9 billion gallons) of water from the aquifer. Each of the two power tower facilities, according to the company, will use only 150 acre-feet of water per year.”

      • Smokoloco 5 years ago

        Surely waste heat could be recovered and thermally stored?

        • JonathanMaddox 5 years ago

          Not for re-use in the same heat engine, that would be a perpetual motion machine. Heat engines run on the temperature differential between their heat source and the temperature at which they reject that heat. There’s a fundamental physical limit on the amount of energy which can be extracted:

          .. basically, if you want to save the “waste” heat, you can’t give it back to the engine.

          Combined-cycle engines do achieve some additional efficiency by using the waste heat from one not-so-efficient engine with a high exhaust temperature to recover some mechanical energy from its “waste heat” in a second one, but the vast majority of engines and power stations use a single optimised cycle. With a high enough temperature differential, achievable thermal efficiencies are comparable.

          • Smokoloco 5 years ago

            So if you recover that heat energy by using a heat pump to jack it up to a temperature high enough to charge the thermal storage, that’s less efficient than soaking up new solar energy, even at night? Forgive me if this is a stupid question – I struggle with these concepts at times!

          • JonathanMaddox 5 years ago

            Well yes. An engine and a heat pump do the same things in opposite directions, but neither is perfectly efficient, there will always be round-trip losses. Certainly you can use a heat pump to store heat (and cold, since a heat pump moves heat from one place to another) for later use, but it takes power to do so. You don’t get it for free.

            But using a heat pump to store power in the form of a temperature differential is a great idea. The pump becomes the engine when it’s discharging. These guys are doing exactly that:

        • Ian 5 years ago

          A steam turbine works in this manner, steam has a high pressure and it drives the turbine blades using specially designed nozzles. To get rid of the steam on the exhaust side of the turbine it has to be converted to water. How do you convert steam to water? You cool it down. how do you cool it down? You can use evaporative cooling of waste water in a big cooling tower, or you can use cold air. As you can imagine, evaporative cooling is so much better at removing heat from the steam to make it condense but huge amounts of water is consumed, just as our friends in China have discovered with their wonderful fleet of coal power stations. They have literally sucked their country dry cooling all those fossil fuelled power plants. Those poor people not only have to contend with stifling air, but their rivers and aquifers have run dry! By the way, the water on the condenser side of the cycle is cooled down only sufficiently to condense into the liquid phase at a decent low pressure and then pumped away to the heating and steam generating part of the cycle, ie throught the hot salt storage medium. There actually is no wastage of heat. Steam- high pressure. Water – low pressure. Steam very hot, Water cold enough.

      • Fareham 5 years ago

        I suspect that the comment was made more in mind about water to keep the reflecting surfaces clean and free from dust etc.

        • JonathanMaddox 5 years ago

          There are two comments, one mentioning “dry cooling” and one mentioning “hybrid cooling system designed to enhance performance during peak electricity demand periods while reducing water consumption relative to wet-cooling systems.”

          I take this to mean that air cooling is used most of the time but that at certain times a small amount of water is indeed allowed to evaporate.

          I’m sure there’s also some water used for other purposes including mirror washing.

      • Ian 5 years ago

        600 acre feet is 740 000 m3 or 296 Olympic swimming pools or 7.4 million baths of water, or about 400 tonnes of irrigated wheat, not very water efficient considering this power plant draws water from a precious aquifer. One would think they could throw in a few more mirrors, or solar panels and sacrifice thermal efficiency to save water with a purely air cooled condenser. Deserts generally get very cold at night allowing a high temperature differential between the thermal storage salt and the surrounding air but in the day, the air would generally be hot. PV panels would then be a better bet to produce power in the day light hours and reserve the solar thermal storage for night use.

        There is another factor which may be useful and that is the clear night desert sky would act as a very cold radiant body, heat radiation panels could chill the exhaust steam from the solar thermal turbines, in addition to or instead of air cooling. Another idea to circumvent the use of water evaporation to cool exhaust steam would be ice storage. As a separate cycle an ammonia absorptive refrigeration plant could exploit the temperature differential between solar heat in the day and radiant cooling at night to create an ice storage resource. This could allow the solar thermal plant to run day and night with a high efficiency.

      • onesecond 5 years ago

        That is still a lot of water though.

      • rlhailssrpe 4 years ago

        Is there any information on the blow down from evaporative cooling? All evaporative cooling schemes concentrates dissolved solids which at some set concentration must be discharged as more water is added to control the concentration. What are the limits? The better the make up water, the cheaper the process. This can be a degenerative process, good at first, not so good later. The ability to cool, either dry or wet or both, normally dictates power level. A hybrid system seems expensive and is probably used to limit water use, make up and blow down.

        The “baseload” wording is suspect, perhaps the reason it is within quotation marks. Is this interruptable power, a lower priced commodity common in industrial applications? Or a load following scheme for peaking purposes. There is no enough information given to assess this. I suspect, do not know, that fossil fuels are expensive for this power load.

        To repeat a basic question, what is the levelized unit cost for this plant?

        I, a retired engineer, know nothing of this plant or grid but have engineered over sixty US thermal steam plants.

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