Many electricity providers offer their customers time sensitive, or time of use, pricing plans. These plans reflect the actual cost of producing electricity at the time it is needed. They are designed to encourage customers to lower their electricity use during times when the cost of producing electricity is high. People and businesses use varying amounts of electricity throughout the day and power utilities adjust to these changing demands. When demand is low, utilities can supply electricity using less expensive sources, but when demand is high more expensive sources must be added to supply enough electricity.
- Select pricing plan Hourly Plan - Summer and notice the red dot moving along the graph showing time and price. Current Time and Current Price are also shown at the top of the applet. What is the lowest price and during what times of day does it occur? Change the pricing plan to Hourly Plan - Winter. Now, what is the lowest price and when does it occur?
- Choose the 175 W solar module from each of the Appliances menus. (You may need to use the scroll bar to see it.) Reset the time and watch for 24 hours. What happens? How does the time of day affect the production of the solar module? Under which pricing plan does the solar module save the home consumer most money? What happens when one 175W solar module and the PC are the only connected appliances?
- If only your Playstation 3 and 42" Plasma TV are on for four hours starting at 7:00 PM on a summer evening, how much do you pay for the energy used using the Hourly Plan? How much under the Three Tiered Plan?
- Your utility offers a Three-Tiered Plan. During what times should you avoid using the clothes washer during the summer? During the winter?
- Your utility offers an Hourly Plan. How much do you pay for energy if you use your clothes washer on a winter weekday from 8:00 AM to 10:00 AM compared with using it from 7:00 PM to 9:00 PM? If you wash clothes three times per week, how much could you save during one year by changing your washing time from evening to morning?