11 July 2012 ­ – The City of Sydney has denied there could be health risks from trigeneration systems set to power the city unless adequate filtration was used, after warnings from a scientist who pushed for the removal of lead from petrol.

Dr Vyt Garnys, from CETEC, said nitrogen oxides, which could form nitrogen dioxides – a toxic compound, were a byproduct of trigeneration.

Dr Garnys told a local Sydney newspaper, the Inner West Courier, that the elderly and young children were particularly vulnerable to nitrogen dioxides, especially with  20 to 25 per cent of the population having asthma.

“We know nitrogen dioxides aggravate the throat and lungs,” he said in the article.

“As trigen gains popularity, we are potentially shifting energy production from our regions into the city, and as combustion produces nitrogen dioxides it has the same effect as a car exhaust.”

The warning comes after a World FM Day at Federation Square, Melbourne, which discussed the recent assessment to model and physically test the nitrogen oxide and nitrogen dioxide levels resulting from the trigeneration system and other emissions levels at a five star Green Star building in Melbourne.

CETEC spokesman Jack Noonan said the three-year case study on the building, which had implemented a trigeneration system, had also been presented at Ideaction 2012 in Canberra and Healthy Buildings 2012 in Brisbane.

Mr Noonan said, in summary, the green building revolution had seen the emergence of cogeneration and trigeneration systems as a means of generating energy on site and reducing the environmental impact of the building.

“At present, there are approximately 44 sites across Australia, which have adopted the technology with varied success,” he said.

“A by-product of trigeneration systems is nitrogen oxides (NOX) which have the potential to form nitrogen dioxide (NO2) in the atmosphere.

“NO2 is a toxic compound and can have adverse health effects with short term (acute) and long term (chronic) exposures if not properly assessed.”

Mr Noonan said the assessment of the Melbourne building included modelling and measuring emission levels “at various wind speeds and directions and at several intervals, including at and within the air intakes to the building”.

“Results indicated elevated levels of NOX and NO2 levels at several air intakes,” he said.

“Consequently, there remains a need for designers, builders, energy providers, policy makers and project managers of sustainable buildings to consider the air quality implications of choosing a cogeneration or trigeneration system for their new project.

“The impacts may be seen by occupants, facilities managers, and policy makers for many years over the life of the building, with significant and costly outcomes.”

However Mr Noonan said while there were a number of solutions to the issue “the problem has been that the solutions haven’t been incorporated into a lot of designs thus far”.

They included strobic fans, emission scrubbers and gaseous filtration but were all additional costs, both in terms of capital costs and maintenance costs, he said.

“Additionally, some do not solve the problem adequately,” he said.

“(As well) not all trigen and cogen projects pose a problem, so a thorough risk assessment and physical testing of the system needs to be conducted so that these unknowns can be answered.

“As bigger sites adopt the technology and we shift from a ‘green building’ focus to a ‘green precinct’ focus, we will see bigger cogen and trigen systems, which could lead to emissions that have even more serious health implications.”

Sydney’s low-carbon energy network is to provide 70 per cent of the City of Sydney’s electricity requirements by 2030, at a cost of $440 million.

A City of Sydney spokesman said the city’s trigeneration engines would be fitted with the latest air quality control technology, including catalytic reduction systems similar to devices in the exhaust systems of modern cars.

“Nitrous oxide emissions will be up to 80 per cent lower than the NSW government air quality standard,” the spokesperson said.

“By 2030, the trigeneration network could produce a small 0.2 per cent increase in nitrogen oxide emissions in Sydney.

“That’s compared to transport, in particular motor vehicles, which produces 78 per cent of Sydney’s NOX emissions.

“The 0.2 per cent NOX emissions are expected to be more than offset by other City of Sydney strategies, particularly the ‘Connecting our City – Transport Strategies and Actions’ plan.

“CSIRO modelling shows the impact of nitrous oxide emissions by trigeneration plants in the City of Sydney region are ‘negligible at the scale of the Sydney LGA and at the regional scale for the emission scenarios’.”