Energy Production and Usage - AP Environmental Science

The energy output from a hydro-electric dam is substantial enough to result in most of America's major rivers being damned. The more pressing issues that these damns cause are changes to the aquatic ecosystem and restriction of movement for migratory fish species.

While there are federal wetland conservation laws geared at protecting aquatic habitat, there is currently no federal ban on constructing hydroelectric dams, and the returned energy investment for hydroelectric is quite substantial. The dominant issue with expanding hydroelectric energy production is that in the U.S., we have dammed most if not all of the significant energy-producing water bodies. Further expansion of hydroelectric power will not yield as much energy as the current dams operating in the U.S.

Producing nuclear energy is a lot cleaner than most people realize, and while it is expensive (but still profitable), it represents a legitimate option for producing cleaner energy. The main drawback is that the resulting "spent fuel" has to be secured and stored, because it cannot be safely disposed of without significant repercussions.

Ethanol can be made from cellulosic—or woody—plants such as switchgrass, poplars, and willows. Cellulose, or plant tissue, sequesters a huge amount of carbon and contains a great deal more energy per unit than corn. Scientists believe that within the next two decades, research will have figured out how to quickly and efficiently break down plant tissue for fermentation into fuel.

Biodiesel made from corn is environmentally safe to burn; however, it requires a great deal of water and resources to grow and harvest.

Agricultural wastes can have a negative impact on air quality due to the pollutants they generate when burned, such as sulfur oxide, nitrogen oxide, and carbon monoxide.

CAFE is a standard enacted by U.S. Congress in 1975 with the objective to improve fuel economy for all vehicles produced for sale in the U.S. The acronym stands for Corporate Average Fuel Economy, because it applies to automotive corporations marketing cars in the U.S. and the objective was to improve average fuel economy.

CAFE is an ever-increasing average fuel economy standard that automobile manufacturers must satisfy in order to market their fleet of vehicles in the United States. This regulation is targeted toward new vehicles.

Example: Current CAFE standards mandate a manufacturer's fleet average miles per gallon in fuel economy. If a car company produces three cars, rated at 35, 30 and 20 mpg, average fuel economy would be determined as:

Based upon their average fleet fuel economy, this car company could now sell their vehicles in the United States for the 2015 model year.

The fuel economy standards established by CAFE are more strict and demand more fuel efficiency for passenger cars than for light trucks. Passenger cars are defined as having a Gross Vehicle Weight Rating (GVWR) of less than 8500 lbs, while a light truck is a vehicle with a GVWR greater than 8500 lbs. The light truck classification was initially for utility and commercial vehicles, but since many SUVs exceed the GVWR rating for a passenger car, they are regulated separately from the fleet of passenger cars and are not subject to stringent fuel economy standards.

First we want to determine the difference in minimum fuel economy standards and the actual fuel economy of Company A's fleet:

Given that Company A's fleet is out of compliance by and they have sold passenger cars in U.S. markets, we can calculate the fine as such:

Therefore, the total penalties for Company A totals for the entire fleet.

Light trucks, such as diesel trucks and SUVs, are covered by CAFE standards, as well as cars. Semis, however, are not regulated by this legislature.

We aren't quite to 40 miles per gallon yet, but 2011 was the first year that CAFE regulations set the standard for over 30 miles per gallon. The standard from 1990 up to 2011 was just over 27 miles per gallon, still a vast improvement from 1978's 18 miles per gallon.

Currently available natural gas reserves are expected to last another 75 years at the current rate of consumption.

The least efficient and most abundant form of coal is lignite; after this comes bituminous coal, then, lastly, anthracite. Anthracite is a very hard form of coal with an extremely high carbon content. Anthracite also burns the cleanest of any coal, but unfortunately it is the least abundant and hardest to reach form of coal. Charcoal is not coal at all, but rather compressed and burned wood, consisting mainly of carbon and any remaining ash.

The United States is 5% of the world Population and consumes 25% of global fossil fuel production. In addition, North America peaked in oil production in the 1970's which, when combined with a disproportionately high demand, results in a national dependence on foreign-sourced oil.

Clean coal technology is a promising solution to minimizing pollution from coal plants, and coal is one of the most abundant fossil fuels on the planet, with reserves potentially lasting up to three hundred years. Coal is also very energy-dense when compared to biomass or other renewable energy sources; however, the sulphur content of coal varies based on geographic location, and in areas that depend on locally sourced, sulphur-rich coal, the resulting emissions contribute heavily to acidic precipitation.

Dams can be huge boons to local economies, and are a landmark of human engineering and achievement; however, they do carry serious consequences to the natural environment. They lead to sediment buildup, which hurts the flow of nutrients downstream, ruins the natural riverscape, and can cause the area behind the dam to become more shallow.

Dams carry numerous drawbacks, but one benefit of dams that they do not increase air pollution. Hydroelectric power is considered to be one of the cleanest forms of energy.

The fuel efficiency of the vehicle can be calculated as such:

This equation gives us the energy converted to forward motion per gallon of gas. We can use this value to determine the percent of total fuel energy that is devoted to forward motion:

From these calculations, we can determine that 25% of the energy from a gallon of gas is converted to actual forward motion of the vehicle, giving us a fuel efficiency value of 25%.

All of the answers are part of energy conservation. But to be net zero the building has to produce energy and cannot be using any more than it produces.

U-235 differs from U-238 in that U-235 is able to produce a fission chain reaction. U-238 is the most common isotope of uranium, with the U-235 isotope constituting less than 1% of natural sources. Uranium enrichment is the process by which U-235 is separated out, and it is this product that is most commonly used to manufacture nuclear weapons. Pu-239 is produced from U-238 and can be used for nuclear weapons as well, but Pu-239 is not an answer choice.