FRACKING: MAY HELP TO DELIVER ENERGY SELF-SUFFICIENCY – BUT WITH HUGE CAVEATS
David Cameron recently announced that local authorities would receive all the business rates collected from shale gas schemes. With all the local authority funding cuts of late, this could be seen as a pure and simple bribe to encourage shale gas production, so what does it mean for the environment?
What is shale gas and fracking?
Shale is a finely grained sedimentary rock made up of layers of clay particles, interspersed with organic matter. Gas, typically 90% methane, can be retained in the shale in fractures, or adsorbed in the particles. The principal method of accessing this natural gas is via high-volume hydraulic fracturing (HVHF), commonly known as ‘fracking’. This involves a vertical well being drilled to the production zone, usually situated at a depth of 1.5 to 3km. On reaching the shale, the wellbore turns horizontally to expose a larger section of the shale. A ‘fracking fluid’ - consisting of sand, water and chemicals – is then injected at high pressure down the wellbore to fracture the horizontal section. This releases the natural gas into the production well, which is brought to the surface and collected together with the resulting ‘flowback water’.
Simple schematic of shale gas production (Source: ReFINE, 2013)
Shale gas production has dramatically changed the energy landscape in the United States, however scientific evidence indicates environmental implications arising from the process, so is it worth the risks?
Impacts on the water environment
Shale gas production requires large volumes of water and chemicals for the drilling and hydraulic fracturing. This leads to the production of significant quantities of wastewater, which must be managed and disposed of. A recent AMEC report has estimated that under the ‘high activity scenario’ (up to 120 well pads over a 20 year period) the water use of the UK shale gas industry could amount to 9 million m3 a year, which would represent around 18% of mains water currently supplied to the energy, water and waste sectors. This additional demand for water resources could exacerbate pressure on rivers and wetlands, particularly sensitive water bodies and those already suffering from over abstraction, such as chalk streams. Furthermore, under the same scenario up to 108 million m3 of wastewater would require treatment, which would place a significant burden on existing wastewater treatment infrastructure.
As with all drilling operations spills, blowouts and equipment failures are also issues that must be effectively mitigated. In addition, the release of methane during hydraulic fracturing can result in groundwater contamination, as well as induce seismic events. The possible impacts of hydraulic fracturing with regard to groundwater, if not correctly managed, are significant and potentially long lasting or even irreversible.
Habitat loss and fragmentation, and disturbance to wildlife
The drilling and hydraulic fracturing process can be a 24-hour/7-day operation with associated visual and noise disturbance, compounded by hundreds of truck movements required to shift equipment and wastes, including naturally occurring radioactive materials.
Each well pad occupies up to three hectares and with as many as 120 well pads proposed to be constructed and linked by infrastructure in the UK over the next two decades, if sited in the wrong place and/or constructed at the wrong time of year, impacts could be damaging to important and protected species. Site selection will be a key factor in minimising impacts on species and habitats.
Climate change impacts
The exploitation of shale gas diverts efforts away from the UK’s legally binding commitments to achieve an 80% reduction in greenhouse gas emissions by 2050. There is an ongoing debate about the relative leakage rate of methane into the atmosphere from the exploitation of shale gas in comparison to the emission rate from conventional gas. This is potentially important because a high leakage rate might mean that methane released by shale gas operations into the atmosphere could have a higher net greenhouse gas footprint than coal, for instance.
The S&TCUK, along with other conservation organisations including RSPB, is calling for the Government to ensure the regulatory framework applied to the industry is fit for purpose and provides sufficient protection to the natural environments. This includes:
- Avoid sensitive areas for wildlife and water resources by creating shale gas extraction exclusion zones.
- Make Environmental Impact Assessments (EIA)mandatory for shale gas extraction proposals.
- Require shale extraction companies to pay for a world-class regulatory regime.
- Prevent taxpayers from bearing the costs of accidental pollution.
- Make water companies statutory consultees in the planning process.
- Require all hydraulic fracturing operations to operate under a Groundwater Permit.
- Make sure the Best Available Techniques (BAT) for mine waste management are rigorously defined and regularly reviewed.
- Ensure full transparency of the shale gas industry and its environmental impact.
- Ensure monitoring and testing of shale gas operations is rigorous and independent.
- Minimise and monitor methane emissions.