apes unit 6

KEY POINTS

- The nuclear power fuel cycle has a low environmental impact and a low accident risk, but high costs, a low net energy, long-lived radioactive wastes, and its role in spreading nuclear weapons technology have limited its use. - Conventional oil, natural gas, and coal are plentiful and have a moderate to high net energy, but use of these fossil fuels, especially coal, has a high environmental impact.

Identify the benefits of using natural gas.

Natural gas can be used in a variety of energy applications. It can be transported by cooling it to liquefied natural gas (LNG). When burned, it releases less than coal, and natural gas power plants are cheaper to build than other conventional power plants.

Net Energy Equation

Net energy = Energy output - Energy input

Identify the drawbacks of harvesting and using natural gas.

Disadvantages of natural gas include low net energy for LNG, fracking uses and pollutes huge volumes of water, groundwater can be polluted by the extraction process when well casings fail, and earthquakes can result when the waste slurry from fracking is forced into too many underground hazardous waste storage wells in the same general area.

Energy Efficiency

E = Energy produced/Energy consumed x 100

Hydroelectric power

Hydroelectric power does not generate air pollution or waste, but construction of the power plants can be expensive, and there may be a loss of or change in habitats following the construction of dams.

Hydrogen fuel cells

Hydrogen fuel cells have low environmental impact and produce no carbon dioxide when the hydrogen is produced from water. However, the technology is expensive and energy is still needed to create the hydrogen gas used in the fuel cell.

Define net energy as it relates to nonrenewable energy resources such as coal, oil, natural gas, or nuclear power.

Net energy is the difference between the amount of high-quality energy available from a given quantity of an energy resource minus the high-quality energy needed to make the energy available. If it costs more to obtain an energy resource than its market value, then using that particular energy resource many no longer be economically viable.

Nonrenewable resource

Nonrenewable energy sources are those that exist in a fixed amount and involve energy transformation that cannot be easily replaced

Renewable resource

Renewable energy sources are those that can be replenished naturally, at or near the rate of consumption, and reused.

Solar energy

Solar energy systems have low environmental impact and produce clean energy, but they can be expensive. Large solar energy farms may negatively impact desert ecosystems.

Identify some of the outcomes of the accident at the Fukushima Daiichi Nuclear Power Plant in Japan.

Some of the outcomes of the Fukushima accident were increased public fear in Japan and throughout the world of nuclear power, the additional cost of $200 to $400 billion in expenses related to the accident, the decision by some European countries to phase out nuclear power and shift to clean energy instead, coal imported to Japan exposed its citizens to additional air pollution, and it motivated Japan to conserve energy and cut energy waste.

Net Energy

The amount of energy available from a resource minus the amount of energy needed to make it available.

Identify the benefits of using coal as an energy source.

The benefits of using coal are that coal has a medium to high net energy, is plentiful, and has a low cost when environmental costs are not included.

Identify the benefits of using oil as an energy source.

The benefits of using oil as an energy source include ample supply for the near future, medium net energy, low land disruption, and an efficient distribution system. Identify the drawbacks of using oil as an energy source.

Geothermal energy

The cost of accessing geothermal energy can be prohibitively expensive, as is not easily accessible in many parts of the world. In addition, it can cause the release of hydrogen sulfide.

Identify the drawbacks of using coal as an energy source.

The drawbacks of using coal are that it is the dirtiest of the fossil fuels, mining results in severe land disruption and water pollution, particulate (soot) and toxic mercury emissions threaten human health, and burning coal emits large amounts of and other air pollutants.

Identify the drawbacks of using oil as an energy source.

The drawbacks of using oil as an energy source include water pollution from spills and leaks, environmental costs are not included in the price, release of and other air pollutants, and vulnerability to international supply disruption.

wind energy

Wind energy is a renewable, clean source of energy. However, birds and bats may be killed if they fly into the spinning turbine blades.