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Question

Can solar energy lead the way to solve the world's dire need for clean water?

Gil Karie's picture
Head of Innovation Ignite Power

Gil Karie is the Director of Innovation of Ignite Power, a leading Pan-African developer and financier of solar solutions, providing more than a million users through Africa with sustainable and...

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  • Jun 22, 2020
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Solar power will present the perfect solution for Africa to meet the enormous need for clean water supply: By using green, safe, sustainable, and available resources, and combining it with technological vision, creativity and boldness, tangible inventions can be deployed, solving the greatest need of our time.

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Solar power will present the perfect solution for Africa to meet the enormous need for clean water supply: By using green, safe, sustainable, and available resources, and combining it with technological vision, creativity and boldness, tangible inventions can be deployed, solving the greatest need of our time.

The heat shed by photovoltaic solar panels could be captured and used to generate clean drinking water. I understand that this is suited even for saline, brackish and contaminated surface water.  It is also believed that this is far more efficient than conventional solar sills.  The water evaporates into a membrane and condenses into water.  This will be ideal IF major industrial units adopt the technology to save the depleting water resources not only in Africa but, every other part of the world.  This will not only supplement the conservation practices but more importantly allow water availability for a longer period than predicted. 

This is also a better technology compared to the water conversion from the atmosphere – humidity.  The serious drawback of this conversion is that it renders the atmospheric air dry which in my opinion, is not beneficial in the long run.

As I said earlier, the recent pandemic has delivered unusual environmental benefits – cleaner air, lower carbon emissions, freedom for the wildlife and this would be an ideal opportunity for humans to capitalise on.

Efforts seem to be on for large scale demonstration and the success of which will be greatest contribution to mankind.

It looks more attractive even from the construction cost of prototype at Rs.800/ with least maintenance.  The principle seems to be based on solar thermal heating – Concentrating Solar Power (CSP) is tracked by large mirror fields which concentrate energy towards absorbers which in turn transfers it thermally to the working medium.  Ultraviolet rays of sun kill pathogens in water as well.

Solar Water Disinfection (SODIS) is another application that helps killing/inactivating diarrhoea generating pathogens in water.  Ultraviolet radiation of the sun heats up contaminated water in either bottles or PET bottles (exposure not less than 6 hours) and kills pathogens.  This suits small units where centralised water supply is not available.  It does not however change chemical property, non-effective for water of more than 30 NTU turbidity and understandably during rainy or cloudy days.

Solar will allow us to get clean water everywhere. It will also radically change global agriculture and food production...and for the better!

Solar power is really important nowadays and there are many companies who are taking the initiative and focusing more on natural energy. Sterlite power is one of the company which is focusing more on renewable energy. This will also help in cleaning the water.

Matt Chester's picture
Matt Chester on Jun 30, 2020

Can you share an example or two of how your organization is using solar to further the cause of clean water generation?

Processes for traditional water treatment and reverse osmosis for desalination are moving toward far lower costs, including much reduced energy costs, in the form of Aquaporin, the discovery of which was awarded a Nobel Prize in 2003. 

The application of this technology at scale for the home, in industry and communities is revolutionary.  Check it out at Aquaporin.com.

It is not only the power and utility industries that are undergoing radical changes in technology. So, solar may be more applicable for ensuring clean water supplies than one might otherwise think.

Unlike other power sources, solar (and wind) do not require use of water so, to the extent it displaces power sources that require more water, it can be part of the solution.  Floating photovoltaics, or “flotovoltaics”, can be employed on reservoirs and other man-made bodies of water to reduce evaporation loss (see NREL analysis at https://www.nrel.gov/state-local-tribal/blog/posts/floating-solar-photovoltaics-could-make-a-big-splash-in-the-usa.html).  There is also technology in development that uses solar PV to pull water vapor from the atmosphere and turn it into drinking water (https://www.businessinsider.com/zero-mass-water-solar-panels-solution-water-crisis-2019-1).  Furthermore, with respect to desalination, using waste-heat from solar panels is a technology solution that is promised (see, e.g., https://www.fastcompany.com/90373438/these-solar-panels-dont-just-generate-power-they-produce-drinking-water, https://www.elementalwatermakers.com/solutions/solar-desalination-gravity/ and https://www.youtube.com/watch?v=J9MqzlMJOkQ).

Hil Gil: As you likley know, we do not have a worldwide water problem.  We have a potable water problem.  The amount of water on Earth today is very similar to the amount of water that was on the Earth when the dinosaurs roamed.  The answer to potable water availability will be solved in one primary way, and a major secondary way. The answer is desalination as the primary solution and atmospheric (condensation) production of water.  Both are highly energy intensive applications.  Renewable energy combined with energy storage becomes the way to meet this need globally.  Solar energy, wind energy, and geothermal energy should all be looked to as the source of energy for potable water production.  The cost of renewable energy on a worldwide basis has now been clearly documented as having the lowest cost per kWh compared to all other energy sources. Utility scale energy storage through multiple means is now practical. 

An issue that we face in this arena is improper pricing of water.  Most major water utility companies in the United States offer their water for pennies a gallon.  This pricing fails to recognize the cost of infrastructure, maintenance and administration.  We need to learn how not to lie to ourselves and develop water pricing models that capture the full cost to deliver a gallon of water to wherever.  Deceptive water pricing leads to dams that fail, pipes that burst, and water that fouls when an insufficient investment is made in our water infrastructure.

Desalination driven by renewable energy can take advantage of existing infrastructure, and we can provide new infrastructure in remote locations through public/private partnerships built on a proper pricing model.  I do understand that desalination comes with the issue of salt disposal.  With proper design, the mineral content of salt water can be captured and utilized for myriad uses. Ultimately excess salt can go back in the ocean with proper dispersal to avoid contamination.  Ultimately, Earth's water does not disappear. It just needs to be treated with proper respect and effective engineering to meet the world's need for potable water.

 

Somashekar Hariappa's picture
Somashekar Hariappa on Jul 6, 2020

Agree with Larry, potable water is the issue. In India we have unique set of challenge associated with Solar PV Plants.  Several Megawatts of Solar plants have  been installed in the desserts of  Rajasthan where the irradiance is great. The asset owners however want to clean these modules every month to increase the performance of the plant ! This to me is not fair as the people in that region have no drinking water and the rich asset owners transport water to clean thier PV modules. 

Need your thoughts on how the module cleaning is done in other parts of the world. Im aware of robotic cleaning , but hasnt been effective in this part of the world.

Short answer - I agree. Go through the link below for details.

https://www.energycentral.com/c/ec/watts-and-water

Although I tend to stay pretty close to home for my papers (California and then the U.S.), the technologies covered in the above-linked post don't necessarily need to do this - they are applicable world-wide. Someone just needs to foot the bill (Mr. Gates, are you listening?).

-John

Because solar and wind energy are intermittent, they couldn't possibly provide a reliable supply of clean water - in Africa or anywhere else.

So in a word, no - creativity, boldness, and technological vision notwithstanding.

john Liebendorfer's picture
john Liebendorfer on Jun 22, 2020

Bob;   They have this thing called a water tank or tower - been around for 100 years or so - have you heard of them?  As I look out my window I can see one of my city's water tanks, which I happen to know they fill up at night when pumping costs are low and then we use the water during the day.  Seem to work.

 

Bob Meinetz's picture
Bob Meinetz on Jun 23, 2020

Where I live in Los Angeles, John, like in NYC, Rio de Janeiro, London, Beijing, Moscow, Tokyo, etc., there aren't any water towers - they don't hold enough water.

In smaller communities water towers, like windmills, have been around a lot longer than 100 years. They're never filled up with electricity from solar panels, though. People still need fresh water at night and during cloudy weather, and during those times solar panels don't work at all.

This is a great question... with the changing (decreasing) cost of PV applications that previously you'd have never considered come into play. 

 

Best question, of course in isolate region solar power play an importance role to supplly these locations by the necessaries needs like electricity, water, network communication.......Etc. but the question is, can solar power solve the problem of lake water in the futur when the undergroud water decreasse due the climate warming. The usefulness of solar pumping is limited on the extraction of water from the subsoil, and the water reserves is decreasing due to drought and global warming. If solar energy plays another role such as transporting water from one region to another will be very useful for these areas. Thanks

Dr. Amal Khashab's picture
Dr. Amal Khashab on Jun 22, 2020

You make it hard.

But, yes solar power can help in the transportation of water from one region to another using Electric Trucks. This water may be desalinated seawater by the RO technique using PV power.

Bob Meinetz's picture
Bob Meinetz on Jun 23, 2020

Amal, when I bought my Nissan Leaf EV in 2011, there was a $650 option available that included a solar panel installed on the roof to "help power your Nissan Leaf". The solar panel was about 12'' x 9'', above the rear window. Nissan was, of course, taking advantage of customers' "energy illiteracy" - the panel wouldn't help very much.

In fact, it wouldn't help at all. Even if left in the bright sunlight all day long to charge the car's batteries, electricity stored by the panel wouldn't budge the car one inch. At best, it could power the car's stereo for about 3 hours.

Many well-meaning people don't understand how truly insignificant electrical energy from PV panels is compared to the energy they use every day. For example, "transportation of water from one region to another using Electric Trucks" and "desalinating seawater by the RO technique using PV power" would require hundreds of square miles of PV panels, just to provide fresh water for a small city of 100,000 residents. It would require $billions in Li-ion batteries just to pump the water when the sun isn't shining. After all, residents need fresh water then, too.

There is no amount of technological innovation that can change the amount of sunlight hitting the Earth.. It's not enough, and it's not even close.

Dr. Amal Khashab's picture
Dr. Amal Khashab on Jul 24, 2020

Hi BoB

Sorry for being late.

For a small city of 100000 residents  one has to make plan and selelct the most profitable solution. It may has a combination of wind/solar/backup battery and diesel . Also storage water tank is mandatory to save desalinated water for use in the night. Only for small comunity one can use rooftop PV for RO desalination .  Hereinafter a link : {  https://www.engineeringnews.co.za/article/africas-first-solar-powered-desalination-plant-passes-10-000-k-mark-2019-02-27 Africa’s first solar-powered desalination plant passes 10 000 kℓ mark} .

 

Not only water but food also.

Solar power can be used for Reverse Osmosis desalination.

Potable water enhances food production processes. 

Gil - good question, solar and many other low water usage energy sources will be needed.  Consumptive water use from power generation is not well reported on a per unit (KWH) basis, of course all the steam cycles with cooling towers are massive users - including biomass plants.  Also evaporation from reservoir hydro facilities is very large.  NREL did a presentation in 2013 (https://www.nrel.gov/docs/fy12osti/55028.pdf) that has extensive data by technology and is a good resource for analysis and comparison.  Many new combined cycle gas and coal plants plants are now air cooled, so their water usage is much reduced, most nuclear plants are not.  Solar and wind are great resources that do not impact long term consumptive water use and as your article states, we get both the power and the lack of need for more power to produce water!

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