In Chapter 8, we discussed the world's supply of fossil fuels — oil, coal and natural gas and how it is being depleted slowly because of constant use. Fossil fuels are not renewable, they can't be made again. Once they are gone, they're gone.
In Chapters 11 to 16, we learned that there's no shortage of renewable energy from the sun, wind and water and even stuff usually thought of as garbage — dead trees, tree branches, yard clippings, left-over crops, sawdust, even livestock manure, can produce electricity and fuels — resources collectively called "biomass."
The sunlight falling on the United States in one day contains more than twice the energy we consume in an entire year. California has enough wind gusts to produce 11 percent of the world's wind electricity. Clean energy sources can be harnessed to produce electricity, process heat, fuel and valuable chemicals with less impact on the environment.
In contrast, emissions from cars fueled by gasoline and factories and other facilities that burn oil affect the atmosphere. Foul air results in so-called greenhouse gases. About -81% of all U.S. greenhouse gases are carbon dioxide emissions from energy-related sources.
Renewable energy resource development will result in new jobs for people and less oil we have to buy from foreign countries. According to the federal government, America spent $109 billion to import oil in 2000. If we fully develop self-renewing resources, we will keep the money at home to help the economy.
Continued research has made renewable energy more affordable today than 25 years ago. The cost of wind energy has declined from 40 cents per kilowatt-hour to less than 5 cents. The cost of electricity from the sun, through photovoltaics (literally meaning "light-electricity") has dropped from more than $1/kilowatt-hour in 1980 to nearly 20cents/kilowatt-hour today. And ethanol fuel costs have plummeted from $4 per gallon in the early 1980s to $1.20 today.
But there are also drawbacks to renewable energy development.
For example, solar thermal energy involving the collection of solar rays through collectors (often times huge mirrors) need large tracts of land as a collection site. This impacts the natural habitat, meaning the plants and animals that live there. The environment is also impacted when the buildings, roads, transmission lines and transformers are built. The fluid most often used with solar thermal electric generation is very toxic and spills can happen.
Solar or PV cells use the same technologies as the production of silicon chips for computers. The manufacturing process uses toxic chemicals. Toxic chemicals are also used in making batteries to store solar electricity through the night and on cloudy days.. Manufacturing this equipment has environmental impacts.
Also, even if we wanted to switch to solar energy right away, we still have a big problem. All the solar production facilities in the entire world only make enough solar cells to produce about 350 megawatts, about enough for a city of 300,000 people. that's a drop in the bucket compared to our needs. California alone needs about 55,000 megawatts of electricity on a sunny, hot summer day. And the cost of producing that much electricity would be about four times more expensive than a regular natural gas-fired power plant.
So, even though the renewable power plant doesn't release air pollution or use precious fossil fuels, it still has an impact on the environment.
Wind power development too, has its downside, mostly involving land use. The average wind farm requires 17 acres of land to produce one megawatt of electricity, about enough electricity for 750 to 1,000 homes. However, farms and cattle grazing can use the same land under the wind turbines.
Wind farms could cause erosion in desert areas. Most often, winds farms affect the natural view because they tend to be located on or just below ridgelines. Bird deaths also occur due to collisions with wind turbines and associated wires. This issue is the subject of on-going research.
Producing geothermal electricity from the earth's crust tends to be localized. That means facilities have to be built where geothermal energy is abundant. There are several geothermal resource locations in California. The Geysers area north of San Francisco is an example. In the course of geothermal production, steam coming from the ground becomes very caustic at times, causing pipes to corrode and fall apart. Geothermal power plants sometimes cost a little bit more than a gas-fired power plant because they have to include the cost to drill.
Environmental concerns are associated with dams to produce hydroelectric power. People are displaced and prime farmland and forests are lost in the flooded areas above dams. Downstream, dams change the chemical, physical and biological characteristics of the river and land.
Unlike fossil fuels, which dirties the atmosphere, renewable energy has less impact on the environment Renewable energy production has some drawbacks, mainly associated with the use of large of tracts of land that affects animal habitats and outdoor scenery. Renewable energy development will result in jobs and less oil imported from foreign countries.
Note: For those working on a school assignment comparing renewable vs. non-renewable energy, we'd suggest creating a Pro and Con list for each energy source. That will give you a a way to compare the various energy resources.
Go to Chapter 18: Energy for Transportation.