Strategies to power desalination with solar technology
Desalination of seawater is becoming essential as demand for freshwater expands well beyond the capacity of current reserves to sustain it. But on its own, desalination threatens to help feed the catastrophic climate change that is helping to accelerate water scarcity around the globe.
Desalination is notoriously energy intensive, and energy consumption represents 50% to 60% of total operation costs for a plant. For early adopters of the technology, such as Saudi Arabia and other oil-rich states in the Middle East and North Africa, that wasn’t a problem.
But with the growing understanding of a carbon-fueled climate catastrophe, using oil to power desalination is increasingly not a viable option, however low the price of oil sinks.
Combining solar and desal
On the other hand, whether desalination is based on thermal technology or reverse osmosis the falling costs and climate-friendly nature of renewable energy make it a potentially attractive option for powering the process.
And as the most water-stressed regions on earth often enjoy a high percentage of sunny days, harnessing the power of the sun seems an obvious fit for desalination’s energy requirements.
There are a number of combinations of desalination and solar technology available to developers. The two main approaches are using the power of the sun to directly heat saltwater, or using electricity generated by photovoltaic (PV) solar cells to power reverse osmosis.
Pros and cons of PV solutions
As the price of PV solar continues to fall, it has become an increasingly alluring proposition for powering desalination. Indeed, work has already started on a PV solar-powered desalination plant in the King Abdullah Economic City (KAEC) in Saudi Arabia, scheduled to go live this year.
Moreover, there seems to be a recognition in the kingdom that the days of burning cheap oil to produce drinking water may be coming to an end. But there are some limitations for PV in the desalination arena that need to be addressed. The most obvious is lack of power at night.
In addition, any reduction in sunlight during the day due to cloud cover, for example, could be problematic. If the pumps of a reverse osmosis plant stop, there is danger of damage to its essential membranes.
As a result, shortfalls in electricity would have to be mitigated by some form of backup energy storage, or through combination with other renewables such as wind.
In the case of the KAEC facility, the desalination plant will simply switch to grid power during the hours of darkness, expanding the plant’s carbon footprint. Elsewhere, lithium ion battery energy storage becoming increasingly affordable to developers.
Currently a more expensive option, fuel cells could become an effective energy storage technology for solar as economies of scale bring down costs.
Desalination of seawater is becoming essential as demand for freshwater expands well beyond the capacity of current reserves to sustain it. But on its own, desalination threatens to help feed the catastrophic climate change that is helping to accelerate water scarcity around the globe.
Desalination is notoriously energy intensive, and energy consumption represents 50% to 60% of total operation costs for a plant. For early adopters of the technology, such as Saudi Arabia and other oil-rich states in the Middle East and North Africa, that wasn’t a problem.
But with the growing understanding of a carbon-fueled climate catastrophe, using oil to power desalination is increasingly not a viable option, however low the price of oil sinks.
Combining solar and desal
On the other hand, whether desalination is based on thermal technology or reverse osmosis the falling costs and climate-friendly nature of renewable energy make it a potentially attractive option for powering the process.
And as the most water-stressed regions on earth often enjoy a high percentage of sunny days, harnessing the power of the sun seems an obvious fit for desalination’s energy requirements.
There are a number of combinations of desalination and solar technology available to developers. The two main approaches are using the power of the sun to directly heat saltwater, or using electricity generated by photovoltaic (PV) solar cells to power reverse osmosis.
Pros and cons of PV solutions
As the price of PV solar continues to fall, it has become an increasingly alluring proposition for powering desalination. Indeed, work has already started on a PV solar-powered desalination plant in the King Abdullah Economic City (KAEC) in Saudi Arabia, scheduled to go live this year.
Moreover, there seems to be a recognition in the kingdom that the days of burning cheap oil to produce drinking water may be coming to an end. But there are some limitations for PV in the desalination arena that need to be addressed. The most obvious is lack of power at night.
In addition, any reduction in sunlight during the day due to cloud cover, for example, could be problematic. If the pumps of a reverse osmosis plant stop, there is danger of damage to its essential membranes.
As a result, shortfalls in electricity would have to be mitigated by some form of backup energy storage, or through combination with other renewables such as wind.