September 2015 – Jennifer Straka

Lego Mindstorm Lab Activity #2

My teammate, Jill Swan, and I experimented with three power settings for the motors, keeping both motors the same. We did three trials per power setting. The results are as follows:

Wheel Diameter= .055 m Circumference= .1728 m

The experiments show that the more power the motors had, the farther the robots went. In order to make a full rotation, the power needs to be over 55, as our experiments show that 55 just slightly not enough for an entire 360 degree rotation. The margin of error varied across all the studies anywhere from less than a percent to 12% error with no definitive link between the variation of results. The experience was helpful to reinforce the concepts of distance, velocity, and dealing with diameter, radius, and circumference from the lecture. It also was beneficial in learning to work with the robots and the computer software associated with them.

Fracking

What is fracking? Fracking, otherwise known as hydraulic fracturing, has been in use since the 1940’s but has recently seen a rise in the United States in part due to the economic benefit it brings to the communities where these resources are located and also because of the desire for energy security. The process of fracking begins with a well drilled vertically or horizontally 1-2+ miles into the Earth. In order to reduce the risk of leakage into the groundwater, the well is encased in steel and/or cement. At the time the vertical well reaches the layer of rock where the oil or natural gas is located, the well curves to about 90 degrees to drill horizontally along the rock layer, extending potentially over a mile. Next, fracking fluid is pumped into the well at pressures high enough to fracture the surrounding rock, creating fissures that allow oil or gas to flow through. This fracking fluid, also called slickwater, while mostly water, contains a range of additives and chemicals as well. Proppants are also pumped into the well and are used to keep the fractures open so the oil or natural gas can flow freely through the fissures. The reservoirs of oil or natural gas are then pumped back to the surface along with flowback liquid containing numerous contaminates. The flowback liquid is eventually injected deep in the ground below groundwater or disposed of at wastewater treatment facilities. The image below provides a graphic representation of how fracking works.

Pros:

>Fracking provides economic benefits such as jobs in the communities where the wells are located. (Reference 2)

>Fracking allows the US to produce their own energy resources, decreasing dependency on imported oil and fossil fuels and the costs associated with that. (Reference 2)

>Fracking can stimulate new production from older wells. (Reference 1)

Cons/Environmental Impact:

>An average of 400 tanker trucks are required to carry water and supplies to and from the site, contributing to air pollution and use of fossil fuels. (Reference 3)

>Millions of gallons of water are used in each fracturing job.

>About 40,000 gallons of chemicals (up to 600 types of chemicals such as lead, uranium, and mercury) are used in a fracturing job.

>Groundwater used by nearby towns for drinking water can be contaminated from leaching of the chemicals during the fracking process sometimes causing health complications.

>Up to 50% of the fracking fluid (not biodegradable) is not recovered and is left in the ground.

>Fracking fluid left to evaporate releases harmful VOC’s into the atmosphere contributing to acid rain, contaminated air, and ground level ozone.

References:

1. What is fracking?

http://www.what-is-fracking.com/what-is-hydraulic-fracturing/

2. Live Science

http://www.livescience.com/34464-what-is-fracking.html

3. Dangers of Fracking

http://www.dangersoffracking.com/

US Energy Grid

What is the energy grid?- The energy grid, or power grid in the United States is the system by which electricity is distributed to consumers across the country. The grid connects the energy producers and the consumers through a complex electrical system composed of three interconnected systems.

What composes the infrastructure of the energy grid?- As stated above the energy grid is composed of three interconnected systems. The systems are divided into the Western Interconnection, the Eastern Interconnection and the Texas Interconnection. According to the US Energy Information Administration, “The interlinked systems now include about 2,000 electric distribution utilities, more than 300,000 miles of transmission and distribution lines, millions of customers, and 7,000 power plants.” The image below is a graphic representation of the energy grid, showing the three interconnections.

How does the energy grid work?- The first step of the grid is the power source, whether that be a from a renewable source such as a hydro-electric plant or a non-renewable source such as a coal plant. Once the power is generated, it is stepped up at a transmission substation in order to be able to travel long distances. In order for the power to be used, it comes off the transmission grid to the distribution grid where it is stepped down at a distribution substation. On the distribution grid it is then stepped down a second time through the transformers so the power is now at the 120 or 240 Volts that we use in our homes and businesses.What are Smart Grids?- Smart grids are a way of modernizing the power grid by adding technology to the current grid such as meters, sensors, and synchrophasors. This incorporation of digital technology enables communication between the grid, consumers, and the operating network providing data on consumption, voltage, damage, and potential problems among others. According to the US Energy Information Administration, “A smarter grid makes the electrical system more reliable and efficient by helping utilities reduce electricity losses and to detect and fix problems more quickly. The smart grid can help consumers conserve energy, especially at times when demand reaches significantly high levels or when an energy demand reduction is needed to support system reliability.”

Pros:

1. Provides power to the country

2. Contributes to the economy in ways such as providing jobs anywhere from at the power plants to the installation of new lines.

Cons:

1. Security threats: “In fiscal year 2014, there were 79 hacking incidents at energy companies that were investigated by the Computer Emergency Readiness Team, a division of the Department of Homeland Security. There were 145 incidents the previous year.” CNN

2. Siting new transmission lines when there is opposition to construction.

3. Reaching renewable energy generation sites can be challenging.

References:

1. US Energy Information Administration: http://www.eia.gov/energy_in_brief/article/power_grid.cfm

2. CNN: http://money.cnn.com/2014/11/18/technology/security/energy-grid-hack/

3. How Stuff Works: http://science.howstuffworks.com/environmental/energy/power4.htm

4. Office of Electricity Delivery & Energy Reliability: http://energy.gov/oe/services/technology-development/smart-grid