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North Dakota natural gas fields can be seen from space

NPR's Robert Krulwich circled this bright spot on a night-time satellite image of the United States. As Krulwich points out, this cluster of lights is new — it wasn't there in 2005. And it's not a city.

Instead, that bright spot is a shining reminder of the natural gas boom. What you're seeing are the lights from drilling rigs and flares burning gas.

Fracking earthquakes

Human activities can cause earthquakes. It sounds a little crazy to say, but it's something we've known about for a while. For instance, seismologists say that a 6.3 magnitude quake that struck India's Maharashtra state in 1967 was directly caused by the 1963 construction of a major dam and reservoir project in that region.

Basically, fault lines exist. When we start messing with them—applying very heavy weights, taking very heavy weights away, or lubricating the fault line with various liquids—we can trigger movement. Usually, these are not large earthquakes. But they can be felt. And they are something we want to avoid.

Now, a study done by the Ohio State Department of Natural Resources has concluded that a series of small quakes in that state were directly caused by improper disposal of wastewater from a natural gas fracking operation.

Fracking, as a reminder, is a process of freeing up trapped natural gas by injecting liquid into the Earth. The force of the water cracks rocks so the gas can flow through. This is not the part of the process that's been implicated in the Ohio earthquakes, however. Instead, it's about what happens to that liquid once the fracking is done.

Fracking liquid is called "brine" and it's often referred to as being water, but it's actually water mixed with a lot of other stuff, some of it toxic. Wastewater treatment plants aren't set up to deal with this kind of contamination, so the standard way of disposing of this liquid is to pump it into the ground. In Ohio, regulators say, the site chosen for wastewater disposal wasn't vetted carefully enough. Instead of being geologically inert, it turned out to be the site of a fault line. The liquid lubricated the fault line and helped it move. The result: Earthquakes.

Now, according to the Associated Press, fracking operations disposing of wastewater in Ohio are going to have to follow much more stringent rules and provide a lot more geologic data to the regulators before they'll be allowed to pump any more liquid into the ground. The report states that this process can be done safely. It just wasn't being done that way.

Image: Earthquake damage - Bridge Street., a Creative Commons Attribution Share-Alike (2.0) image from 23934380@N06's photostream

Natural gas and the trouble with estimating fossil fuel reserves

Over the past few years, I've heard several people in the natural gas industry estimate that the United States is sitting on 100 years worth of natural gas. Every time I've heard the 100-year estimate batted around, it's been presented as a positive thing, a shorthand way of saying, "We've got tons of home-grown energy, people! We don't need to worry about the future of energy at all!"

It's an interesting example of the fundamental disconnect between short-term and long-term thinkers.

All things considered, 100 years is not really a very long time. Especially given the fact that estimates like this are based on current natural gas usage rates, but are presented with an implication that we should be using more natural gas than we currently do. I don't think that a 100-year-supply of something as critical as energy represents a time of plenty. I think it represents a ticking clock. At best, what you've got there is a transitional energy source—something with the potential to be cleaner and less politically complicated than coal and oil, that you can use while you build up an energy infrastructure based on something other than fossil fuels.

But the critique of that "100 years of gas" estimate goes even deeper. That's because any estimate of fossil fuel reserves is made under the limitations of corporate secrecy. Different well owners estimate reserves in different ways, so you can't just add up everybody's estimates and compare apples to apples. There's no way for independent sources to check estimates. And there's not really any independent bodies reviewing the state of fossil fuel reserve estimation science. (The closest you'll get to that is a review of oil reserves done in 2009 by a small group of researchers in the US and UK.)

Meanwhile, as energy analyst Chris Nelder points out on, if you take a close look at the information about the estimates that is available, you'll find that "100 years of natural gas" doesn't necessarily mean 100 years of natural gas.

But what is that estimate based upon? Those details haven’t been made freely available to the public, but their summary breaks it down as follows here and in the graph below: 273 tcf are "proved reserves," meaning that it is believed to exist, and to be commercially producible at a 10 percent discount rate. That conforms with the data of the U.S. Energy Information Administration. An additional 536.6 tcf are classified as "probable" from existing fields, meaning that they have some expectation that the gas exists in known formations, but it has not been proven to exist and is not certain to be technically recoverable. An additional 687.7 tcf is "possible" from new fields, meaning that the gas might exist in new fields that have not yet been discovered. A further 518.3 tcf are "speculative," which means exactly that. A final 176 tcf are claimed for coalbed gas, which is gas trapped in coal formations.

I'd recommend reading Nelder's full article. It's a nice summary of why estimates of fossil fuel reserves need to be approached skeptically, why the job of measuring this stuff is difficult to begin with, and why we don't really have enough information to declare a "Golden Age" of natural gas.

Image: Natural Gas Flare, a Creative Commons Attribution Share-Alike (2.0) image from rickhurdle's photostream