Why are Melbourne and Sydney regularly declared two of the most liveable cities in the world? Access to education and health, culture, infrastructures, the criteria are numerous. Other criteria are environmental care and sustainable development. And in these fields, Sydney has started the transformation from an old town to a green and sustainable city… a proactive transformation which will soon be an example for any major city around the world.
We met Bhakti and Nik on April the 27th,
at Sydney City Hall. On this picture is Nik!
In 2008 the City of Sydney launched the program Sustainable Sydney 2030 and committed the city to becoming a “green, global and connected city”. At the end of April we met Dr. Bhakti Devi and Nik Midlam who work for the City of Sydney as managers defining and implementing the program. Bhakti is managing water strategy and Nik is responsible for carbon strategy. “Around 5 years ago, global context made the climate and carbon emissions issues be in the forefront”, says Nik. Bhakti adds : “the City of Sydney has an old city center, with old systems. It had to be rethought. The ambitious program could start, with the push of Allan Jones who is the leader of the development program and who performed a similar and successful job before in London”.
“A key objective of the program is cutting down the carbon emissions”, Bhakti says. “The City of Sydney has set a target of reducing greenhouse gas emissions by 70% below 2006 levels by 2030”.
A leading environmental performer
Solar panels on the roofs of
Sydney City Hall.
Nik explains : “It is a global transformation that will occur. Concerning the choice of renewable energy, solar energy will be promoted as much as possible. The City of Sydney has the chance to be located in a sunny region”. Bhakti adds : “We are also working on adding a new pipe in the water supply network, a recycled water pipe, which shall be used for flushing for instance. Adding a second pipe in the water networks is a big investment but it will allow saving lots of energy. Today in a building an average 20% of the consumed water is used for flushing! Recycled water should be used instead of drinking water.”
The program sets out a global path for reaching the targets by improving energy efficiency, encouraging people to cycle and walk, utilising waste as a resource, converting non-recyclable waste to energy, recycling water and… implementing a Decentralised Energy Network, powered by Trigeneration.
What is Trigeneration?
The City of Sydney requires approximately 4 million MWh of electricity per year. Traditionally, this electricity has been provided by large, regionally located coal fired power plants. These power plants produce large amounts of electricity, but also produce significant amounts of greenhouse gas emissions. The electricity sector is responsible for approximately half of all Australia’s greenhouse gas emissions as well as approximately 80% of greenhouse gas emissions within the City of Sydney (City of Sydney).
Nik explains : “Trigeneration is the simultaneous production of electricity and the exploitation of waste heat from the generation process to supply heating and hot water needs. In addition, the heat can also be converted into cooling via a heat–driven chiller”. Electricity, heating and cooling…
Trigeneration system (Picture: City of Sydney)
In a first instance, the trigeneration system will burn gas, which is a fossil fuel, and therefore will not provide carbon free electricity. However the system produces far fewer greenhouse gas emissions than the traditional coal fired power stations.
Presentation of trigeneration
Subsequently, renewable gases will be used. “These renewable gases will come from the city waste! They will be created using waste to gas conversion technologies”, says Bhakti. This will displace fossil fuel gas in the trigeneration systems, enabling them to provide carbon free electricity, as well as carbon free thermal energy for heating and cooling…
Nik concludes : “By 2030, the City should have the capacity to meet up to 100 per cent of electricity demand by local electricity generation". A self-sufficient green city… let’s follow Sydney!