Methane is the second most important greenhouse gas next to carbon dioxide (CO2).

Although emissions of methane are much lower, its global warming potential is far higher, meaning that small emissions have a large impact. Dr Paul Balcombe at the Sustainable Gas Institute (SGI), Imperial College, has started working on a project with Enagás SA, the Spanish natural gas transmission company and Technical Manager of the Spanish gas system.

Their joint-mission is to understand methane’s contribution to climate change and to assess the potential role of gas in the future, especially in transportation.

1. What is the role of natural gas in transportation?

Natural gas currently plays a big role in heat and electrification, but it’s typically played a smaller role in transport. International shipping is responsible for over 2% of global greenhouse gas emissions, which is more than the emissions from a country like Germany. Liquefied natural gas (LNG) fuel for shipping could potentially reduce the carbon footprint of the maritime industry. Moreover, LNG will reduce air emissions in compliance with environmental regulations in the Emission Control Areas (ECAs) and improve air quality in cities with ports.
However, LNG’s sustainability credits as a transitional fuel still need to be explored in depth.

2. How did the collaboration come about with Enagás?

I was introduced to Tania Meixus Fernandez (Coordinator of Regulatory Development) from Enagás, in a coffee break during the Global Methane Forum conference in Washington in March 2016.

Tania had read our last White Paper on methane and CO₂ emissions in the natural gas supply chain, and was interested in finding out if there was an opportunity to work together.

3. What are the main aims of the study?

There are three main aims, all of which follow on from findings from the last white paper. The first is to explore the impact of methane on the climate through the different climate metrics existing. The second aim is to determine the uncertainty surrounding our estimates of methane emissions, to help us understand what we really know about our emissions. Then, we will be looking at the role of LNG in shipping, but including all the upstream emissions from the supply chain, from extraction, processing, transmission, storage, liquefaction, delivery and consumption.

4. So what steps are involved?

Firstly, we are going to assess how potent methane is compared to CO2 in terms of its impact on climate change. There are numerous ways and several different climate metrics used to assess the potency of a greenhouse gas.

Global Warming Potential (GWP) is a metric that everyone knows and is most commonly used. However, the meaning of GWP is quite complex and in certain circumstances other metrics may be more useful. These metrics are also used under various assumptions. For example, around radiative forcing or the effect of temperature in different areas of the world. We wanted to fully explore what these are by reviewing what the current knowledge is.

5. The study will ultimately examine the environmental impact of LNG and compare the footprint against different fuel sources? What will this involve?

I will also be carrying out an economic assessment looking at the cost and efficiency of LNG compared to alternative fuels such as fuel oil and biofuels. LNG could reduce greenhouse gas emissions and air emissions significantly, although other aspects as engine efficiencies or specific methane slips should be also analysed.

We will focus on determining where there is real benefit in switching to LNG, but also determining the ‘hotspots’ of emissions in LNG supply chains.

The hotspots refer to the major areas within the supply chain that either contribute most to emissions or are the most uncertain. This might be a piece of equipment or a super emitter where there is a big variation in greenhouse estimates and therefore a lot of uncertainty. There also might be other areas where there is a real lack of data.

6. What do you mean by ’hotspots’?

From our white paper, for liquids unloading there was a lot of uncertainty. This is where liquids that have accumulated in a gas well are removed.

Another area where there is a lot of uncertainty is regasification. After transporting LNG, it must be degasified at the terminal. There is very little data on methane emissions associated with this process. The aim will be to establish where we see the most uncertainty and to identify how we will fill those gaps.

7. Why is it important for your research to collaborate with industry? How will they help?

Industrial collaboration is vital for us to make a material difference with this research. The research will provide insight into the environmental and economic qualities of natural gas and will shed light on how we can best reduce emissions and best use gas in the future.

To be the most useful and to have the biggest impact, we need to work together with industry partners and policy makers, to translate these findings into real-world action.

8. Where and when will the findings be available?

The Kick-off meeting for the project was held on 8 May 2017 in Barcelona and we are due to finish in the first quarter of 2018.

We want to publish our findings as soon as possible and we have already completed the first section of the work, and understand more about climate metrics associated with methane.

Dr Paul Balcombe is based in the Department of Chemical Engineering at Imperial College London.

A two page summary of the Paul’s’ White Paper is available to download ‘Understanding methane & CO2 emissions from the natural gas supply chain report’.