In order to establish sane long-term policies about how we, as Tahoe residents, and every other citizen produce, transport and use energy we need to understand the difference between renewable and sustainable energy. These terms are frequently used interchangeably as if they meant the same thing. Let's learn why...
Renewable energy is an energy source that exists in forms that are continually, if sporadically, created by nature. Common examples would include wind, solar, tides. These supplies are created whenever the wind blows, sun shines or tides come in and go out. Another well-known renewable energy source is water power, which has been used widely since at least the Middle Ages. Rivers power water wheels or have water collected behind dams which when released powers electric turbines. Another energy source, geothermal (thermal energy from beneath the earth's surface) is often consider renewable because it purportedly exists in large "nearly inexhaustible" quantities.
All of these energy sources are considered relatively diffuse - widely distributed around the earth's surface, but concentrated more in some regions than others. Fossil fuels, on the other hand, are very concentrated forms of energy, which is the main reason humans have found oil, natural gas and coal so valuable. When first discovered, these fossil fuels seemed inexhaustible. It wasn't until the mid 1950s that solid evidence indicted this was not the case. The idea that oil, natural gas, and coal are finite resources and have a rate of extraction that peaks and then declines remains controversial, One of these versions of the theory, "peak oil," remains politically charged today even though peak oil theory is more of an objective observation than a theory yet to be proved.
What's the difference between renewable and sustainable energy? A sustainable energy source, which should more accurately be called a sustainable energy system, is capable of indefinitely supplying useful energy to human society while also generating enough energy to cover all the costs of manufacturing, transporting, installing, maintaining and eventually replacing the system. Using this definition, it's highly unlikely that any existing solar or wind system today would be considered sustainable. Renewable energy? Yes. But are these systems sustainable? Not unless they produce a good deal more energy than they now yield.
So, if renewable energy systems are not really sustainable, at least today, should we still keep developing them? Yes, we should because even though they are not currently sustainable, their efficiencies continue to improve and their prices are dropping. They still need a fossil fuel subsidy (in the form of manufacture, transport, and maintenance) and are therefore quite a ways from being truly sustainable. But some of solar approaches, especially passive solar (really, just good architectural design) and solar hot water heating show the most potential for becoming sustainable soon.
Can solar (or wind) electric systems ever become sustainable? Can they ever produce enough electricity to pay for their own manufacture, transport, installation, maintenance and eventual replacement? It's too soon to know with any certainty, but we have to make this a goal, even if we're not that close today.... unless we're prepared to abandon electricity! Therefore, the best approach right now is to adopt as many energy conservation techniques as we can afford in order to use as little electricity as we can somewhat comfortably survive on. Add to that: whenever possible, use electricity that is generated from renewable resources: solar, wind, water power.
In the Tahoe area we have a very good amount of solar energy, but very limited ways that we can turn that into electricity without damaging the natural environment. The wind energy we have fluctuates a great during over the course of a year, and during each day. As with solar power, we cannot easily install wind power systems, to capture this wind energy without impacting the natural beauty of the area. So, do we still have any options to use renewable energy, and hope that some day it becomes sustainable? In fact we do. They involve purchasing electricity generated by wind or solar sources, at sites that are on the national electric grid, so that we can, in effect, go renewable without installing systems at the Lake.
What else can we do? We can boost the amount of insulation where we live: more in the walls, more in the ceiling, and as good a set of windows as we can afford. This cuts down on the heat energy we have to pay for and makes our houses and apartments more affordable in the long term. And if you're lucky enough to be designing your own new house, go passive!
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