Arizona Public Service 8-K Results of Operations and Financial Condition

Exhibit 99.5

Pinnacle West Capital Corporation

Major Factors Affecting Consolidated Earnings Outlook
for Year Ending December 31, 2010
Compared with Year Ending December 31, 2009
(Earnings Per Diluted Share Outstanding)

Estimated 2009 earnings — a reasonable range around (excluding potential real estate results)	$	2.30
Projected increases (decreases) in 2010:
Retail revenue increase from general rate case settlement in excess of interim revenues		1.10
Other regulated electricity segment gross margin (revenues net of fuel and purchased power costs, excluding Renewable Energy Surcharge and similar rate adjustors) including: transmission revenue increases; higher fuel and purchased power costs (net of deferrals); and minimal weather-normalized retail sales growth		0.15 - 0.25
Increased operations and maintenance expense (excluding costs for Renewable Energy Standard and other regulatory programs) primarily due to inflation; and pension and other post-retirement benefits; partially offset by cost efficiency efforts, including cost reductions reported to ACC		(0.05) - (0.15	)
Costs related to utility capital expenditures (such as depreciation, property taxes and interest expense, net of capitalized financing costs)		(0.30) - (0.35	)
Miscellaneous other items — net		(0.10) - (0.15	)
Estimated 2010 earnings — a reasonable range around (excluding potential real estate results)	$	3.00