Wednesday, 2 May 2018

A new Post Doctoral Research Associate in shale gas geochemistry at the BGS…by Joe Emmings

Joe Emmings presenting research at the European
Geosciences Union General Assembly
Joe Emmings is the new Post Doctoral Research Associate in shale gas geochemistry at the British Geological Survey’s Stable Isotope Facility and Centre for Environmental Geochemistry. Here, Joe tells us about his PhD at Leicester University and future research at the British Geological Survey…

The world is gradually turning to renewables, such as wind and solar, as the main source of energy. This is great news for the environment, particularly for reducing greenhouse gas emissions. Yet all sources of energy, such as natural gas, nuclear energy, but even renewables, have pro’s and con’s. The expansion of renewables and batteries used to store this ‘green’ electricity is increasing the demand for metals, such as Co and Ni. These will need to be mined somewhere in the world.

Renewables cannot entirely replace the demand for hydrocarbons, either. For example, hydrocarbons are used as fertilisers and gas central heating in UK households, will be difficult to replace. So the transition to renewables must proceed now, but gradually – if it is done too quickly, the environmental and economic costs are large.

It is in this context that locally extracted natural gas is potentially a ‘bridge’ between coal, oil and gas and sustainable sources of energy. In a global context, locally extracted gas is preferable over imported gas, because in the UK we have strict regulations which protect the environment, and the fugitive emissions by long gas pipelines is significant. The method of extracting natural gas from shale, hydraulic fracturing, is contentious. Yet much of the science that informs our understanding of the pro’s and con’s of this technique has not been conducted.

I have been and will be continuing to work on the science that contributes to this debate, by shedding light on the composition of black shales in the UK that are of interest to exploration companies. On a microscopic scale, black shales are incredibly varied. No two shales are the same; the amount of gas stored in the rock varies substantially. This ultimately comes down to the environment of deposition – in other words – what did the environment look like millions of years ago?

Through my PhD research, we know Mississippian black shales in the UK were deposited in shallow seaways. By studying the geochemical composition of UK black shales, we know these were deposited in seawaters that lacked oxygen (termed ‘anoxic’), an environment that is similar to the modern Black Sea. Understanding when and how seawaters became oxygenated is important for understanding the amount of gas that is now trapped in the shale. The geochemical proxy record also shows that seawaters were also rich in hydrogen sulphide (H2S), a gas that is highly toxic to aerobic organisms. H2S is produced when other ‘electron acceptors’, such as oxygen, are absent. Anaerobes that live in the water instead respire using dissolved sulphate (SO4) and produce H2S as a product. This means UK black shales contain lots of pyrite (FeS2, ‘fools gold’) and are enriched in many ‘redox-sensitive’ metals, including Co and Ni. So black shales in the UK may represent an important resource of metals, which are used in renewable technologies, and this is something that I will be looking at.

Overall, Joe is interested in understanding ancient marine biogeochemical processes, by integration of sedimentology and organic and inorganic geochemistry. Please contact Joe if you are interested in his research field at josmin65@bgs.ac.uk


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