Energy Generation - Landfill Gas: 2011

What is landfill gas?

Landfill is a type of biomass; biological material used as a renewable energy source. It usually comes from waste plant and animal matter. When they decompose, they produce a mixture of methane and carbon dioxide, both greenhouse gases. This mixture is known as ‘landfill gas’.

These green house gases escape into the atmosphere if not collected. Landfill gas is a valuable resource and can be extracted. It can be used as a clean and safe energy source to produce electricity or heat.

How environmentally damaging is methane?

Methane, an odourless and colourless gas, is lighter than air and is 21 times stronger than carbon dioxide. Carbon dioxide is known as the greatest contributor to climate change, and methane is only second to carbon dioxide. Methane can create explosions if there is 5-15% of it in the air; it can also become flammable if the percentage increases from 15%.

When there is too much methane in the air, there is not enough oxygen, causing a problem for people because they can't breathe.

What are its environmental impacts?

A large number of environmental impacts may occur due to the landfill operations. There can be accidents where scavengers get buried under waste piles, pollution, release of methane and carbon dioxide, and harbouring of diseases by rats or flies.

As landfill sites must be licensed by Environmental Protection Agency (EPA), they won't cause pollution if operated correctly. Special training is required for the correct operation and management of these sites.

Where can landfill sites be located or developed?

Landfill sites can be located where local authorities and industries take their waste to be buried and compacted with others. They are also permitted to be located at remote sites, with the use of 'rail-haul' permits.

There are quite a few landfill sites in Melbourne, and a nine are currently developing. There is a total of 133 plants currently operating in Australia and there are 25 in Melbourne alone.

How sustainable is it?

Landfill gas is sustainable as long as it is extracted at a reasonably consistent flow and quality, so as to not decrease the landfill available. This is achieved by the process used to extract landfill gas.

How is landfill gas extracted?

Landfill gases are extracted at gas extraction and power generation facilities. A blower is used to extract the gas from the landfill sites into the extraction system. It goes through an set of wells interconnected by a network of buried pipes. The landfill gas is extracted and combusted to generate electricity.

What are the advantages & disadvantages of landfill power?

'Green' energy source	Advantages	Disadvantages
Landfill Gas	• Needed to reduce methane gas emissions • Efficient use of waste products • Positive extraction prevents soil infiltration, preserves vegetation • Clean, visually and audibly unobtrusive sites • Makes electricity, heat and fuels • People willing to pay for 'green energy' (e.g. organic food)	• Recycling reduces landfill available • Generation site must relocate when gas is exhausted • Much larger volumes of landfill are required for the same amount of electricity produced by fossil fuels

What are the different companies involved in extracting landfill gas?

In Australia the companies involved in extracting landfill gas include AGL, Landfill Gas & Power (LGP), LMS Energy and Energy Development Ltd.

AGL owns and operates several landfill gas and biogas generation facilities across Australia. They also help reduce greenhouse gases by capturing and destroying methane.

Landfill Gas & Power (LGP) owns power stations in Perth, Western Australia, Canning Vale & Tamala Park; they also have 18 years of experience from the waste industry to energy industry. Not only does LGP design, construct and operate power stations with local partners, they also provide Design & Project Management services. LGP can troubleshoot power stations not performing up to the standard, and provide landfill gas capability assessment services.

LMS Energy has been involved in over 20 years of landfill gas projects. They have an international reputation for delivering effective, innovative solutions in the extraction and combustion of landfill gas. Their main focus is the development of high quality gas systems and combustion facilities. The correct landfill design and installation can lead to long-term solutions for landfill gas management. LMS Energy can deliver quality gas recovery systems and ensure gas resources are effectively managed.

Energy Development Ltd has many landfill gas projects in Australia, the United Kingdom, Europe and the United States of America. They are the world leader in landfill gas power generation, and they are the largest operator of landfill gas power generation in Australia.

What are the advantages and disadvantages of other ‘green energy’ sources?

'Green' energy sources	Advantages	Disadvantages
Wind	• Free • Renewable • No dangerous emissions • Can be used in remote areas • Can be used with other renewable energy sources	• Needs a reliable source of wind • Wind speed can change • Noisy and visually unappealing • Turbines expensive to maintain • Energy storage devices (batteries) are necessary
Hydro-electric	• Renewable • One of the most efficient energy sources (kinetic energy of water converted to electrical energy) • No dangerous emissions • No fuel is needed • Less expensive to run compared to other sources • Energy can be gathered straight away (other generation stations take hours to start) • Electricity can be stored for later use • Hydroelectric plants only need a turbine and generator	• Construction is expensive • Site specific ( you can’t build wherever you want) • Hydroelectric plants have a negative effect on environment (areas are flooded, habitats are lost, people lose their land)
Solar	• Sunlight is free • Renewable • Climate suitable for solar energy • No dangerous emissions • Converts sunlight directly to electrical energy • Can provide energy to remote areas	• Solar cells can impact on the environment • Energy must be stored in batteries • Thermal solar systems are expensive • Takes up a large area • Dust, smoke and weather conditions affect performance of energy collectors
Tidal	• No dangerous emissions • Renewable • Provides secondary benefits (bridges and roads built over tidal generators)	• Facilities are expensive to construct • Can raise tidal levels • Changes the sedimentation and turbidity (how clear it is) of the water system • Can flood shoreline (affects marine population)
Geothermal	• renewable • produces no greenhouse gases • limited land necessary for mining structures • limited impact on landscape	• sites can run out of heat for significant periods of time • difficult to safely dispose of hazardous minerals that are produced • difficult to find and use suitable reserves of geothermal energy

Summary

As there are growing concerns regarding Australia's 'green' energy sources, the production of a facility of an alternative energy source has been proposed. Despite the few flaws still currently present, with time and investments landfill gas will become one of Australia's main 'green' energy source. No urging should be needed to accept this proposal for an increase of gas extraction & power generation facilities.

Reflection

Whilst creating this submission, there were few difficulties encountered. One difficulty concerned the sustainability of landfill gas in Australia. This problem was solved when discussed among others and researched once more. Another problem regarded the locations of landfill sites; it was difficult to find information showing where those sites were. This problem was solved after searching for a while, and finding a renewable energy map.