The fifth instalment of the UN Climate Change report was issued last week. A review of the commentary suggests more conviction that man-made greenhouse gases, primarily from the burning of fossil fuels, are at the root of rising global temperatures. It's not a surprising conclusion given the convincing correlations. Nor is the prescription remarkable: Reduce global emissions ASAP.
Knowing that is the easy part. An unwritten edition must reconcile the fact that a staggering 88 per cent of our uncompromising global energy needs comes from burning coal, natural gas and oil. Pulling the plug on these systems is idealistic. So astronomical is the entrenched scale and utility of fossil fuels that at current rates of consumption growth and substitution it will take 1,000 years to displace them with renewable sources like wind and solar (ARC Energy Charts). Ironically the solution to blowing less fossilized carbon into the atmosphere may be paying more attention to fossil fuels.
Globally, the root issue is the accelerated use of coal, especially in emerging economies, over the past fifteen years. World coal use is steadily growing by 5.1 per cent every year, almost four times as fast as oil on almost equal levels of consumption. The double emissions whammy is that coal is also the most carbon intense of the three fossil fuels. For every unit of energy burned, coal emits 1.5 times as much of the vilified element as oil, and 1.8 times as much as natural gas.
Let's flip those number around: On an energy-equivalent basis, burning one unit of natural gas produces 20 per cent less CO2 than burning oil, and 45 per cent less CO2 than burning coal. So, if the objective is to reverse our carbon-belching problem quickly, the most compelling large-scale substitution is swapping out coal-fired power plants – existing or proposed, wherever they may be – with natural-gas-fired units.
The benefits accruing to natural gas don't stop with lower carbon intensity. Our figure this week shows amazing 64-year efficiency trends (1949 to 2012) in U.S. power plants. Energy out divided by energy in: Efficiency in Figure 1 is the amount of electrical energy produced by the three different types of power plants – coal, natural gas and oil – divided by the amount of respective fuel consumed by those plants. Obviously, the higher the efficiency the better, because it means more of the fuel is put to useful work; or more intuitively it means less fuel is needed to keep a light bulb on. Less fuel equals less emissions.
The positive efficiency trend for natural gas is obvious, while the lack of trend for oil and coal sticks out like a sore smoke stack. Overall efficiency gains in U.S. natural gas power generation, up from 34 per cent to 44 per cent, is highly significant; compared to 10 years ago, an average utility today needs 23 per cent less natural gas to generate the same amount of electricity.
Meanwhile, the trend in coal plants is unimpressive. Average efficiency of coal power plants has not changed in 30 years. In fact, there is a slight downtrend, in part because producing power while conforming to stricter environmental standards requires equipment that demands additional energy – in other words, more coal is being burned up to drive processes to clean up coal emissions (scratch head in bewilderment now). Strapping on parasitic processes, like carbon capture and sequestration (CCS), would just cannibalize the efficiency ever more. Clean coal may be achievable, but not nearly as efficiently as the already cleaner natural gas.
In fact, the best modern gas-fired power plant today requires 35 per cent less energy to generate a unit of electricity than its coal equivalent. Cascading that fact with the low carbon intensity of natural gas means that new gas-fired systems emit approximately 65 per cent less carbon than an average coal equivalent.
Oil-fired power plant efficiency doesn't spark the imagination either, but that's because there are hardly any of these dinosaurs left in developed countries like the U.S. and Canada. Nevertheless, emerging countries still use diesel fuel for a noticeable amount of their power generation. The good news is that it's too expensive to burn oil these days, so its growth potential relative to natural gas is very limited in power generation.
Natural gas is the least carbon-intense fuel, most efficient to burn and becoming progressively cheaper with new extraction technologies. So why aren't we using more of this stuff? We're starting to in North America; U.S. data already show that "Energy-related carbon dioxide (CO2) emissions in 2012 were the lowest in the United States since 1994" (Energy Information Administration, 2013). That's called "progress." But if a dent in the global carbon emissions profile is to be made, then emerging countries need to embrace this clean, cheap and efficient fuel more readily than coal. That will be called a "solution" that need not wait for the UN Sixth Edition.
Peter Tertzakian is chief energy economist at ARC Financial Corp. in Calgary and the author of two best-selling books, A Thousand Barrels a Second and The End of Energy Obesity.