31/10/2012 12:54 GMT | Updated 27/12/2012 05:12 GMT

Natural Gas as the Backbone of a Sustainable Energy System


By Wim Thomas

If we are serious about meeting our long-term energy needs in a sustainable way, then we need to get serious about using natural gas to provide the backbone of a low carbon energy system. For early gains in cutting CO2 emissions, natural gas can replace coal in power generation cost-effectively. Gas-fired power generation can also provide the flexibility to accommodate a growing share of renewable energy, which by nature is intermittent and needs back-up - for example when the wind does not blow or at night when solar PV panels do not work. That's why natural gas should become a core part of our future energy mix.

The world's population is set to reach some nine billion people by 2050 and that population is becoming more prosperous; it will need a lot of energy. The emerging middle classes in economies in cities like Sao Paulo, Mumbai and Shenzen rightly want access to a similar quality of life that we enjoy here in the developed world. By 2050, energy demand will likely double the 2000 levels and providing this at a much reduced carbon footprint will be a huge challenge. Most if not all future growth in energy related CO2 emissions will come from these emerging economies. The task for the developed world is to develop cost effective carbon mitigation technologies that can be deployed affordably in these fast-growing economies.

Why go for gas?

Gas is a vital part of how we can meet these challenges because it is abundant, acceptable and affordable. The progress we're making on renewable energy is crucial, but even with Government subsidies, our analysis shows only 20 to 25% of the world's energy needs can be met from renewables by 2050. This leaves a big gap to fill. Natural gas can and must help fill this gap if carbon reduction targets are to be met. The benefits of gas can be summed up with what we call 'The Three A's':

Abundance - on a very practical level, there is a lot of gas which can be economically and safely extracted and used for our energy needs. There's enough to last us 250 years at current consumption levels according the International Energy Agency. This means gas can provide a long-term solution, but it must be de-carbonised (at some stage) to be able to become, with renewables the backbone of a sustainable energy system.

Acceptable - burning gas is considerably cleaner than burning coal. The growth in coal-fired power generation is responsible for the fastest increases in CO2 emissions worldwide. In contrast, modern gas plants emit around half the CO2 of modern coal plants and emit significantly less than one-tenth the particulates associated with health problems. Better still, combining natural gas with carbon capture and storage (CCS) can reduce a power plant's CO2 emissions by up to 90%.

Affordable - Gas fired power plant investment costs are significantly lower per MWh than coal, nuclear or renewables, and even with fuel and operational costs it remains competitive. The need for cleaner sources of energy is urgent, but building new infrastructure for renewables will take decades and large scale CCS technologies are still in a demonstration phase for reducing costs. We can't wait 20 years for these technological advances, so choosing gas now can reduce CO2 emissions immediately by replacing coal - giving us a window of time to build an infrastructure that offers more options later.

What we need for a gas future in the UK

The environmental and economic advantages of natural gas are clear but there are a number of critical factors that need to be met if the UK is to realise the benefits of gas.

Best is a strong and functioning carbon market that sends the right price signals for power generation that incentivises investments in low-carbon technologies such as Carbon Capture and Storage (CCS). We need clarity on the long-term role of gas within the energy mix: yes, renewables need to play an important part, but gas will be needed to provide the natural backbone of such systems, by providing cost-effective flexibility to accommodate a growing share of renewables.

Finally, we want a renewed sense of urgency from industry and governments to move CCS forward. CCS with gas must be practical on a commercial scale no later than the late 2020s if the long-term goals of a lower carbon future to 2050 is to be assured.

This will in turn help us to meet the energy needs of the nine billion people who will live on our planet by then - but at a much reduced carbon intensity of their economies, enabled by the western world developing cost effective lower carbon technologies now.

Wim Thomas is Chief Energy Advisor at Shell.

Watch Thomas speaking at the recent Intelligence Squared event 'A Natural Gas Revolution: Hot Air or Dose of Sanity. An Evening of Debate'. The event, which featured four other world experts on gas, was part of the Switched On series of live debates and discussions in partnership with Shell.