PDS AP Environmental Science 5th Period 2010-11

Could someone explain to me how each happens in plain English?

Also, what is each used for in the process of making nuclear energy?

I have in my study guide the phrase carbon neutral as part of the benefits of biomass energy, and I was hoping someone could remind me of what that is because I don’t have a description to go along with it, and I don’t remember what the phrase means.

Though biodiesel is still an infant industry, it serves as a reasonable alternative energy source to petroleum. Most cars in the United States have gasoline engines, but Mr. Thompson suggested that a diesel engine transition would benefit the environment in the long run. Of course this would be the case only if biodiesel were used in the engine. Diesel engines squeeze air more tightly than gasoline engines and more energy is involved. Gasoline engines are suitable for smaller equipment, and involve air and spark combustions, and a piston.

Formation of Biodiesel:

Biodiesel is made from natural oils (origin: soy, canola, poultry fat, algae, jatropha) in a chemical refinement process.

Advantages:

• Better lubricant for inside of engine than regular diesel
• Reduces carbon emissions by 78.4%
• Not carcinogenic
• Not flammable
• Not hazardous
• Biodegrades quickly

Disadvantages

• Not yet available in great quantities
• Not cheaper than petroleum
• Doesn’t behave well at cold temperature (begins to form a gel between 30-50°F
• Problems with solvent

According to Mr. Thompson,  if biodiesel were the main fuel source, global warming would have less of an impact on the planet. Nonetheless, there is no proof that more gas mileage is gained from the usage of biodiesel, and it’s shelf life is only six months.

Photo Credit to Mr. Willard

Hydrogen Energy is created by passing Hydrogen through a membrane which separates the protons and electrons. In this process, the electrons are diverted to create electricity and H2O is given off as a byproduct. As a fuel source, Hydrogen is clean, with practically no pollutants released, it is efficient, can be up to 90% efficient if heat is harvested, and is safe, when kept in high pressure environments provides no risks.

Here is a quick video on how the fuel cell works http://video.nationalgeographic.com/video/player/environment/energy-environment/fuel-cells.html

Hydrogen Fuel Cell

Currently, scientists are researching how to harvest Hydrogen from algae. If this process is perfected, Hydrogen fuel cells would be a fully renewable energy source.

http://www.biodieselmagazine.com/articles/4268/harvesting-hydrogen-from-algae

Four Types Of Problems

1. E = Energy- basic unit is joules (J)- P x T

P = Power- basic unit is watts (w) = J/sec- E/T

T = Time- E/P

Example: How much energy (in J) does a 30 w bulb if on for 30 min?

E = P x T = 30 J/sec x 60 sec/min x 30 min = 54,000 J

2.  Heat Transfer:

Q = mc x change in temp.

Q = heat energy in calories         m = mass          c = specific heat of water = always equals 1

English version of this equation is in BTU’s- British Thermal Unit

BTU = lb x 1 btu/lbxF x change in temp.

3. Cost / Price:

Units used x Price/Units = Price = cost or bill

4. Efficiency of Devices:

Input = output/efficiency

example: 60 w = output/ .05 = 3 w to light

Commonly asked Efficiency

• Incandescent bulb = 5%
• CFL = 20-25%
• Coal Plant = 30%
• Nuclear Plant = 25%
• Car Engine = 20-25%
• Photosynthesis 1%

Energy not used for energy is lost to heat.

If you thought the photo by Richard Box of the “leaky” high voltage transmission lines was neat, you can check out more of his photography here.  I thought that was an interesting intro to a subject your book seems to ignore-how the electricity gets from all those different types of power plants to your home:

Power Transmission Infrastructure

Image source (and article on how there are plans to replace our “dumb” grid with a “smart” one): http://newsone.com/nation/associated-press/obama-administration-will-spend-3-4-billion-toward-smart-power-grid/

You need a basic working knowledge of “the grid” if you are going to make sense of some of the free response math questions on the AP exam.  If you missed class, the best makeup lesson I can offer is to go through the web pages of How Power Grids Work at HowStuffWorks.com.

*Someone else has scribe duties for the energy math problems covered in class today, so look for another post soon.

Why use solar energy? Lots of reasons. Unlike burning fossil fuels, solar energy is waste-free and results in zero emissions into the atmosphere. It is also a renewable resource, and can be relied on to last as long as the sun does. Despite the initial costs of solar technologies, the use of solar power saves money in the long run because it depends on the free use of sunlight rather than fluctuating oil prices.

Tons of scientists are working not only on how to create new technologies for solar energy that lower the costs, but also how to boost efficiency of the current technology. This Discovery Channel video features a scientist trying to pinpoint the best possible places to capture the sun’s rays: Solar Prospecting (Source: discoverychannel.com)

There are two main types of solar energy technologies:

1. Photovoltaic (PV)- this converts sunlight directly into an electrical charge
2. Concentrating Solar Thermal (CST)- this uses the heat from the sun to create steam which then turns a turbine and powers a generator

Most of the solar panels used on rooftops are photovoltaic. Here is a simple video showing how solar energy can be used to generate electricity for a home: Solar Powered Home (Source: Youtube)

Something that I found even more interesting about solar energy is that it is not limited to single buildings or small scale areas. It is being used in much larger scale projects, like this one in Spain that generates enough electricity to power over 15,000 homes: Solar Plant in Spain (Source: discoverychannel.com)

Improvements in solar technology are being explored every day. This article goes through the history of solar energy and how it has changed from 1979 to 2010: Solar Improvements Article

Wind Energy, put simply, is using the wind to move turbines, which then in turn provide power. The turbines are mounted atop very tall towers in order to capture the most wind. This is by far one of the most sustainable and cleanest types of energy available. The wind turbines produce no toxic or heat trapping emissions, creating an extremely viable energy alternative. According to the Union of Concerned Scientists, Wind Energy is becoming much more cost-competitive and is on the rise. In 2007 and 2008 alone more wind turbines were installed than in the last 20 years combined, making this an almost 27 billion dollar investment. The turbines are pretty complex pieces of material, so I hope this pictures helps to show the parts. Although they do seem complicated they are becoming incresingly cost-efficient

I found a really good video to use to help explain this process throughly and simply. Unfortunately my computer is not letting me embed this video so I hope it’s not too much trouble to navigate away from the page, it’s definately worth it.

http://science.discovery.com/videos/deconstructed-how-wind-turbines-work.html

Also found a great link to an article explaining how these wind turbines are becoming more and more efficient in creating energy. The article comes from the Alternative Energy group and is pretty neat.

http://www.alternative-energy-news.info/efficiency-of-wind-turbine-blades/

*Note: SargeK moved to the other class, but since we have no one to do geothermal, here is a guess post by him.

Earth's Natural Heat

Geothermal Energy is essentially using the earth’s natural heat for power. One way the process works is the heat from the earth warms water, which evaporates to steam. The steam is then used to turn turbines that then generate electricity. Geothermal energy is a good clean way to power and heat the world’s towns and cities without needing too much coal. There are many towns around the world reliant on geothermal energy, such as this one in China:

The concept of using the earth to heat our homes is pretty cool, if you are more interested in figuring out how this direct geothermal energy works, check out this link from howstuffworks.com: http://www.howstuffworks.com/environmental/energy/geothermal-energy.htm.

Keeping the Japan Nuclear Crisis in mind, you can’t help but wonder if other sources of energy can/would help Japan recover. To ease you curiosity, check out this news report about the potential for geothermal energy in Japan: http://www.sify.com/finance/analysis-hot-air-can-geothermal-help-japan-in-crisis-news-economy-ldyoksdhfid.html. In the grand scheme of things, geothermal energy provides a generally renewable source of energy. Although it cannot be used to fuel vehicles like biomass has potential to do, it is very efficient for heating and cooling buildings. Geothermal energy is a solid investment in the world’s future.

Currently, about one-fourth of the world’s electricity comes from hydroelectric energy. Humans have created dams and hydroelectric power plants all over the world in order to harness the energy in rivers to produce electricity. The method in which the dam produces electricity is pretty simple:

1. The dam blocks the flow of the river, flooding the region around it.
2. The dam controls the amount of water it releases to the other side.
3. As the released water moves through the dam, it turns the turbines in the dam.
4. The turbines are hooked up to generators, which essentially produces the electricity.

If you are interested in learning more about how a dam operates, Howstuffworks also has a great in depth explanation.

With the construction of the largest dam in history, China has become one of the major producers of hydroelectric energy. In 2006, the Three Gorges Dam was completed, becoming to world’s largest dam and power plant. However, the enormity of the project has resulted in huge social and environmental impacts. Flooding has displaced over million residents in the area. The relocation of the residents in the flooding area has been one of the biggest relocation projects due to the construction of a hydroelectric energy facility. The Al Jazeera video below discusses the impact the Three Gorges Dam has been having on the people in the surrounding area:

The flooding is also disrupting habitats of wildlife, decreasing biodiversity. An even greater concern is the amount of sediments that is being trapped behind the dam, preventing those nutrient rich sediments from reaching the floodplains further down the river. In addition, the lack of sediments past the dam is causing erosion further downstream of the Yangtze. The article below better describes some of the environmental problems associated with the Three Gorges Dam:

http://www.reuters.com/article/2007/05/21/environment-china-environment-dam-dc-idUST31738620070521

Another potential issue brought up by dams is the possibility of dam failure. In the case of severe flooding, the reservoir could exceed its water carrying capacity. As a result, the dam could break, allowing the water that was trapped behind the structure to be released downriver. In 1975, 62 dams in China broke, causing extreme flooding over huge areas downriver.

But are these problems worth the benefits? Well, Three Gorges Dam has already benefited China in many ways. The dam currently provides as much electricity as a dozen of coal power plants, reducing the number of coal plants needed. Without these coal plants, China is not releasing the amount of carbon emissions, sulfur, nitrogen, and mercury that it could have been releasing. In addition, hydroelectric energy is renewable, meaning the means that generates electricity is naturally replenished. So do you think the benefits outweigh the costs?