Videos & Presentations

Managing Mackay’s Landfill Gas Emissions

Sustainability in Public Works Conference
27 – 29 July 2014
Paper 9A

Presentation by Graeme Alford, CEO, LGP


Recognising that their landfill methane is their major source of greenhouse gas emissions to the atmosphere, Mackay Regional Council has commenced a programme for the management of these emissions. The capture of methane created from the breakdown of the waste in landfills and its controlled combustion will be up to 21 times less damaging than letting the gas escape into the atmosphere.

Since commencing their programme, the former Gillard Federal Government introduced the Carbon Pricing Mechanism (CPM) and the Carbon Farming Initiative (CFI). Both of these have had an impact on the management of their active landfill at Hogan’s Pocket. The newly elected Abbott Federal Government is about to bring about further change to the management of carbon in Australia.

Some key factors to consider are:

  • Adopting to CPM and CFI and the journey to destroy the landfill methane at Hogan’s Pocket active landfill.
  • Landfill Gas flow monitoring and reporting requirements.
  • What will the new paradigm mean for the landfill operators.

This paper will cover:

  • The effects of landfills and their emissions on the atmosphere.
  • Insights into government legislation; and
  • Discuss the methodologies and practical solutions for landfill gas capture and destruction, based on the experiences of the Mackay Regional Council
    KEYWORDS: Landfill Gas Emissions, Carbon Pricing Mechanism, Carbon Farming Initiative, Direct Action.

1. Introduction

This paper covers the topic of managing gas emissions from landfills and in particular methane gas from the anaerobic breakdown of organic matter in a landfill and its impact on the environment.

It will look at:

  • Greenhouse gas emissions and their effect on climate change.
  • The use of an engineered landfill gas collection system to manage the methane emissions from a landfill; and
  • An update on the latest Federal Government actions relating to carbon.

It will relate back to work completed at Mackay Regional Council’s (MRC) Hogan’s Pocket landfill, undertaken by Landfill Gas and Power Pty Ltd (LGP) over the past three years.

2. Greenhouse Gases and Climate Change

The earth is coping with a crisis. The effect of technology within the industrialised world has resulted in greenhouse gas (GHG) emission levels that are damaging the earth and threatening our way of life.
Global warming will affect all of us if changes are not made to the amount of carbon dioxide (CO2) being put into the atmosphere.
The amount of CO2 in the atmosphere has now reached 400 parts per million (ppm) or 33% above the previously highest recorded level of 300ppm. During the past 650,000 years, measured from ice core samples, the CO2 concentration has ranged between 180 and 300ppm.
The concentration is now increasing at a rate greater 20ppm per decade. It was 380ppm some six years ago.
Temperature projections indicate an increase of 0.5 and 1.5oC by 2030 and between 1 and 5oC by 2070. Some experts say a change greater than 2oC is irreversible.
What are the GHGs? We always talk about CO2, but there are six main gases which are recognised by the IPCC as contributing to the greenhouse effect and global warming,

These being:

  • Carbon Dioxide (CO2)
  • Methane (CH4)
  • Nitrous Oxide (N2O)
  • Hydroflurocarbons (HFCs)
  • Perflurocarbons (PFCs) and
  • Sulphur hexaflouride (SF6)

The two main gases from the breakdown of organic waste in landfills are CO2 and CH4.

According to the IPCC Methane to Markets Landfill Subcommittee, landfills are the third largest source of methane emissions.
What is causing the problem?
The earth is becoming more populated and more urbanised and our demands for energy are increasing at an alarming rate, although they have abated a little in recent years resulting from the global financial crisis (GFC). Our world population has doubled in the past 50 years to be now over 7 billion people.
We are still experiencing the problems from the emissions discharged into the atmosphere back in 1974. Likewise our present emissions will be felt up to 2054. Scary thought. And there will probably be 10 billion people by then.
What is Australia’s carbon footprint in a global context?
Our portion of the greenhouse gas emissions is less than 1.5% of the total for the globe, yet we have one of the highest rates per capita at about 20 tonnes per person, which is more than double the rate in Japan and over three times the rate in China.
Total Australian CO2 emissions in 2012 were 552Mt. The decrease over the recent years is due to the GFC and lesser stationary electricity generation, which contributes the majority of emissions.
Waste contributed 3% to these emissions or up to 8% if the embedded energy in creating the waste products is taken into account of the total emissions.
The capture of methane created from the breakdown of the rubbish in our landfills and its controlled burning will be up to 21 times less damaging than letting the gas escape into the atmosphere. The Federal Government is increasing the rate to 25 times in 2017 in terms of the threshold calculations.
The MRC embarked on a programme of undertaking gas monitoring works at five of its landfills, including the active Hogan’s Pocket site, the closed Bayersville landfill and three small landfills located near towns outside of Mackay to determine their methane emissions.
This paper will relate to the landfill gas infrastructure works already completed and proposed at their Hogan’s Pocket landfill.

3. Engineered Landfill Gas Collection Systems

There are several key elements to an engineered landfill gas recovery and utilisation system:

The well-field to collect the gas from the landfill. Mackay engaged LGP to installed wells into the closed and capped Cell 1 at Hogan’s Pocket;
Gas pre-treatment plant to process the gas for combustion;
The power station to generate the electricity by the burning of the methane, where sufficient gas flows exist. The next step to renewable electricity generation at Hogan’s Pocket is subject to gas flow verification, with this work expected to be completed in 2015;
Connection to the grid to export the electricity generated; and
Flare to destroy any gas not combusted in the engines. Presently installed and operating at Mackay.
The engineered landfill gas capture system works silently in the background operating under a vacuum to draw the gas out of the landfill.
Post closure of the landfill and individual cells as landfilling progresses, vertical wells are installed. With the current active cell, in conjunction with the landfill operator, it is possible to install a combination of sacrificial horizontal and vertical wells as the landfilling progresses to immediately maximise the gas collection and destruction of the methane from the site as it progresses. LGP are about to embark on the next installation of such wells at Hogan’s Pocket into the active Cell 2 landfilling operations.
A gas pre-treatment plant, where electricity generation is proposed, prepares the gas for combustion in the engines built for landfill gas. Inside a landfill, it is usually about 50oC when anaerobic processes are taking place. The gas has to be cooled and cleaned before injecting into the engines for combustion.
In short, the gas must meet the engines manufacturer’s specifications to ensure maximum operational life from the engines.
Where electricity generation is proposed, the electrical equipment, including the grid connection is installed by qualified tradesmen to the required local grid standards. The cost of a typical grid connection for electricity export is upwards of $0.5 million, although it depends on the existing grid infrastructure. At Mackay, due to the distances involved, the grid upgrade costs will be considerably more.

A flare is required to destroy the landfill methane under the following circumstances:

  • When the gas is not being used for electricity generation in the short term whilst the generation equipment is not operating
  • When there is an excess of gas extracted from the landfill beyond what is being used for electricity generation; or
  • When there is no generation equipment installed at the site. As mentioned, at Mackay, LGP has installed the flare and we are currently monitoring gas flows prior to reporting on whether sufficient gas exists to support commercial electricity production.

Power stations and flares can be monitored from a remote central location and thus the stations can be down the street, across the country or even overseas. With Mackay, we monitor the gas destruction from our Belmont, WA Operations Centre.
It is possible to diagnose a problem from a remote location, address the problem and to re-start the engine or flare from your computer, and in recent years, from the mobile telephone, without even visiting the site. This is the position for all of LGP’s installations including the flare at Mackay.
On site personnel are required to attend to active well field monitoring and undertake routine maintenance works.

4. Landfill Gas Modelling

This following Graph 1 shows the typical landfill gas production over the life cycle of a landfill.

Landfill Gas Emission Profile Graph

Landfill Gas Emission Profile Graph

Graph 1: Atypical Emissions Profile

The emissions threshold for liable landfill operators for the Carbon Pricing Mechanism (CPM) is above 25 Kilo-Tonne of CO2 equivalent (25kTCO2e) per annum in any given year.
In this atypical case the landfill closed before 2012 and thus all emissions will be legacy, being from waste placed prior to 30 June 2012. If this site was still open then it would exceed the carbon tax threshold and permits would have to be purchased.
In the case of Mackay, as their landfill has many years to operate, they are presently on the upward trending part of the gas curve with gas production to steadily increase as further waste is deposited over coming years.

5. Federal Government Action

5.1 Renewable Energy Target

In 2000, the Howard Federal Government set targets under the Mandatory Renewable Energy Target (MRET) through until 2020 for electricity generated from renewable sources, which included landfill methane.
The MRET targets were increased by the Rudd Government and became the RET. Renewable energy production was projected to move from 300GWh in 2000 to 9,500GWh in 2010 under MRET to 45,000GWh in 2020 under RET.
The Abbot Government is presently undertaking a review of the RET. We await release of the Energy White Paper, in September 2014, which will contain input from the RET Review Panel, which conducted hearings in May/June 2014 and accepted submissions.

5.2 Existing Carbon Pricing

In 2011, the Gillard Government passed the Clean Energy Act putting a price on carbon emissions from 1 July 2012. The CPM changes to an Emissions Trading Scheme (ETS) in 2015 and has been linked to the European Union (EU) ETS.
As mentioned above, where a landfill facility has more than 25kT CO2e emissions per annum, then permits are to be purchased for emissions on waste deposited post 1 July 2012.
“Legacy” wastes are excluded from direct permit liability but NOT from threshold calculations as to whether the landfill will be included. Permits are purchased on the new waste emissions when emissions exceed 25kT CO2e per annum.
Although not disclosed by Mackay, LGP would expect the methane presently being destroyed by the flare would be sufficient to bring their total discharge below the threshold and thereby avoid the need to purchase permits.
The Gillard Government also provided a carrot in the form of the Carbon Farming Initiative (CFI), with the methodology for landfills already in place and many projects already approved.
Carbon credits, representing the abatement of GHGs, being the destruction of landfill methane in this case, are created for approved projects. Once created, they can be sold in the carbon market.
Carbon credits will generally be used to offset statutory permit requirements, but may also be purchased and used by individuals or companies to voluntarily cancel out or ‘offset’ the emissions they generate during their day-to-day life or normal course of business, for example, by consuming electricity or catching a plane.
With CFI, a number of integrity principles apply, with the key ones being:

Additionality. The project baseline is the methane that would have been emitted from the landfill in the absence of the project.

  • Where no regulatory requirements to capture and destroy methane emissions prior to project commencement, this is equivalent to the methane emissions from the landfill.
  • Where there were regulatory requirements to capture and destroy methane emissions prior to project commencement, this is equivalent to the methane emissions from the landfill minus the methane captured and destroyed to meet regulatory requirements. This is represented by the Rp factor in the formulae.

The abatement calculation does not require an estimation of baseline fugitive methane emissions from the landfill, but it does require an estimation of the amount of methane captured and destroyed to meet existing regulatory requirements for the landfill. This estimate is based on relevant landfill gas management regulations at the beginning of the crediting period.

Other integrity principles include:

  • The landfill gas infrastructure must be permanent for the life of landfill methane emissions and have been substantially installed after 1 July 2007; and
  • The emissions destroyed must be measured to enable reporting and their verification to international standards.

Mackay is registering as a CFI project and will receive income from the methane destroyed from waste deposit prior to July 2012.

5.3 Proposed Carbon Pricing

With the election of the Abbott Government in September 2013, we are seeing a change of direction with the management of carbon.
Already a number of actions have been taken to wind-back existing carbon and climate change programmes. The abolition of the CPM and replacing it with the Direct Action Plan is the next item on their agenda.
The Abbott Government in delivering the 2015 Budget in May 2014, confirmed $2.55 billion of funding, over 10 years, for their central climate mechanism, the Emissions Reduction Fund (ERF).
The original Direct Action Plan proposed by the Abbott Government comprises a ‘baseline and credit’ scheme.
The Emissions Reduction Fund Green Paper proposes a subtle re-design via the creation of a secondary market for abatement units, a strict definition of ‘additionality’ and the potential application of ‘absolute’ emissions baselines.
At the time of writing, this legislation is yet to pass the Federal Parliament.

6. Conclusion

Total Australian CO2 emissions in 2012 were 552Mt with 3% from waste or about 8% if embedded energy in the waste products is considered.
The IPCC Methane to Markets Landfill Subcommittee, states that landfills are the third largest source of methane emissions.
The capture of methane created from the breakdown of the organic matter in our landfills and its controlled combustion is at least 21 times less damaging than letting the gas escape into the atmosphere.
The current carbon policy and action plans are presently in a state of flux with the Abbott Government’s changed direction and at the time of writing we await the form of the changes once legislated.
As well, landfill operators may be able to generate tradable carbon credits from the destruction of legacy landfill methane under CFI to offset part of the cost of the engineered landfill gas management infrastructure installed for this purpose.
Mackay Regional Council has taken the proactive step of installing landfill gas management infrastructure to manage its methane emissions and may in the future be able to generate renewable electricity, subject to gas flow verification.
The support of Jason Grandcourt, Manager Waste Services and his team at Mackay Regional Council, is greatly appreciated and acknowledged.