The network of gas-fired engines that are planned to power the Sydney CBD could emit up to 660kg of harmful nitrogen dioxide every hour.
That is more than the combined emissions from the Shell and Caltex oil refineries in the region.
Estimates of the pollution produced by these new-generation power plants are contained in an interim policy paper by the NSW Department of Environment and Climate Change.
The City of Sydney has pledged to install more than 100 trigeneration turbines - which burn gas to generate electricity and then capture the exhaust to heat and cool buildings as necessary - in a bid to reduce carbon emissions and ease the strain on the existing electricity grid.
They also potentially pose a risk to air quality - and in turn the health of all those who live and work in Australia’s largest city.
The network, championed by Lord Mayor Clover Moore, is expected to generate 330 megawatts of electricity, meeting about 70 per cent of Sydney’s energy needs.
But, according to the DECC interim paper, the Sydney CBD could accommodate uncontrolled emissions from just 10MW of “co-generation” (a similar engine that heats but doesn’t cool buildings) before “health-based nitrogen dioxide goals” are possibly exceeded.
Furthermore, emissions from about 200MW of power would result in those nitrogen levels being breached “across the CBD”.
High levels of nitrogen dioxide (NOx) and other nitrogen compounds in the atmosphere are linked with a raft of serious health issues, such as respiratory illness and asthma. Children are considered particularly vulnerable.
The City of Sydney defended its plans, saying in a statement last night that the figures cited in the interim report were based on untreated emissions which “are not relevant” to the energy proposal. “Our master plan … will comply fully with … NOx guidelines,” the statement said.
However, that report specifically cites the council’s trigeneration strategy by name and was cited in the council’s own briefing paper, entitled Removal of the Barriers to Trigeneration.
“On an hourly basis 330MW of gas-fired co-generation (the amount envisioned in the City of Sydney strategic plan) could emit up to 660kg per hour of NOx; this is more NOx than the combined emissions from the Shell and Caltex oil refineries in Sydney,” the department’s report reads.
It also highlights that the proposal is centred on the CBD, where pollution levels are already the highest.
“As a result there is little ‘headroom’ available to accommodate uncontrolled emissions from cogeneration without causing local health impacts,” it says.
The National Environment Protection Council has developed air quality standards that govern the allowable levels of nitrogen dioxide that can be released. The benchmark is 0.03 parts per million, averaged over a year.
The City of Sydney would not comment on the implications of meeting the NEPC standards.
However, the council said it would find reductions in NOx emissions from cars through its integrated transport plan.
“The vast majority of NOx come from motor vehicles. The city’s cycling, walking, car-share and public transport strategies will also see real reductions in local NOx,” the statement said.
