Beyond Zero Emissions

1 October 2012 — The City of Sydney is planning to roll out gas burners within the city limits for a regional electricity and heating/cooling grid, powered by gas, known as “trigeneration”.

When campaigners pointed out this rollout of gas generation would support the rapid development of the devastating coal seam gas industry, their response was confused (and confusing).

At first the City’s chief development officer of Energy and Climate Change, Allan Jones, said that “trigeneration cannot run off coal seam methane as this contains damaging trace elements which would destroy the trigeneration engines… the effect would be similar to filling up a petrol car with diesel fuel”.

This is also stated in a briefing note for the Lord Mayor.

Addressing this confusion about whether “gas is gas”, the Australian Energy Market Operator, in the 2011 GSOO Gas Statement, notes that:

“The major chemical constituent of both conventional and unconventional gas is methane. Although unprocessed gas from either source contains various minor components and contaminants, gas from conventional and unconventional sources can be mixed before or after processing to industry quality standards and used interchangeably in gas transmission and distribution networks.”

The Australian Energy Market Operator predicts that 84-85 per cent of the nation’s future gas will come from unconventional (read coal seam or shale gas) fields.

The live depiction of the gas market here, shows a significant amount of gas flowing from Queensland, predominately Roma (CSG collection area) into Adelaide and Sydney via Moomba.

The City of Sydney obviously doesn’t want to be seen supporting coal seam gas. Its next response was to argue that renewable biogas could at some time in the future be substituted for the fossil gas currently in the network.

Fellow travellers and consultants continue to claim that the biogas age will arrive and the system will be fine. But we have to ask: how many years would Cogent, Origin Energy’s subsidiary, contract existing conventional fossil gas supplies? Those contracts would be with Origin, who is the biggest name in CSG.

Trigen supporters cite biogas developments in Denmark (and to a lesser extent, across Europe) to support their case.

But biogas is not the booming renewable sector in Denmark. For electricity they’re shifting the entire country to 50 per cent wind power by 2020. They’ll have about 5000 wind turbines (with the majority of turbines, and capacity, onshore like in Australia).

The country doesn’t have an explicit biogas target but does have a renewable heating target which can include things like heat pumps (geothermal and reverse cycle airconditioning) as well as biomass and biogas for providing domestic, commercial and industrial heat. Of the biomass portion, solid biomass is a significantly greater contributor than biogas.

The biogas production in 2001 was 3.6 petajoules and that has risen to 4.2 PJ in 2011, a rise of about 16 per cent in a decade.  The biggest power plant producing electricity from biogas is the Lemvig plant, built in 1992.  Nothing bigger has been built in the 20 years since.

Lemvig produces the equivalent annual net electricity of just one Enercon E-126 wind turbine (rated capacity 7.5 megaWatt). The entire nation has less than 200 biogas plants, which produce the equivalent net electricity of 16 E-126 turbines, or roughly the same as Tasmania’s Woolnorth wind farm.

To supply the projected gas requirements of the City of Sydney trigen precinct it would require four times as much biogas as the entire country of Denmark produced in 2011. Denmark has been building up this sector for over two decades.

Chemical and industrial processes that rely on gas as a feedstock are considerable.  Australian Bureau of Agricultural and Resource Economics‘s figure for chemical processes in Australia is 115 PJ.

It would be ridiculous to put a limited resource (biogas) towards a new dedicated energy demand (burning fossil fuels inside the City of Sydney) when that demand can effectively be serviced by electricity from solar and wind, and much more efficiently.

In the medium term biogas can be produced, but must go to industrial processes where it is essential, if we want to reduce greenhouse emissions from fossil fuels. Wind and solar electricity, coupled with rigorous energy efficiency programs, can provide a far more sustainable energy solution for the City of Sydney.

Matthew Wright is executive director Beyond Zero Emissions