POWER DISPATCHING AT OLD DOMINION
Link with entire case – http://yunus.hun.edu.tr/~aulucan/pdf/304cases/23_DOMINION_ENG.pdf
Case: The demand for electricity varies greatly during the day. Because large amounts of electricity cannot be stored economically, electric power companies cannot manufacture electricity and hold it in inventory until it is needed. Instead, power companies must balance the production of power with the demand for power in real time. One of the greatest uncertainties in forecasting the demand for electricity is the weather. Most power companies employ meteorologists who constantly monitor weather patterns and update computer models that predict the demand for power over a rolling, seven-day planning horizon. This forecasted seven-day window of demand is referred to as the company’s load-profile and is typically updated every hour basis.
Every power company has a base-load demand that is relatively constant. To satisfy this base-load demand, a power company utilizes its most economical, low-cost power generating assets and keeps them running continuously. To meet additional demands for power above the base-load, a power company must dispatch (or turn on) other generators. These other generators are sometimes called “peakers” because they help the power company meet the highest demand or peak-loads. It costs different amounts of money to bring different types of peakers on-line. And because different peakers use different types of fuel (e.g., coal, gas, bio-mass), their operating costs per megawatt (MW) generated also differ. Thus, dispatchers for a power company continually have to decide which generator to bring on-line or turn off to meet their load profile in the least costly manner.
The Old Dominion Power (ODP) Company provides electrical power throughout Virginia and the Carolinas. Suppose ODP’ s peak-load profile (that is the estimated load above base-load) in MWs is currently estimated as follows:
Load (in MWs)4,300 3,700 3,900 4,000 4,700 4,800 3,600
ODP currently has three peaking generators off-line that are available to help meet this load. The generators have the following operating characteristics:
Generator Location Startup Cost Cost per Day Maximum MW Capacity per Day
New River $800 $200 + $5 per MW 2,100
Galax $1,000 $300 + $4 per MW 1,900
James River $700 $250 + $7 per MW 3,000
To get an off-line generator up and running, a startup cost must be paid. Once a generator is running, it can countinue to run idefinitely without having to pay this startup cost again. However, if the generator is turned off at any point the setup cost must be paid again to get it back up and running. Each day that a generator runs, there is both a fixed and variable cost that must be paid. For example, any day that the New River generator is on-line, it incurs a fixed cost of $200 plus $5 per MW generated. So, even if this generator is not producing any MWs, it still costs $200 per day to keep it running (so as to avoid a restart). When they are running, each generator can supply up to the maximum daily MWs listed in the final column of the table.
Implement your model in a spreadsheet and solve it.