Wednesday, November 10, 2010
Trigen solution is short of gas
The so-called trigen units are locally installed gas-fired plants which generate electricity for buildings and then capture the exhaust to heat and cool them.
They have become increasingly popular in the past year as they can produce electricity for as little as 8c an hour and are three times more energy efficient than coal-fired power.
The City of Sydney has announced plans to install a network of more than 100 trigeneration turbines which it says would meet 70 per cent of Sydney's electricity needs by 2030.
But Simon Bennallack, the national manager of Urban Energy, who has consulted with the council over its plans, says that introduction of a second power network into the city will be far from straightforward.
Although he remains an advocate of the trigen technology as he believes it is cost-effective and will alleviate pressure on the existing grid, he described the council's plans as "typical (Lord Mayor) Clover Moore -- throw the dart and hope it hits a target".
"Not enough thought really went into it," he said.
"There are only pockets of the CBD that has enough gas supply to support it. So instead of having a problem with electricity supply into the city, now you'll have gas supply issues.
"It's like putting V8s on a racetrack. You're going to need a lot of petrol to make them all go. "
Matthew Wright, the founder of Beyond Zero Emissions climate group and Australia's Young Environmentalist of the Year, cites health risks and uncertain costs and says such a network would be only a bandaid solution to the long-term energy crisis.
He says that although these gas-fired plants are highly efficient in more extreme weather conditions -- as the exhaust is used to either heat or cool a building as well as power it -- the milder conditions most of the year mean they are much less efficient.
"The promoters of it make it seem like it's the best day, every day, which is not the case. They might operate at peak efficiency for two or three months of the year," he said.
Mr Wright also notes the plants emit nitrous dioxide, which has been linked to respiratory problems and asthma.
"Why burn fossil fuels in local areas and high density spaces like cities? Isn't that what we've been trying to avoid since the industrial revolution? It doesn't make sense," he said.
And while proponents talk of decentralising the power supply, these plants would still be connected to a central onshore gas source, and the price of gas would remain an issue, he said.
"It's just not the panacea it's being sold as. There's no life guarantee on the price."
In a statement, a spokesperson for the City of Sydney said gas and coal prices were linked, and trigen avoided the sulphur dioxide and particle pollution of coal-fired power stations.
Jemena, the gas network operator, has also provided technical details on the supply of gas to the council's consulting consortium -- Kinesis, Cogent and Origin -- which is preparing the trigeneration masterplan for the Sydney CBD. The plan will be released soon.
"Council has committed to this project because it will reduce greenhouse gas emissions, and it will help insulate council, city businesses and ratepayers from future electricity price rises and provide a more reliable source of power," the statement read.