With governments and industries around the world working to reduce carbon dioxide emissions, the clean energy sector is experiencing a boom.
The UK’s wind and wave resource, coupled with its mature offshore industry, would seem to make it ideally suited to becoming a leader in clean energy expertise.
Current notable projects include the Gwynt y Môr offshore wind farm in North Wales (in relation to which this firm acted on the sale of a stake by RWE last year) and the Longannet carbon capture and storage (CCS) project.
Most CCS proposals involve the storage of CO2 offshore in underground geological formations, such as depleted oil fields, gas fields and saline aquifers.
CO2 is already injected into some onshore oil fields in North America, primarily for the purpose of Enhanced Oil Recovery (EOR). Statoil’s Sleipner West field hosts the world’s first offshore CCS installation, which has captured and stored around one million tonnes of CO2 produced from the field every year since 1996.
In the UK, DECC aims to have 40GW (gigawatts) of CCS in operation by 2050. It launched a CCS demonstration competition in 2007 for one project (Longannet being one of the two remaining candidates in this competition), and now plans up to four commercial scale demonstration projects.
These will allow the UK to gain understanding of different capture technologies, to build experience in the transport and injection of CO2 and act as test cases for the storage licensing regime (the UK has probably the most advanced licensing scheme for CCS in the world) and, later, for monitoring and verification, while also exploring the potential of North Sea (and possibly Irish Sea) storage for future projects.
Up to £1billion was awarded in the October 2010 spending review for the capital costs of the first demonstration project. Under the last UK Government it was expected that the other three projects would be funded by means of a levy on electricity supplies but, to the disappointment of the burgeoning CCS industry, the Tory-Lib Dem coalition has decided to reassess the question of whether funding should be provided through general public expenditure or a specific levy. This will delay the launch of the process to select participants for the remaining three projects until at least the autumn of 2011.
Risks of CCS
Like many energy technologies, CCS has major accident hazard potential and operators will need to ensure that suitable controls are in place to mitigate the risks.
The volume of CO2 produced by CCS schemes makes transport as a gas impractical. It must instead be transported at high pressure as a supercritical fluid. This presents a new risk; when pressure is lost in a supercritical CO2 system – for example if there is a break in containment – the volume of the supercritical gas rises dramatically and its temperature falls to as low as -80C.
At that temperature, particles of solid CO2 (also known as dry ice) form which can be expelled at high velocities, creating impact and cryogenic burn risks.
The warming of the ejected dry ice may create a subsequent asphyxiation risk as it turns to gas. The extreme temperatures also pose a risk to asset integrity and the Health and Safety Executive (HSE) has emphasised the importance of gas monitoring systems that are sufficiently robust to withstand them.
Almost all existing knowledge regarding the behaviour of carbon dioxide at high pressures has been obtained from EOR operations, and it is likely that future CCS projects will utilise higher pressures (upwards of 200 bar).
HSE view the extreme properties of supercritical carbon dioxide as a significant safety hurdle. They are proposing that appropriate scale experiments be carried out to further our understanding of what happens during large-scale supercritical carbon dioxide releases.
In addition to the unique risks of pressurised carbon dioxide, existing risks associated with the energy industry will arise. For example, a range of organic amines and other chemicals are commonly used in carbon dioxide capture processes. These substances are well known to be hazardous to health and are already categorised under the Control of Substances Hazardous to Health Regulations 2002.
What health and safety laws apply?
The capture and storage of carbon dioxide gas deep underground as a means of mitigating the use of fossil fuels is a relatively new concept and one which is not specifically addressed by UK safety laws. While HSE believe that some laws must be amended to take account of specific risks from CCS or expressly include such activities, they consider much of the current health and safety regime up to task.
That is largely because the majority of the perceived risks are not new to the UK energy and offshore industries. While most of the UK’s health and safety laws apply to offshore installations and wells by virtue of the Health and Safety at Work etc Act 1974 (Application Outside Great Britain) Order 2001, the scope of that order will require extension if it is to include installations dedicated to CCS (those not also producing oil or gas). Two further examples are set out below.
The Offshore Installations (Safety Case) Regulations 2005 require operators of offshore installations to submit safety cases. In a safety case, operators must describe management systems and show a systematic and structured approach to managing the major hazards on the installation.
Again, these regulations may apply where CCS installations are also producing oil or gas but in their present form they are insufficient for dedicated CCS installations. Amendment or new regulation to fill the gap is anticipated, but HSE will still expect operators of demonstration projects to prepare safety cases in the meantime.
The Pipeline Safety Regulations apply to both onshore and offshore pipelines. CO2 is not currently classed as a dangerous fluid in terms of the Pipeline Safety Regulations, which means that the notification and Major Accident Prevention requirements of the regulations do not apply. Similarly, CO2 does not by itself fall under the Control of Major Accident Hazard Regulations (COMAH) 1999, or the Planning (Hazardous Substances) Regulations 1992, which apply onshore.
Penelope Warne is head of energy at international law firm CMS Cameron McKenna
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