Methane matters: the science and the challenges

Last edited: 24 September 2018

As member companies of the Oil and Gas Climate Initiative announce collective action on methane, we look at why targeting this powerful greenhouse gas is a vital step towards a low-emissions future.

What is methane and how does it relate to natural gas?

It’s a gas whose molecules are made up of one atom of carbon and four atoms of hydrogen and it is the main component of natural gas. Natural gas is the fastest-growing hydrocarbon fuel and one that plays a part in reducing greenhouse gas emissions.

How can natural gas reduce emissions if it also creates them?

Because it can be substituted for coal and much less carbon dioxide is then emitted when it is burned. If gas is used to replace coal in power stations, the emissions will typically be halved – which has helped drive US emissions down to 1990s levels. It’s also a flexible, economical source of heat and, in liquid form or as a compressed gas, it can be used as a transport fuel. Only around 20% of all energy-related carbon dioxide emissions come from natural gas.

Methane molecules consist of carbon and hydrogen, with the formula CH4

So gas is viewed as a good thing but methane as a bad thing. Why is that, when they are basically the same thing?

Gas is a good thing when it is produced, distributed and consumed without reaching the atmosphere first. However, methane – the main component of natural gas – is understood to have a higher global warming potential than carbon dioxide if it finds its way into the atmosphere before it’s burned. That potential is estimated to be at least 25 times that of carbon dioxide over 100 years.

So, while there is far less methane in the atmosphere than carbon dioxide, it accounts for around one-fifth of man-made global greenhouse emissions on a like-for-like basis.

Methane has a shorter lifetime in the atmosphere than carbon dioxide, so its impact as a greenhouse gas is shorter-lived.

But, stopping leaks is important to avoid adding to future levels of greenhouse gases and maximise the emissions-lowering potential of gas as an alternative to coal.

Does all methane come from the energy industry?

No. Methane is released in many ways. Some comes from natural sources such as wetlands, freshwater and volcanoes while up to three-fifths are estimated to come from human activity. Of that proportion, around two-fifths are thought to come from agriculture and around one-fifth from oil and gas production. Methane is emitted in the energy industry when gas is vented or flared – which was once routine but is now increasingly avoided – or when it escapes from pipes or equipment, as so-called ‘fugitive’ emissions. BP is supporting Princeton University’s work to improve scientific understanding of methane.

Potential sources of methane emissions across the gas supply chain

So what is the industry doing to crack down on emissions?

A lot of the ground work is simply to create better kit to detect and measure methane emissions. For example, the Oil & Gas Climate Initiative, of which BP is a founder member, has launched an independent study to measure and compare methane emissions in global gas supply chains. It is also looking at new technologies to tackle emissions.

Moreover, the World Bank has led a campaign for zero routine flaring of gas by 2030, which BP and others support. And eight companies, including BP, signed a set of principles for tackling methane challenges in November 2017.

What is BP's methane intensity target?

Methane 'intensity' refers to the amount of methane emissions from BP’s operations where gas goes to market, expressed as a percentage of that gas. BP is targeting a methane intensity of 0.2%, and holding it below 0.3%.

The Oil and Gas Climate Initiative (OGCI) companies (which includes BP) has set a target to reduce by 2025 the collective average methane intensity of its aggregated upstream gas and oil operations by one fifth to below 0.25%, with the ambition to achieve 0.20%, corresponding to a reduction by one third.

How will BP's target be pursued?

There is a lot going on, from upgrades in mature production fields to new designs and technologies in new fields. One huge area of focus is BP’s onshore gas production in the United States – other than Alaska – what’s called the Lower 48. The business pioneered a technique there known as ‘green completions’, which captures gas that would otherwise be flared or vented as wells are completed. Pneumatic controllers that bleed some gas as part of normal operations are being upgraded with versions that allow less methane into the atmosphere.

In production, BP is increasingly using long horizontal wells which avoid multiple vertical ones; fewer well pads, less associated piping and other equipment reduce the potential for leaks. It is also trialling pumps powered by solar energy rather than gas.

What about newer projects?

In newer projects, it’s possible to ‘design out' methane emissions. In the Khazzan giant field in Oman, for example, where there are hundreds of wells, instead of having multiple well-heads or clusters of equipment for each well, the gas is fed by pipe to a central processing facility. This dramatically cuts down the number of locations and pieces of equipment where leaks could occur.

View from a climate scientist

Professor Steve Pacala from Princeton University is a leading climate scientist and co-director of the Carbon Mitigation Initiative, a partnership established between BP and Princeton nearly 20 years ago. He gave his personal view to BP Magazine:

“When I first heard BP's 0.2% methane intensity target, it really grabbed my attention. As a scientist I've looked at a lot of data on methane emissions from oil and gas infrastructure and the average across all companies is more than ten times higher than that 0.2%. 

If the industry as a whole were to adopt BP's target then methane emissions from oil and gas infrastructure would no longer be a major component in the global warming problem. In fact, it would become a minor, almost negligible component.  So it really is an extraordinary number.”

What technologies are you using to target methane?

As well as taking steps to reduce emissions, BP is contributing to the effort to detect and measure methane emissions more accurately, using technologies such as drones and truck-mounted laser sensors and infrared cameras. At BP’s forthcoming Ghazeer project in Oman, there are plans to install continuously operating cameras with a 1,700-metre scanning radius linked to software to quantify levels of emissions. That technology sums up what’s happening across BP – using technology and experience to pinpoint methane emissions and eliminate them wherever feasible.

 

This article was first published in June 2018

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