Demand Response

When one thinks of the cost of electricity usage, many think that the rate is calculated based on the average day-to-day use of electricity, and never realize that the rate actually changes due to peak times of the day where power is worth more.  This is where demand response comes in.

The U.S. Department of Energy established demand response in order to motivate customers to change their habits when it comes to electricity. An appliance is never truly off if it’s still plugged in, so millions of people across the globe are wasting money by leaving items such as cell phone chargers and toasters plugged into outlets all day when they’re not even home using them.

Supply and demand on the electricity grid need to be in balance at all times to avoid an outage. System operators pay very close attention to the electric usage at all hours of the day so that the supply can always be met with the demand. If the supply runs short, demand response moves in (D.O.E.).

There are two types of demand response, economic and emergency. Economic demand response is when demand increases and the cost to acquire supply increases. “Economic demand response lowers that average cost by providing incentives for customers to use electricity off-peak.  For example, many utilities offer time-of-use electric rates, which are higher during the day and lower at night” (Energy DSM). Emergency demand response occurs when electricity peaks in the middle of the day due to unusually hot or cold weather, and the supply sometimes isn’t always available. When this happens, electric utilities call on their emergency resources to avoid outages (EnergyDSM).

Many companies such as EnerNOC, Comverge, and CPower are leaders in demand response, offering numerous programs to energy end-users (Tweed). CPower’s program helps companies lower their energy usage while making significant revenue and environmental benefits. Their chart, showing peak times, is quite helpful in understanding demand response and their role in energy consumption and management.

Overall, I think demand response is a positive thing if regulated. It’s nice to see companies like EnerNOC, which is Boston-based, managing energy use in a city where electricity bills are through the roof. EnerNoc is current load management is about 5 gigawatts after buying two other companies, and is a role model for staying ahead in such a competitive field.

Works Cited

“Benefits of Demand Response and Recommendations.” energy.gov. U.S. Department of Energy, n.d. Web. 13 Feb. 2011. <www.oe.energy.gov/DocumentsandMedia/congress_1252d.pdf>.

Tweed, Katherine. “The Top Five Players in Demand Response : Greentech Media.” Green Technology | Cleantech | Green Energy – News, Research, & Resources. N.p., n.d. Web. 13 Feb. 2011. <http://www.greentechmedia.com/articles/read/top-5-demand-response/>.

“What is Demand Response?.” EnergyDSM.com. N.p., n.d. Web. 13 Feb. 2011. <http://www.energydsm.com/demand-response/>.

“demand response | demand energy | smart grid | cpowered.com.” energy management | energy demand response | cpowered.com. CPower, n.d. Web. 13 Feb. 2011. <http://www.cpowered.com/demand-response.php>.

Lego Mindstorms

Working with the Lego Mindstorms has been a really great opportunity to have these past two classes. My group had a few troubles getting some of the pieces together in the beginning, (we seemed to have a few things backwards…must’ve been a case of the Mondays.) Once we had everything put together and plugged in, I wasn’t too sure what we would be doing with them, I had never been one for programming, but the software used for the Mindstorms seems to cater to both amateur and advanced users. I will definitely need more time with the program to really get the feel for it, (and maybe a manual too…) but sticking with basic power functions eased my worries.

On the first day with the Mindstorms, we only had time for some basic functions, such as going forwards and backwards, left and right, and speed control. On our second meeting, we learned how to create an entire string of commands and also how to loop it so it can happen more than once. It wasn’t long before our robot began doing our own routine that included a short little musical number throughout the motions.

Later, we calculated the diameter of the tires before measuring the distance traveled by the robot. The wheel circumference was .1700m, and the distance we measured was about 15cm or 16cm. The problem with measuring the robot in this fashion is that you will never have the ruler perfectly at the back or front of the tire. The robot also does not travel in a perfectly straight line, so as it leans, the person doing the measurement leans, so there’s a large margin for error in this situation. We did not repeat this experiment with other power modes, nor did we calculate the number of wheel turns since we then moved onto the next experiment.

Next, we programmed the vehicle to participate in a small challenge to make the robot travel clockwise in a one-meter circle, travel counter-clockwise, do both and make a sound, and then we programmed both tires to opposite directions as our unique trajectory. It was a bit challenging trying to choose speeds for each tire in order to make the robot travel in the one-meter circle. We started a 40 seconds, but then dwindled down to using about 20 seconds for the circle, it was difficult to measure due to the cramped space in the classroom, so if we were to do this again I’d want to pick an open area (where I can also mark off a meter circle on the floor in tape) and make the robot travel the circle. For the tire speeds, the power modes for the first one we chose were 85 for one side and 70 for the other. We then tried power modes of 55 and 40, and then power modes of 65 and 65 for the opposite moving trajectory.

Overall, I did enjoy working with the Mindstorms and hope to do more with them in the future. It is unbelievable the amount of power that these small machines possess! And I know that it’s going to take a lot longer than a few classes to get the hang of the program and learn more of its features, but this class provides a nice sampling to robotics that I probably won’t receive in any other class that I take at Suffolk. (And I think I finally understand why my father, an electrical engineer, gets so excited when he used to talk about working with the Mindstorms when he was in college!) It’s certainly a nice break from textbook readings!