Letter from America: Water, water everywhere...

Professor Doug Crawford Brown has left Cambridge to settle on the West Coast of the USA. He will be keeping in contact by sending ‘Letters from America’ for this Think Piece section of the website.

Setting the stage
Several billion people live in communities with high water stress, meaning their rate of withdrawal of water for personal and business activities is above the replacement rate for their available supplies. The result is that those supplies will eventually become unusable, often in less than 10 years. Many of these communities are also in nations needing economic growth to raise the poorest populations of the world off the bottom of the ‘economic pyramid’. As this economic development advances and populations increase, so too will the rate of water use. For at least potable water (excluding the oceans), the available sources of re-supply are dwindling as glaciers recede around the world.

My new home state of California is no exception in being stressed for water (although it certainly is not on the bottom of the economic pyramid). When I arrived in early 2017, I stepped off the plane into three days of extreme rainfall that washed out bridges and caused flooding up and down the Pacific Coast Highway. My instinct was to complain that I had been promised 300 days of sunshine each year, only to set foot in a state with the same or even rainier skies than in the UK. I felt cheated.
Colleagues in the water industry soon pointed to my error. The state had been in a drought for the past four years. Water levels in reservoirs were down to 10% or less, levels at which evaporation threatens loss of the entire supply. Mountain snowfall had decreased as temperatures in the region rose, slowing the flow of water from the north to the south of the state. The highest levels of water restrictions were in place in towns such as Santa Barbara, with hose-pipe bans, soaring water tariffs and requirements for drought resistant plants.
The experience of California over the last four years is an uncomfortable and life-threatening norm for the nations in red shown in the figure above produced by the World Resources Institute and Aqueduct (you can find the original article at www.wri.org/blog/2013/12/world%E2%80%99s-36-most-water-stressed-countries).    

Solutions to make water suitable to drink
One of the solutions in Santa Barbara was construction of a desalination plant opened in summer 2017, revived from a disused one first built decades ago. The cost is large (up to 100 million dollars in capital cost, with 4-5 million per year in operating costs). It will cause energy consumption and carbon emissions to increase dramatically as water is pumped through the reverse osmosis membranes. But the source of the water is a free ocean off the coast, and it will supply a third to half of Santa Barbara’s total water demand out through 2030.
While viable for a rich community, this solution simply will not work for the poorer nations in the figure above. Those communities tend to have both their economies and their own food supplies reliant on local agriculture. Irrigating with a California-style desalination plant would bankrupt them at a time when all resources must go towards economic development. And the reverse osmosis system of Santa Barbara and other rich communities sends highly saline water back into the ocean. For communities that rely equally on agriculture and off-shore fishing, this discharge can kill off vulnerable fish populations.
The solution? Much more appropriate technologies for poor nations, including both desalination and pumping systems. Researchers have developed a desalination process that uses a new, low cost, filter followed by evaporation and then collection of clean water. It is a process of ‘pervaporation’. The evaporation stage is often driven by fire (putting desalination into competition with cooking materials), but concentrated solar is increasingly considered in the sunnier regions; this has already been demonstrated to be viable at scale. The result is a large reduction in saline discharges back to the ocean, decreased energy use and much lower carbon dioxide emissions than the desalination plant in Santa Barbara.
It is sustainable environmentally, economically and socially. It addresses both water stress and climate aims. It is tailor made for poorer communities. It is therefore of increasing interest at the Green Climate Fund or GCF (see www.greenclimate.fund), the arm of the United Nations Framework Convention on Climate Change or UNFCCC that is financing climate mitigation and adaptation projects in poor nations. This solution brings both mitigation and adaptation benefits, and so ticks both of those boxes as well as improving the resilience of local economies.     

The UK Cleantech Sector     
So where does the UK cleantech sector fit into this vision and opportunity? The potential funding for technology development within the GCF is large, assuming one can form a partnership with a National Designated Authority or NDA in a recipient country. The aim of the GCF is to have 100 billion USD per year available by 2020; they are at 10 billion at the moment, with the USA contributing about a third and the UK in third place with a tenth. So both the USA and the UK have legitimate claims to becoming core suppliers of this technology as they are also core suppliers of the financial pot.
What is needed to make this idea a reality? There is need for more efficient and lower cost membranes using polymer or ceramic advances. The cycle of extracting water from the ocean and returning increased salt concentration to that ocean has not yet been closed off; there is a pressing need for a process that is a final sink for the removed salt and pollutants. While the energy use by pervaporation is greatly reduced, it is still a third of that used in reverse osmosis, which is a challenge for communities for which new energy generation capacity is needed for homes and industries. They cannot afford for this new generation capacity to be diverted to water supplies. Greater efficiencies of the pumps and of the evaporation process will remove this burden of power going to a local desalination plant. Development of solar pumps will further improve this performance.
Do you have a solution to any of these (or other) issues around desalination? If so, the first step is to encourage the UK government to continue contributions to the Green Climate Fund, contributions which place UK innovators at the top of the table when GCF funds are sought. I am doing the same on the USA side, and so you could contact me for connections to US firms that are moving in the same direction. Then you must find an NDA in a country with populations that are water stressed but sufficiently close to sea water. They are the ones who have read the Rime of the Ancient Mariner and know the phrase “Water, water everywhere, but not a drop to drink”. Without an NDA, the project is dead in the water.
Finally, you must stand ready to demonstrate that your innovation is technologically appropriate to poor communities. We might be able to afford your advance in sunny, wealthy Santa Barbara, but coastal communities in India will find it impossible to pay those prices, even with a GCF award. So think innovation, affordability and clean plentiful water for all.
Dr Crawford-Brown is Professor Emeritus at the University of North Carolina in the USA. He retired as Director of the University of Cambridge Centre for Climate Change Mitigation Research in 2016 and moved to Santa Barbara, California. His work now focuses on helping the State of California meet ambitious climate and sustainability targets through international collaboration, in the face of an increasingly hostile agenda from Washington. These Letters from America are aimed at helping Cambridge Cleantech members identify opportunities for collaboration with the California programme.