The following text is an excerpt from the article ‘Look to Windward: The Case for Wind Powered Desalination’ by William Steel, published in WaterWorld.
As a popular renewable energy, wind power has the potential to help lower the desalination carbon and energy footprint. Yet the coupling of the two industries, for direct wind powered desalination, has not progressed. Why?
As a characteristically energy intensive industry desalination has, historically, relied heavily on fossil fuels. It is estimated that currently installed and operational desalination plants worldwide emit around 76 million tonnes of CO2 per year; an amount expected to grow to around 218 million tons by 2040, according to the Global Clean Water Desalination Alliance (GCWDA).
Change, however, may be on the horizon. With the convergence of heightened calls for clean power production and the advent of technologically advanced renewable energy systems, the feasibility and rationale of powering desalination with clean energy has never been greater.
“Aside from environmental or climate issues, the economics of renewable energy and the costs of power production really suggest that this is the direction desalination should take,” Leon Awerbuch, director of the International Desalination Association tells WWi. “In fact, it’s already the direction we see being taken.”
Desalination processes are powered predominantly by electricity; though a majority of large desalination plants in the Middle East Gulf do operate through thermal processes. Both electricity and heat, however, may be supplied through clean, renewable energy – dramatically lowering desalination operating costs.
Of the methods of renewable energy production available, solar photovoltaics and wind power stand out as the most accessible means of powering desalination. Already the leading source of new renewable energy capacity, wind power is an especially promising route for decarbonising desalination.
Precise economic advantages of wind powered desalination will invariably be project specific as wind turbine power generation is highly dependent on geographic location. However, innovations in the form of wind turbines designed for low wind speed operations are useful in the context of powering desalination — allowing for reliable energy production at wind speeds as low as 3 or 4m/s and available in many regions.
Markus Forstmeier, vice president business development, Electrochaea, but previously involved in researching the feasibility of wind powered desalination while working with GE, tells WWi: “As far back as the middle of the last decade we concluded that wind-powered desalination was cost-competitive with other desalination systems. The economics of these systems are even more favourable today thanks to innovations in the wind industry.”
He adds: “Wind power and desalination would seem a natural fit but it’s somewhat fallen between the cracks of the two industries.”
Remarking on this potential Awerbuch says: “Consider reverse desalination (RO), which is today the most efficient desalination process, using roughly 3.5kW/h per cubic meter of water. If you took just a single 7MW wind turbine, you have power for producing over 48,000 m3 water per day.”
“If you consider some of the wind farms being built today, of hundreds of megawatts in capacity – you could produce a huge amount of water from this, with a cost of energy that fossil fuels cannot compete with.”