OC can do Desal better: Use salt to lock up CO2 emissions.




Vern here.  As dissenting OC Water Board member Phil Anthony told us recently, if Orange County decided we really needed a desalination plant, “we could make it quicker, cheaper and better than Poseidon would,” given our world-famous Groundwater Replenishment System.  Here, our friend geologist John R. Hoaglund III presents a technology – a proven, patented technology – which would make Poseidon’s project better, more efficient, and less polluting;  but will Poseidon  listen?  Thus far they’ve rejected any constructive ideas that would compromise their short-term profits.  But if they don’t listen to Dr. Hoaglund, and their project for one reason or another doesn’t happen, we may still have a chance to try his idea ourselves some day.  (We are also printing a more detailed, footnoted version of this piece for those of you who really want to get into the technical weeds of this – click here.)

OC can do Desal better: Use salt to lock up CO2 emissions.

By John R. Hoaglund, III, Ph.D.

Two local environmental problems – AES Corporation’s existing CO2 emissions and Poseidon’s proposed marine brine disposal—could be solved together by making … wait for it … baking soda!

baking sodaA controversial project all around

Poseidon needs CA Coastal Commission (CCC) approval to break ground on a controversial desalination plant. With the debate intensified by drought, the connection between politics, the economy, and the environment is in sharp focus. The political debate continues with strong institutional support for the plant duking it out with strong grassroots opposition. The economic aspect remains muddy, with the OC Water District’s proposed term sheet somewhat compromised by their challenge in finding “customers” for the expensive water. And on the environmental front the CCC is requiring Poseidon to address:   1) CO2 emissions related to energy use, and 2) brine (aka “concentrate” saltwater) discharge. I would like to offer some suggestions on these last, environmental matters.

The Poseidon facility will be using a significant amount of energy to remove a significant amount of salt from seawater. AES, an energy company, is cooperating with Poseidon, a water company, but only on the use of property and infrastructure. The desalination water project is Poseidon’s. The energy they use will come from the “electric grid” generally, not the AES power plant specifically, but Poseidon will use the equivalent of about 4.5% of the AES power plant’s maximum capacity. This makes Poseidon an “indirect emitter” of a considerable amount of CO2, “liable” for about 200,000 metric tons a year. With the passage of AB-32[i], California now regulates CO2 emissions in excess of 25,000 metric tons per year[ii].

Proposed plans for CO2 and salt

Poseidon currently plans to comply with the Commission’s greenhouse gas mitigation requirement by offsetting, i.e. “by purchasing renewable energy credits and reforesting a state park, among other measures,[iii]” essentially buying the right to emit CO2 into the environment. Offsetting separates the location of environmental damage and an unrelated restoration.

Poseidon also plans to discharge its brine directly into the ocean. Ironically we’ll be using a considerable amount of energy to make drinking water from our ocean trashcan, removing not only salt but energy related contaminants. The brine will have double salt and double ocean contaminant concentrations. Salt “concentrate” disposal is regulated as waste disposal[iv].

At maximum capacity, the AES power plant produces 120 railroad cars (100 metric tons each) of CO2 per day. At 65 million gallons of freshwater, Poseidon will be discharging 177 railroad cars of “salt” into the ocean per day. Thus two “point sources” of different pollution will be sitting side by side, split along economic interests, split along environmental problems.   It’s time to change “dilution is the solution for pollution” global thinking into local acting.

An alternative solution

Alternatively, “carbon mineralization” processes use the CO2, and brine to make marketable commodities: hydrogen gas, oxygen gas, acids, chlorine compounds, and baking soda. Electric current is applied to the saltwater, and then CO2 is passed through the solution to precipitate mineral solids. The salts are consumed out of the brine solvent water—the leftover half of the desalination process—thus potentially doubling the output of freshwater.[v] The electric energy used is an “energy penalty,” which due to entropy, is a part of ALL carbon sequestration techniques.

Some of the “energy penalty” is recoverable as hydrogen fuel or in the production of algae biofuel. The hydrogen can be used as fuel for your home (stationary fuel cells) or to run your car[vi].

The baking soda can be used in industry, or environmentally to neutralize acid contamination, such as in mine drainage. Reacted with the acid, it can deliver CO2 to algae to “sequester” (de facto “recycle”) CO2 into biofuel. Any use of the baking soda re-liberates the CO2 and returns the salt. Unused, the baking soda stores CO2 as a solid mineral.

The technologies exist from R+D aggressively funded by the DOE, and are patented. Like any “technical fix” there are drawbacks, in this case chlorine byproducts. But the industrial process is already the most common for making these products. If anything, this Californian finds it deplorable that elsewhere in industry, freshwater and salt are being mixed as raw materials.


The aqueducts and desalination now use the same energy for the same water, but the desalination water is more expensive owing to new infrastructure costs. Previous generations of federal taxpayers had the foresight to pay for the State Water Project aqueducts. A new generation of local water users, a considerably smaller population, will be paying a private company for the new desalination infrastructure. That is the heart of the economic controversy. If approved, energy will be expended to produce desired freshwater, but will also concentrate unwanted brine. A little more energy invested can eliminate brine disposal and CO2 emissions, and produce marketable products: a return that could lower those rates.


Unfortunately, the presence of money tends to create a condition of advocacy, or understandably leaves the suspicion thereof, but both impede understanding. I do not have a business relationship with either AES or Poseidon. I also do not have the patents for the processes described above, nor a business relationship with those who do. Full disclosure: I have been in contact with those who do have these patents, and I have made some calculations of the salt budget and the energy penalty that support the concept. But I think I have been forthright in discussing both the pros and cons of the technology.

rock doctorJohn R. Hoaglund, III, Ph.D.

Dr. Hoaglund taught hydrogeology, environmental geology, and glacial and climate geology at the University of Michigan, then joined Penn State’s Earth and Environmental Systems Institute involved in coupled hydrological / climatological modeling research.   He moved to California in 2007 into private environmental and sustainability consulting. He is the founder and principal hydrogeologist of Carbon Negative Water Solutions, LLC.


[i] http://www.arb.ca.gov/cc/cc.htm

[ii] http://www.arb.ca.gov/cc/capandtrade/capandtrade/unofficial_c&t_012015.pdf p.65

[iii] http://www.ocregister.com/articles/water-658616-desalination-county.html

[iv] http://www.nap.edu/openbook.php?record_id=12184

[v] 2NaCl (aq) + 2H2O (aq) + 2CO2 (g) + e => H2 (g) + Cl2 (g) + 2NaHCO3 (s)

[vi] http://en.wikipedia.org/wiki/Fuel_cell


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