Energy comes in different flavors Therese Peffer c.1992 Therese Peffer To some, energy is measured in BTUs and kilowatt hours. To others, energy is the stuff that allows us to move about in the morning; the food in our bellies refuels us for another day. Energy warms the earth, makes plants grow, lights our lamps, heats our tea. Energy comes from different sources. Here at Home Power, we throw around many descriptions of energy depending on its source. What do the various terms mean? Alternative Energy One term is alternative energy. "Alternative to what?", you might ask. We mean alternative to the "norm", the centralized utility-powered grid. In Northern California, Pacific Gas & Electric supplies energy in the form of electricity and natural gas. Electrical energy is usually measured in kilowatt-hours. If you live on the grid, your utility charges you by the kilowatt-hour every month. Those living off the grid in a recreational vehicle or on a site remote from the power lines are using alternative energy to power lights and heat food. We are our own utility, and generate and store our own watts of electrical power. The sources can be photovoltaic modules, wind generators, water turbines, or diesel or gasoline generators. We use batteries to store this energy for use at other times. Propane or kerosene can be used for cooking or lights. The word alternative doesn't mean settling for second best, it just means we can have electricity off the grid. The generation of energy brings us to another definition: renewable energy. Non-Renewable versus Renewable Energy What does it mean for energy to be renewable or nonrenewable? The source of energy can be used up in the process of making energy, never to be used again. This is non-renewable energy; examples are coal, oil, and gasoline. Millions of years ago, organic matter such as algae fossilized under the right conditions to leave pools of oil beneath the earth's surface; the Middle East had more favorable conditions than the U. S.! The oil is pumped from under the ground, refined, and made into various substances. Some are used for energy such as kerosene and propane for lights or cooking stoves, and gasoline for automobiles. These fossil fuels are nonrenewable sources Ð once the fuel is used up, that's it. Other centuries-old sources of energy don't get used up and are called renewable energies. The sun, wind, and water are a few examples. Folks have used the sun to warm their bodies and shelters and wash water for thousands of years. The sun's thermal energy can be used for cooking and heating water, and is exploited in the design of houses for space heating. The sun can be used for another energy, to generate the flow of electrons or electricity. Photovoltaic cells harness light (photo) to make electric potential (voltaic) form in certain materials. The primary material used in PV cells is silicon, which is made from sand, one of the most abundant materials on earth (see HP #23 for further details). The wind is another source. Wind turbines are used to pump water and to generate electricity. Flowing water is also a renewable source of energy. Streams and rivers have been used to grind grains for centuries and are still used to transport things and generate electricity. The sun, wind, and water are renewable sources of energy. The sunshine is not diminished no matter how many solar panels are up. The flow of wind and water is not used up by the turbines. The sun shines, the wind blows, and the water flows and will continue whether or not we tap their energies. Not all alternative energy is renewable, and vice versa. Many RVers and we folks living in the country use gasoline generators, either full time or as a back-up; this is alternative energy, but not renewable. While many utilities in the U.S. use coal to produce electricity, some use hydroelectric power or wind. Sustainability Another word to add to our vocabulary list is sustainable. To sustain is to last, to withstand, and maintain. What is a sustainable energy? Energy that is sustainable is more than just renewable. Sustainable energy use is good for ALL of us And by all, I mean the air, water, land, plants, humans, and other animals on this earth. There are no easy answers Ð what is sustainable for some may not be for others. Some examples: Oil is not renewable and cannot sustain our society. Once oil is burned, that's it. We have only 30 - 60 years of oil reserves at the current rate of use and present efficiencies. Fossil fuels have a bad environmental track record. As with any industry, we must trust the manufacturers to be responsible and not endanger the environment or population. But there is the inevitable oil spill on land or water, and air pollution due to oil fires. Go ask a Minnesotan what a gas-powered speed boat would do to the tranquil Boundary Waters. As for air, any person from Los Angeles could tell you that using gasoline to run our cars contributes to air pollution. Smog is unhealthy to breathe and hides the beautiful San Gabriel mountains. And lately we've been hearing about the greenhouse effect due to carbon dioxide released from burning oil. Our current lifestyle cannot sustain the use of oil as our primary source of energy. We can conserve more, and drive efficient cars or ride bicycles, busses, or trains Ð maybe the oil reserves will last into the century after next. So why don't we all drive hydrogen-fueled cars or solar-electric vehicles and conserve more? Oil and gasoline are cheap, thanks to government subsidies, and easy to transport, and gosh, we've been doing for the last century anyway. But wouldn't it be nice not to import our major source of energy, and not mar the beautiful coast with oil wells? Another source of energy is wood. Is cutting down trees for wood burning stoves a sustainable activity? Wood is renewable in the sense that trees grow back. Whether it is a sustainable practice depends how the cutting and replanting are managed. If so many trees are cut that the top soil erodes away, sediment clogs the streams, and wildlife disappears, then certainly this is not sustainable. Some wood burning stoves release more pollutants than others. There are other forms of heating, and good design can help conserve. We must also consider that wood has other uses, such as construction, furniture, and paper. Alternatives look promising Ð most paper used to come from hemp (don't laugh). There are countries now reconsidering this fast growing option to wood pulp. . The next example is large scale hydroelectric such as the Hetch Hetchy hydroelectric dam in northern Yosemite National Park in California. Hetch Hetchy Reservoir supplies the San Francisco area with water and Northern California with electric power. Hydroelectricity is certainly a renewable form of energy as long as the snow and rain continue to fall, but is it a sustainable source of energy? John Muir, a naturalist and father of Yosemite, would argue that Hetch Hetchy is not sustainable for environmental and aesthetic reasons. A beautiful valley was covered when the dam was built. Many hydroelectric dams prevent salmon from returning to their spawning ground; the salmon have all but disappeared from the Columbia and Snake Rivers in Oregon. Can large scale hydroelectric be a sustainable source of energy? Some argue that they can be sustainable Ð design stairs for salmon, the energy is worth the cost. Others say it cannot be sustainable. Photovoltaics are a renewable source of energy, but sustainable? Depending on the manufacturer of the PV modules, the process can be benign or harmful to the environment. Some of the materials used are toxic; the same case can be made for batteries. It's our responsibility to buy from responsible manufacturers who treat and recycle the toxic materials. What flavor is your planet? Defining what is sustainable is not easy; sustainable can apply to resources as well as energy. The word reflects a spirit or attitude Ð we're all in this mess together! We can maintain our livelihood while respecting the right of other species to coexist. Sustainable activities endeavor to work with the process of nature and not against it. Obviously people have some impact on the environment, but we have a choice as to whether this impact is a crushing blow or a light step. We've developed land and built buildings, and introduced new plants and animals that affect the land. But there are choices. Buildings can be made with materials native to the land, a material the land can sustain without our great grandchildren noticing its loss. Agriculture can use pesticides or not use pesticides; consumer choice plays a role here. Cars and buildings can be designed to use much less energy. We can produce energy from sources that will be around for generations to come , and not pollute the air, water, and land. Energy is certainly necessary, but the source Ð the flavor Ð is our choice. Some flavors are tasty in terms of the price tag, but don't smell or look so good. What we taste now determines what our great- grandchildren will have Ð we may need to refine our palate. Access: Therese Peffer c/o Home Power, POB 130, Hornbrook, CA 96044, 916-475-3179.