Some Renewable Energy Types Promise a Bright Future. Others are Merely Sci-Fi Fantasy Kevin Gardner Science & Medicine, Society & Culture Global warming is pressuring the world to cut back on fossil fuels. Even if it weren’t, we have largely run out of the most easily accessible, cheapest sources of fossil fuels. This means that fossil fuels are going up in cost, thereby helping to make alternative energy energy sources more attractive. That is the essence of the issue summed up with the term “Peak Oil.” We aren’t running out of oil, but we have mostly run out of cheap oil. This is a game changer. Good Options for Energy Solar power comes in three varieties. Radiant energy can be captured and either converted to electricity or used to provide heat; photovoltaic systems can create electricity; and passive solar building design uses radiant heat to keep buildings comfortable without running a heating system at all. Wind farms convert wind into electricity. You get a lot more wind during storms. This can cause capacity issues. High energy levels during storms can cause damage to the system and there are currently challenges in storing the types of energy created during high wind events. These issues are a major focus for people in the wind energy sector. Solving such problems will make wind a great deal more useful, reliable and valuable. Large scale hydroelectric dams have a bad reputation for harming the environment, but newer takes on hydroelectric are much more environmentally friendly. Smaller scale solutions and solutions that capture the energy without a dam are rapidly becoming the future of hydroelectric. Geothermal heat is only available in certain areas. It is a great resource when available, but it is very location dependent. Surprisingly, we can even use the ocean to produce electricity via either thermal or mechanical means. You can capture wave energy or the latent heat of the water and use either one to create electricity. Popular But Unrealistic Options Although science fiction likes to posit that hydrogen is a clean, futuristic energy source, it may be more realistic to say its heyday has come and gone. Hydrogen was the lighter-than-air gas holding up the Hindenburg and contributed to the disaster, thereby harming the reputation of this gas for a long time to come. It also faces significant practical barriers to adoption. Since it takes fuel to create hydrogen, no, it isn’t realistic. So don’t worry. The plot to Chain Reaction is not going to come to pass. Its primary appeal is probably the idea that it would readily substitute for fossil fuels and could be used in a similar manner, but burn cleanly. It’s the idea that cars just like we have today could simply burn cleanly. It may not be a realistic idea at all. Bioenergy is renewable in that it comes from biomass. These are fancy words that mean energy derived from organic sources, aka plants. In other words, these are terms that cover both gasoline substitutes made from corn and firewood burned in a fireplace. They have a lot of issues associated with them. Indoor cooking fires are known to promote serious health issues and burning such fuel is very hard on the environment. Like with hydrogen, the primary appeal here seems to be the idea that we can find some readily available gasoline substitute and carry one much as we always have. If we are going to have a bright future with a high quality of life, this is not a realistic scenario. Solar, passive solar, wind, ocean and geothermal are generally much better options than either hydrogen or bioenergy. In some sense, the best energy may be no energy. Passive solar is an approach that dramatically reduces the amount of energy needed to keep a building a comfortable temperature. That, plus the practice of daylighting—judiciously positioning windows so you don’t need to turn the lights on during the day—can reduce a building’s electric bill down to the $5-per-month range. Photo: Wind turbines at White Water / Palm Springs, Riverside County, California, at sunset. (c) 2014, Tony Webster.