Altela, Inc. Treating water naturally A Novel Solution for the Energy/Water Nexus: Low-cost Water Desalination Using Waste Heat from CSP 23 October 09 Water and Land for Renewable Energy in the Southwest Ned Godshall, CEO
The Energy/Water Nexus The inextricable link between Energy and Water is well-known, and usually forms a great Catch-22 : Huge amounts of clean water are required for electric energy generation, and Huge amounts of electricity are required for the generation and transportation of clean water But must this be so? Could the huge amounts of low-grade waste-heat from electric generation generate clean water for virtually free? Could the spent steam from CSP plants, entering the cooling towers, be used instead to desalinate brackish water in the desert?
Concentrated Solar Power (CSP) Locations in U.S. Southwest Require Water in an Arid Location Access to non-brackish water for wet-cooling limits CSP in the arid Southwest, and dry-cooling adds cost and lowers efficiency: Much of U.S. Southwest has unusable underground brackish water aquifers, but little clean water for use in new CSP plants Conventional desalination of such underground brackish water is uneconomic, and would use too much of the electricity generated from the CSP plant CSP, like all thermoelectric (steam) generation, wastes about half of its incoming energy as waste heat, due to Carnot efficiency thermodynamics The ideal solution?: to use that low-grade waste-heat to desalinate local underground brackish water for virtually free Unfortunately, all conventional water desalination is driven by electricity not low-grade waste-heat available at all conventional and CSP electric plants
Low Cost Water Desalination one of the last great technical problems to be solved in the world The key to realizing a major breakthrough in world desalination is to reduce its high electric energy costs. The keys to accomplishing that are: Eliminate electricity as the driver of the desal process; electricity is by far the most expensive form of input energy To eliminate electricity, eliminate pressure pumps which drive all the world s present desal processes To eliminate the pressure pumps and their electricity, eliminate pressure from driving the desal processes for which then corrodible metals are also eliminated, since they are no longer needed for pressure vessels Develop a new zero-pressure process which nevertheless mimics present pressurized flash thermal distillation techniques, which use the heat of condensation many times over to offset the heat of evaporation (i.e., Mother Nature s process of making rain water from unpotable ocean water)
Water Desalination throughout the World All present water desalination processes use pressure; two kinds: Membrane: Reverse Osmosis (RO), nanofiltration, microfiltration, etc. use pressure to overcome osmotic pressure to force water through tiny pores Non-membrane: MSF, MED, MVC use pressure to flash water to increase thermal distillation efficiency by lowering operating energy needed ( f ) But the use of Pressure causes both High CapEx and High OpEx Costs: CapEx: pressure requires pressure vessels, which requires big thick steel, which corrodes in presence of brackish water, which requires expensive stainless or exotic metals to reduce such corrosion, causing very expensive plants: pumps, valves, pipes, tanks, vessels, etc. all must be made of metal OpEx: pressure requires big electricity to run pressure pumps; electricity is the most expensive form of energy (high-grade, vs. low-grade, energy) All Present Desal Processes Unfortunately use Pressure
What the New CSP Industry Needs Ideally, the world would have the best of all these, but not use pressure: The simplicity and non-fouling nature of thermal distillation (non-membrane) But without the use of pressure, which requires expensive metals and high-grade, high-cost electrical energy But still somehow gets the f efficiency gain of present flash, by re-using the heat of condensation over and over again for the heat of evaporation step Altela has developed just such a breakthrough: we use no pressure! Our CapEx is very low because we use only inexpensive plastics no exotic metals to corrode and our plastic does not foul or scale-up like metals do Our OpEx is very low because we use virtually no electricity 99% of all our energy is from low-grade, low-cost heat used to make ambient-pressure steam (i.e., to simply boil water)
Altela s Water Desalination Energy Source Altela uses low-cost low-grade waste-heat energy that is otherwise wasted: Waste heat from conventional power plants (fossil or nuclear) Waste heat from industrial plants (e.g., compressor stations, industrial, etc.) Unused flash gas at oil and gas wells, refineries, etc. Co-located with industrial plants that already generate (and reject) such low-grade, low-temperature, waste heat over half of all their fuel input Altela s OpEx goes to nearly zero CSP plants similarly could generate clean distilled water from underground brackish sources for nearly zero operating cost
Treatment of Produced Water, Piceance Basin, CO Real-world oilfield customer brackish water is high in both TDS and BTEX Single pass through Altela tower strips clean distilled water (on left) from black foul-smelling underground water (on right)
Even Man-made Chemicals are Removed, Piceance Basin, CO
Produced Water Treatment Near Spirit River, Canada
The Technology IP-protected evaporation/condensation process: like nature s rain from ocean salt water Makes 4 gallons of clean water from the heat energy that would usually only make 1 gallon Operates on low-grade waste heat or waste well-head gas free in many locations Robust: no pressure, no high temperatures, no membranes; manufactured from inexpensive plastics that do not corrode, rather than metal
Mother Nature s Water Desalination Process Rain water comes from brackish unpotable water the oceans: Step 1: Passive solar energy evaporates water at the ocean surface Using low-grade heat and no pressure This clean water vapor is later released as rain in: Step 2: Cold air cannot hold as much moisture as hot air So rising air gets colder, causing condensation rain And the amount of energy given off in Step 2 is equal to the amount of energy used in Step 1: Mother Nature is very energy efficient.
Mother Nature s Water Desalination Process Mother Nature has been desalinating water for 4.5 billion years Why not follow her lead? One disadvantage is that Steps 1 and 2 often occur thousands of miles apart So the energy given back in the condensation step is not physically close to where it s needed in the evaporation step A second disadvantage is that the amount of energy is fairly large, although it is low-grade (inexpensive) heat
Improving on Mother Nature s Desalination Altela has developed a new commercial water desalination process that mimics Mother Nature, but improves on her too: AltelaRain brings Steps 1 and 2 together just 200 microns (0.008 ) apart, rather than thousands of miles apart So the energy given back in the condensation step is used over and over again in the evaporation step: Reducing the amount of even this low-grade inexpensive heat to only one-fourth of what it is for conventional thermal distillation That is, Altela desalinates 4 gallons of water for the energy to evaporate 1 gallon conventionally Since we use no pressure, all components are made with inexpensive plastics, rather than metals that corrode
The Technology
The Water Quality Results Total Dissolved Solids (TDS) Concentration (mg/l) 45,000 40,000 35,000 30,000 25,000 20,000 15,000 10,000 5,000 0 41,700 106 1,000 10 Before After Maximum Reporting Altela Altela Allowable Limit
Low-cost Water Desalination Using Waste Heat from CSP Carnot efficiency limitations dictate that about half the input solar energy in a CSP plant is wasted as low-grade low-temperature waste-heat Huge amounts of low-grade waste-heat from CSP electric generation could be used to generate clean water, from underground brackish sources, for virtually free, using a new zero-pressure low-temperature process Stage-3 spent steam from CSP plants, instead of being wasted currently, could be used instead to desalinate brackish water in the desert And the AltelaRain process of desalination further reduces the need for conventional cooling towers (since the process condenses stage-3 steam to distilled water ideal for return to the steam loop) A new source of clean water in the arid Southwest
Once you understand what we do, you ll see where we can go.