"The more I find out, the less I know."

Wed - July 5, 2006 at 10:15 PM in

There Is No Energy Problem


Conventional wisdom right now is that we (that is, the United States and the global economy) have an energy problem.

That's not quite true.

What we have are three distinct problems, all related somehow to energy.

First, we have a fuel problem. Specifically, there's a developing shortage of the stuff we most frequently use as fuel for motor vehicles.

Second, we have an electricity storage problem. There is no economical way to store large quantities of electricity to carry excess supply at one time of day to match excess demand at other times.

Finally, we have a carbon dioxide problem. Most of our biggest sources of energy release carbon dioxide into the atmosphere after that carbon had been locked underground for millions of years, causing a sharp increase in atmospheric CO2 levels.

There Is No Energy Problem
We have plenty of energy. The energy streaming onto the Earth from the Sun amounts to thousands of kilowatt-hours per year for every square meter of the Earth's surface. The roof of a typical home captures enough solar energy to more than meet that home's energy needs, even at an efficiency of solar collectors on the order of 10% or so (meaning that 90% of the energy goes wasted).

We could, in theory (and with appropriate infrastructure) meet the United States' entire energy needs through solar power with far less land than is currently devoted to growing food.

That's not even counting wind power, hydroelectric, nuclear, and other less-developed energy sources such as tides and waves.

Farms are nothing more than mechanisms for converting solar energy (plus water, labor, and fertilizer) into chemical energy in the form of corn, wheat, etc. This conversion is absurdly inefficient, orders of magnitude worse than solar electric conversion. Despite this inefficiency, we still consider it worthwhile to use corn and soybeans as a commercially viable source of fuel. That's how much extra solar energy we have.

The Fuel Problem
Unfortunately, this abundance of solar energy does not occur at the times and places we need it most, and it isn't concentrated enough to power a car (much less an airplane) with current technology. So we need concentrated chemical fuel for the energy to be useful.

Currently, we use oil and to a lesser extent natural gas. Those fuel sources are convenient, reasonably plentiful, and still (despite recent price increases) cheap. But they are not renewable, and they will run out at some point.

So the problem is finding some other source of concentrated chemical energy to use for a fuel in vehicles and for heat in the winter. Biofuels seem to be the most promising alternative right now, despite the insanely poor conversion rate from solar energy to ethanol or biodiesel.

But what we really need is some process that converts solar energy into a liquid chemical fuel without the intermediate step of growing an organism. Imagine, for example, a solar reactor which has a catalyst submerged in a mixture of carbon dioxide and water (that is, seltzer water). When intense enough light hits the catalyst, it converts the water and CO2 into a simple hydrocarbon plus oxygen.

The Electricity Storage Problem
Electricity is the most versatile of all forms of energy. Like chemical energy, electricity can be used for heat and light, but unlike chemical energy, electricity can power electronics and be converted into motion with nearly 100% efficiency (as compared to 20% to 40% efficiency for chemical fuel). Unlike chemical energy, electricity can't be cost-effectively stored, which means it basically has to be used at the same time it is generated.

Small amounts of electricity can be stored, such as in batteries and capacitors. That works for some specialized applications, like mobile power, but you can't economically power a city from giant banks of capacitors.

This is important because some of the most promising alternative sources of electricity--wind and solar in particular--are intermittent. There's no way to store the wind from a windy day to a calm one, and no way to store the sun from a sunny day to a cloudy day.

But if we can devise a way to cheaply store massive quantities of electricity (on the order of thousands of megawatt-hours) for periods of up to 24 hours, many alternative energy sources suddenly become a lot more viable. It is also worth point out, though, that we still have tons of cheap coal around, and the only reason to be looking at alternatives is because of the carbon dioxide problem.

The Carbon Dioxide Problem
Every time we dig any sort of fossil fuel out of the ground and burn it, whether that's oil, natural gas, or coal, we release carbon dioxide into the atmosphere from sources which had been locked up for millions of years. Conversely, all living things lock carbon in their bodies (or stems or whatever), which removes carbon dioxide from the atmosphere until that organism completely decomposes.

The problem is that we've been removing so much fossil carbon from the earth and releasing it as carbon dioxide that the Earth's atmosphere now contains far more CO2 than it has had in tens of thousands of years. This is almost certainly having an impact on global climate, and the impact will only get worse.

Unfortunately, there isn't much we can do at this point to prevent any effect from increased CO2. It is already happening. What we can do is work to find fuel and energy sources that don't rely on burning ancient deposits of carbon-based chemicals, so as to reduce future emissions.

The devil is that if we were faced with any two of the three problems, it would be fairly easy to solve them with current technology. But all three at once....that's hard.

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