The Solar / Carbon Equation

I’ve noticed a slew of stories relating to CO2 emissions and solar technology lately. It’s not surprising, given how closely the two issues are related and how close we are to a tipping point in the environment. It’s also not surprising that there is so much misinformation out there as a result of poor science education and intentional deceit. So let’s set a few things straight, starting with the most basic, but keeping it as simple as possible for those of us that hated chemistry class. If you make it through this one page, you might just understand what the fuss is about, and what to do to fix it.

Carbon, you see, is either a blessing and a curse, depending on where it lives. Carbon is fairly important to us — it’s only the basis of all life on Earth, along with Oxygen, Hydrogen, and Nitrogen — without it, we simply wouldn’t exist. We’re literally made of the stuff, as is coal, diamond, sugar, carbon-monoxide, carbon-dioxide (CO2), and methane gas, to name a few.

Hydro-carbons like sugar, coal or oil, store easy energy in carbon bonds. Our bodies generally get their fuel from sugars, adding oxygen and liberating the carbon atoms — and enough energy to keep us alive. But as with all burning of carbon, carbon + oxygen escapes as a gas. And with too much of that gas in the air, things really start to heat up. Too much sunlight gets trapped in the atmosphere, and the Earth gets cranky to life as we know it.

The best and most natural solution to global warming has always been the idea of "sequestration" — storing carbon where it can’t do harm, vs. in the atmosphere. And that’s been going on naturally for a billion years before we lit our first camp fire. Plants take water and CO2 from the environment and use sunlight to create the sugars we depend on. They later burn those sugars (just as we do) for energy, putting some of that same carbon back into the air. The remainder is used for building new cells, growth, and fruit. But 100% of the carbon taken in — every last atom — is set free the end, once the plant decomposes or is burned. Plants are, by natural design, a temporary solution.

The only question is: how long can the plant keep that carbon? In the case of oil or coal in the ground, the answer is hundreds of millions of years — practically forever — until we come along and burn it. And that’s the key to understanding this crisis — no carbon is created or destroyed in this cycle. But it can be stored for millions of years in a harmless form, until we burn it, and send it into the air. That’s true whether the carbon comes from burning spinach, coal, or oil. Once burned, sequestration is over, until some other plant recaptures that carbon and sequesters it all over again.

Which is why, when it comes down to it, coal is just as bad as natural gas is just as bad as oil or even the new ecologically friendly biomass technologies that are coming on line, at least when it comes to the greenhouse effect. There are varying amounts of carbon and energy in each of those forms, and varying methods for trying to sequester the carbon. But it’s all the same in the end. They all burn carbon to release energy. They all result in CO2 or other carbon-based gases escaping and harming the planet, from our point of view.

It’s the unnecessary burning that has to stop. A little is fine. Plants and animals will obviously need to exhale CO2 and other carbon gases to survive. But wholesale burning of hydrocarbons is too much for the planet to absorb — it just can’t handle it.

Fortunately, there are forms of energy release that don’t involve burning carbon. Solar energy is completely carbon-free, unlimited, and incredibly simple. And it has always been the key to energy independence, despite lots of false claims and misdirection. The principal challenges have always been cost and storage of energy, e.g., at night. But it’s pretty clear that if we put anywhere near the money into solar as we do into oil and coal, we’d solve those problems in no time.

For example, we put about $2B a year into coal, in R&D and tax subsidies. We put trillions more into oil — this war in Iraq alone is going to cost us 1 trillion, not to mention all of the normal oil subsidies, tax breaks, foreign policy, and cheap rights to drill on public lands. Solar gets about one 1/20th of our coal budget and one thousandth of what we spend to offer consumers such relatively cheap oil.

So what will it take? There are a lot of options, actually. The simplest is solar heating of water to steam, which can drive turbines or special engines to make electricity. Next up the chain is photo-voltaics, solar-to-electric converters, which are now at least as efficient as any organic solar process. It’s gotten to the point where solar would be cheaper than any other energy form, if it weren’t for the other subsidies. And the only thing holding us back is the political will, and the best way to store all that extra energy.

But in terms of the future, solar-chemical energy is getting even more interesting. Just as plants currently take sunlight + water + CO2 to make sugars, we may someday be able to engineer plants or machines that produce energy and permanently sequester carbon at the same time. What would happen, for example, if an organic machine, instead of producing sugar using photosynthesis, resulted in pure hydrogen and oxygen in storage tanks? Combining those later releases no carbon, but lots of energy. And with some of that excess energy, it’s not hard to imagine plants that actually take CO2 from the air and turn the carbon into nanotubes — a material as important as iron, steel or plastics were in their respective revolutions.

Now that’s sequestration. Imagine it — a roof covered in plants that turn sunlight into electricity or heat, store it indefinitely, and also turn any found carbon into useful household products.

We’ve got a lot of work to do. But we’re not getting there until we give up on oil, coal, and anything burned.

In some sense, we’re still at the dawn of civilization, burning kindling for warmth and light. Aren’t we ready to move on to the next phase? Given our impact on the planet, isn’t it finally time to evolve?