Winds of Change for Reverse Osmosis Seawater Desalination?

Membrane desalination capacity is growing globally but so is its demand for power, usually supplied through fossil fuels. With renewable energy sources such as wind power being proven, are there opportunities to combine the two? Joachim Käufler, Robert Pohl and Hadi Sader discuss the practical and economical feasibility of wind powered seawater reverse osmosis.

Energy consumption of industrial scale seawater desalination has decreased significantly over the past few decades. Advantages in membrane technology and energy recovery devices have led to a relatively low specific energy consumption (SEC) of reverse osmosis (RO) processes to around 2 – 4 kWh/m³.

Lower energy consumption per unit, lower investment costs, a simple process control and a very flexible plant design have all helped RO to gain a significant market share within the field of small and large-scale desalination plants (< 100,000 m³ daily).

However, due to the ever expanding desalination market, total electric energy consumption of desalination, especially RO, will increase. With nearly all electric energy for commercial seawater reverse osmosis (SWRO) generated by fossil fuels, this presents challenges and concerns. This includes costs (energy can represent 30% to 60% of total water production (RO) costs), through to reliability. For example, if fossil fuel energy sources are supplied internationally, then reliability of supply could be affected negatively by political conflicts.

These concerns can be avoided or minimised by using locally available renewable energies, such as wind or solar power. And feasibility studies carried out could see wind powered RO desalination proven in Bahrain, in the Middle East.

In February 2011 a Memorandum of Understanding was signed between SYNLIFT Systems and Jade Consultancy to help develop the concept of wind powered seawater desalination. Extensive laboratory studies simulating Gulf region conditions suggest the concept is both technically and commercially available. The basis of which will be presented in the following article.

Currently preparations are underway for the implementation of the first system module described above. Already today wind power offers low and long-term stable costs of energy and therefore is able to compete with large scale conventional power generation. Using wind power directly for energy intensive industrial processes requires an optimised hybrid configuration as well as a balanced load and/or energy management. WWi