The debate about coal seam gas drilling in Australia is intensifying, amid calls from The Greens to further investigate its emissions profile.

So what is the emissions profile of coal seam gas? How does it stack up against coal and renewables? We spoke to a US researcher whose study was among the first to raise concerns about emissions. We also asked two Australian researchers to provide different perspectives on the issue.

Renee Santoro is co-author of a study from Cornell University which has been much quoted in discussions about the emissions of natural gas versus coal. That study found that, assuming a 20-year timeframe and using the most up-to-date figures for the global warming potential of methane, natural gas potentially contributes more to climate change than coal does.

The Conversation spoke to Renee about how applicable this study was to Australian conditions. She told us that while their work was conducted on US shale and conventional gas using US geological conditions, for production-to-end-use, emissions should be applicable to CSG: “gas is gas at that point,” she said.

Their figures from the pre-production emissions for gas would not necessarily translate to Australian gas or Australian geology and she encourages an assessment specific to CSG well development and completion; depending on location, fugitives associated with well development could be lower or significantly higher.

The study provided a range of emissions for the transport of the gas, and where Australia falls within that range would depend on the quality of our transmission infrastructure. She noted that some US infrastructure is from very early on and is notoriously leaky, but that their figures represent the US average and thus take into account newer infrastructure from other parts of the country.

Where regulation is stronger, she said, infrastructure and industry practice can be better and emissions can be lower.

Dennis Cooke is Program Manger for Unconventional Resources at the University of Adelaide, and Patrick Hearps is a Researcher at Melbourne University’s Melbourne Energy Institute. We asked them to explain what we know about coal seam gas emissions.

What is the emissions profile of coal seam gas?

Dennis Cooke: It’s lower than coal. Laboratory measurements burning both coal and gas have shown this.

If you look at the total amount of coal burned by eastern Australia, and the type of coal, and if you take the energy demands from that, a switch over to natural gas instead of brown coal will reduce the amount of CO2 generated by about one half.

Patrick Hearps: When natural gas is burned in a combined cycle gas turbine power plant it results in fewer carbon dioxide emissions: roughly half, per unit of electricity, of what black coal produces.

However, electricity production is not the only way that coal seam gas contributes to climate change. Policymakers need to consider the greenhouse gas emissions produced in the full lifecycle — including extraction, transport, processing and compression.

There hasn’t been enough empirical, ground-up research into the full lifecycle emissions from coal seam gas taking into account fugitive emissions from all steps in the chain from reservoir to power plant.

What are fugitive emissions, and how significant are they?

Dennis Cooke: They come from an unintentional leak in the natural gas that comes out of the well in the form of methane. The reason I’m doubtful that they’re as bad as people say is because it’s essentially throwing away money. It would be like having a leaky pipe in your house and allowing it to continue.

Methane is actually more damaging to the atmosphere than CO₂, if you look over a very short time period. It traps more heat, but methane breaks down quickly. CO₂ traps less heat but it sticks around for a long time.

Of course when people burn natural gas, they are not leaking methane into the atmosphere. It’s only leaks in a natural gas pipeline that allow methane to get into the atmosphere. That’s what people are referring to when they talk about fugitive emissions.

I have only seen one published study on fugitive emissions, from Cornell in the US. I’ve heard that study quote fugitive emissions at around 7%. It’s potentially an important issue but it’s a controllable issue.

And fugitive emissions from alternative power sources haven’t been investigated. Of course wind and solar don’t have fugitive emissions, but I suspect there is a huge amount of fugitive emissions from mining coal that are unaccounted for. If they were there would make coal look even worse than it’s currently considered to be.

Patrick Hearps: Fugitive emissions from coal seam gas are significant. Even if only a few percentage points of fugitive emissions across the whole process are released then the supposed benefits of gas will be eroded.

Methane is 25-times worse than CO₂ over a 100-year period. But when its impact is considered over a 20-year period — which is a reasonable timeframe given our proximity to climate change tipping points – the climate change forcing is 72-times greater than carbon dioxide.

Taking into consideration the total life cycle emissions of coal seam gas, particularly methane, its emissions intensity is likely to be a lot closer to coal fired power. Increasing the use of coal seam gas will increase the difficulty of achieving mid- to long-term emissions reduction goals.

Coal also produces fugitive emissions that are sometimes vented and sometimes flared. Such emissions would also need to be considered by national greenhouse accounting.

There hasn’t been enough research. In Australia, it’s standard practice to estimate fugitive emissions based on general factors from the American Petroleum Institute’s Compendium. It could be argued that using these figures is not as impartial or independent as it could be, or that they do not accurately reflect the Australian industry.

Given that we are moving to a future where all emissions must be accounted for to account for the cost, policymakers will need Australia-specific research to guide decision making.

Could problems with fugitive emissions be fixed with better regulation?

Dennis Cooke: I’d hope so.

Patrick Hearps: The onus should be on the CSG industry to prove that fugitive emissions are not a problem. Current regulation does not account for all production emissions, including hydraulic fracturing emissions and migratory emissions due to destabilised ground.

Improved regulation might help deal with part of the CSG fugitive emissions problem. Introducing stringent independent monitoring and assessment to help policymakers find out what’s really going on would be a good start.

There are still a lot of unknowns, especially when it comes to the reservoir extraction side of the process. It is correct to say “the jury is still out” on CSG.

Is it possible to skip “transition fuel” and move to renewables straight away?

Dennis Cooke: Everybody would like to have a future environment where there’s pollution-free energy, and eventually we’ll have to get there. Solar and wind will probably play a large part of that, I suspect nuclear will too. But getting there is a question of price, cost and time. I think that natural gas is an easy first step. A lot of Greens would propose that we bite the bullet and go straight to total renewables now it’s a political, economic, societal debate.

Renewables are a lot more expensive

Before the ETS, natural gas is a little bit more expensive than coal. Using concurrent solar technology that’s being deployed today, natural gas is much cheaper than solar.

The Productivity Commission recently came back with a report studying different energy alternatives in different countries, and it shows that natural gas replacing coal is the most successful path to take. They compared different programs in Germany, North America and Great Britain and the cost in how much CO₂ was removed from the environment and natural gas came out a clear winner.

Patrick Hearps: Renewable baseload energy technologies are now commercially available, the most notable of which is concentrating solar thermal. Other renewables like photovoltaics and wind can work with pumped hydro to provide reliable electricity.

A transitional pathway to a zero-carbon stationary energy sector will require a large-scale deployment to bring the costs of renewable technologies down. Measures that grow the industry as fast as possible will quicken the pace of the transition to renewables. A gas transition will have the effect of delaying the switch to renewable energy.

Corporate giant GE expects photovoltaics to reach grid parity within the decade. If this is realised then investments in gas infrastructure today are at risk of becoming stranded assets. Committing Australia to gas infrastructure rests on the hope that renewables will not be cost competitive in the short- to mid-term and ignores historic and forecast cost reductions.

The joint Melbourne Energy Institute/Beyond Zero Emissions Zero Carbon Australia Stationary Energy Plan shows how Australia can transition to a 100% renewable energy in 10 years.