A Southern Star Oil rig platform in Taranaki. Photo: Supplied
New data from a project New Zealand is involved in shows the United States oil and gas industry is releasing much more of the potent greenhouse gas methane than official estimates show.
Campaigners says the figures show using gas in factories and home appliances is no better for the climate than using coal, meaning using gas to transition off coal "makes no sense".
But the New Zealand oil and gas industry says it is much better regulated than the industry in parts of America, and rogue emissions are less likely here.
The Ministry for Business, Innovation and Employment says New Zealand's way of reporting methane emissions from oil and gas production errs on the side of caution, and is less likely to underestimate than the US system.
However, the researchers behind the US measurements say there's no way of knowing whether we are missing emissions without getting measurements from the air.
Those measurements may come from a methane-detecting satellite which New Zealand has helped to fund, but not for a few years yet, according to those involved in the project.
Planes and satellites
The US findings come from MethaneAIR, which mounted sensors on planes flying over the United States and took readings over the majority of oil and gas fields.
The project was a test run for MethaneSAT, a satellite project partly funded by the New Zealand government, which is currently taking readings over much larger areas of the planet. It aims to cover 80 per cent of global oil and gas production within its first year in orbit.
Harvard University Professor Steven Wofsy, who is involved in both methane projects, says the average loss rate of 1.6 per cent of methane from US oil and gas fields is four times higher than reported in the US national greenhouse gas inventory and eight times higher than the industry's target of 0.2 per cent losses.
The escaped gas wasn't all from accidental pipe leaks; some seemed to be from oil and gas well maintenance or deliberate releases, said Professor Wofsy.
Older fields, smaller operators and fields whose primary purpose was producing oil, not gas, tended to perform worse.
"A lot of these aren't leaks, a lot of these are operational," said Wofsy.
"These are things that people are actually doing. When that happens in the field, the companies don't really know how much methane is being emitted, they're not measuring it," he said.
"These activities are estimated according to a spreadsheet and it's pretty clear that the spreadsheet is underestimating."
Senior Harvard scientist Maryann Sargent, who also works on MethaneAIR and MethaneSAT, says studies consistently find that measurements over gas fields reveal more methane emissions than are being officially reported, for a whole host of reasons. She says scientists only partly understand the drivers.
"The true losses that we can see in the atmosphere are much higher," says Dr Sargent.
"One thing is that you have wells of different ages, so when you first tap the well it is producing a lot of gas and then later in its life it might be producing a lot less gas but leaking the same amount, so that fractional loss rate gets higher."
"They just don't know"
New Zealand's gas fields are nearing the end of their lives, leading to faster-than-expected gas shortage and a conundrum for many gas users about where to go for energy.
The the oil and gas industry here says it is much better regulated than some parts of the United States, and will have less rogue emissions.
John Carnegie of Energy Resources Aotearoa says he's confident methane leakage is far less likely in New Zealand because the "vastly lower" number of wells here have rigorous monitoring, robust regulations and companies must pay for their methane leakage together with their other gases under the Emissions Trading Scheme.
The Ministry for Business Innovation and Employment says official loss estimates for New Zealand's oil and gas production err on the higher side compared with the US, so are less likely to under-report.
Routine emissions from oil and gas production are estimated using a spreadsheet method, while gas field operators self-report their deliberate venting and flaring of methane, says the ministry.
Economist Suzi Kerr of the non-profit Environmental Defense Fund (EDF), which runs MethaneAIR and MethaneSAT, says there's no way to know if we are missing any methane emissions without measurements from the air.
"They just don't know, that's kind of the point," she said.
"The reason EDF did all this work is that you just don't know. There are sources we didn't even consider or didn't know how big they were, but we'd done studies in dozens of countries around the word before MethaneAIR that had shown this under reporting systematically."
The Government is looking to increase New Zealand's gas supply to lower the country's planet-heating emissions, on the basis that gas produces less planetary heating than coal, for the same amount of energy.
Huntly power station, for example, burns more coal when gas is hard to come by and hydro lake levels are low.
But Kerr says the research shows that using more gas does not add up as a climate solution.
"That argument does not stack up at all in New Zealand. The comparison in New Zealand is not between coal and gas, it's between gas and renewables. We don't need to use coal any more in New Zealand. I know there are some industrial uses, like dairying, that still use it, but they can go directly to electric." (Kerr acknowledged that gas would be needed for electricity production for a while yet).
350 Aotearoa climate campaigner Adam Currie cited research out of several US universities, including Brown and Harvard, which found that if just 0.2 percent of methane gas leaks during production, gas heats the planet as much as coal.
"We don't just have to worry about the gas we are burning, we have to worry about the gas that's leaked in the process of getting it from the ground to where it's used," says Currie.
Currently there's no equivalent to MethaneAIR looking at oil and gas fields in New Zealand, so Kerr and her colleagues don't have any data on New Zealand fugitive emissions.
NIWA's Alex Geddes, a scientist working on New Zealand's contribution to MethaneSAT, says the satellite will look at offshore Taranaki but it won't be the first thing it does.
MethaneSAT's first focus in this country will be zooming in on parts of New Zealand with a high concentration of dairy cow burps, starting with Waikato.
"The [gas producing] Taranaki region is one of our other targets, it's in our big target deck for the future of the mission, but for New Zealand initially we want to do an agricultural-focussed campaign and the Waikato is the perfect place to do that," says Geddes.
Geddes has been out in the fields placing sensors at ground level in dairying areas of Waikato, so that NIWA scientists can cross-check their readings with readings from the satellite.
Both the satellite and on-the-ground readings will also be cross-checked against methane estimates for agriculture from the New Zealand government, which are considered strong compared with most government estimates.
The first results from MethaneSAT were originally going to be published in mid-2024, but the Harvard scientists say it will now be early 2025 before the first findings are released.
Wofsy says the scientists want multiple readings from each location before releasing their results.