Case study: How we’re reducing the carbon footprint of both our swimming pools and our HQ

We’re keeping the City’s swimming pools at the perfect temperature while reducing the emissions these facilities produce. And using an innovative energy-saving system to power our headquarters in the CBD.

Our pools

You’ve told us you love Sydney’s pools, which include the Ian Thorpe Aquatic Centre in Ultimo and the Cook+Phillip Park Aquatic and Fitness Centre in the CBD. And we know that greening our city is important to you. That’s why we’ve set ourselves a challenge: to keep the pools heated while reducing the impact of that on the environment.

To achieve this, the City of Sydney has installed a cogeneration system at Ian Thorpe and will shortly install one at Cook+Phillip. This system uses a gas-powered internal combustion engine that generates both electricity and useful heat simultaneously.

“By running this type of engine, you generate a lot of heat,” explains Pratik Patel, Project Development Engineer, Green Infrastructure at the City of Sydney. “Instead of letting the heat simply dissipate, we capture it with a device called a heat exchanger and use it to heat the pool water.”

Meanwhile, the electricity generated by the engine satisfies the other energy needs of the swimming pool complex. The cogeneration unit is powered by natural gas, enabling huge carbon savings of about 740 tonnes per year.

Town Hall House

Similar technology is also in place at Town Hall House, the CBD high-rise where many of the City of Sydney’s employees work. There, a trigeneration unit produces not just electricity and heat but also cooling. The electricity, heat and cooling are used throughout Town Hall House and in the adjacent Sydney Town Hall.

“A trigen system uses the heat generated by the engine to power an absorption chiller which works in the same way as a heat-powered refrigerator,” says Patel. “The great thing about it is that you can use the heating and cooling capabilities individually or have them both running at the same time.”

Like cogeneration systems, trigeneration is energy efficient: in fact, the natural gas-powered system at Town Hall House produces less than half the emissions than the equivalent power from a coal-fired power plant. Over its 30-year lifetime, it is expected that the building’s trigeneration system will cut carbon emissions by more than 40,000 tonnes.

Its success is also a great example of how high-rise buildings can be fitted with significant sustainability features, even if they do not have sufficient roof space for rooftop solar.

Could cogeneration or trigeneration be right for you?

Ask yourself the following questions to determine whether either of these systems could be a good option for your building:

Would you like to improve your NABERS rating [Link: ]? Cogeneration and trigeneration are useful options for buildings that cannot install rooftop solar but would like to reduce their reliance on grid electricity and improve their sustainability ratings.
Do you have a strong need for heating or cooling? The systems make more sense in buildings that require significant heating or cooling: for example, office towers that employ climate control throughout the year.
Are you surrounded by other businesses with similar energy needs? Some businesses that install cogeneration or trigeneration systems sell the excess electricity or water they produce to surrounding buildings, further reducing their net energy cost.
Is energy security important to you? Buildings in areas with high energy demand, such as the CBD, occasionally lose grid power when the system can’t cope. Patel says gas-powered cogeneration and trigeneration are more reliable and could be a good way to power critical infrastructure such as data centres.

More ways we’re making an impact

Want to learn about other carbon-busting projects the City of Sydney is undertaking? Click through for info on our rooftop solar roll-out [Link: new link to Help Centre case study on the solar] and our state-of-the-art Alexandra Canal depot [Link: new link to Help Centre case study on the depot].