A Thousand Splendid Power Plants

Xcel Energy’s Valmont East Terraforming Station in Boulder, CO. As a side effect, it powers all the lights you see in the background.

James Watt’s industrial revolution was fired by coal, is fired by coal, and shall be fired by coal under the current plan, until death do us part.  Anthracite, lignite and bituminous — it is all nearly pure carbon, sequestered in the shallow inland seas of the Carboniferous, scavenged from a powerful greenhouse atmosphere by the first macroscopic life to colonize the land, 350 million years ago.  It was into these scaly fern tree forests, club mosses, cycads, and giant horsetails that we tetrapods laboriously crawled so long ago, to gasp our first desperate breaths.

Industrial power, carbon and coal are deeply synonymous.  The SI unit of power is named for Watt, and the word “carbon” is derived from the Latin carbo, which means coal.  Many of the super-human abilities we are accustomed to wielding today are intimately bound up with this strange rock that burns.  Our purpose in burning it is to release usable heat, and we consider the release of carbon dioxide and other pollutants to be a side-effect of that process.  In the fullness of time I suspect we will come to see that relationship reversed.  When we look back at today’s coal fired power plants a few centuries from now, we won’t see them as electricity generators.  We will instead see them as components of a massive, coordinated and yet unintended climatic engineering project.  We are effectively terraforming the Earth, participating in the transformation of our planet as a new force of nature.  It’s not the first time life has done something like this.  The cyanobacteria began pumping oxygen into the atmosphere 2.5 billion years ago, incidentally making both fire and macroscopic organisms possible for the first time.  And also incidentally oxidizing away a lot of previously stable atmospheric methane, a powerful greenhouse gas, plunging the Earth into the deep freeze for three hundred million years.  I hope that we can be more mindful of the consequences of our actions than the blue-green algae were, but honestly I’ve got my doubts.

I’m not just trying to be poetic here.  The energy released in the combustion fossil fuels is literally dwarfed by the amount of heat the resulting CO₂ ultimately traps on Earth.  Running 10 terawatts (a terawatt = 1 TW = 10¹² W) of fossil fuel power for a century results in a radiative forcing of a few W/m² globally for 500-1000 years.  The surface area of the Earth is about 5 x 10¹⁴ m², and so we can calculate a rough ratio between the fossil energy we use, and the solar energy we eventually accumulate as a result.  I’ll use terawatt-years as an enormous unit of energy:

(10 TW) * (100 yrs) = 1000 (TW yrs)

So a century’s worth of global industrial civilization (say, 1930-2030 or 1950-2050), powered as it is now, needs something like 1000 terrawatt-years of fossil fuel energy.  The International Energy Agency says in its 2010 World Energy Outlook that if nations actually follow through on their excruciatingly modest 2009 Copenhagen pledges, we will roughly double of the CO₂ content of the atmosphere to 650 ppm, which gives a radiative forcing of about 4 W/m².  We can get a total additional solar power input equal to that (power per area) x (surface area of the Earth):

(4 W/m²) * (5 x 10¹⁴ m²) = 2000 TW

Now, the thing is we’re going to get that additional solar energy input for a long, long time.  We’ll have to live with it for about 500 years.  To get the total energy ultimately absorbed, we need to multiply the above power by that duration:

(2000 TW) * (500 yrs) = 1,000,000 (TW yrs)

Meaning that for every unit of primary energy we extract from fossil fuels, we also get a thousand-fold that much energy ultimately absorbed by the Earth from the Sun.  This is why I say that the useful power we think of as the primary output of our generating stations seems more like a side effect of the CO₂ emissions.  We get a little bit of heat today and we use it to smelt the iron ore, or pump the water out of our mines, or turn the gears in our textile mills, or run our air conditioners in Phoenix and our datacenters in San Francisco, but we get much, much more heat as a result of the change wrought on the atmosphere by that combustion.  Clearly this calculation is a simplification, but when all you’re interested is a sense of scale, simplifications can be very illuminating.  That’s probably the most useful thing I ever learned in physics.

The coal trains which feed Denver’s terraforming stations. Soon all that carbon will be part of the atmosphere.

Unfortunately, we know that several positive feedbacks do exist, and so this is an underestimation.  Without those feedbacks, doubling CO₂ would result in about a 1°C increase in surface temperature, with them the heating is roughly 4°C.  This relationship between how much change you put into the system and how much you get out is known as the climate sensitivity.  So instead of a thousand-fold multiplier, it’s more like 4000-fold.

A typical coal-fired power plant is a few hundred megawatts to a gigawatt of primary power.  But if instead you see them through time-lapse eyes, looking back from the future — if you see them as the terraforming stations they really are, if in your mind you let them embody the heat which is the necessary consequence of their operation, as if they were massive campfires, trying to warm one of the many dark and sunless wandering worlds between the stars, then each one represents 1-4 terawatts.  Each one is a blazing inferno as intense as a Saturn V rocket at liftoff — enough power to accelerate a sizable building to 25 times the speed of sound in two minutes.  They burn day and night, by the tens of thousands, scattered all around the globe.  If you lived within ten miles of one (and you probably do), you would hear the roar and crackle of those fires.  You would feel them rumbling in your chest.  You would be able to read by their light at night.  They would be an ever present reminder of the heroic project we have embarked on, to restore the Eocene cypress swamps and alligators to Ellesmere Island in Canada’s high arctic.

http://www.youtube.com/watch?v=2rXtG3vfAlA

As it is, we ignore this extra-terrestrial effort, because the CO₂ dissolves seamlessly into the sky.  Instead of searing localized conflagrations, the heat will come silently by sunlight over centuries, distributed evenly across all the Earth’s continents and oceans, and then buried deep within the thermally swelling waters.  Then one year or one lifetime, change will come on a timescale we can relate to.  The monsoons will fail utterly, or a grounded ice shelf will finally collapse, and a billion people will be starved or chased from the coastal cities, and we will act surprised.  It is precisely the same story that was told in 1877 by William Kingdon Clifford in The Ethics of Belief, but writ ten million times larger:

A shipowner was about to send to sea an emigrant-ship. He knew that she was old, and not overwell built at the first; that she had seen many seas and climes, and often had needed repairs. Doubts had been suggested to him that possibly she was not seaworthy. These doubts preyed upon his mind, and made him unhappy; he thought that perhaps he ought to have her thoroughly overhauled and refitted, even though this should put him at great expense. Before the ship sailed, however, he succeeded in overcoming these melancholy reflections. He said to himself that she had gone safely through so many voyages and weathered so many storms that it was idle to suppose she would not come safely home from this trip also. He would put his trust in Providence, which could hardly fail to protect all these unhappy families that were leaving their fatherland to seek for better times elsewhere. He would dismiss from his mind all ungenerous suspicions about the honesty of builders and contractors. In such ways he acquired a sincere and comfortable conviction that his vessel was thoroughly safe and seaworthy; he watched her departure with a light heart, and benevolent wishes for the success of the exiles in their strange new home that was to be; and he got his insurance-money when she went down in mid-ocean and told no tales.

Only we have no insurance, nature doesn’t do bailouts, and we are passengers on the ship.

The shadows cast by other sources of power are not as long as fossil fuels, but they are sometimes more obvious.  We must admit that there’s no way to get access to tens of terawatts without serious unintended consequences.  We may carpet our deserts with mirrors and saline bags of genetically engineered algae, and fill our mountain passes and seaside views with wind turbines.  We might choose to live with the possibility of nuclear weapons proliferation and a long-term responsibility to store radioactive wastes.  We may even go so far as to change what we call wealth.  We must also consider living in a world with many, many fewer of us overall.  In all likelihood, we will pursue some combination of these strategies.

Because we won’t keep doing what we’re doing — we could’t, even if we wanted to — and I for one don’t want to anyway.