No easy fix for gases coming from landfill

Australian
Monday 1/9/2008 Page: 32

A HALF-EATEN hamburger discarded at the opening ceremony of the Brisbane Commonwealth Games in 1982 is as you read this still decomposing in the depths of the nearby Ferny Grove landfill. Which means it's still contributing to Australia's greenhouse inventory, more than 25 years after Matilda the giant winking kangaroo lurched around the stadium.

Debate over the design of a national greenhouse emissions trading scheme has focused mainly on the multi-billion-dollar consequences of the treatment of major facilities like power stations, aluminium smelters and LNG facilities. But the dark corners of the scheme, like how to include and ultimately reduce emissions from places like landfills, are proving just as much of a handful to iron out.

There are an estimated 500 active landfill sites around Australia and another 1000 that have already been filled up and closed. All of them contain decades of decomposing organic waste. The decomposition of these carbon-based materials deep underground without oxygen produces methane, a highly potent greenhouse gas that eventually finds its way to the surface and into the atmosphere.

Depending on the climate and moisture levels, organics can take up to 50 years to completely break down. As a result, most of these sites are believed to be releasing thousands of tonnes of greenhouse gas each year, totalling 20 million tonnes or nearly 3 per cent of total national emissions. Simply including all these emissions in the Carbon Pollution Reduction Scheme poses a number of problems. While power stations emit greenhouse gases only if they burn fossil fuels, the greenhouse footprint of a tonne of organic waste extends for a generation after its disposal.

Requiring permits for these emissions means making current landfill users pay for emissions generated by decades of previous users. Owners of the 1000 closed landfill sites will be hit with a carbon bill of a few hundred thousand dollars each year, without any revenue stream to pass on the costs. Many of these sites are still owned by local councils, which are strongly in favour of free allocation of permits for these historical emissions. Councils also make formidable political enemies, so Penny Wong will ignore their concerns at her peril.

Waste management companies like Veolia and SITA have flagged a compromise requiring all sites that emit more than 10,000 tonnes of CO2 equivalent a year to be mandated by law to fit gas capture and flaring devices at a one-off cost of $300,000. Modern landfill design has been primarily concerned with stopping heavy metals and other potentially hazardous materials dissolving in moisture and leaching out into the surrounding soils and water table.

Only in the last decade or so have landfills been shaped and lined to maximise the recovery of methane gases, which can either be flared off to reduce their impact, or in larger-scale operations used as green energy. But that still won't stop between 30 and 70 per cent of the emissions. It's also not entirely clear which sites would quality for such a threshold test, because it's not entirely clear how much gas is coming from each landfill.

For obvious reasons, rubbish has tended to be a relatively inexact field of study. There are three different methodologies to estimate landfill greenhouse emissions. The easiest and most common is based on rates of decomposition according to temperature and rainfall as prescribed by the Intergovernmental Panel on Climate Change (IPCC). But it's also the least accurate. Using this method, two similar, neighbouring landfills Mugga Lane in Canberra and Woodlawn in NSW are given wildly different rates because they sit either side of the ACT/NSW border.

The industry estimates it will take another five years to directly measure methane emissions from landfills with the same accuracy as power stations or other point sources. But perhaps the biggest problem lies with the effectiveness of a trading scheme to drive reductions in emissions. It's possible to pre-treat organic-rich rubbish from households, restaurants and cafes to accelerate their decomposition and reduce their greenhouse intensity. But it's expensive.

Ideally, if this flow of garden waste and food scraps can be managed carefully to prevent contamination from things like paints, car batteries and gas cylinders, then they can be converted into bulk composts and reapplied to Australia's carbon-starved soils.

Composts also reduce pathogens, reduce water consumption and accelerate plant growth. It's the ideal long-term solution, but it will need more than just a reasonably stiff carbon price to make it happen. Recyclers of other materials like steel, plastics, glass and aluminium are also crying foul, as they get no help from a trading scheme. Using recycled materials as part of the feedstock reduces energy demand saving on both power bills and carbon permits.

But most of these recycled commodities are now traded internationally, so suppliers like Visy Recycling and local councils are unable to bank any of the embodied greenhouse benefits. Only a global price on emissions will shift demand and with it the world price for recycled aluminium cans. All these debates, for just 3 per cent of emissions, are too big to ignore but difficult to fix.