Existing Solutions

desalination, reverse osmosis, energy recovery, Perth, wind farm

technical

The Perth seawater desalination plant, with a production of 143,000 cubic meters per day, is currently the second largest reverse osmosis plant in Australia and in the Southern Hemisphere. It began supplying municipal drinking water in November 2006.

The desalination plant, developed under a DBO project by Western Australian Water Corporation, is able to produce 17% of the total potable demand for the Perth Integrated Water Supply System (IWSS).

As part of Water Corporation’s and Western Australia’s (WA) sustainable strategy and commitment to promote energy efficiency and reduce greenhouse gas emissions, the Perth seawater reverse osmosis (SWRO) plant is one of the largest facility of its kind in the world to be powered by renewable energy.

The plant buys its power from electricity generated by the Emu Downs Wind Farm, located 200 kilometers north of Perth. This wind farm has a capacity of production of 80 MW, more than three times the maximum consumption of the desalination plant. The 48 wind turbines contribute over 272 giga-watt-hours (GWhr) per year into the grid, fully offsetting the Perth SWRO Plant’s estimated electrical requirement of 180 GWhr per year.

Perth seawater desalination plant was the first large RO plant in the World to be fed by renewable energies.

The plant utilizes ERI® PX Pressure Exchanger® (PX®) energy recovery devices to reduce energy consumption. The high-pressure (HP) pumps are sized and operated for maximum efficiency. The supply pumps, booster pumps and second pass pumps operate on variable frequency drivers which provides for flexible operation and low energy consumption. These devices combined with state-of-the art low-energy membrane elements make the Perth plant one of the highest-efficiency reverse osmosis plants of its size operating in the world today.

The plant was elected Desalination Plant of the Year in 2007 during Global Water Awards organized by Global Water Intelligence

The Perth seawater desalination plant is located in Kwinana, an industrial area approximately 25 km to the south of Perth in Western Australia (WA).

The plant is a DBO (Design Build Operate) project developed by the Western Australian Water Corporation using an Alliance style contracting strategy with a public-private partnership.

This plant forms a key part of the Water Corporation’s strategy of “security through diversity” taking into account Perth’s growing population and the limitation of the supplies. The design and construction of the desalination plant was accelerated and the schedule tightened by the Water Corporation due to the reduced rainfall in the Perth’s catchment areas and increased water demand from a solid population growth. The plant’s innovations regarding energy consumption is part of Water Corporation’s and WA’s commitment and strategy to promote energy efficiency and reduce greenhouse gas emissions.

 The plant has been built by proAlliance, a Joint Venture 50-50% of Degrémont (Suez Environnement) and Multiplex with 25-year operation by Australian Water Services, a local subsidiary of Degrémont.

The plant is fully operational since end 2006. Since then,every month, a complete report is submitted to the Western Australia Water Corporation to establish all plant operation data.

 The reduction of energy in desalination processes, and the reduction of the carbon footprint of desalination is a relevant and prioritary goal.

The issue at stake here is the optimisation of energy consumption in desalination by reverse osmosis thanks to energy recovery and  coupling with renewable energy.

The Perth seawater desalination plant represents a significant milestone for the development of large-scale SWRO technology by operating on renewable energy at a very low energy consumption level.

This plant is the first  large SWRO Plant powered with the electricity generated by a Wind Farm and the largest SWRO Plant operating with PX devices.

It is designed to optimize the energy consumption:

-          2.2 kW.h/m3 in the first RO pass

-          3.2 – 3.5 kW.h/m3 for overall Plant

The lowest specific consumption ever reported for large-scale SWRO

So far, Perth Plant operates since 2006 as designed, with 20 years left to improve further the energy consumption.

 The PX energy recovery devices used in the plant are operating at the highest efficiency ever reported

for such devices at this scale.

The Perth plant represents a significant milestone for the development of large-scale SWRO technology by operating on renewable energy at a very low energy consumption level.

All operating and performance data are monitored continuously, including power consumption.

Each year, a target is set with Western Australia Water Corporation to further optimize the plant operation.

Such optimization of energy consumption thanks to energy recovery and  coupling with renewable energy is replicable in most SWRO.

It is already being replicated by Water Corporation with a new plant Perth 2.

The largest SWRO in Australia and the South Hemisphere is being constructed in Melbourne by Degrémont, with the same type of energy strategy (building a wind farm and  the use the next generation of the same energy recovery devices).

Perth Sea Water Desalination Plant is a milestone in the Desalination World for many reasons but especially for the very low Energy Consumption and for the use the renewable energies (wind generators) to supply energy to the desalination plant having neutral balance in the carbon footprint.

From 2006 PSWDP is operating at full production with excellent results. Many Congresses can demonstrate these results and specially the last three IDA World Congresses: Mas Palomas 2007, Dubai 2009 and Perth 2011.

Since the designof this plant in 2004, the majority of large scale RO Desalination plants have used work exchangers like energy recovery devices to optimise  energy consumption.

The use of Renewable Energies in Reverse Osmosis Desalination, by Wind Farms,  has been copied and followed for other States in Australia

The success of Perth seawater desalination plant Perth 2 and the growing water demand led Water Corporation to launch a similar plant, Perth 2.

Similar plants under the same basis are been and are being constructed in other states of Australia, as Victoria Desalination Plant.

Miguel Angel SANZ, Degrémont

miguel.angel.sanz@degremont.com