Eight Reasons Gas Can Be Green

on June 17, 2011 at 1:45 PM

Last week was a good one if you happen to own a natural gas well. Two reports on the outlook for natural gas, both in the U.S. and worldwide, gave a glowing assessment of the fuel’s future prospects.

The International Energy Agency (IEA) cheekily titled its report, “Are We Entering a Golden Age of Gas?” The conclusion: global gas use will rise, in one scenario, by more than 50 percent by 2035. So, yes, it would seem the “golden age” is nigh. Meanwhile, the U.S.-centric report from the M.I.T. Energy Initiative, “The Future of Natural Gas” blasted critics who claimed that gas, when it comes from shale formations, is worse for the environment than coal.

Of course, your impression of these reports may differ if you’re a climate change activist rather than, say, a Chesapeake Energy shareholder.

The IEA report, for example, concluded that increasing use of gas puts greenhouse gas emissions on a trajectory to stabilize at 650 parts per million, which would bring a long-term temperature rise of 3.5 degrees Celsius.

This figure, by any measure, is an unacceptably high level of warming and made Climate Progress blogger Joe Romm, very unhappy: “Absent a high CO2 price,” Romm wrote, “gas displaces as much low-carbon electricity as it does high-carbon coal.”

But there are many reasons to think Romm and IEA are being overly pessimistic. While it’s clear that an elevated carbon price – for example, a carbon tax – would incentivize the adoption of renewable energy, gas could, in the near term, mean the end of coal as a major fuel source. It can encourage the adoption of renewables along a realistic timeline – one that allows green technology to catch up with green ambition.

Here are some reasons why:

1. Natural gas enables renewable energy. Natural gas power plants can fire up quickly and adjust their power output rapidly. That makes them the ideal dance partner for wind and solar, which are variable energy sources. There may be a time in the next few decades when renewable resources don’t need fossil fuel backup, but we’re not there yet.

2. Renewable portfolio standards (RPS) mandate renewables. A growing number of states and countries are requiring a certain percentage of wind, solar and other non-fossil fuel on the electrical grid. In California, for example, that target is 33 percent renewable energy by 2020. In the European Union, the target is 33 percent by 2020. As long as legislators hold the line on those mandates, natural gas can’t crowd out renewables.

3. Integrated Solar Combined Cycle is crazy efficient. Modern natural gas plants working in combined cycle – a configuration that uses waste heat to drive a steam turbine – have efficiency ratings in the upper 50 percent/60 percent range. Introduce concentrated solar power (CSP) to the equation and efficiency can shoot up to 70 percent. How? CSP uses mirrors, or heliostats, to direct sunlight that boils liquid in a central tower. The steam then drives a turbine to create electricity. In this new configuration, the CSP can share the steam turbine and increase the efficiency of the system without burning any more fuel. General Electric, this magazine’s sponsor, has teamed up with CSP pioneer eSolar to introduce this technology.

4. Carbon Capture and Storage (CCS) is advancing. CCS is often discussed in conjunction with coal but the technology, which involves storing carbon dioxide from power plants underground, has perhaps even more potential for natural gas.
This technology actually works – it’s been tested and proven at multiple sites – but is still too expensive to deploy at scale. While some in the environmental community think utility-scale CCS is a Macguffin, others believe it has enormous potential for decarbonizing energy if costs can be brought down.

5. Methane emissions from natural gas can be curbed. Recent attacks on natural gas have focused on leaks of methane, the principal component of gas and a potent greenhouse gas, during its lifecycle – the drilling, transportation and end use. While the most dire scenario of lifecycle emissions has been discredited by some researchers, methane emissions remain a problem. But it’s possible to recapture the leaking methane and there is an incentive for industry to do it, since this is fuel that can be sold.

6. Gas plants can, and likely will, knock out old coal plants. This is a point made in the IEA report but it’s worth stressing. In the U.S., tightening emissions regulations will make coal plants expensive to retrofit and natural gas plants, which emit about half the carbon dioxide, will likely pick up the slack. The emissions savings in the United States could be 150 million tons of carbon per year if 66 gigawatts of coal plants are replaced, according to one estimate. Just Thursday, one utility, American Electric Power of Ohio, announced plans to shut down five coal-fired plants by 2014 to comply with the new guidelines.

7. There is a lot of idle natural gas capacity on the grid. Those power plants are of a relatively recent vintage – most were built in the 1990s – so they’re efficient. This means that the emissions savings from natural gas are already built into the system, they just need to be activated. M.I.T. researchers believe total carbon emissions in the U.S. could decrease by 8 percent if natural gas plants are utilized at a higher level.

8. China has a lot of natural gas, which is a good thing. For all the talk about China’s renewable power ambitions, right now coal is the superpower’s fuel of the future: gas is expected to represent 63 percent of primary energy consumption by 2015. Continued dependence on coal will have disastrous consequences both for carbon emissions and for pollution in China’s already smoggy megacities. Tapping China’s vast gas resources could help make cities cleaner and electricity generation less carbon intensive.

Picture: eSolar’s CSP technology, which will be paired with natural gas to drive up efficiency. Courtesy eSolar.

This blog was originally published on GE’s The Txchnologist.

Breaking Energy Editor’s Note: Breaking Energy published an opposing view on natural gas this week, The Gas Is Definitely NOT Greener. We would love to hear your opinion about this contentious issue – please leave your comment below.