desalination plant in Los Cabos.
Electric-powered desalination plant in Los Cabos.


A desalination system that doesn’t require electricity and can be used in dry, coastal communities is under development by students of the National Autonomous University.
The university’s Engineering Desalination and Alternative Energies Institute is testing out a laboratory prototype for the first geothermal modular desalination system to be developed in Mexico, and is also in the process of obtaining a patent.

The prototype, powered by clean geothermal energy, is up to 20% more efficient than current technologies and can be used in coastal communities that do not have electricity.

The technical coordinator of the institute, Héctor Miguel Aviña Jiménez, said they are looking for desalination processes which could work for and with the variety of renewable energy resources the Baja California peninsula offers, such as solar, wind, geothermal, tides and currents.

Baja’s natural resources makes geothermal energy the simplest and most beneficial solution to for the region, which is full of geological faults that produce cracks, fractures, and landslides that generate heat and with its proximity to seawater can be leveraged in sites such as Ensenada, Puertecitos, Los Cabos, La Paz, San Felipe and San Quintín.

The desalination system employs a process of reverse osmosis through heat exchangers where seawater evaporates and condenses. The heat is provided by the hot liquid from geothermal wells or ponds.

“Marine liquid generally has 35,000 parts per million of chloride, sodium, potassium and other salts; that which we obtain in the desalination contains five to 10 parts per million.”
According to Aviña Jiménez, one of the many advantages of using geothermal energy is its abundance; it is available 24 hours a day, unlike solar energy with which “we would have to rely on a thermal storage system during hours when there are no sun rays, although hybrid systems can be used.”

In terms of cost, he said that a cubic meter of desalinated water by reverse osmosis costs about US $1. “We hope that with technology based on a natural resource, like geothermal energy, the price will decrease to 80 cents.”

Typical desalination costs run from less than 40 cents at plants in Israel, which relies on the process for 40% of its domestic water, to a dollar or more.

Water consumption last year in Tijuana and Rosarito totaled 114 million cubic meters, of which 94% came via the 70-mile aquaduct that carries water from the Colorado River.

According to Geo-Mexico, there are about 70 desalination plants on the Baja California peninsula. Most are small and and are powered by electricity.

A large, $48-million plant to be powered with electricity is under construction in Ensenada, where water shortages have been a problem. It is scheduled to begin operating next year when it will produce 5.7 million gallons of water a day for about 96,000 people. It will be the second utility-scale desalination plant in Mexico.

Ensenada is the only municipality in Baja California that is not supplied by the Colorado River.

Source: Plaza de Armas (sp)