This month, the Intergovernmental Panel on Climate Change will begin releasing its fifth assessment report. Like earlier reports, it will undoubtedly lead to more calls to reduce emissions of carbon dioxide worldwide.
As the discussion unfolds, I would urge everyone to keep four numbers in mind: 32, 1, 30 and 1/2. These are the numbers that explain why any transition away from our existing energy systems will be protracted and costly. Lets take them in sequence.
First, 32: Thats the percentage growth in carbon dioxide emissions that has occurred globally since 2002. In the past decade, these emissions have increased by about 8.4 billion tons. And nearly all of that has happened in the developing world. In Asia, emissions rose 86 percent; in the Middle East, 61 percent; and in Africa, 35 percent.
In the U.S., meanwhile, carbon dioxide emissions were 8 percent lower in 2012 than they were in 2002, largely due to a surge in shale gas production, which has reduced coal use. In Europe, carbon dioxide emissions have been essentially flat for a decade.
That 32 percent increase in global carbon dioxide emissions reflects the central tension in any discussion about cutting the use of coal, oil and natural gas: Developing countries -- in particular, fast-growing economies such as Vietnam, China and India -- simply cannot continue to grow if they limit the use of hydrocarbons. Those countries refusal to enact carbon taxes or other restrictions illustrates what Roger Pielke Jr., a professor of environmental studies at the University of Colorado, calls the “iron law of climate policy”: Whenever policies “focused on economic growth confront policies focused on emissions reduction, it is economic growth that will win out every time.”
Over the past 10 years, despite great public concern, carbon dioxide emissions have soared because some 2.6 billion people still live in dire energy poverty. More than 1.3 billion have no access to electricity at all.
Now to the second number: 1. Thats the power density of wind in watts per square meter. Power density is a measure of the energy flow that can be harnessed from a given area, volume or mass. Six different analyses of wind (one of them is my own) have all arrived at that same measurement.
Wind energys paltry power density means that enormous tracts of land must be set aside to make it viable. And that has spawned a backlash from rural and suburban landowners who dont want 500-foot wind turbines near their homes. To cite just one recent example, in late July, some 2,000 protesters marched against the installation of more than 1,000 wind turbines in Irelands Midlands Region.
Consider how much land it would take for wind energy to replace the power the U.S. now gets from coal. In 2011, the U.S. had more than 300 billion watts of coal-fired capacity. Replacing that with wind would require placing turbines over about 116,000 square miles, an area about the size of Italy. And because of the noise wind turbines make -- a problem that has been experienced from Australia to Ontario -- no one could live there.
Theres no question that wind energy is growing rapidly. Last year, global production of electricity from wind totaled 521 terawatt-hours, a fivefold increase over 2005 output. Thats more than five times the contribution made by solar, which produced about 93 terawatt-hours of electricity last year. And while the rapidly declining cost of solar panels that weve seen over the past few years is encouraging, any major move toward renewable energy would require installing a staggering number of wind turbines -- on vast tracts of land.
Could wind turbines be moved offshore? Sure. But thats unlikely to make them less controversial -- look at the years-long fight against the Cape Wind project proposed for Nantucket Sound, off the coast of Massachusetts. Furthermore, offshore wind turbines cost about three times as much as turbines on land.
Now lets turn to the third number: 30. This represents the massive scale of global energy use, which is about 250 million barrels of oil equivalent per day, or the output of about 30 Saudi Arabias. (Since the 1970s, the Saudis have produced about 8.2 million barrels of oil per day.) Of that 30 Saudi Arabias of daily energy consumption, we get 10 from oil, nine from coal, seven from natural gas, two from hydro and 1 1/2 from nuclear.
That remaining 1/2 -- the final number -- represents the amount of energy we get from all renewable sources, not counting hydropower. In 2012, the contribution from all of those sources amounted to about 4.8 million barrels of oil equivalent per day, or roughly one-half of a Saudi Arabia. Put another way, we get about 50 times as much energy from all other sources -- coal, oil, natural gas, nuclear and hydropower -- as we do from wind, solar, geothermal and biomass.
The essential truth about energy transitions is that they occur over decades, even centuries. That can be seen by looking at coal, the worlds fastest-growing source of energy. Yes, coal use in the U.S. is declining. But its soaring in the developing world. Its also booming in Europe. Germany -- which has more solar capacity than any other country -- is building 11,000 megawatts of new coal-fired power plants.
Last year, global coal use surged by 2 million barrels of oil equivalent per day -- three times as much as nonhydro renewables grew. That increase in coal use, more than any other factor, is what is driving the rise in carbon dioxide emissions.
There are two punch lines here: First, climate scientists can warn us about carbon dioxide emissions and their effect on the atmosphere and global temperatures, but politicians cannot ignore the basic physics and math of the worlds $5 trillion-a-year appetite for energy.
Second, if policy makers are committed to reducing global carbon dioxide emissions, then they will have to get serious about promoting sources of electricity production that can compete with coal on price. Those sources must be scalable, meaning they can be deployed all over the world fairly rapidly, produce fewer carbon emissions than coal, and not take up too much land.
Fortunately, we already have those energy sources. They are natural gas and nuclear.
Original Source: http://www.bloomberg.com/news/2013-09-20/four-numbers-say-wind-and-solar-can-t-save-climate.html