Demand Response

Consider the following: It is mid-august and a four day heat-wave has just begun. Luckily you have central air conditioning. For a little added comfort you also bought a few new fans to help circulate the air. Unfortunately, you are not alone. The heat-wave is affecting the entire region. Virtually every household is blasting the A/C and turning on those extra fans. This type of situation can cause a dramatic increase in the use of electrical power in entire states and regions. If the demand, or amount of power that is being used exceeds the supple, or amount of power that is available for use, there is a strong possibility that power outages could occur.
Demand Response is a system that could prevent situations like this. Basically, demand response would utilize a two-way smart grid. Energy would be flowing out to residences and business with data flowing back from them. If the demand starting rising too quickly, and threatened to surpass the supply, the flow of energy could be automatically reduced to prevent a crisis. Another use of demand supply is to balance out the energy use during peak and off peak hours. Automatic systems could be installed to dim the lights, or turn off the air conditioning for several hours during the day at businesses and homes. This may not seem like it would have a significant effect, but if it is utilized over an entire state or region, it could help to stabilize the power supply. This has the potential to make it unnecessary to build new power plants. Since plants have to be designed to supply the highest demand, if the demand was balanced throughout the day, utility companies could avoid building plants for increase in overall power use. In theory, these savings would then be passed along to the customer, as well as the savings from the reduced power usage they are already agreeing to.
Although Demand response is not widely in use, it does have great potential for balancing power use and preventing crisis like blackouts. Major power companies are offering financial incentives for businesses to participate in demand response. Businesses can agree to reduce their power usage specific amounts each day. If they exceed the power use on that day, or whatever time period they base it on, the company can be charged fees. If they are under their usage limit, they may be given monetary compensation or credits to use if they exceed it again. In this way it is beneficial for all parties involved. The companies and households can save money. The power grid will be more stable and less susceptible to blackouts, and power companies will save money in the long run by not having to build additional plants.

NXT Robots

We built a robot vehicle using the LEGO NXT Robot kit. Our vehicle has three wheels. There is one wheel in the rear that is not connected to a motor. There are two wheels at the front which are each connected to their own, independent motors. At the center of our vehicle is the NXT brick, which is used to translate the programs we design on the computer into tasks for each motor to perform. Using the software we can control the speed of each wheel, as well as the length of time it will move. Once the program has been designed, we can download it into the brick, and unplug the vehicle from the computer. Then we can place the robot in an open space with room to fulfill the programmed task. We can also stop the vehicle at any time by pressing the orange button on the brick.

Our first challenge was to create a program that would cause the robot to drive in a circle with a 2 foot diameter. To achieve this, we gave each wheel separate commands. One wheel was given a speed of 100, the other a speed of 50. Since one wheel was moving much faster speed, and since both wheel were consistent, the vehicle drove in a circular shape. We then adjusted the speeds several times until the vehicle successfully performed the (approximate) two foot diameter circle at the highest speed possible.

For our next challenge we programmed the vehicle to move forward in a straight line for exactly one second. We used a ruler to mark the starting position of one tire, then measured the distance it traveled. We measured this distance to be 26.7 cm. We then used the program to look up the exact distance travelled, or the distance that was supposed to be travelled. This was 26.4 cm. There was a 3 mm difference in measurements. We then figured out the percentage error. To do this we followed a simple formula. First we found the difference between our measurement and the actual measurement; This was .3 cm. We then divided .3 cm by the average of the two measurements, which was 26.55 cm. The percentage error we calculated was 1.13%. A percentage error this small was undoubtedly caused by human error. First of all, we could have simply measured incorrectly. Perhaps we marked the table slightly in front of, or behind, the exact place the where the wheel was resting at the beginning or end. We my also have placed the ruler too far forward when measuring the resting place. Another possibility is that the vehicle did not actually travel the distance it was supposed to. This may have been caused by the cords hanging off the back of the vehicle causing drag. It is possible that the drag from the cords caused the tires to spin just enough to set the vehicle back a few millimeters. It was almost certainly one of if not both of these possible errors that caused our slight difference in measurement.

Fukushima Daiichi Nuclear Disaster

On Friday, March 11th, 2011, an undersea earthquake occurred 43 miles off the coast of Japan. The Tohoku Earthquake, a magnitude 9.0 quake, was the fifth largest in recorded history, and the largest to ever hit Japan. In addition to damage done by the earthquake itself, a devastating tsunami soon hit the Japanese shore.

One of the many coastal towns hit by the tsunami was Okuma, in the Fukushima region. This town is home to the Fukushima Daiichi Nuclear Power Plant, one of the 15 largest power plants in the world. By the time the tsunami hit the power plant, all six generators (Boiling Water Generators) were shut down. Generators 4, 5, and 6 had been shut down for maintenance prior to the quake. Generators 1, 2, and 3 turned off automatically when the earthquake occurred.

Reactors 1, 2, and 3 were being cooled by emergency generators when the tsunami hit. The reactors were built to sustain waves of about 5.7 meters, but this tsunami brought 14 meter high waves. The waves damaged the generators, preventing them from properly cooling the reactors.  The damage also prevented workers from accessing these areas of the plant. The overheated reactors experienced hydrogen explosions, propelling the situation into a full blown nuclear meltdown. Sea water was used to cool the reactors which led to radioactive contamination of sea water. Radioactive material also contaminated the ground and air. Only two workers died at the plant during the earthquake. About 60 other civilians died during the evacuation after the tsunami. Experts say that the radiation from the Fukushima disaster will cause cancer in somewhere between 100-1,000 individuals.