Solar ‘ponds’ energy could rival fossil fuels in UAE

A general view shows part of a new 15 million euro solar plant, funded by the German government, that emits some 12.9 megawatts during its official inauguration at the Zaatari refugee camp, in this November 13, 2017 photo. (AFP)

LONDON: The lagoons and salt flats around the UAE’s coastline could be used to generate a new source of clean energy for the country, according to new research carried out by the United Arab Emirates University.
The energy produced within so-called “solar ponds” could be a viable and far more environmentally-friendly alternative to liquefied natural gas and other fossil fuels, particularly for rural areas already rich in salt.
“Heat from solar ponds is expected to be competitive with the use of liquefied petroleum gas and electricity in rural areas,” said Dr. Samir Abu-Eishah, a professor of chemical engineering at the university in Al-Ain, who led the research.
The ponds would be used for the production of salt as well as the generation of thermal energy required in water desalination processes. “For the long-term, the technology makes use of renewable solar energy and is sustainable. The technology itself is environmentally-friendly and, if implemented, would serve as a sustainable energy source for the desalination of saline waters.”
According to Dr. Abu-Eishah’s study, the UAE’s coast has many highly salty lagoons surrounded by sabkhas or salt flats where salinity-gradient solar ponds (SGSP) could be created that would act as “heat sinks” due to their high concentration of salts trapping in solar radiation.
“The SGSP technology uses high-density saltwater to store thermal heat,” said Dr. Abu-Eishah in his paper. “The pond absorbs solar heat, but a portion of it is trapped within its ‘lower convective zone’, which has high salt concentration and density. This thermal energy can be harnessed at a later time for processes that require water temperatures between 50-90 degrees Celsius.”
The hot water could be used to drive low-temperature energy-generating turbines, which are used in salt production, water supply as well as in the dairy, grain, fruit and vegetable canning industries.
His research found that the prospect of developing this cleaner energy source is becoming “increasingly attractive” due to declining costs.
Abu-Eishah said that the ponds also help bring agricultural land considered too salt-heavy to be farmed or developed and brought back into use. “SGSP technology is expected to have several economically and environmentally advantageous returns for the UAE, with the most significant being environmentally-friendly renewable fuel,” he said.