# 7.6: Chapter 6 Excercises

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P7.1 (10pts)

Using the latest EPA E-GRID ‘Power Flows’ spreadsheet available on the internet, you will find electricity export and import estimates for all of the states in the US.

a) What are top 5 importing and exporting states in terms of GWh? What about in terms of percent of state consumption? What are the reasons why states may import significant amounts of electricity?

b) Focus on the twelve Western United States. Does the western grid region come close to providing a 'zero balance' of imported and exported power? If not, what might be the cause of the net import or net export of this entire region?

c) Make a small optimization model to estimate the power flows in the 12 Western US states (i.e. try to match up the importing and exporting states and make the overall power flow balance). If necessary, use import/export data for a ‘super’ region located near Chicago to help your balance. Make a summary table, spreadsheet, etc. that shows where states get their imported power from (or export to). Assume that utilities try to minimize the transport cost of electricity, which is roughly proportional to distance between states; you can use a rough estimate of distance accurate to the nearest 500 miles. Report your results as a matrix in which entries represent the estimated flow between states and column and row totals represent exports and imports of power given from e-grid.

d) Let us simulate a storm along the west coast, with all transmission capability among WA, OR and CA knocked out (so these three inter-state distributions are set to zero. Other inter-state distributions are ok as well as in-state generation.). Re-estimate your flows for this case. What has changed, if anything?

This page titled 7.6: Chapter 6 Excercises is shared under a CC BY-SA license and was authored, remixed, and/or curated by Donald Coffelt and Chris Hendrickson.