Among those who spend their working lives and/or spare time worrying about climate change, there are many subjects that still provoke heated debates, so to speak. Chief among them is the wisdom or folly of turning to natural gas as a “bridge” between the carbon-intensive oil- and coal-dominated present and the clean renewable future that we all know is coming sooner or later. The opponents just found their case a little bit stronger thanks to another controversial issue: nuclear power.

Natural gas is, as anyone with a basic grasp of the fundamentals of greenhouse gas forcings can tell you, only  half as good at warming the atmosphere as coal. So replacing coal-fired plants with natural gas alternatives should get us half-way to cutting our emissions to zero. Right?

Well, not quite. Natural gas is almost entirely methane, which has 20 times the warming potential of carbon dioxide over a century, and several times that in the near-term. And as all operations involving natural gas also involves some release of methane directly into the air, the effect of that methane has to be added to the calculations used to compare the emissions impact of each fuel.

Let’s say for argument’s sake an operator could get “fugitive” emissions of methane down to 1 or 2 percent, which is quite possible, though much lower than what is probably the industry norm these days. Consider also that gas-fired plants are more efficient than coal. So the best-case scenario is gas will cut the effective warming of gas by 30 to 40 percent. Whether that is sufficient given the amount of time we have left before triggering irrevocably serious climate change is also a matter of some debate. After all, we know we need to get to zero, so why pour scare resources into switching to one alternative only to spend even more in a decade or so to switch again?

But all this is only relevant when comparing gas with coal, which supplies only about 40% of the American electricity mix. What about nuclear power? Its carbon footprint is measurable, but tiny compared with coal. So if you replace a nuke with a gas-fired plant, you’ve increased your emissions budget from near-zero to 100% of whatever the non-nuclear alternative was.

Geoffrey Lean at the Telegraph asks “Is shale gas killing nuclear power?” Several nuclear power plants in the U.S. are being replaced by gas, undoing a significant portion of whatever minor advantage gas presents in the effort to reduce carbon emissions.

Add to this the complicating factors of the cooling aerosols associated with coal, and natural gas is starting to look more than a little problematic.

Yes, natural gas can provide real carbon-emissions reductions in some situations. It’s relatively easy to install, the technology is well understood, and it’s a fossil fuel, so the status quo doesn’t feel so threatened. But the math suggests it isn’t going to do the trick.

Comments

  1. #1 Lyle
    March 14, 2013

    Actually natural gas is better also because a new combined cycle plant is 50% more efficient at turning the energy in methane into electricity compared to coal (60%+ to at best 40% for coal). That is because a gas turbine has a higher combustion temp that the steam in an turbine in an external combustion coal plant, and Mr Carnot, says that higher top temps yields more efficiency in any mechanical process.
    As to nuclear, the main issue is it takes to long to build and when you start you have no idea what power will cost or when the plant will be done, since an aweful lot of it is still custom building. A combined cycle plant is more standardized and takes a far shorter period to build, thus meaning better understood costs, and thus electric pricing.

    Assume a de-regulated environment such as CA or TX has. You are an electric retailer and need more power to meet your customers demand, do you sign a contract for more power in 3 years at a fairly well constrained price, or in 10 years and a price that can vary widely? Going nuclear for these folks is a ticket to bankruptcy, thus in deregulated states no more nuclear will be build. A regulated state allows the utility to shove whatever costs it has onto the consumers of electricity. Thus the new plants are being built in areas where more traditional electric regulation still exists. Thus Ken Lay and Jeff Skilling with their emphasis on de-regulation killed off Nuclear in the US.

    Fair points. Thanks for the numbers on the efficiency advantage of gas. And yes, nuclear does take too long. One could write volumes on the economic and practical problems with nuclear power. My point is simple that replacing a nuke with gas will lead to higher carbon emissions. — jh

  2. #2 Adam Grant
    Toronto
    March 14, 2013

    Now that wind and solar are approaching grid parity, and realistic energy storage and transmission technologies are becoming available, the world’s economies need a strong price signal to release the grip of fossil fuel companies and their owned politicians.
    Cautious optimism may be warranted, in that various blogs suggest that the current price of shale gas is held artificially low by an unsustainable influx of investor’s money, and that in a couple of years this will run out, raising US gas and oil prices as the cost of solar becomes decisively cheaper.
    Other analyses suggest that oil producing nations are keeping an increasing fraction of their production, leaving less for export, a situation that will again increase prices in importing nations.

  3. #3 Wow
    March 14, 2013

    Lyle, a solar power plant is infinity efficient in turning the energy in methane into power.

    Oh, and you know all that whining about China building 1000 coal power stations? Remember your “Modern builds are more efficient” and remember to note when complaining about China about how many coal plants they are closing, m’kay?

  4. #4 Wow
    March 14, 2013

    ” Mr Carnot, says that higher top temps yields more efficiency in any mechanical process.”

    Solar power turning photons at 6000K into energy.

    Just saying.

  5. #5 Radical Rodent
    April 25, 2013

    …the clean renewable future that we all know is coming sooner or later.” Erm, in what form, exactly?

    Also, what do you mean by “clean”, bearing in mind that anything we do will have some negative impact upon the environment? What do you mean by “renewable”, bearing in mind that there is no such thing as perpetual motion?

    Lyle presents a good argument; natural gas does seem to offer a viable solution for the foreseeable future, while nuclear keeps tantalising us, in much the same way as Tantalus was – nearly there, but never quite. However, the oil resources keep on growing; why give up on a proven winner?

  6. #6 Wow
    May 1, 2013

    In the form of renewables.

    Duh.

    Oh, and if you’re now so worried about the environment, I would suggest you move to Africa and live off the land with minimal footprint.

  7. #7 Radical Rodent
    May 3, 2013

    Renewables… such as… wind turbines? Made from… well, lookee here, hydrocarbons! Oh, yes, and rare earth metals, the extraction of which is laying waste to square miles of land. But it is only in Mongolia and China, so no need to worry about that, then. When they break, they cannot be repaired and have to be discarded to a landfill, and replaced (perhaps that is what is meant by “renewable”?) – which handily keeps the jobs going… in China.

    So, how reliable are wind turbines? Answer: not very. At their most productive, they are only about 30% efficient, however, their most frequent contribution is NIL. So, they cost more in energy to erect than they will ever return. Sounds wise to… well, you, for one, Wow. Duh.

    Solar cells? Requiring rare earth metals, similar problems as above. I have a friend who asked about installation onto his house; cost: £15,000. How long would it take to return that investment? Probably never. Double duh.

    Natural gas is a proven winner; it burns cleanly and efficiently, with minimal CO2 emissions, and there is rather a lot of it lying under our feet, almost begging to be released. So, what do we do? In the UK; nothing. We have centuries of inexpensive fuel under our feet, and we do nothing. Why? “Because it has not been tested…” or similar such excuses. But it has; the USA has been fracking shale for years, bringing fuel costs down 25% – that is £20 per month off an average UK home gas bill. Not forgetting the knock-on of cheaper gas also meaning cheaper electricity. Oooh, triple duh.

    Of course, oil is about to run out. Experts have been predicting the demise of oil in about 30 years since, well, about 1860. So, about 150 years of “soon to run out”, yet we keep finding more: under Utah and Colorado, the Green River Formation holds at least as much oil as the entire world’s proven reserves; in the Black Sea, Romania and the Ukraine are quibbling over the territorial rights for another vast field; under the Aegean lies a field at least the size of the Saudi fields.

    While I do agree that more education is needed for the preservation of species and environments, we do not need to worry about our energy reserves, or that its use will seriously affect the climate – remember, the CO2 levels are still rising, but the temperature has remained pretty steady for 16 years. Has it peaked or has it stalled? We can only wait and see. Need we be worried? No.

  8. #8 Wow
    May 3, 2013

    Renewables… such as… wind turbines? Made from… well, lookee here, hydrocarbons!

    Well, I suppose this explains your lack of accuracy about renewables. Really. You think that the power source of wind power is the turbine?!?!?!?

    ROFLMAO!

    Answer: not very. At their most productive, they are only about 30% efficient

    Get in the 21st Century, boy. 40% and growing. Meanwhile nuclear, for example, manages only about 60% efficiency.

    Natural gas is a proven winner;

    You misspelt “fossil fuel” and “non-renewable”.

    with minimal CO2 emissions

    You mean “lots of CO2 emissions”.

    and there is rather a lot of it lying under our feet

    So much, that is, until they start drilling for it, then the reserves drop 80%…

    almost begging to be released

    By which you mean “Needs forcing out of the rock with toxic chemicals and huge amounts of water”. And you already whine and whinge about hosepipe bans…

    We have centuries of inexpensive fuel under our feet

    We have billions of years of inexpensive fuel running over our coastlines.

    Experts have been predicting the demise of oil in about 30 years since, well, about 1860.

    Only 100 years out of date!

    ROFLMAO!!!

    And the USA reached peak oil in the 1970′s. As an example. We reached peak oil since some time in the 2000′s worldwide. There’s a reason why Saudi Arabia don’t let anyone see their reports on their reserves.

    remember, the CO2 levels are still rising, but the temperature has remained pretty steady for 16 years

    Entirely and utterly false.

    For example, from 2011-2012, the temperature trend was 0.6C per decade.

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