Carbon-Free Energy

Jul 18th, 2008 | By | Category: Energy, Featured Articles, Lead Article

Former Vice President Al Gore, seeking to shake up an energy debate that is focused mostly on drilling, challenged the United States to shift its entire electricity sector to carbon-free wind, solar and geothermal power within 10 years, and use that power to fuel a new fleet of electric vehicles.

Can it be done?

To answer that, let’s get to know our fossil fuels by rewinding to the Carboniferous era. Pangaea has just come together, with the fusing of the Northern and Southern super continents. Dropping sea levels have generated many new swampland real estate opportunities. Enter lignin, a chemical compound that has made wood hard for 350 million years.

These swamps were filled with plants held together by this funny, new substance—a substance too new to be eaten by microbes. Rather than degrade, the remains of lignin-baring plants soon filled swamps (much like how we’ve filled the oceans with plastic grocery bags).

Lignin, like most things in life, is made up of long chains of carbon atoms. All of this carbon-containing waste built up, becoming buried over hundreds of millions of years before bacteria evolved to eat lignin. And free oxygen didn’t reach this material, either, so those untouched hydrocarbon chains entombed deep in rock became coal. Similarly, algae buried under the ocean floor, without oxygen, eventually becomes oil and natural gas.

Convert that story to hard numbers: All of the fossil fuel consumed in 1997 represented over 400 years of the total plant and animal growth on the ancient planet Earth.

Almost all living systems eventually come back to energy from the sun. But that fact has its own astounding ratio: It took a half-millennium of solar energy capture by all of the living things to generate the energy we typically consume in a single year.

Those ratios are alarming, but they also make fossil fuels’ case. The upsides are so attractive: density (huge amounts of energy in small volumes/masses), stability (won’t lose much energy during storage or transport), and usability (fossil-fueled machines are far less complex than virtually any other power source).

All of the alternatives available to humanity are, in some way or another (complexity, initial investments, geography, distribution), inferior to fossil fuels. So when we consider ending our use of fossil fuels, the combination of alternatives we settle upon must match or exceed these properties–or we must adjust our lifestyles to reflect the inherent inferiority of the non-carbon fuel sources.

Now, in the twilight of fossil fuels, we have a shot at building such a combination. We can take the last remaining supplies of carbon fuels and build the networks of solar, wind, geothermal and nuclear power plants neccesary. Or we can accept that in the future–the near future–our lives will be far less rich than they are now.

So starts a new series here on Dear Science, where I’ll be reviewing some of the science behind wind, solar, geothermal and biomass energy. I’ve already covered nuclear power, the unwelcome (by some) member of the carbon-free energy club.