The final candidate for the primary, carbon-free energy source is nuclear energy. Fission may be very important in bridging the gap between the current carbon-dependent world and a world based around a fairly shared, renewable resource system (Ernst, 2002). Nuclear energy is generally perceived as a Janus-like concept, either the answer to the global energy crisis, or something akin to playing with fire, after disasters like Three Mile Island and Chernobyl. The nuclear fission process is becoming more efficient, as reactor technology improves. The WRLI of Uranium is approximately 80 years, but could be made essentially renewable if reprocessing of fuel or the development and use of breeder reactors becomes viable (RAE, 1999). In the short term, the current drive should be to increase efficiency, and to put nuclear costs into proper perspective with respect to the costs of dealing with climate change (Cooper, 2005).
The Transition Period: from Carbon-based to Carbon-free Energy
Oil and other carbon-based resources will still be crucially important as the transition to more sustainable and environmentally friendly energy sources occurs. It is argued by some authors that carbon-based energy sources are in fact the most viable and cost effective for the foreseeable future (Lackner, 2002). However, the realities of increasing atmospheric CO2 are inescapable, thus the major carbon-based growth area should in fact be carbon management techniques, as fossil fuel use in the short term is likely to be limited by the environmental impact.
Carbon management techniques need to be developed, both to capture and subsequently to dispose of CO2. In the short term, it may be easier to render these carbon-based fuels environmentally friendly than it is to replace them by renewable and sustainable energy sources.
Rendering carbon-based fuels environmentally friendly can be done in two ways; by reducing the output of CO2 and by trapping and sequestering the CO2 that is produced. Various storage options for the CO2 have been suggested, including storage in the deep Atlantic (ocean storage) or into carbon sinks such as soil or biomass. Perhaps a more viable option is the use of CO2 as an injector compound to produce oil, as has already been used in West Texas oil fields (Lackner, 2002). This process stores CO2 although there area still questions and issues over the stability and sustainability of this, also the amounts used are very small. Viable sequestration of CO2 requires a site with a long retention time, which can often be predicted using available hydrocarbon modelling technology. Sites need to have a retention time of over 100years to be a viable method of reducing atmospheric CO2. Potential storage sites include giant oil and gas fields and deep aquifers as has been achieved in Norway and is planned for Indonesia (RAE, 1999).
The figures cited in the earlier sections relate to the lifespan of the known fossil fuel reserves, but more time for the transition to a carbon-free economy can be bought by exploring for and exploiting unconventional oil reserves. Major new frontier regions include deepwater offshore drilling sites and pristine Arctic sites such as Alaska and the Canadian Arctic (Ahlbrandt, 2002). Existing processes need to be made more efficient and development of new frontier sites needs to take an understanding of ecosystem integrity and preservation into account (Ernst, 2002). In addition, an improved understanding and characterisation of current marginal reserves will condition new exploration strategies and recovery technologies (Einaudi, 2000). A further unconventional reserve of hydrocarbons with great producing potential is tar sand regions, e.g. Athabasca, Canada, and more recently, Nigeria (Carter, 1991; Olabanji et al., 1994).
The Changing Face of the Geosciences
In the transition period from a carbon-based to a carbon-free energy production system, there must be two main thrusts of research and development for geoscientists. One is a focus on exploration, efficient extraction and remediation of the environmental impacts of extraction. Fossil fuel use and resource extraction are rapidly becoming more efficient, so the transformation is already happening (Woodward et al., 2000). The second is the development of research-generated advances towards low impact and cheap energy, tending one day to a steady state resource use and development of resources such as geothermal energy (Ernst, 2002).
As already outlined above, shortages of the four principal energy reserves are likely within the next 100 years. Fundamentally, this can only be combated by education and collaborative research in geology, environmental science, mining technology and across the spectrum of engineering disciplines, thus it is necessary to consider how a typical geosciences department could be restructured in 2050. Existing expertise needs to be redistributed in order for new geoscience departments to function as high calibre research groups at the international level within a new, sustainable energy approach. Many major geosciences departments have around 35% of the research and teaching power concentrated on the hydrocarbon industry, with a substantial proportion of geology graduates heading off to work in the hydrocarbon industry. As well as efficient exploitation and creative exploration for new, often unconventional reserves, it is also necessary to invest in recycling of resources and in developing innovative substitutes for the present energy sources. The proceeds of current hydrocarbon companies should ideally be invested in outward looking ways, in education and in the development of sustainable and substitution technology to remove the reliance on oil and gas. The damage from mining and from hydrocarbon extraction also needs to be ameliorated.
The three major energy sources proposed above for a post-carbon energy system hold great promise for innovative geosciences research in the next 50 years. The exploitation of hydrogen resources will rely to a great extent on the development of the same new exploration and exploitation techniques developed for efficient extraction of remaining oil reserves and for CO2 sequestration. Hydrocarbon and Basin Analysis groups will be able to specialise in creative exploration techniques for unconventional resources or to diversify into exploration and production research for geothermal energy sites. Much of the present technology should be relatively easily adaptable to the new demands, for example modelling flow pathways and timescales for gas migration in underground storage sites.
The development of reservoirs for the sequestration of CO2 will also involve technology previously developed for the hydrocarbon industry, namely the identification of structural traps in facies suitable for gas storage. Fracture, fluid flow and stress modellers will also be in demand to develop new fluid phase models for high pressure gas and use these in predicting residency times for the gas in the subsurface. The expertise of climate and ocean scientists will be needed in assessing the potential for other carbon storage reservoirs such as the deep ocean.
Within the geothermal energy industry, the expertise gained from exploration and drilling for hydrocarbon production will be in high demand, particularly as, due to the high fluid pressures involved, drilling in geothermal regions is far more of a technical challenge than drilling for hydrocarbons. Some remediation methods are also required for geothermal energy sources, such as surface disturbance and potential subsidence, and the possible release of chemicals and alteration of the subsurface chemistry (Kristmannsdottir and Armannsson, 2003).
Another major focus for 21st Century geoscientists will be in the areas of Uranium exploration for nuclear fuel, specifically, perhaps, the development of extraction methods for extracting and purifying Uranium from seawater (RAE, 1999). New opportunities for collaboration between structural geologists and minerals or mining geologists will open up as a result of the need to locate and produce from new uranium mines. Another collaborative effort may see geochemists working closely with chemical engineers and mining engineers in the extraction of uranium from seawater.
Correspondingly, the structure and emphasis of the taught courses will have to evolve, ultimately, replacing petroleum-targeted courses with nuclear energy courses, by uranium exploration modules, by geothermal exploration, by geothermal drilling, production and modelling techniques. Much more integration with other discplines will be required, including both cross-faculty research and teaching, with fuels engineers, chemical engineers and nuclear engineers. It is likely that this will also require international collaboration, although this leads to the rather paradoxical situation of needing international collaboration to decentralise the energy supply, as most renewable energy resources are highly localised, thus a global energy industry based on renewable energy sources is likely to become a highly decentralised energy production system. Hopefully, this will also reduce global power struggles and politicization of energy (RAE, 1999).
Geoscientists already promote themselves to potential employers as graduates trained to make excellent decisions based on limited evidence and this must now be turned towards the policy problems associated with the energy industry. Specifically, geoscientists should actively engage in policy analysis and learn to communicate with policiticians (Goulder, 2000). Energy policy needs to undergo a radical change and the prospects for actually achieving this are rather bleak as it appears that the issue is not being taken seriously enough. Policy surrounding the development of sustainable energy, needs to take into account the energy supply and consumption dynamic, and the efficiency of generation. Conservation issues and therefore decreasing the waste produced, health and safety and also reducing the pollutant load are also crucial factors (Jefferson, 2006). Geoscientists also need to actively become more and more international, both in the consideration of the problem and in collaboration to find sustainable solutions. The future energy crisis is not simply an EDC issue, but will become a major factor in aiding the development of LDCs as well (Woodward et al., 2000).
There are generally three emphases within the development of energy policy: to mitigate climate change, switch to renewable energy and decrease pollution (Rafaj et al., 2006). Current policy targets are generally unrealistic, e.g. the UK reduction of CO2 levels by 20% by 2010, by using wind power, although resources like wind power are a realistic option with significant long term planning (Jefferson, 2006). Another, arguably too drastic measure, is to remove the subsidies given to fossil fuel companies, and levy a tax on these companies instead. By reforming the direction of research in the geosciences, it will be possible to influence the research areas that are considered of national importance and are therefore funded by the government and research councils. However, this process requires that geoscientists learn to communicate effectively to policy-makers, rather than assuming that the results speak for themselves (Einaudi, 2000).
Traditionally, the geosciences have been intimately associated with the oil and gas industries, and as such, become a scapegoat for many of the problems now facing the Earth. However, quietly, imperceptibly, almost unseen, the oil and gas companies have been transforming into twenty-first century energy businesses (Stankiewicz, 2003). As this transfiguration becomes evident to the general public, geoscientists will once again take pride of place on the global stage.
Acknowledgements
Grateful thanks go to Dr Matt Eaton (Imperial College London) for many stimulating discussions and useful references.