Sand could be the key to unlocking more efficient solar power, Masdar scientists find
ABU DHABI // Masdar Institute scientists have published a breakthrough research into more efficient solar power – and they will not have to look far for the raw material needed.
Using sand, they hope to drive concentrated solar power technology to compete with the traditional photovoltaic method.
Named “Sandstock”, the research published at the Solar Power and Chemical Energy Systems Conference in South Africa yesterday, showed sand can withstand temperatures of up to 1,000°C.
Concentrated solar power, or CSP, uses mirrors to reflect heat from the sun to one point, most typically a tower filled with a material capable of storing heat and then converting it into electricity.
CSP’s benefit is that the energy derived is easy to store, but in recent years it has lost out to the more popular photovoltaics, which is more cost-efficient.
That may now change.
“Sand is really always a drawback in this country but in this project we wanted to use it as an advantage because it can withstand very high temperature, and of course it is very cheap here,” said Dr Nicolas Calvet, assistant professor of mechanical and materials engineering, and guide for the research project.
Dr Calvet said that scientists and PhD students working on CSP research were always looking for materials capable of withstanding higher temperatures.
“The higher you can push your temperature, the more efficient your plant will be in generating electricity,” he said. “With sand we can push it to 1,000°C and it’s available.”
CSP is significantly more efficient than photovoltaics at storing energy after sunset, and the Masdar researchers are finding potential in sand’s ability to store energy.
“Basically you heat up the sand during the day, and at night when you don’t have sun you can use the heat from the sand to continue to generate energy, which is not possible with PV because it is too expensive to store at this moment,” Dr Calvet said.
The limit for conventional CSP systems is capped at 600°C because molten salt, the most common material, begins to degrade beyond that point. Sand can store it at 400°C higher than molten salts.
“PV is more popular because of more than 40 years of research, and the Chinese entering the market and driving prices down,” Dr Calvet said.
“If you want to make CSP more competitive you must significantly reduce the cost.”
The main costs for CSP are the reflective material, and whatever is used for heat transfer and storage. Dr Calvet and his students are using sand for the last two steps at almost no cost.
“When you build a CSP plant you need to import usually several thousand tonnes of molten salts from Chile,” he said.
“With this concept you can just build your plant in the desert and you don’t have to bring any other material, you have it on site.”
Dr Behjat Al Yousuf, interim provost at the Masdar Institute of Science and Technology, said: “The research success of the Sandstock project illustrates the strength of our research and its local relevance.”
Updated: December 29, 2015 04:00 AM