43- www. energy- future. com 4.2- A sustainable future Cutting emissions: the big challenge Fossil fuels are going to provide a signifi-cant part of our energy needs for decades to come. We need to use green energy, but replacing oil, gas and coal overnight with re-newable or nuclear power would be both im-practical and very expensive. That means en-ergy companies need to make their industry as sustainable as possible by exploring all av-enues to cut carbon dioxide ( CO2) emissions. Their expertise has been important in for-mulating a global response to climate change at forums such as the UN- sponsored con-ference, held in Copenhagen in December 2009. Some of the industry's views are chan-nelled through the International Petroleum Industry Environmental Conservation Association ( IPIECA), a body with observer status at UN talks, which provides a con-duit for the latest initiatives coming from its members in the oil and gas industry. " The oil and gas industry realises major challenges and opportunities lie ahead in ad-dressing climate- change risks. These include taking actions now to reduce emissions, pro-viding new, more powerful energy options and gaining a clearer understanding to better guide society's response," IPIECA says. But what does this mean in practice? To stem carbon emissions, companies can reduce the emissions they produce in the first place; stop the CO2 and other green-house- gases ( GHGs) they do produce from entering the atmosphere; or help reduce emissions from other sources. Oil and gas firms are active in all these areas. Going underground The technology that has perhaps gener-ated the most headlines in the fight against global warming is carbon capture and stor-age ( CCS), which enables CO2 to be cap-tured at source - at an oil and gas process-ing facility or power station for example - and then buried out of harm's way in de-pleted oil and gas reservoirs, or other un-derground chambers, such as aquifers. This is an enticing prospect, because if that can be made to work, then fossil fuel will be a lot less damaging to the atmosphere over the remainder of this century ( see p94). Although it is a costly technology, which has yet to be adopted on a widespread basis, the signs from pioneering projects around the world are encouraging. Proponents say there is no reason the technology cannot be scaled up for wider use. The coal industry is being targeted initially for CCS use, because coal burning results in more carbon emissions than the combus-tion of oil or gas. But oil and gas companies are not sitting on their hands, as they know their industry also needs to act. Some of the pioneering work was led by the IEA Greenhouse Gas Programme in the early 1990s. Within this programme the first carbon- storage monitoring exercise was set up in the North Sea with Norway's StatoilHydro and its partners. StatoilHydro has managed to keep the CO2 content of Energy firms must make the industry as sustainable as possible by exploring all avenues to cut CO2 emissions

44- www. world- petroleum. org 4.2- A sustainable future the gas produced from its Sleipner West gas field to below the 2.5% level needed to meet local environmental requirements. The CO2 is removed by passing the gas through solutions of chemicals commonly known as amines- a process also used in oil refin-eries and petrochemicals plants - and is then buried in an aquifer over 800 metres below the seabed. By the end of 2008, the project, which started in 1996, had stored almost 11 million tonnes of CO2, which has been carefully monitored so that the industry has a better understanding of how the gas spreads underground when new projects are developed. Oil companies are even helping the coal industry to cut CO2 emissions. Synthetic gas, or syngas, can be created from the heavy residues created in oil refining, which can then be used to produce power, or in other industrial processes. But this can also be done with coal in a way that makes the business of stripping CO2 out at the power plant easier and cheaper than it would be if the coal were burned directly. While coal gasification adds around 10% to the cost of coal- fired power stations ini-tially, it comes into its own when CCS is ap-plied, as it is much easier and cheaper to strip CO2 from syngas than from power- plant flue gases. According to Shell, a pioneer in gasification, that could make syngas nearly 10% cheaper than coal, if CCS is used in both cases. Shell is working to make the technology more attractive in places such as China, where coal is fuelling much of the country's rapid economic growth. Flares go out of fashion Less high- profile than CCS, but equally im-portant in emissions cutting are efforts to re-duce the use of flaring at oil and gas fields - the practice of burning unwanted gas. When the world was a less environmentally aware place, flaring or venting seemed a convenient way to get rid of an unwanted by- product. Now it looks like a waste of a valuable commodity and a way of pumping methane - a danger-ous GHG - directly into the atmosphere. The industry is now coming up with so-lutions to this problem. For example, when Marathon Oil became operator of the Alba field off the coast of Equatorial Guinea in west Africa in 2002, the focus of production Norway's Sleipner West project has been capturing and storing around 1 million tonnes a year of CO2 since 1996 Photo courtesy: Dag Myrestrand/ StatoilHydro