by Gage Taylor
A research project known as “Sandstock” at the Masdar Institute of Science and Technology in the United Arab Emirates (UAE) has successfully demonstrated that desert sand from the UAE can be used in concentrated solar power (CSP) facilities to store thermal energy up to 1000°C. Replacing traditional heat storage materials, such as synthetic oil and molten salts, with an inexpensive material like sand could potentially represent a major step forward in plant efficiency due to increased working temperature (and, naturally, lower costs).
In recent years, the popularity of CSP technology has fallen in favor of photovoltaics, specially layered semiconducting materials that convert sunlight directly into electricity, due to cost. However, CSP, which typically uses mirrors to reflect sunlight at one concentrated point in order to store heat, has the advantage of being easy to store, and this new discovery of the ability of UAE sand, rich in quartz and carbonate particles, to store massive amounts of heat could change the cost-efficiency game entirely. Conventional CSP systems have been capped at 600°C in the past because molten salt, the most common material, degrades at that point. Sand would then offer 400°C more than molten salts, a number that puts photovoltaic methods and their typical battery storage systems to shame. Additionally, the research even suggests that the sand could be used not just as storage, but as a direct solar absorber, no mirrors required.
In an interview with the National [http://www.thenational.ae/uae/environment/sand-could-be-the-key-to-unlocking-more-efficient-solar-power-masdar-scientists-find ], Dr. Nicolas Calvet, assistant professor of mechanical and materials engineering and guide for the whole project, said that, “PV [photovoltaics] is more popular because of more than 40 years of research, and the Chinese entering the market and driving prices down.” Given that, we’re certainly a long ways off from CSP technology becoming competitive, but a move towards a common and local material like sand is a step in the right direction. Masdar’s next move will be a prototype at pre-commercial scale, for which they hope to potentially find an industry partner.
Al Jarman, Shaima. “Masdar Institute Research Successfully Proves UAE Desert Sand Can Store Solar Energy up to 1000°C.” Newswise. Jan 4, 2016. [http://www.newswise.com/articles/masdar-institute-research-successfully-proves-uae-desert-sand-can-store-solar-energy-up-to-1000-c]
Hays, Brooks. “Desert sand from UAE efficiently stores thermal energy.” UPI. Jan 7, 2016. [http://www.upi.com/Science_News/2016/01/07/Desert-sand-from-UAE-efficiently-stores-thermal-energy/4911452188143/]