Shale Gas and the Environment
Energy has become an integral part of how we live and work. Our demand for an affordable, readily available and convenient energy supply continues to increase. We all use it and we couldn’t function without it. Energy production has always been dependent upon new technology to make it commercially viable for energy companies and affordable for industry and consumers. Public concern over new forms of energy technology has always existed. It is the responsibility of both policy makers and the energy industry to mitigate any risk by developing a transparent regulatory and enforcement framework and build an appropriate social license.
This section deals with the relationship that shale gas could potentially have with the environment. To understand the full industrial process and working of a drill site, please visit this page.
Working towards a greener future
As the European Commission has recognised, “shale gas in Europe can be a possible substitute for more carbon intensive fossil fuels, an indigenous source of natural gas reducing dependency on non-EU energy suppliers”. This would be particularly relevant in those Member States where coal remains a significant part of the domestic energy mix. Similarly it could replace imported gas from abroad or where existing domestic gas supplies are declining, responding to the additional needs for a secure and affordable supply.
A further study by the Commission found that modern gas-fired power plants have a carbon footprint that is 41 to 49% lower than that of coal-fired plants, 2% to 10% lower than emissions from electricity generated from conventional pipeline gas produced outside Europe, and 7% to 10% lower than electricity generated from LNG imported into Europe. Another report by the International Energy Agency shows that due to a major shift from coal to gas-fired power plants, the shale gas boom in the US has enabled a reduction in energy-related CO2 emissions by 450m tonnes over the past five years.
Europe can benefit from this opportunity.
Developing a regulatory framework
In 2012 the International Energy Agency (IEA) published its ‘Golden Rules for a Golden Age of Gas’ report calling for a robust and appropriate regulatory regime and outlining a series of recommendations for the safe development of unconventional gas, such as shale gas.
“Governments need to devise appropriate regulatory regimes, based on sound science and high-quality data, with sufficient compliance staff and guaranteed public access to information”
European legislators have ensured that the exploration and production of natural gas in Europe is one of the most highly regulated processes in the world. Gas from shale development is regulated by 17 different pieces of EU legislation, as well as a strong existing regulatory regime at national and local level.
European Commission’s Communication and Recommendation
In January 2014, The European Commission published its Recommendation on the exploration and production of shale gas in the European Union. The fact that it decided to issue a Communication and Recommendation, rather than legislative measures, recognises that the industry is already heavily regulated.
The Communication clearly states that Member States have the right to determine the conditions for exploiting their energy resources, as long as they respect the need to preserve, protect and improve the quality of the environment. It subsequently draws on the example set by the IEA report and highlights the minimum principles required for the extraction of shale gas in the European Union.
Therefore it is now up to each Member State to determine how best to these principles. In turn the European Union will continue to monitor the Recommendation’s application in each country. Progress will subsequently be reviewed in July 2015 to see if further legislative action is required to enforce good industry practice.
Managing the environmental footprint of shale gas
Industry good practice:
Safe and environmentally sound development of all of Europe’s energy sources is absolutely critical for Europe’s energy future. The extraction of natural gas from shale has been rigorously monitored and evaluated for many years in the United States, which has an established shale gas industry. Decades of successful development ensure that the risks are not only fully-understood but that technology and processes have been developed to manage them.
Industry and Authorities should also cooperate and establish a dialogue to address public concerns through the open sharing of information and knowledge.
So how could shale gas impact the environment and how do regulation and industry good practice help mitigate any risk?
What is regulated?
Every stage of oil and gas operations is regulated, including:
I. Exploration activities. Companies require a permit from a national or local agency in order to explore for shale gas. To secure the permit companies must provide extensive information relating to, for example, the environmental and geological impacts of their activities.
II. Use of chemicals. All chemical substances meeting a certain volume threshold used in shale gas extraction must comply with REACH, the regulation of the European Union adopted to improve the protection of human health and the environment from the risks that can be posed by chemicals. Industry also supports the public online disclosure of the additives used in hydraulic fracturing (such as ngsfacts.org in Europe, fracfocus.org in the United States or in their own websites), which includes maximum component concentrations.
III. Use of water. Extraction of groundwater is strictly controlled, frequently requiring a permit.
IV. Treatment of water. Appropriate government authorities issue permits for handling and disposal of flowback/produced water. This procedure is consistent with the EU Mining Waste Directive.
IV. Waste management. Strict standards to prevent water and soil contamination must be adhered to.
V. Noise and local disturbance. Strict limitations on noise must be observed.
Which regulations apply?
Each Member State will determine the regulations that apply to shale gas activities on their territory. However there are a number of pieces of EU legislation that must be applied in all Member States, including:
I. Hydrocarbons Directive: Lays down conditions for granting and using authorisations for the prospection, exploration and production of hydrocarbons that are fully applicable for shale gas
II. Water Framework Directive: Lays down requirements for surface waters to achieve good ecological and chemical status and for reversal of human-induced pollution under specific circumstances
III. REACH Regulation (Registration, Evaluation, Authorisation and Restriction of Chemical Substances): Ensures effective management of risks associated with chemical substances through reporting of information along the supply chain and phasing-out of dangerous substances
IV. Habitats Directive and Birds Directive: Sets up a system of strict protection of sites and species that applies to all activities including extractive industries
V. Groundwater Directive: Covers all potential sources of water contamination. Requirements include establishing groundwater quality standards, carrying-out pollution trend studies and reversing pollution trends
VI. Mining Waste Directive: Lays down risk-focused provisions covering planning, licensing, operation, closure and after-care of waste facilities.
Water is our most precious natural resource. It also plays a critical role in most types of energy production, including the extraction of shale gas. While shale gas operators are committed to protecting and preserving fresh water supplies, reducing its consumption to a minimum, concerns have been raised about how much water is used as part of the process and any potential risk to contamination of ground water supplies.
- The amount of water used per unit of energy produced from shale gas over the lifetime of a well is actually lower than coal, nuclear or concentrating solar power plants
- To drill a vertical exploration well to a depth of around 3,500m approximately 500-750m3 of water will be used, and to perform multi-stage hydraulic fracturing between 10,000 and 20,000m3
- Before drilling and fracturing a well, operators commission comprehensive studies to evaluate the sustainability of the water supply and to develop a resources management plan. This process includes consideration of volume and water quality requirements, regulatory and physical availability, competing uses, proximity, means of transport and characteristics of the geologic formation to be fractured (including water quality required to fracture it).
- Depending on the geological conditions, between 20 and 40% (sometimes up to 70%) of the water injected in the geological formation as part of a hydraulic fracturing treatment is recovered on the surface and stored.
- As part of the industry’s efforts to reduce fresh water consumption, flowback water is being increasingly reused for future hydraulic fracturing operations
Impact of the Drilling Process
While shale gas operators are committed to protecting ground water resources, concern has been voiced about any possible contamination of supplies as the drilling process could, but not always, drill through the local water table. We now look at two processes associated with the extraction of shale gas and how any potential risk will be managed and mitigated.
I. Drilling operations
The first process is general drilling operations associated with the extraction process. The proper casing of shale gas wells is vital for the safety of operations. Good practice well construction techniques employ multiple layers of impermeable cement and steel casing to isolate the well. This layered design ensures that even if one of the casings should rupture, nothing would be able to migrate outside the well bore. In addition all wells are pressure tested to guarantee integrity before hydraulic fracturing takes place.
For more information on well-casing, please visit ‘The Process of Shale Gas Development’.
II. Hydraulic fracturing:
The second process, hydraulic fracturing, involves fracturing fluid being pumped at high pressure into the shale rock in order to open fractures.
Experts have consistently found that hydraulic fracturing poses no credible risk of contaminating groundwater. This is due to the fact that shale formations are typically found between one and three kilometres below drinking water supplies and water resources are also protected from fracturing activity by multiple layers of impermeable rock.
Using highly sensitive seismic measurements taken during hydraulic fracturing operations, researchers at Durham University have shown that the micro fractures created by hydraulic fracturing typically extend less than 180 metres upwards from the well bore. The peer-reviewed academic paper by Professor Richard Davies, “Hydraulic fractures: How far can they go?”, highlighted that the probability of stimulated hydraulic fractures going higher than 350 m is around 1%, which still leaves a considerable distance between the maximum reach of hydraulic fractures and aquifers.
Measurement and Protection of water
As stated above, any industrial process and all energy production need to be in accordance with national and European legislation. Throughout shale gas operations, industry best practice will also ensure the protection of our water resources. Collectively, this will be undertaken and enforced in a number of ways:
I. Water sampling:
Good industry practice states that groundwater sampling is carried out in a pre-designated area around a new well site. Within this area sampling will take place prior to and after both drilling and fracturing. The testing may include water wells and surface water such as rivers, ponds or lakes in the immediate vicinity of the planned well. However the exact process will depend on applicable regulations, local conditions and operator policies. During the sampling procedure measurements will typically be taken for levels of iron, solids, organic matter, naturally occurring radioactive material (or ‘NORM’) and methane.
II. Treating Flow Back Water:
Depending on the nature of the geological formation, between 20 and 40% (sometimes up to 70%) of the water used for hydraulic fracturing is recovered during the first 2-5 weeks of production. This part of injected water recovered is known as flowback water. Water from the gas bearing formation could also be delivered to the surface. This is called produced water.
In the United States where there is an established shale gas industry the temporary storage of flowback and produced water from shale gas operations in open container ponds has historically been a means of management before treatment. However this method is being phased out and steel container tanks are increasingly being used to safely store water before it is then treated or recycled. A recent development has been that flowback water is being increasingly reused for future hydraulic fracturing operations as the economics of reusing flowback water is ever more viable.
III. Surface Water Protection:
In addition to the use of sealed tanks for the storage of flow back water, each drill site is also prepared to prevent any chemicals used on-site from contaminating local surface water resources.
When a drill-site is identified, the fertile topsoil is removed and stored, ready for replacement upon restoration of the plot. The work surface of the drill-site is then covered with a waterproof membrane, measuring approximately 100 x 135 m. Once in place this membrane is then covered with gravel to aid drainage. On top this, concrete blocks are laid to create a stable surface for operations. Together these measures ensure that if any chemicals are spilled onsite, the risk of them migrating into local surface water is minimised.
IV. Baseline Monitoring:
Baseline monitoring provides authorities with a clear understanding of the chemical status of water sources before and after shale gas operations. As a result this is something that is firmly supported by the industry and normally performed as part of an Environmental Impact Assessment (EIA) and/or agreed on as part of the drilling permitting process. Once gathered it is up to individual authorities to decide how this information is shared with local communities.
“Compared to other fossil fuels the overall water use intensity of shale gas is low and claims by some opponents that the shale gas industry represents a threat to the security of public water supplies is alarmist”Shale Gas and Water Report, Chartered Institution of Water and Environmental Management, UK (January 2014).
Air quality: Operators are committed to reducing emissions associated with shale gas operations, taking a number of proactive steps to reduce on-site, and off-site, emissions of both methane and carbon dioxide.
Minimising Fugitive Emissions: Fugitive emissions can occur during natural gas drilling operations or as part of transmission, due to pipeline leaks. In addition to environmental commitments, all companies across the value chain of the natural gas industry have a continuing commercial interest in reducing such emissions.
Minimising Fugitive Emissions:
Fugitive emissions can occur during natural gas drilling operations or as part of transmission, due to pipeline leaks. In addition to environmental commitments, all companies across the value chain of the natural gas industry have a continuing commercial interest in reducing such emissions through the following processes:
I. Flaring and Venting: Flaring is the controlled burning of natural gas produced in routine oil and gas production operations, whilst venting is the controlled release of unburned gases directly into the atmosphere. The option to release gas to the atmosphere by flaring or venting is an essential practice in oil and gas production, primarily for safety reasons. However, a number of steps can be taken to limit this practice and further reduce the lifecycle emissions of shale gas against other fuels, such as coal
II. Use of Reduced Emission Completion (REC) technology — also known as green completions: REC technologies separate and capture the methane emitted during well completions and flowback, clean it and send it to pipelines, avoiding the need to flare or vent. The use of this technology is dependent on a pipeline being laid up to the well-pad, but is now applied to the majority of new wells in the United States. The ability to lay such pipelines will vary from basin to basin. However, the advanced planning, favoured by the existing European licencing framework, allows for a timely coordination of drilling and pipeline installation. Industry is working with suppliers to ensure that the availability of such equipment keeps up with demand
III. Use of more efficient plant machinery at the well site, and a greater use of natural gas or electricity as a power source: by using natural gas instead of diesel in onsite equipment, the emissions associated with mechanical site activity can be reduced, along with the need to flare or vent. Such emissions gains may also be possible off-site by utilising pipelines to transport water to the well-site, rather than trucks.
Shale gas can be transported in Europe using existing gas infrastructure
Land use and landscape protection
Shale gas wells require only a very small area of land. It is current industry practice to cluster such wells together on a single pad. This means that the surface footprint of extraction operations is minimised while also reducing vehicle movement within the site. The use of horizontal drilling during the production phase also means that operators can access more gas reserves from a single well pad, reducing the overall number of wells.
When individual sites are being selected, detailed geological surveys are carried out of each concession to examine the local structure of the shale rock beneath the surface and to calculate the most efficient placement of the drilling sites. This further allows for the maximum extraction of resources, with minimum disruption to the communities and environment present within the concession. Below an example is provided of how the detailed planning of drilling routes can be combined with the results of such geological survey activity.
Comparative land use: A recent report by the Institute of Directors (IoD) in the United Kingdom calculates that by applying good industry practice, a single 0.02 km2 site could support 40 horizontal wells that at peak production could provide enough natural gas to power 747,000 homes. To put this land use into context, the Scout Moor wind farm in Lancashire has 26 turbines and covers 5.45 km2. The IoD calculates that assuming this wind farm continues to generate electricity at the same level that it has for the first few years of its operation, it could be expected to generate only 1/5th of the energy that a 0.02 km2 shale gas site could over its lifetime.
The full exploratory process is outlined here. Part of this process is called hydraulic fracturing. Hydraulic fracturing utilises a mixture of water, sand and chemicals pumped underground to create fissures in the sedimentary rocks and release the fuels within. Opponents of hydraulic fracturing are concerned that earthquakes could be induced by the process.
Only in exceptional circumstances can hydraulic fracturing cause earth tremors which are felt at ground level. These events are extremely minor , causing no property damage or human harm. Scientists from Durham University, UK looked at seismicity induced by hydraulic fracturing and highlighted that Hydraulic fracturing is not an important mechanism for causing felt earthquakes.
Operators undertake in-depth geological surveys prior to performing hydraulic fracturing to ensure that they understand how the rock will respond. Drillers are also putting in place real time monitoring of seismic activity during fracturing operations. This will enable them to take any necessary action should significant seismic events appear likely to occur.
The main sources of noise related shale gas development operations are the transportation of materials to the well site and the drilling and hydraulic fracturing process itself.
Transport: There will be a spike in traffic during the construction of the well site and just before hydraulic fracturing takes place, however disruption is minimal for the rest of the life-cycle of the well.
Drilling process: At the site, noise is mainly caused by power generators, diesel engines and mud pumps; this is minimized through installing soundproofed barriers around the well site.
On average, the noise level of an active drill site will not exceed 86 dB (decibels) from a distance of 200 metres. As a comparison, noise generated by traffic in a city is about 80 dB.
Monitoring and Regulation
Regulations exists which determines strict noise limits surrounding well sites, especially in the case of residential areas. Operators are constantly monitoring their noise levels in order to decrease the impact on the community.