Sydney to cut emissions through trigeneration

by Aaron Cook

A method of power generation as old as the light bulb is set to help the Sydney Local Government Area meet 70 per cent of its electricity needs through local electricity production, while slashing the City’s carbon emissions.

The City of Sydney is pushing ahead with plans to install 330 megawatts worth of a “trigeneration” technology by 2030 and is calling for tenders from electricity companies for the first stage of implementation.

Trigeneration works by capturing waste heat used in electricity production and using this to run both the heating and cooling systems of buildings. It is three times more energy efficient than coal fired power, which is responsible for more than 80 per cent of Sydney’s carbon emissions.

Allan Jones, a British energy expert hired by the City of Sydney, said that trigeneration makes electricity cheaper to produce and less carbon intensive. The capital investment for the scheme is likely to need a loan, but the benefits achieved will make the venture economically viable.

“These schemes are big enough to warrant an energy services company implementing them,” said Jones. “You have the capital investment, you have the fuel costs to run that capital investment and you have the operation and maintenance costs.

“It follows that the interest you’re paying on the loan, the costs that you’re paying on the fuel input, and also the operation and maintenance, has got to be lower than the income you get from selling the electricity, heat and cooling.”

The location and size of the first plant is still to be decided, dependent upon the tender process to be completed in the next few months. This process will also decide the financial structure of the venture, which could involve a partnership between the City of Sydney and a private company.

Mr Jones also said the plans have the potential to save the state billions of dollars, which will otherwise need to be spent on two new coal fired power stations for the Hunter Valley, as well as upgrades to the electricity network to cater for the new stations.

“You’re going to reach a situation where 60 per cent of your electricity bill is network charges, the cost of shifting the electricity from the Hunter Valley to Sydney” said Mr Jones.

However a spokesperson for Energy Australia said that although the City’s trigeneration plans may lead to a small long term reduction in costs, the $17 billion being invested in the electricity network across NSW between 2009 and 2014 is still required.

“Much of the electricity network is being upgraded and replaced because it is reaching the time when it will begin to become less reliable,” said the spokesperson.

The Stockland’s building in the CBD has already got a private trigeneration system installed, but the City’s plans will lead to the first public trigeneration supply in Australia. Lord Mayor Clover Moore said the City could be a role model for other cities in Australia. “Australian cities could halve their greenhouse gas emissions over the next 20 years if they implemented a plan similar to ours,” said Ms Moore.

At present, regulations would prevent the City from selling any excess power it generates back to the grid, but the City has made a submission to the Prime Minister’s Energy Efficiency Task Group, seeking a change to the rules.

Coal fired power generation has traditionally been thought of as the cheapest method of producing electricity, because of Australia’s ready supply of cheap, high quality coal. But existing coal fired stations are located more than a hundred kilometres from Sydney in the Hunter Valley.

Chris Dunstan from the Institute for Sustainable Futures at the Sydney’s University of Technology has carried out modelling on the costs of various methods of additional power generation. He said that when the price of transporting electricity is taken into account, building trigeneration closer to the city is a cheaper option.

If the federal government eventually places a price on carbon emissions through a tax or emissions trading scheme, then trigeneration, which is less carbon intensive, will become even more cost effective than coal fired generation.