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| Fossil fuels | Highly combustible substances formed from the remains of organisms from past geologic ages. The three most commonly used today are oil, coal ad natural gas |
| Uses of fossil fuels | Besides providing for transportation, heating, and cooking, fossil fuels are used to generate electricity. |
| Renewable versus non-renewable | Things like geothermal and tidal energy are considered perpetually renewable because they won’t be depleted by our use. Other sources are seen as renewable if we don’t harvest them too quickly. Things like oil and coal are nonrenewable because at our current rates of consumption we’ll use them up. |
| Where do fossil fuels come from | Fossil fuels come from the tissues of organisms that lived 100-500 million years ago. They were formed when organic materials were broken down in an anaerobic environment (one that has little to no oxygen, like an ocean). Over millions of years organic matter accumulates at the bottoms of such bodies of water and is converted into fossil fuels. |
| Distribution of fossil fuels on earth | Fossil fuel deposits are localized and unevenly distributed over Earth’s surface, so some regions have substantial reserves of fossil fuels whereas others have very few. Nearly two-thirds of the world’s proven reserves of crude oil lie in the Middle East. |
| Does fossil fuel use vary by country? | Citizens of developed regions generally consume far more energy than do those of developing regions. Industrialized nations use roughly a third of energy on transport, a third on industry, and a third on all other uses. Developing nations devote a greater proportion of energy to subsistence activities like agriculture and food preparation. |
| Net energy and fossil fuel extraction | Net energy expresses the difference between energy returned and energy invested. The EROI ratio expresses Energy returned/Energy invested. Fossil fuels are widely used because their EROI ratios have historically been high. |
| Coal | Forms from organic matter (generally woody plant material) that was compressed under very high pressure to form dense, solid carbon structures |
| History of coal's use | People have extracted coal from the ground and burned it to cook food, heat homes, and fire pottery for thousands of years |
| Coal: subsurface mining | Underground deposits are reached by digging networks of tunnels deep underground |
| Coal: strip mining | Heavy machinery removes huge amounts of earth to expose and extract the coal. Mountain top removal is a kind of strip mining in which entire mountaintops are cut off to obtain the coal |
| Qualities of coal | Lignite The least compressed kind of coal (least energy); Sub-bituminous In the middle between; Anthracite Most compressed form of coal, has the most energy |
| Impurities in coal and their contribution to acid rain | Sulfur, mercury, arsenic, and other trace metals (sulfur content depends on whether coal was formed in salt water or freshwater). Coal in the eastern U.S. is high in sulfur because it was formed in marine sediments. When high-sulfur coal is burned, it released sulfate air pollutants, which contribute to smog and acidic deposition |
| Natural gas | The fastest growing fossil fuel in use today. Provides 25% of global commercial energy consumption. Consists of methane and other volatile hydrocarbons |
| Natural gases: Biogenic gas | Created at shallow depths by bacterial anaerobic decomposition of organic matter – “swamp gas” |
| Natural gases: Thermogenic gas | Results from compression and heat deep underground |
| Natural gases: Kerogen | Organic matter that results when carbon bonds begin breaking. It’s source material for natural gas and crude oil |
| Petroleum | A mixture of hundreds of different types of hydrocarbon molecules. Formed 1.5 - 3 km (1 - 2 mi) underground. Dead organic material was buried in marine sediments and transformed by time, heat, and pressure |
| History of petroleum use | Oil (petroleum) is the world’s most used fuel since the 1960s. Worldwide use has risen over the past decade by 17%. Modern extraction began in the 1850s |
| Petroleum production versus use in different countries | The top producers often use less than the countries they export to |
| Primary oil extraction | The initial drilling and pumping of available oil |
| Secondary oil extraction | After primary extraction, secondary extraction begins, in which solvents are used or underground rocks are flushed with water or steam to remove additional oil |
| Ratio of reserves to extraction | The amount of total remaining reserves divided by the annual rate of production (extraction and processing). At current levels of production (30 billion barrels/year), we have about 40 years of oil left |
| Why is peak oil hard to predict | Companies and governments do not disclose their amount of oil supply, there is disagreement among geologists, and oil consumption increases at an unpredictable rate in developing countries |
| What are the likely effects of passing peak oil | “The long emergency”: from lacking cheap oil to transport goods, our economies collapse and become localized. Suburbs will become the new slums, a crime-ridden landscape littered with the hulls of rusted out cars. More optimistic observers argue that as supplies dwindle, conservation and alternative energy supplies will kick in, and we will be saved from major disruptions |
| US. dependence on foreign oil | The US imports 60% of its crude oil, meaning other nations control our energy supplies. We are vulnerable to supplies becoming unavailable or expensive |
| Lopsided global trade in oil | Relatively few nations account for most exports, and some nations are highly dependent on others for energy |
| Nuclear power | Accounts for 11% of the world’s energy use. Generated using uranium, which is mined from various places around the world. |
| Pros and cons of nuclear power | Pros: Cheap, doesn’t produce greenhouse gasses, produces large amounts of energy from small amounts of fuel, produces little waste. Cons: The waste that is produced is very dangerous, much money must be spent on safety, if something goes wrong it can be a disaster (meltdown and radiation), uranium isn’t renewable |
| Solar power | Every minute enough energy reaches the earth from the sun to meet our energy needs for the whole year, we just don know how to harness it properly. |
| Solar cells | Convert light into electricity. One square meter can generate enough power to run a 100 watt light bulb |
| Solar water heating | Involves using glass panels to heat water. This can be a cheap way to get warm water in certain climates |
| Solar furnaces | Use mirrors to concentrate light and produce extremely high temperatures. Can be used to generate steam and drive turbines. Not widely used and is still in its experimental stage |
| Pros and cons of solar power | Pros: Free, doesn’t generate waste, can be used in remote places in sunny countries, renewable until the sun burns out. Cons: Doesn’t work at night, can be expensive to build, can be unreliable in sunny places. |
| Wind power | Blowing wind turns turbines, which generates electricity. Needs an average wind speed of 25 km/h to be profitable. Usually involves many tall wind towers lined up in rows |
| Pros and cons of wind power | Pros: Free, no waste, land beneath wind towers can be used to do other things, can be used in remote locations, can be tourist attractions, renewable. Cons: Wind isn’t predictable, can only be used in some areas (coastal), can kill migrating animals, can be noisy |
| Hydroelectric power | Involves the building of a dam to trap water and turn turbines |
| Pros and cons of hydroelectric power | Pros: Reliable, water can be stored, renewable • Cons: Very bad for the environment, expensive to build |
| Two basic designs used to create tidal power | Tidal barrages involve building a dam-like structure on a tidal river. As water funnels past the dam it turns turbines which generate electricity Offshore turbines turn in the current and produce a more consistent source of energy |
| Pros and cons of tidal power | Pros: Free energy once its built, no waste, tides are predictable. Cons: Some of the environmental issues associated with dams apply to tidal barrages, expensive to build, tidal barrages only produce power when tide is moving, only works in areas with large tidal range, can be expensive to maintain. |
| Wave energy | Wave generated power stations use ocean waves to force air past a turbine and generate electricity |
| Pros and cons of wave energy | Pros: Free energy once made, not expensive to maintain, renewable. Cons: Can only be used in coastal areas with consistently large waves, can be noisy, waves aren’t reliable, must be able to withstand storms |
| Geothermal energy | Molten rock within the earth can be used to generate steam, which turns turbines. Holes are drilled down to hot spots |
| Pros and cons of geothermal energy | Pros: Free energy, require a minimal amount of space, renewable. Cons: There aren’t many places where geothermal energy can be easily accessed, can release toxic gasses from beneath the earth, may stop working for extended periods of time |
| How is the carbon in bio-fuels different from the carbon in fossil fuels | In principle, energy from biomass is carbon-neutral, releasing no net carbon into the atmosphere. While burning biofuels emits plenty of carbon, this is balanced by the fact that photosynthesis had pulled this amount of carbon from the atmosphere recently. |
| Bio-power and biofuels | Bio-power: Generating heat and electricity in the same way that we burn coal for power. Biofuels: Liquid fuels used primarily to power automobiles |
| Ethanol | The alcohol in beer, wine, and liquor. It is produced as a biofuel by fermenting biomass, generally from carb-rich crops in a process similar to brewing beer |
| Corn ethanol | About 21% of US corn crop today is used to make ethanol. However, corn ethanol only yields a modest amount of energy relative to the energy that needs input. |
| Palm oil as fuel | Can be used as biodiesel, but contributes to deforestation |
| Switch grass as a fuel | Native grass of the American prairies, fast growing, provides fuel for bio-power and is being studied as a crop to provide cellulosic ethanol. Has a much better EROI than corn ethanol. |
| Algae as a fuel | Several species of algae produce large amounts of lipids that can be converted into biodiesel. Carbs in algae can be fermented to create ethanol |
| What are some of the environmental impacts of bio-fuel production? | When we burn crops or plant matter, we deprive the soil of the nutrients, leading to soil infertility. |
| Environmental downside of bio-fuels | In our attempts to attain things like palm oil we contribute to deforestation. Also, many major crops grown for biodiesel and ethanol exert heavy impacts on the environment. |
| Hydrogen fuel cells | Essentially hydrogen batteries that can be used to produce electrical energy as needed to power vehicles, computer, cell phones, home heating and other applications. |
| Infrastructure and hydrogen energy | One major drawback is that to convert a nation to hydrogen would require a massive and costly development of facilities to transport, store, and provide fuel |
| Byproducts of hydrogen power | Hydrogen cells are silent and nonpolluting. Pure water and heat may be the only waste products from a hydrogen fuel cell, along with some negligible traces of other compounds. |
| Pros of hydrogen power | Hydrogen is the most abundant resource in the universe (wont run out), it can be nontoxic and nonpolluting, hydrogen cells are energy-efficient, and fuel cells are silent/nonpolluting, could alleviate dependence on foreign fuels |
| Cons of hydrogen power | Countries lack infrastructure to begin using it, and it may deplete the stratospheric ozone and lengthen the atmospheric lifetime of of methane (a greenhouse gas). |
