With the advent of unconventional gas technologies, the energy industry has turned toward natural gas as an alternative to coal, a step to energy independence and a solution to climate change worldwide. However, without CCS, natural gas will be unable to achieve needed reductions from the utility sector without carbon capture and storage (CCS). Coal with CCS is in fact better than gas without CCS.
Switching from coal to natural gas without CCS won’t solve the climate problem. By mid-century, virtually all of the CO2 emissions from the power sector must be virtually eliminated. Yet without CCS, that goal cannot be achieved. The best natural gas can do, absent CCS, is a 50 per cent cut in carbon dioxide relative to coal, and that assumes no leakage of methane, a very powerful climate forcing gas. While a 50 per cent reduction is helpful, it’s only a half step and a solution that may, in fact, delay the development of CCS technology.
According to the International Energy Agency’s (IEA) World Energy Outlook (WEO 2011), the most optimistic picture – the 450ppm scenario – puts the share of fossil fuels in the energy mix as declining only from 81 per cent to 62 per cent in 2035. Fossil power will therefore need major reductions in CO2 that natural gas alone can’t provide.
The question is whether it is possible to cover both the growing demand for energy and to achieve the large reduction needed in emissions of greenhouse gases based on renewable energy and increased energy efficiency alone by 2030. Even given a massive change in energy policy, it is highly unlikely that the necessary increases in renewable energy production and energy efficiency can be achieved that at the same time accommodate the increasing demand for energy in developing countries. Therefore, fossil fuels will continue to play a major role in supplying energy for decades to come.
Coal is currently the dominant fuel in the power sector, accounting for 38 per cent of electricity generated in 2000, with hydropower accounting for 17.5 per cent, natural gas for 17.3 per cent, nuclear for 16.8 per cent, oil for 9.8 per cent and other renewables for 1.6 per cent. Coal is projected to still be the dominant fuel for power generation in 2020, while natural gas generation will surpass hydro to be the second largest (IEA, 2008). This makes rapid development of large-scale CCS essential for all fossil power, including gas, if we are to cut greenhouse gas emissions fast enough to meet international goals that would curb catastrophic warming of the planet.
Post-combustion capture (PCC) technology is commercially available for natural gas combined cycle plants. The technology faces fewer technical hurdles than coal PCC in part because the emissions from gas contain fewer contaminants. At the same time, new capture technologies are being developed (for example, at the Technology Center Mongstad, Sargas and Next Power) that could drive current natural gas CCS costs down.
In the EU and especially in the UK, there are renewed debates on the future of gas. In July, the UK’s Department of Energy and Climate Change set out its plans for investment in renewable energy as part of its Renewables Obligation. However, at the same time they said: “We do not expect the role of gas to be restricted to providing back up to renewables, and in the longer term we see an important role for gas with CCS”. After 2030, the Government expects to use gas fitted with CCS but will rely on gas without CCS only as needed for backup power. Critics are concerned that recent developments will simply allow gas to be used as a feedstock unabated for decades to come and with no serious commitment to capturing emissions. This would be a setback for commercialization of CCS, which will require substantial lead time.
Between now and 2030, world fossil use for power is projected to almost double. Without CCS on both gas and coal, it’s ‘game over’ on climate change. Renewables, energy efficiency and nuclear power can prevent some of this fossil growth, but even with massive increases in use of these alternatives, the fossil CO2 footprint will be huge.
To be sure, natural gas CCS faces challenges. Natural gas is presently cheap and new natural gas plants without CO2 controls promise reduced CO2 and at the same time the least expensive source of new power. Yet, in the long run, reliance on natural gas alone now may serve to delay rather than speed greenhouse gas reductions from the power sector. CCS needs to be commercialized now to make genuine progress in reducing greenhouse gases from fossil power. The cost gap could be reduced if stricter CO2 emission limits on gas plants are imposed, incentives for enhanced oil recovery are expanded, and if governmental support for commercial scale-up of CCS is increased, rather than diminished.
At a time when progress on climate change seems stalled because CO2 emissions continue to grow worldwide, natural gas CCS creates a new lower cost low carbon option that can drive down global CO2 emissions and accommodate energy demand growth in the next half century.