A few weeks ago I came upon a blog post named If energy were free and unlimited, by David Gold. It’s an interesting “limits analysis” — if energy cost approached zero and energy availability approached infinity, what would happen? David’s main thesis is that economic prosperity would reign, but I think that this is incomplete. It’s true that energy is interwoven into everything that we do. Mass, however, is also interwoven into everything. Even disregarding what Einstein said, we still have to deal with inherent connections between mass and energy.

What do we use energy for? The National Academies broke down our energy usage into the categories of home & work, transportation, and industry, but I prefer to look at more fundamental categories:

• Conversion and treatment: making raw materials into products, filtering air and water, processing information, and applying electricity toward heating, cooling, and lighting.
• Extraction and harvesting: bringing materials into the human social system through mining or farming.
• Movement: taking stuff from one place to another through vehicles, fans, pumps, and the like.

Say energy were free and unlimited. Say for simplicity’s sake that we’ve moved away from combustion entirely — the only carrier of energy we use as a society is electricity, generated from wind, solar, wave, and other renewable non-fuel sources. Everything in the three categories above still has a dependence on mass in some way.

Let’s focus on extraction and harvesting. In the year 1995 the United States consumed 3 billion metric tons of materials, and only 8 percent of those materials was renewable. Free energy won’t replace those materials even though it may drop the dollar costs of consuming them. Agriculture in particular is very mass-intensive (PDF). In the year 2007, US farmers treated 265 million acres of land with commercial fertilizer, lime, and soil conditioners. They also covered 226 million acres with chemicals to control the growth of weeds, grass, and brush. Free energy may help us desalinate water or maybe even grab it out of the air to irrigate those fields; it may help us harvest our crops and get them to market, but we still have to deal with the fact that today’s agricultural system depends on huge amounts of mass input.

We do need to begin a transition to a fully renewable energy system. This may solve many social and environmental problems, but not all. Fully renewable energy may effectively be “free,” but mass will never be free. If we unlock more energy to consume resources in the same ways that we’ve been consuming, we’ll accelerate even faster toward environmental problems like deforestation and dead zones. Instead, let’s leverage a renewable energy transition to tackle another major transition: the shift to fully renewable and closed-loop mass systems.

Photo “Seedlings Common chickweed” by –Tico–, on Flickr