I have reported on innovations—especially in alternative energy—for about four years now and got curious about how they had turned out. I have reported three that had proved to be viable technologies, although, unfortunately, none of them have been scaled up to have much environmental impact yet. Today, we look at a couple of duds.
Both of these projects are economically unfeasible. One of them also runs afoul of one of the immutable laws of nature. It’s important to understand why some seemingly brilliant ideas turn out not to be practical. It’s good for inventors to know in advance that an idea is intrinsically impossible.
It’s also good for the rest of us to be patient. Alternative energy now takes up a small fraction of our energy needs. We can blame entrenched special interest for only a small part of the reason.
It takes a long time to find workable ideas, and then another long time to turn them into viable products. The path of innovation is always littered with ideas that didn’t and can’t pan out.
The human powered gym
When you visit a gym, you see people using treadmills, stationary bikes, and elliptical machines. The machines provide a great aerobic workout, but they’re terribly boring.
So gyms provide a bank of televisions to keep the people entertained. That takes energy. Gyms have plenty more besides treadmills and televisions that they have to plug in somewhere.
As long as people are expending energy on these machines, why not convert it into electricity and offset some of the costs? An examination of the Recreational Sports Facility at the University of California, with its 28 elliptical machines shows gives two reasons, one based on economics and the other on physics.
First, the economic reasons
- The amount of electricity that those elliptical machines could conceivably generate is less than 1% of the gym’s annual energy consumption. The estimated value of the electricity is about $1000.
- Elliptical machines aren’t designed to capture energy. Retrofitting them with energy-capturing devices would cost about $20,000.
- Therefore it would take at least 20 years to generate enough electricity to recoup the cost of the retrofitting.
- Elliptical machines don’t last longer than about six or seven years.
It has only been within the past century than anyone has needed expensive gym equipment to stay in shape. Once upon a time, people walked everywhere. Such technology as people generally used required their bodies to provide the energy. The amount of energy they took in by eating and expended just by living pretty much balanced out.
Nowadays we have cars so we don’t have to walk. We have phones so we don’t have to go anywhere in order to communicate. We have the Internet so we don’t even have to get up out of our chairs to look up information. Meanwhile we eat more than any previous generation.
Gyms exist to help people burn off the extra calories that come from overeating and being essentially immobile all day. But here’s where the physics comes in.
The second law of thermodynamics states, “in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state.”
In other words, when food energy is exchanged for the energy expended using the elliptical machine, some of that energy dissipates as heat. The output from the elliptical machine is necessarily less than the input from the food.
Ethanol from seaweed
Ethanol as a fuel seemed like a good idea in response to the Arab oil embargo of the 1970s and the phasing out of leaded gasoline. It was made from corn, which made farmers and corn-belt politicians very happy.
Unfortunately, the amount of energy derived from ethanol is less than the amount of energy it takes to make it. That has nothing to do with entropy and thermodynamics.
Tractors and other farm machinery take energy. Trucks to transport the corn from the farm to the ethanol manufacturing facility (with stops between) take energy. And by that time, most farmers were using fertilizers made from petrochemicals. So the cost of fertilizer has to include the energy expended in drilling the oil, refining it, and manufacturing the fertilizer.
Not only that, but corn used to make ethanol can’t be used to feed people. Increased demand for corn leads to increased prices. So food costs more because of ethanol.
Non-food plants like switchgrass have complex sugars called lignans. It is difficult and expensive to break them down into the simple sugars necessary to make ethanol.
Seaweed has no lignans, but it does have another complex sugar, alginate. A company called Bio Architecture Labs discovered a way to make microbes break down the alginates and in 2009 started a project in Chile to start making ethanol from seaweed.
The company abandoned the effort in 2013. They could only sell their ethanol for 75¢ per kilogram. The algae they needed for feedstock costs $1.30 per kilogram. Unlike making human-powered electricity, the technology works. As long the cost of making something is greater than the market value of the product, it is not economically viable.
That is basically the same problem that caused the solar film company Solyndra to go out of business. Bio-Architecture Labs has not gone out of business, just shifted it business strategies. If it ever becomes economically feasible to make ethanol from seaweed, they know how to do it.
Are there any microbes that eat lignans? Switchgrass is still cheap.
Could the energy from gym workouts be harnessed? / Cecil Adams
Laws of thermodynamics / Estrella Mountain Community College
Bio gives up on seaweed-to-ethanol effort in Chile / Stephan Nielsen (Bloomberg) — Link no longer works as of June 2017.
NLACM leads to changing times at Bio Architecture Lab / Jim Lane (Biofuels Digest)
Money down the drain.Some rights reserved by Images of Money.
Exercise bikes.The Greenasium (San Diego)
Seaweed. © Copyright Lairich Rig and licensed for reuse under this Creative Commons Licence