Renewable Resources

The Physics of Reuse

Earth's biosphere, what we commonly refer to as “Nature” or “Life” is constantly perfecting the art of reusability. Countless species that include plants, animals, and microbes ingest, process, and expel mass and energy, most of which can over time be used by others.

Mass exists either as atoms, joined atoms (called chemical compounds, found in one or some combination of gas, liquid, or solid), or unbound subatomic particles. Life is primarily concerned with chemical compounds, which may under specific circumstances be either inert or reactive. While inert compounds stay unchanged in the presence of others, reactive compounds join with others to form new ones, and in the process either absorb or release energy. Energy itself exists in any of several forms: chemical (exchanged between atoms), nuclear (exchanged between particles that form atoms), electromagnetic (carried by massless light particles), and gravitational (embodied in space and time, which connect everything to everything else). From a purely theoretical perspective, mass, energy, space, and time are likely to be manifestations of the same thing, ultimately indestructible and eternal in some larger sense that none of us will ever be able to comprehend.

Within the confines of our experience, however, Life “uses” mass and energy to maintain, propagate, and modify itself. Maintenance preserves the individual, propagation preserves the species, and self-modification includes not only reproductive experimentation (evolution) but also changing one's immediate physical and emotional condition. The grunt work of performing these functions is done by cells: biological micro-machines evolved over eons to build, tear apart, and move mass throughout an organism while managing the energy required doing so. When too many cells become disabled from wear and tear, reproductive errors or catastrophic external “modification,” the organism loses integrity and its parts are either disassembled for use by other organisms or more randomly broken down by non-biological processes for potential use over a much longer period of time (such as oil). Even artifacts, buildings and machines built by humans to control how they feel, will eventually be available for use, in some other form, by someone or something else.

Renewable R’s

When a “renewable resource” is consumed by people in a given year, it's consumption will not diminish the overall amount of resources available during that year. There are at least three ways this could happen.

The first way is for the resource to be replenished from some external source. Solar energy is “renewable” because the Sun is constantly emitting light, which replaces the light previously absorbed by us and other species. Wind is renewable because it is (usually) replaced by more wind. Members of other species are renewable if they reproduce themselves faster than we kill them.

The second way is for it to be replaced by us so it can be consumed again. A trivial example is a sand castle, which exists for a short time in its artificial form and then dissolves into its original state. Most of what we consume, however, assumes a different and often unusable form when we are done (“waste”); if we started consuming our waste, the original resources would become effectively renewable because we would not be depleting our supply of raw resources.

The third way is to slow down how fast we consume resources. By increasing durability and efficiency (collectively known as “reliability”), we can get many years of use out of what we produce, reducing the need to use new resources for the same purpose. Insulating our homes, sealing water leaks, and using materials that last long are all examples of this.

Utilizing the “renewable R's” of replenishment, replacement, and reliability, we can go far toward reducing our load on the resources we depend on without diminishing consumption and population.

There is an important difference between the terms “renewable resource” and “renewable technology.” “Renewable technology” commonly refers to the set of tools, materials, and methods that enables people to use renewable resources to perform a certain function.

Renewable technologies often rely on the use of non-renewable resources. For example, a technology that converts renewable (replenished) energy from the Sun into electricity could include non-renewable metals and silicon that have been processed using non-renewable chemical products; in addition, it is likely to depend on a large array of non-renewable technologies, including transportation and electrical distribution.

We can judge just how “renewable” a technology really is by assessing the fraction of total resources it uses that are renewable (as defined by the Renewable R's). The optimum technology will recycle all of the materials it uses (if not the preferably replenished resources it processes) into like or other uses (replacement), and if necessary include components that are functional over a very long time (reliable).

Currently life is the only truly close to optimum technology, and Nature's biosphere provides this technology practically for free. The result of many millennia of development and testing through evolution, it would be very expensive (if not impossible) for us to create such a technology on our own. Alternatives on the horizon such as biotechnology and nanotechnology, one involving tinkering with existing life and the other with something totally different, carry the risk of inadequate testing leading to potential disaster.

[NOTE: This article is a combination of articles relating to renewable resources.]