Saturday, June 27, 2015

Solar Water Supply and Desalination

Well there is a lot of news these days and I am constantly bombarded by articles on solar, on renewable technologies, and the like, but we are in a unprecendented energy and infrastructure revolution.
The overall global picture has to my mind the following salient points:
  1. Climate Change, leading to varied phenomena
  2. Energy and Infrastructure Revolution, combined with the IT and AI revolution
  3. Population Decline, massive movements of people, new religious movements, and the rise of global black population, and global trade
  4. Water resource awareness and scarcity
A lot of times the news focuses on one of the above aspects of change in our world, but I saw an article today which brought together both water scarcity, the energy revolution, and global trade.

Here it is:



What I found very interesting about this article are three points which were not greatly emphasized:

California will soon be bringing the massive Carlsbad desalination plant online, but at the same time, another smaller desalination plant is coming online.  The two have big differences in scale, being orders of magnitude apart in capacity and cost.  The freaky thing is that the smaller (Only $30M US) plant is highly competitive economically, and converts 93% of the intake to distilled water, leaving behind only 7% of volume as highly concentrated brine.  The huge Carlsbad plant has a conversion rate of only 50%.  

And here is a link to website video describing the system in greater detail.

So this small system by WaterFX is efficient, produces a brine rich in minerals that is an appealing economic resource, and is small in scale, is scalable, and is ideal for distributed deployment.  There is some complexity to the system, and the smallest unit produces about 65,000 gallons (250 m3) per day, and requires about 6000 SF (560 m2) of space to deploy.  Possibly a bit too large for a rural house property, but could be excellent for a small campus or a community.  Finally, something deeply striking about this technology and approach:  Watering our crops with water that is cleaner than the groundwater - for hundreds of years now, humanity has been making their fields more and more saline by irrigating these fields with water containing salts (freshwater from streams and rivers has some salts).  Eventually the long-term concentration of salts in soils renders the fields far less useful for growing crops,  Now imagine we water the fields with pure H2O - this is likely over time to reduce the salinity of soils.
I feel this is definitely a technology and a company to look carefully at.

There are others in the race to low-cost, distributed water purification and desalination - this time focused more on drinking water.
Take a look at this one:

http://www.treehugger.com/solar-technology/small-scale-solar-powered-water-desalination-system.html

Looks like a very simple and accessible system, costing some $450, lasting 20years, and requiring no power inputs other than sunlight.  Still in fundraising mode, but also likely to be a major player in the near future.

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