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HZI and the road to zero carbon waste management

road to zero carbon

Dr Marc Stammbach, Managing Director for Hitachi Zosen Inova Australia, says Australia must face some stark realities to become carbon neutral by 2050. He shares his views with WMR.

The waste management sector contributes about three per cent to Australia’s greenhouse gas (GHG) emissions according to the Department of Agriculture, Water and the Environment. The Australian Government wants the nation to be carbon neutral by 2050 but the Intergovernmental Panel on Climate Change (IPCC) has recently suggested the nation stabilise and reduce carbon emissions by 2025.

If this information doesn’t bother you, you have won the ‘climate change snakes and ladders’ game and may declare yourself a winner. 

The readers left in the game are facing some stark realities, among those, the three per cent GHG contribution by the waste sector will be more like 15 per cent once we replace the fossil fuel power stations with renewable energy generation.

Also, our residual waste is still going to landfills. The nation’s population growth has neutralised any improved diversion rates. Landfilled waste is a net contributor to climate change as typical landfills have gas capture rates of 40 to 70 per cent. What we landfill today will continue to spew landfill gas over the next 50 years. Hence, even if we stop landfilling today, we shall continue to emit beyond 2050.

It is timely to propose some winning moves. 

We must separate the recyclables and food and green organics out of our waste stream. This needs to happen now and be mandated. 

road to zero carbonLet’s increase the landfill levies to $180/t nationwide, similar to levels in the United Kingdom. Let’s push the anaerobic digestion of organics producing renewable energy. We can produce peak-power electricity or biomethane ready for alternative transport fuel or gas pipeline injection. To do so, we need significant renewable energy contributions from the Emission Reduction Fund (ERF) or other new sources, similar to $50/t to $100/t for carbon dioxide credits in Europe. This increase will give anaerobic digestion the edge over composting and even more so over landfilling. Move up the ladder.

While it is excellent to reward gas capture and its use for energy production, in reality, the ratio of GHG emissions from captured versus diffuse emissions is terrible. The best landfills with a 70 per cent capture rate emit six times more, and diffuse gas as carbon dioxide equivalent than the captured gas. In other words, instead of rewarding landfills today, they should be paying at least six times the amount they receive. At the lower end, with 40 per cent gas capture, the ratio is 20 times more – for every dollar they get today, they should be paying $20. 

We know from overseas experience that residual waste will still produce landfill gas even with the best separation. It is time to move to Energy-from-Waste (EfW). 

Landfills can only beat EfW once they reach at least 95 per cent gas capture many are stuck at about 70 per cent. Therefore, the EfW of residual waste is the only way to improve our carbon emissions. Moreover, the carbon benefits are more considerable due to bottom ash aggregate and metal recycling.

Let’s climb one more ladder to make us winners by 2050. First, we must capture and sequester the carbon dioxide coming from the EfW plants. Then, as about half of this comes from biogenic sources, we turn EfW plants into net carbon sinks. We need carbon sinks to compensate for future emissions from the legacy landfills from yesterday and today producing greenhouse gases for another 50 years and way beyond 2050. 

The second-last ladder to zero carbon waste management is carbon sequestration. The challenge is not the capture but the storage or use. Unfortunately, there are few suitable reservoirs, and the development time is at least a decade. If our political leaders enable carbon sequestration solutions the rest is easy – the technology is around, the business case will stack up, and the investment will follow. 

HZI is starting with Power to Hydrogen with a project in Buchs, Switzerland. The next ladder will include the methanation of the captured carbon dioxide. In the future, we still require methane for some applications such as base chemicals or replacing fossil methane.

The waste sector’s seemingly tiny portion of three per cent GHG contribution will explode to 15 per cent by keeping the status quo. We must face the facts and figures of waste GHG emissions and their causes. We now have the chance to turn the rudder to zero carbon. 

For more information, visit: www.hz-inova.com


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