FORGET coal, it’s too dirty. Forget nuclear power, it’s too expensive and controversial. Forget renewables, they’re too unpredictable. To meet our energy needs and cut carbon emissions we need an abundant source of clean, cheap energy, available night and day and in all weathers.
We may be in luck. Natural gas is such a fuel, and it’s sitting right under our noses in abundance. Predominantly methane, it’s the cleanest-burning of all fossil fuels (see chart), so using gas rather than coal to generate electricity could halve greenhouse gas emissions from traditional coal-fired power plants.
But hang on a minute: aren’t natural gas reserves depleting just as quickly as oil? And aren’t most reserves found in countries that might not want to share their riches with the rest of the world? Back in 2006, a political spat in Europe led Russia to temporarily cut off its supply of gas to Ukraine. All of a sudden, gas seemed to have just as many problems as other fossil fuels.
While that may have been the case four years ago, things are changing fast. New technology to extract natural gas from what’s euphemistically called “unconventional” deposits means previously gas-poor countries in the Americas, Asia and western Europe could have enough cheap gas to last for another 100 years at present rates of consumption (see diagram).
Unconventional gas tends to be trapped in impermeable hard rock or sandstone, contained within coal seams, or – most promisingly for gas producers – in shale deposits. For Vello Kuuskraa, president of Advanced Resources International, an energy industry consultancy based in Washington DC, unconventional gas “has the potential for changing the long-term outlook for natural gas in a very dramatic way”.
The world consumes around 3 trillion cubic metres of natural gas each year, and the European Union says reserves from proven and conventional sources will run out in 2068. Unconventional reserves could buy us at least an extra 60 years at current rates of consumption. According to research in the late 1990s by Hans-Holger Rogner at the University of Victoria in British Columbia, Canada, there could be 900 trillion cubic metres of unconventional gas worldwide, half of which is shale gas. Of this, the International Energy Agency estimates 180 trillion cubic metres will be recoverable.