The proposal is called “trigeneration.” The city is Sydney, Australia. The plan is to use city roofs and basements to become local sources of power generation to supplement and eventually replace coal-fired power responsible for 80% of Sydney’s greenhouse gas emissions. The goal is to generate 70% of the electrical requirement for the city by 2030 and dramatically reduce dependence on more polluting power generation sources. The balance of energy will be generated by renewable energy sources such as solar, wind and energy from waste.
Sydney is not unlike many other large urban centres on the planet. Although cities occupy 2% of the Earth’s land mass, they are the users of 66% of all the energy we generate and contribute 70% of total carbon emissions.
Trigeneration is a technology that uses natural gas to generate electricity, heating and air conditioning for building clusters. It is better than twice as efficient as the coal-fired power plants it will replace. And with a reduced carbon footprint will improve the city’s air quality dramatically. The city is also switching to LED street lighting throughout to reduce its energy footprint.
The alternative that Sydney faced was one that would have involved building new power stations and a major upgrade to the power grid. By producing power locally the city will avoid the cost of remote energy generation and the transporting of it over power lines.
The Trigeneration plan includes local building projects that not only will generate their own power but will also recycle water from storm-water runoff to flush toilets and irrigate gardens and parks reducing the city’s water usage. In Australia which increasingly faces drought conditions water is as large an issue as air pollution and energy conservation.
The city hopes to save more than $1.5 billion Australian through implementing trigeneration.