Although research on global warming has typically focused on carbon dioxide emissions, methane also has a significant impact. So in order to fully understand the role of natural gas in a lower carbon energy system, we need to have better understanding of methane emissions. Methane is the main component of natural gas and is a very potent shortlived greenhouse gas. Methane is emitted all across the natural gas supply chain, from exploration and extraction, through to delivering the gas to the end-user.
In recent years we have been gathering more data in terms of what these emissions are. In September 2015, our Institute published a white paper which assembled what we currently know about emissions but, more importantly, established what we still need to understand and investigate further. The analysis revealed that methane emissions vary considerably across facilities. Moreover, there are many regions and supply chain stages that we are still yet to measure effectively. Conducting more methane measurements is therefore a major challenge and a priority for understanding the climate impact of emissions.
However, methane measurement campaigns are costly, or they may lack the detail to be useful. In addition, methane emissions change over time so just one campaign is not good enough. We therefore need to regularly – or even continually – measure methane emissions across gas facilities. This is the second major challenge: identifying a cost-effective method for frequent or continual measurement of methane emissions.
If and when we get a more complete picture of what supply chain methane emissions are, what do we do with this information? Broadly speaking, we can then do two really useful things:
We can create full life-cycle models of different supply chain routes to understand how much the gas industry emits compared to other competing energy products, such as coal for electricity generation. We can determine the lowest emitting supply chain routes and gain a greater understanding of the role that we should allow natural gas to play in a low carbon energy system.
We can focus the direction on technological or operational innovation to maximise our emissions reduction. This can then feed back into the first point to understand what kind of a role gas can have as we move forward with decarbonisation.
Another really important challenge for us as researchers, policy makers and planners, is to achieve a clearer understanding of how potent methane is as a greenhouse gas. Typically, methane is considered to be a much more potent greenhouse gas than carbon dioxide and the metric ‘global warming potential’ is used to say that methane is 34 times more potent on average over 100 years, or 86 times more potent on average over 20 years. However, there is a widespread acknowledgement that this global warming potential (GWP) metric is not useful when comparing different greenhouse gases (GHGs). It is essential that we are able to compare different GHGs so that policy decisions can be made with regard to our energy system.
But in order to make these decisions, we do need to find a more accurate metric to use and be more consistent with the use of this metric across different pieces of research across different institutions. The use of different climate change metrics is likely to have a massive impact on the trade-off between different energy fuel sources, and this is a vital time in the context of the UNFCCC COP21 talks in Paris in December 2015.
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Dr Paul Balcombe
Sustainable Gas Institute