Fact versus Fiction: Unpacking the truth about the Sydney Desalination Plant

In an era of unpredictable weather patterns and a growing population, ensuring a resilient drinking water supply is one of Sydney’s biggest challenges. That’s where Sydney Desalination Plant comes in – designed as a safeguard, and a modern-day solution to this problem. Yet, for all its strategic importance, the Plant is often misunderstood.

Perhaps you’ve heard that it’s rarely used, that its water tastes odd, or that it drains energy and harms the ocean.

Today, we’ve spoken with Matt Blaikie, General Manager Business Optimisation, from the Sydney Desalination Plant to get the real story, dismantle these popular myths and uncover the essential role this Plant plays in Sydney’s sustainable future.

Myth 1: Is the Sydney Desalination Plant actually running?

This is perhaps the most common question we hear. Our dam levels fluctuate and have remained high since the last drought broke in February 2020, so people often wonder about the Sydney Desalination Plant’s role in Sydney’s drinking water supply.

The truth is, the Plant is absolutely being used – and has been running continuously since March 2019. It operates all the time as a critical “insurance policy” for Sydney’s water security and has responded to increase production several times during this period to maintain system resilience.

Matt explains that while the Plant initially turned on in response to drought and low dam levels, its role quickly expanded. “The Plant’s been running continuously since March 2019. Even after the drought broke, it continued operating to assist Sydney Water with water quality challenges in dam supplies caused by heavy rainfall.”

Today, the NSW Government’s Greater Sydney Water Strategy values the Sydney Desalination Plant being in a “state of constant, flexible, full-time operation.” This strategic approach allows it to easily respond to future emergencies, support maintenance across the water network, address water quality issues, and proactively keep dam levels high. As Matt notes, this avoids the previous scenario where “the Plant was shut down, and it would take up to a year to restart.”

While the Plant’s average recent production runs around 39-40% of full capacity (delivering about 100 million litres a day), its flexibility means it can quickly adjust. “The Plant runs best at relatively stable production, but we can get to full capacity within a Matt confirms. This ensures the Plant is always ready to ramp production up or

Ultimately, the Sydney Desalination Plant can contribute about 15% of Sydney’s drinking water supply by total demand. Even with high dam levels, running a base load of desalinated water helps keep dam levels up, extending Sydney’s buffer before future drought impacts are felt. It also provides a vital, geographically diverse water source, ensuring continuous supply so Sydney Water can undertake its essential network maintenance schedule.

Myth 2: Does desalinated water taste different?

Many assume ocean-sourced desalinated water tastes odd. Yet, if you drink Sydney tap water, you’re likely consuming it and haven’t noticed. Matt Blaikie clarifies the Plant’s water quality targets, set by Sydney Water and aligned with the Australian Drinking Water Guidelines, “mimic, as far as practicable, the water quality from surface water sources.”

The advanced reverse osmosis membrane process removes salt and impurities, creating pure water. Post-purification, minerals are added “to make it similar to the water supplied by other sources,” ensuring it meets health standards, isn’t corrosive to pipes and tanks, and matches Sydney’s taste profile. Matt suggests desalinated water might even have an edge: “Our water tends to be lower in salinity and other sort of dissolved solids like leaf matter and organics that can often be found in dam or river water.” Any perceived taste differences are likely psychological, not fundamental.

Myth 3: Is the Desalination Plant an energy drain?

Desalination is an energy-intensive process, and concerns about the Plant’s environmental footprint are understandable.

However, the Plant uses 100% renewable energy, a commitment which was a fundamental part of the Plant’s original planning approval.

The Plant’s electricity use is fully offset by renewable energy certificates from NSW wind farms. Notably, Matt points out that the Sydney Desalination Plant acted as a foundational customer for the Capital Wind Farm near Canberra, helping to bring that significant renewable energy project to fruition.

Beyond offsetting, the Plant incorporates cutting-edge efficiency technology, employing energy recovery devices that recapture energy and reduce high-pressure pumping, the major energy consumer, by an impressive 40 to 45%.

Matt offers a surprising comparison to illustrate the Plant’s actual energy footprint: “A typical household uses less than 200 kilolitres (thousand litres) per year of drinking water.  The energy to produce this amount of drinking water is the equivalent to running a medium-sized two-door refrigerator for the year.” Or, even simpler, the relative energy use for the Plant to produce 200 kilolitres is “considerably less than leaving a 100W lightbulb on for the whole year.”

Myth 4: Is the Sydney Desalination Plant ‘too expensive’?

The cost of large infrastructure often raises questions. However, the Plant is an essential investment in long-term resilience, a crucial insurance policy against severe drought. Matt explains most costs stem from its initial 2010 build. These, along with ongoing operation and maintenance, are rigorously regulated: “An independent regulator runs the ruler over all of our processes and procedures and resourcing and set the maximum prices we can charge,” thus ensuring fair pricing.

Crucially, Matt stresses the “insurance policy” value. “We know droughts are going to happen.” The Plant’s existence prevents the massive economic and social costs of severe water restrictions during droughts, which historically could run into billions of dollars and severely impact daily life. Having the Plant ready avoids this catastrophic scenario.

When you break it down, the cost of desalinated water is surprisingly low at about 89 cents for 1000 litres – that’s less than 0.1 of a cent for a litre of water.

Myth 5: Does the Plant harm marine life?

The Plant was designed with comprehensive environmental safeguards and operates under strict regulations to protect marine ecosystems.

The biggest concern is usually the discharge of concentrated brine. However, Matt clarifies this common misconception: “Seawater is roughly 3.5% salt. We take the salt out of about half the seawater we collect so the other half ends up with doubly salty water. But it’s still only around 7% salt. It is liquid and still looks like seawater.”

The saltier water is discharged through “high-rate diffusers that are designed very well” to mix rapidly with the ocean. Within “50 to 100 metres of the outfall, the amount of salt in the water is down to background levels,” ensuring minimal impact. Rigorous independent scientific studies have confirmed that the Plant has minimal impact on marine life – there is no difference to the marine environment beyond this small mixing zone.

Furthermore, the Plant’s intake system is specifically designed to protect marine life. The area where water enters is so large that the water moves “very slowly” akin to “background currents in the ocean,” allowing marine life to easily swim past. Large bars spaced at approximately 10cm intervals across the intake prevent bigger creatures from entering, and a “fly screen” like process at the Plant site catches smaller debris.

From ensuring we have enough water during dry spells to its commitment to sustainability and marine protection, the Plant plays an indispensable role in securing our city’s future. It’s a sophisticated piece of infrastructure, built to deliver reliable, high-quality drinking water, responsibly.

Next time you hear a rumour about the Plant, you’ll have the facts to set the record straight!