New research: natural gas will cook the planet

If there were an Olympics for climate amorality, Australia’s capitalists would be hauling in the medals.

Just consider this quote from Queensland coal baron Clive Palmer in the December 15 Australian: “The Galilee Basin overall has got 100 billion tonnes of thermal coal, so it’s a great reservoir for Queensland in the future, so you’d be crazy not to develop it.”

And it’s not just coal, but any greenhouse-polluting fuel that can be can be dug or drilled from the landscape or seabed. Take Australia’s natural gas industry, poised now for a vast expansion.

More than a dozen liquefied natural gas projects, The Australian said on March 10, are under construction or proposed, representing more than $200 billion of investment.

Woodside Petroleum chief executive Don Voelte, quoted in the same article, said Australia is ready to emerge as a “global superpower” of the liquefied natural gas (LNG) industry, leapfrogging key rivals.

“Within five years,” federal resources and energy Minister Martin Ferguson crowed to Channel 9 News on February 28, “we expect to climb further up the ladder with exports exceeding 50 million tonnes … only Qatar will be exporting more.”

The Australian Bureau of Agricultural and Resource Economics (ABARE), last year predicted that Australia’s natural gas production would quadruple by 2030.

Clean and Green?

But why, you might ask, should natural gas be a problem? After all, we’re told it’s clean and green. When we extract and export it, aren’t we doing the climate a favour?

Compared with coal, natural gas (which in its refined form is almost all methane) undoubtedly burns cleanly.

Unlike coal, it contains no toxic mercury, arsenic or other heavy metals. There is no radioactive uranium or radium.

Per unit of energy, burning natural gas releases less than a third of the nitrogen oxides that result from coal combustion, about 1% of the sulphur dioxide, and next to no fine particles such as soot.

True, natural gas is a fossil fuel, and when burnt adds heat-trapping carbon dioxide (CO₂) to the atmosphere. But compared with coal, the quantities are modest.

Mark Diesendorf, in his book Greenhouse Solutions with Sustainable Energy, says producing a megawatt-hour of electricity in the most modern gas-fired power plants results in the direct release of less than 400 kilograms of CO₂, compared with about 800 kilograms for an up-to-date plant burning black coal.

So if coal-fired plants are shut down, and new gas-fired ones built in their place, aren’t we on a winner?

The trouble here is that even at half the emissions intensity of coal, gas-fired power would still cook the Earth, just taking a while longer to do it.

Leading US climate scientist James Hansen explains that preserving a planet similar to the one on which civilisation developed will require ending all net greenhouse emissions by about mid-century.

But might new natural gas power plants still serve as an energy bridge, a transitional measure keeping emissions down until genuinely clean renewable energy can be introduced?

This was suggested in the 2009 Commonwealth Senate Inquiry into Australia’s greenhouse future. Anyone who urges this course, though, should prepare for the mother of all political battles against gas industry investors.

Beyond Zero Emissions’ Matthew Wright said in a March 8 post to the Grassroots Climate Oz email list: “To those who think we’ll build gas plants and run them for 10-20 years a modern gas plant … is a very efficiently manufactured piece of machinery. With proper operations and maintenance practice it should last for 60-plus years.

“Even if the bank loan is paid off after 15 years, you have some company … sitting on an asset that if it was built from scratch would cost say $2 billion. This company … would be happy to spend $100 million in order to defend that asset.”

The gas that gets away

The essential problem, though, lies elsewhere.

To be burnt in a power station, natural gas has first to be extracted and transported. If this broader picture is considered, natural gas ceases to be particularly “clean” in greenhouse terms even when compared with coal. In fact, it can be downright filthy.

The trouble is the gas that gets away, leaking into the atmosphere without being burnt.

Methane in the atmosphere readily oxidises into CO₂, and after 20 years is almost all gone. But as long as it lasts, it is very effective at trapping heat.

Over a twenty-year period, the United Nations Intergovernmental Panel on Climate Change has reported, releases of methane warm the atmosphere at 72 times the rate of CO₂.

And that’s not all: research at NASA’s Goddard Institute for Space Studies, published in October 2009 in the journal Science, shows that methane in the atmosphere holds back the formation of sulphate aerosol particles that would otherwise reflect heat back into space.

Add in this effect, and the 20-year global warming potential of methane comes to about 105 times that of CO₂.



Still, what’s so dangerous about a gas that vanishes from the atmosphere after 20 years, when CO₂ keeps warming the Earth for centuries?

The problem is that the fate of our climate will not be decided over centuries, but within the next few decades.

Current warming is pressing hard against “tipping points” which, if crossed, would cause a huge release of carbon now locked away in forms such as tropical forests or Arctic peat.

A further big slug of hyper-warming methane could push global temperatures past the point where these natural “carbon sinks” would give way, and vast amounts of greenhouse gases, including methane, would flood into the atmosphere.

Leakage

Environmentalists have known for decades that leakage of natural gas from distribution systems can be very large.

A 1990 Earth Resources Research report estimated that from 5.3% to 10.8% of the gas flowing through Britain’s system was lost, mainly from pre-1950s cast-iron pipes.

In the US, industry spokespeople nevertheless continued to insist that the problem was trivial, citing figures for leakage as low as a few tenths of 1%.

Then Robert Howarth, a professor of ecology at Cornell University in the US, began collecting evidence. Before long he had established that leakage was much greater than had been made out.

With new technology allowing a rapid spread in the drilling of gas-bearing shale rocks in the US, the amounts of methane lost from wells and pipes could only multiply.

Howarth’s initial estimate put real leakage in the US gas industry at about 1.5% of the total gas consumed.

Burning natural gas for electricity adds about 400 kilograms of CO₂ a megawatt-hour to the atmosphere. Howarth’s research implied the carbon footprint of natural gas was close to double this level over a 20-year period.

Recognising that the problem was urgent, Howarth took the unusual step, in April 2010, of releasing his preliminary findings rather than waiting for peer review and journal publication.

In a striking new model of scientific research, the problem of natural gas leakage came to be explored collaboratively via the internet.

People with hands-on experience of gas infrastructure contributed their insights. Even the estimate of 1.5% leakage, it became clear, was too low.

Meanwhile, others pointed out that the comparison with coal was not simple — coalmines emit methane too.

In November 2010, the US Environmental Protection Agency (EPA) released data that firmly debunked earlier low estimates of leakage in the US gas industry.

Crunching the new numbers, analyst David Lewis on the Energy Collective website came up with a most likely figure for the losses of about 3.2%.

Carbon footprints

As indicated by the EPA’s data, leakage occurs all along the chain of natural gas production, processing and distribution.

By far the worst losses are at the production end, either as an unavoidable accompaniment to gas drilling or from sloppy industry practice.

In January 2011, Howarth published an update of his work, with its focus on the booming area of US shale-gas production.

He concluded that about 3.6% to 7.9% of the methane from the shale-gas industry “escapes to the atmosphere in venting and leaks”. For gas from conventional wells, he put leakage at 2.8% to 3.8%.

If we assume 3.2% leakage, where does this put the “carbon footprint” of electricity from conventional natural gas?

Using the global warming potential figure for methane of 72 times CO₂ over 20 years, the footprint becomes 1322 kilograms of Co₂ equivalent per megawatt-hour.

If we use the more recent global warming potential figure of 105 times, the footprint is 1744 kilograms.

To this should be added the indirect emissions from sources such as diesel fuel for the rigs and trucks, and from the production of equipment and gas infrastructure.

Howarth estimates these indirect emissions are at least one-third of the 400-odd kilograms of CO₂ emitted from burning natural gas alone.

The total natural gas footprint then reaches a figure close to 1900 kilograms a megawatt-hour.

In his January update, Howarth provides his own “footprint” calculations for a range of fossil fuels, expressed in grams of carbon (as CO₂ equivalent) per million joules (MJ) of energy over a 20-year period.

His figure for the footprint of conventional gas is 25-50 grams of carbon per MJ; for surface-mined coal, 27; for deep-mined coal, 32; and for shale gas, 35-62.

This indicates that the climate change impact of gas from conventional wells is, at best, roughly similar to black coal. Most likely, is a good deal worse.

Shale gas, meanwhile, is a greenhouse monstrosity. “Compared to coal,” Howarth says, “the footprint of shale gas is 1.3 to 2.1-fold greater on the 20-year time frame.”

Here, Howarth uses the figure for the global warming potential of methane of 72 times carbon dioxide. But if NASA’s figure of 105 proves more accurate, the message for the shale gas industry will be still more daunting.

Coal seam gas

Australia has abundant gas shales, mainly in the Great Artesian Basin. But these are unlikely to be exploited soon, since most resource economists say exploiting the country’s vast reserves of coal-seam gas will yield greater profits.

Coal-seam gas is planned as the basis for a huge new LNG export hub at the port of Gladstone in Queensland.

Extracting coal-seam gas involves sinking bores into coal deposits and pumping out the groundwater they contain. Gas from the pores and fissures of the coal can then be drawn off.

No figures seem to have been gathered for gas leakage from coal-seam wells, but there are reasons to think the rate is similar to the 3.6% to 7.9% calculated by Howarth for shale gas.

As with shale gas, extracting coal-seam gas requires wells to be sunk in mind-bending numbers — a projected 30,000 in Queensland alone.

Gas is routinely vented during drilling operations, and accidental leakage is inevitable from the vast array of pipelines and wellhead installations.

Coal seam gas production also requires using large amounts of energy to pump water.

Liquefying gas for export consumes about 20% of its energy content, so the emissions footprint of electricity from coal-seam LNG could well reach the staggering sum of more than two tonnes of CO₂ equivalent per megawatt-hour.

We may conclude that Australian capitalism’s gift of “clean” natural gas to the world energy market will be just like Australia’s coal exports — a huge dose of poison for the global environment and for the human civilisation that depends on it.

Phasing out gas?

If climate catastrophe is to be avoided, the boom in natural gas drilling will have to cease. Does this also imply the phasing out of existing gas use?

As has been seen, most of the leakage from the natural gas industry occurs during the production phase. The worst of these losses are associated with drilling and equipment installation.

Once infrastructure is operating, losses are much less, and they can be cut further if pipelines are upgraded and maintenance is rigorous.

In theory, this would suggest that gas from existing wells might serve as a legitimate transition fuel for electricity generation.

Relatively small gas-turbine generating plants can provide a back up for wind and solar energy, smoothing out their irregular nature. From a standstill, gas-turbine generating equipment can be brought into full operation in less than 30 minutes.

But as Beyond Zero Emissions explains, molten-salt heat storage facilities attached to concentrating solar thermal power plants can serve this function better, and do not emit greenhouse gases.

Facilities of this type are already operating in Spain, and the technology is expected to become fully commercial in the next few years.

Much better than looking to the gas industry, Howarth argues, would be to move rapidly toward an economy based on renewable energy.

Recent studies, he notes, “indicate the US and the world could rely 100% on such green energy sources within 20 years if we dedicate ourselves to that course”.

It is to renewables, not gas or other fossil fuels, that the billions of dollars now slated for energy investment in Australia should be directed.