“Water, water everywhere, but not a drop to drink,” wrote Samuel Taylor Coleridge about a sailor marooned at sea, surrounded by water, all of it undrinkable. We face the same issue in our modern world as finding clean water is a daily challenge for millions of people. That problem is actually getting worse — not better — because our global population is increasing while drinkable water supplies grow scarcer.
The United Nations estimates a shocking 2.1 billion people worldwide don’t have access to clean drinking water in their homes. Earlier this year, Cape Town, South Africa was counting the days until “day zero,” when water was projected to run out across the city, and in Flint, Michigan, lead in the water supply continues to create a public health crisis. Across the globe, women and girls spend an estimated 200 million hours each day carrying water for their families’ daily needs.
There may be a surprising solution to this ongoing humanitarian crisis. A new research project out of King Abdullah University of Science and Technology has shown that solar panels can be used for more than generating power – they can also produce clean drinking water.
A typical solar panel can turn about 20 percent of its energy into electricity, losing the other 80 percent into the air as heat. Lead researcher Peng Wang says that his team figured out a way to use that heat to desalinate and purify water. The heat that would normally be lost is redirected to tubes full of seawater to warm the water and filter it as it evaporates. The heat is then recaptured so the process can repeat again.
This way, each square meter of solar panels can produce 1.64 liters of water each hour. For context, that means an average solar-powered home operating with 600-square feet of solar roof panels can produce 23 gallons of water per hour. That’s more than enough — according to the EPA, an average family of four uses 400 gallons of water per day, and that’s in America where water usage is far higher than the rest of the world. The team that created and tested the system says it is currently meant to supplement drinking water, but the research has major implications for water-insecure areas, sparsely populated coastal areas, and those looking to live completely off the grid.
Another company, Finland-based Solar Water Solutions is working on a project that also uses solar panels to desalinate water, turning ocean water into drinking water. The process the company uses, reverse osmosis, isn’t new, but doing it with solar panels that work cheaply and without a carbon footprint is revolutionary.
These systems are already impacting coastal and remote areas where drinking water is scarce or too salty. In sub-Saharan Africa, water generated using these desalination systems is drinkable and good for irrigation use too, serving both societal and ecological needs. Today, South Africa and Algeria use desalinated seawater to meet these needs. Algeria’s capital of Oran is home to Africa’s largest desalination plant, providing drinkable water to 5 million local residents each day. Other countries like Ghana, Libya and Namibia also have similar operational plants.
Scientists and entrepreneurs are looking at other creative ways solar power can help produce clean water. Zero Mass Water, backed by a $1 billion fund led by Bill Gates and Jeff Bezos, has created panels that pull water out of the air, filter it and deliver it to your faucet. The solar panel system, called Source, harvests water from air vapor and turns it into liquid. One Source device can deliver 2 to 5 liters of water a day, and the company has just launched a sensor to monitor water quality.
The Indian company Uravu has also created a device that distills 15-20 liters of drinkable water a day from water vapor. Headquartered in Hyderabad, Telangana, the technology is expected to be available for household use by 2020.
In 2018, South Africa introduced its first solar-powered desalination plant that converts sea water into fresh water. Likewise, Berlin-based engineering firm Boreal Light’s “Wintures” is also using solar energy to purify sea water, operating 11 water kiosks on the Kenya coast and is able to sell the water for two-thirds of the market price. As these kiosks help generate employment, the company plans to also expand its presence, installing 192 water kiosks in Kenya and Tanzania by 2020.
Of course, installing more solar power to solve this humanitarian crisis doesn’t come without its challenges. Energy operators and companies have to get on board with these new innovations knowing the intensity of the sun throughout the day makes predictions of photovoltaic (PV) efficiency difficult and desalination during night time challenging.
However, these new solar desalination technologies are inexpensive and simple to install and repair, differing from the costly mechanical and electrical components (like pumps and control systems) required for the installation and maintenance of more conventional desalination technologies. On another positive note, new research shows these solar desalination systems are particularly effective for offering safe and low-cost water to isolated communities during emergency events like floods or tsunamis.
Since there is evidence that by 2025 two thirds of the world’s population could be living in water-stressed conditions, we need to turn to the most obvious source, the ocean, to improve the lives of underserved communities across the globe.