If you are a developer struggling to get a CSP project off the ground, the good news is that clearing up the plant when it reaches the end of its life is not likely to be a problem… and it is something you may not have to worry about for a long, long time. Jason Deign reports.
It is no easy matter building a CSP plant.
Once you have found the kind of backer prepared to pour millions into your project and struggled through mountains of regulatory red tape you still have to manage a construction site the size of a small city in the middle of the desert.
But here is the good news: once your plant is built your worries are pretty much over.
Provided the sun shines and there is a ready market for the power you produce, experts agree CSP is clean and easy.
And that would appear to include clearing up the site once its days are over.
Solar Millennium spokesperson Alexander Jacobsen says: “At the end of the life cycle I think it is feasible to completely remove the structure. It is mostly glass and steel so it is not difficult to take out.”
Sven Teske, Renewable Energies director at Greenpeace International, agrees. “I do not think it is a problem to decommission CSP,” he says. “The main components are steel, concrete, glass, and a lot of copper; all energy equipment has a lot of copper in it.”
There may even be an upside to the decommissioning process, he adds.
“The concrete will remain in the ground but the rest will be taken away, and that is a business opportunity.
“I can think of companies putting an option on taking the steel back.”
In any event, says Sam McIntosh, senior vice president of plant construction and operations at Areva Solar: “We have analysed decommissioning costs and the recycle scrap value generally offsets the dismantling costs.”
Quick process
He adds: “It’s a very quick process. You can decommission a plant in a matter of months.”
Such an easy ride out at the end of a plant’s life cycle makes CSP, along with other renewables, particularly attractive compared to other methods of power generation.
Some of the published shutting-down costs for nuclear plants, for example, range from US$100 million to around $17 billion. But with CSP, decommissioning might not even be necessary for a long, long time.
Solar Millennium’s Jacobsen points out that some of the Solar Energy Generating Systems plants at Kramer Junction in the Mojave Desert have been in continuous operation since the mid-80s and are still going strong.
“They have been working for more than 20 years with no noticeable degradation and no loss of performance worth mentioning,” he says.
“They have a long experience in this kind of technology and are now on the third generation of collector designs, with no degradation of mirrors or metal structures.”
Three decades
Dr Bill Conlon, senior vice president of engineering at Areva Solar, adds: “With our technology, three decades out is the lifespan starting point.
But if you lifted out the power plant you still have all the infrastructure in place to carry on operating with newer technology.”
Emerging Energy Research senior analyst Reese Tisdale concurs. “Some of the older CSP plants were built in the mid-80s and are still operating,” he says. “The expectation is they will last 30 or 40 years.”
Charlie Richardson, a class underwriter at renewable energy market insurance broker GCube, adds that insurers do not see CSP decommissioning as a particular risk. “Once it is there the lifespan is 20 years or more.
“Probably all you will need to do is refurbish the equipment and we would see that as a re-powering project. In wind energy we see wind farms being re-powered all the time and it is to everyone’s benefit.
“The re-powering expense is no different to any other standard upgrade.”
This certainly seems to be the case from the industry’s limited experience of re-tooling and decommissioning plants so far.
Probably the most obvious example was Solar One, the 10 MW test plant built east of Barstow, California, in 1981.
No pollution
Solar One was upgraded (and re-christened Solar Two) in 1995 with the trouble-free addition of additional heliostats, and decommissioned in 1999 without any significant engineering challenges.
“It was decommissioned and rebuilt as a telescope with no problems,” says Richardson. “There was no pollution from the design.”
If the land is ultimately to be returned to its original natural state, then potentially the only additional task required after clearing plant materials would be the reintroduction of vegetation.
According to Tisdale, BrightSource has considered this in its development plans for its Ivanpah solar power complex.
And even this might not be too onerous. Dr Conlon, of Areva Solar, notes that his company’s Compact Linear Fresnel Reflector technology only needs about a third of the area required by other types of CSP.
Plus it has the added advantage of running on water.
“If you have a heat transfer fluid there will always be spills,” he notes. “If the oil gets into the groundwater it’s serious. But when you use water, a spill is an innocuous event.”