alternative energy primer
A Special Joe Primer
Renewable energies are hot. Environmentalists love how they keep our environment clean and our climate cool; security hawks hope they’ll help wean us off of our MidEast oil addiction; and venture capitalists get a new bubble to throw their money into. Yippee!
But with all the excitement for renewable energy, cJ had a lot of questions, starting with what exactly are "renewable" energies anyway? Other things we wondered were how economically feasible are our alternative energy options both today and in the foreseeable future, and are there any down sides to these supposedly green fuels?
Thanks to the fed’s Energy Efficiency and Renewable Energy site along with the National Energy Education Development Project, whose high school briefs cJ was not above boning up on, we were able to begin to piece together a picture – which we share with you (and hope you’ll also weigh in on).
Included on this page is a snapshot of hydropower, biomass, geothermal, wind and solar. We leave out other "alternative" fuels that aren't really renewable, like coal-to-liquid and nuclear energy (which gets its own page). Also missing is hydrogen, because it’s not a source of energy as much as it is a way to transfer energy (like electricity).
Note: given the current excitement and investment in green technology, and the fact that much of the info on this page is from 2004, this may be a rapidly shifting picture. That said, the basic gist shouldn’t be that far off.
At a glance
What - and how much - renewables are we using, out of total energy consumption?
What it is. Today, hydropower is mostly a fancy word for dams, which use the energy of falling water to churn up electricity. In the future, hydropower could harness the energy of tides, waves and temperature differences in large bodies of water, but those technologies aren't yet ready for prime time energy production.
Pricetag. Hydropower is the cheapest power, coming in at 1¢ per kilowatt-hour (coal costs 4 and nuclear 2), but that number doesn’t take into account the cost of building a new dam. (NEED)
Good news. Hydropower is about as renewable and clean as you get.
Bad news. Dams can disrupt wildlife and churn up left over industrial waste in river beds. They also aren’t the most dependable sources of energy, losing power if rain and rivers run low. (NEED)
Outlook. Today we make about 80,000 megawatts of energy from hydropower; the energy department estimates that the US could develop about 30,000 more megawatts. (EERE)
What it is: Biomass is organic matter – trees, plants, animal waste – that can be used to make energy. Energy is tapped from biomass by burning it, siphoning off the gas it emits (from landfills) or converting it into methane, biofuel or alcohol fuel (ethanol). (EERE)
How much we use: 3% of the energy we use comes from biomass, but that number doesn’t include energy that industries produce and use in-house (for example, wood suppliers burning wood chips to fuel their factories). Of the biofuel we use, 71% comes from wood, 19% from garbage and landfill gas and 6% from ethanol. (NEED)
Pricetag: Besides wood, getting energy out of biomass still isn't economically competitive. (Unfortunately we couldn’t find any exact numbers on how much so.) But biomass is being helped along by regulations and subsidies; some that require methane gas be removed from landfill and, increasingly, regulations requiring gas companies use more ethanol. (NEED)
Good stuff. Given that it is grown, biomass is renewable. Also, while biomass creates greenhouse gases, the good news is that the plants that make biomass also absorb those greenhouse gases – so net-net biofuels add fewer greenhouse gases into the atmosphere than do fossil fuels. (NEED)
Bad stuff. The opposite of the “good stuff” above. Even though the plants that produce biofuels absorb greenhouse gases, when burned, they add greenhouse gases into the atmosphere, making them not as clean as wind, solar or hydro power.
Outlook. Biomass, by most accounts, seems to be the most promising alternative energy out there (at least for the near future), especially as new technologies are being developed to efficiently get ethanol out of trees and grasses. Right now, however, aside from burning wood, just about as much energy goes in to making biomass as comes out (see Ethanol below).
What it is: Geothermal energy uses the earth to heat (and cool) homes as well as converting the earth’s heat into electricity. It mostly taps into hot springs under the earth’s surface (heated by magma that sometimes creeps into the earth’s crust). Plants use the steam from really hot springs to create electricity, but for centuries humans have found countless ways to use warm springs for agriculture, industry, bathing and heating homes. Today, many US homes use “geoexchange” systems (just tapping into the earth’s more stable temperatures below) to keep their homes warm in the winter and cool in the summer. (NEED)
How much we use: About 0.3% of the energy we use comes from geothermal energy. (NEED)
Pricetag: Like home solar heating systems, “geoexchange” systems are expensive to install, but pay off over the years (NEED says a family’d save, on average, $20,000 over a lifetime). Electricity-producing geothermal plants are somewhat competitive – producing electricity at 4 – 7 cents a kilowatt (compared to 4 cents
for coal). (EERE)
Good stuff: Geothermal plants are pretty clean (almost no CO2 and low on other pollutants). And, like the sun, the earth’s crust isn’t going to cool out any time soon. (NEED)
Bad stuff: Doesn’t really seem to be any – besides the small amount of pollutant and the fact that it's hard to find economically feasible places to plunk a plant. (NEED)
Outlook: Even though the ground has a potentially unlimited supply of geothermal energy, NEED says today’s economically feasible reserves would only supply about 4% of our energy needs. Of course, as with all other alternative energies, that could change with improved technology further in the future. (NEED)
What it is: Wind energy uses windmills to grab the power of the wind, converting it into electricity.
How much we use: About 0.1% of all our energy comes from wind. (NEED)
Pricetag: Wind energy is pretty cheap, costing about 4 cents per kilowatt hour (similar to coal, but twice as expensive as nuclear energy). (NEED)
Good Stuff: Like the sun’s rays, we’re never running out of wind. Wind energy is also as clean as they come. (NEED)
Bad Stuff: Not everyone loves the look of wind farms. And just as you need a sunny place to take advantage of solar power, wind farms depend upon being in areas (plains, wind funnels) where wind is around most of the time. (NEED)
Outlook: NREL thinks wind could one day produce 20% of our energy needs. (NREL)
What it is: Solar energy taps the energy of the sun, converting it into heat and electricity. It's used to heat homes through solar water heating systems. Photovoltaic cells convert solar energy into electricity. Concentrated Solar Power technologies also grab the sun’s rays to create electricity. (NEED)
How much we use: Even though the sun shoots a lot of energy our way (the rays that hit the US in one day have more energy than the US uses in a year), very little is harnessed – about 0.1% of the energy we use comes from solar energy. (NEED)
Pricetag: Solar water heaters are expensive, but can pay for themselves in five years. Even though they use a free supply of energy, photovoltaic cells are still far off from creating cheap electricity – fossil fuels are about a quarter or a fifth as cheap. Concentrated Solar Power is still in early stages, so it’s not clear how cheap/expensive it’ll be. (NEED)
Good stuff: Solar energy is free and there’s potentially a lot that can be harnessed – and, at least until the sun burns out, we won’t run out of it. (NEED)
Bad stuff: We’re still not so good at converting the sun’s power into cheap power. Also, solar energy converters depend upon the sun shining – so are not so practical for all parts of the country (sorry Seattle). Finally, photovoltaic cells uses silicon and create some waste. (NEED)
Outlook: Even though solar energy may be one of our best bets in the future, it’s still a ways off from being a major energy source. (NEED)
Other cool stuff we've found:
One of the biggest reason folks are gung-ho about green energy is that it cuts down on carbon emissions (believed to be bad for global warming). The Economist printed a graph that looks at how much different measures cut down on carbon, versus how much they cost. Stuff below zero actually save money. The wider measures cut more carbon.
posted June, 2007
Did we miss something, let some slant slip in, lose a link - or do you just have something to say? Drop a line below! In the spirit of open dialogue, cJ asks you keep it civil, keep it real and keep it focused on the message, not the messenger. See our policy page for more on what that all means.