Exhibit 99.8
PINNACLE WEST CAPITAL CORPORATION
QUARTERLY CONSOLIDATED STATISTICAL SUMMARY
GLOSSARY OF TERMS
Arizona Job Growth Percentage growth over the prior
year in total non-farm payroll employment
for the state of Arizona, non-seasonally
adjusted.
Building Permits - Metro Phoenix The number of residential dwellings permitted to be
built by authorized agencies in Maricopa County,
Arizona. Single-family refers to detached buildings
intended to be occupied by one family each.
Multi-family permits represent the number of units
authorized to be built in condominium, townhouse and
apartment complexes.
Capacity Factor The ratio of the average operating load of an electric
power generating unit for a period of time to the capacity
rating of the unit during that period.
Change in Mark-To-Market Value of Forward Sales The gross margin related to the change in
mark-to-market value in the current period of
transactions which have been entered into during the
current period or prior periods for which the
commodities are scheduled for delivery in a future
period.
Degree-Days -- Cooling A measure of temperatures designed to indicate the
amount of electricity demand for cooling purposes.
Cooling degree-days are calculated by summing the
difference between each day's actual average
temperature and a base temperature of 65(degrees)F for the
month. Average temperatures less than the base
temperature are ignored.
Degree-Days -- Heating A measure of temperatures designed to indicate the
amount of electricity demand for heating purposes.
Heating degree-days are calculated by summing the
difference between each day's actual average
temperature and a base temperature of 65(degrees)F for the
month. Average temperatures greater than the base
temperature are ignored.
Electricity and Other Commodity Sales, Realized Marketing and trading gross margin related to
electricity and other commodities that were delivered
in the then-current period.
Electricity Spot Prices --Palo Verde - Off-Peak Electricity average daily spot prices at Palo Verde
substation during off-peak hours. It measures electric
prices at the producer level and is the result of real
time prices used for benchmarking, price comparisons,
and establishing price contracts. Measured in dollars
per megawatt-hour.
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Electricity Spot Prices -- Palo Verde - On-Peak Electricity average daily spot prices at Palo Verde
substation during on-peak hours. It measures electric
prices at the producer level and is the result of real
time prices used for benchmarking, price comparisons,
and establishing price contracts. Measured in dollars
per megawatt-hour.
Electricity Spot Prices -- SP15 - Off-Peak Electricity average daily spot prices at SP15,
a region of California substations, during off-peak
hours. It measures electric prices at the producer
level and is the result of real time prices used for
benchmarking, price comparisons, and establishing price
contracts. Measured in dollars per megawatt-hour.
Electricity Spot Prices -- SP15 - On-Peak Electricity average daily spot prices at SP15, a region
of California substations, during on-peak hours. It
measures electric prices at the producer level and is
the result of real time prices used for benchmarking,
price comparisons, and establishing price contracts.
Measured in dollars per megawatt-hour.
Generation Capacity Out of Service and Total capacity required and economic, yet unavailable
Replaced for Native Load for retail customers and traditional wholesale
contracts due to scheduled or unscheduled outages. Measured
in megawatts per day.
Generation Production -- Coal Amount of net energy produced by coal-fueled generators.
Measured in gigawatt-hours.
Generation Production -- Gas/Oil/Other Amount of net energy predominately produced by natural
gas and oil-fueled generators. A small amount of
energy from hydroelectric and solar power plants is
also included. Measured in gigawatt-hours.
Generation Production -- Nuclear Amount of net energy produced by nuclear-fueled generators.
Measured in gigawatt-hours.
Gigawatt-hour (GWH) A unit of energy equivalent to 1,000 megawatt-hours or
1,000,000 kilowatt-hours.
Marketing and Trading Gross Margin - Pretax Revenues from marketing and trading activities (other
than retail sales, traditional wholesale sales and
retail load hedge management) less the costs of the
related commodities, with mark-to-market gains or
losses, before income taxes.
Mark-To-Market Adjustments to revenues or costs to recognize value
of sales and purchase contracts, for which the
commodities are scheduled for delivery in a
future period, at current forward wholesale prices.
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Mark-To-Market Reversals on Realized Sales The reversal of the gross margin related to
mark-to-market transactions entered into in prior
periods for which the commodities were delivered in the
current period. Realization of prior-period
mark-to-market relates to cash flow recognition, not
revenue recognition or earnings recognition, because in
accordance with mark-to-market accounting, the margin
was already recorded in the prior period. A negative
amount shown in this category represents the arithmetic
opposite of a gain recognized in the period in which
the commodities were delivered; an equal positive
amount is reflected in the realized revenue or margin
for delivered commodities. A positive amount shown in
this category represents the arithmetic opposite of a
loss recognized in the period in which the commodities
were delivered; an equal negative amount is reflected
in the realized revenue or margin for delivered
commodities.
Megawatt (MW) One million watts.
Megawatt-hour (MWh) A unit of energy equivalent to 1,000 kilowatt-hours.
Native Load Retail and wholesale sales supplied under traditional
cost-based rate regulation.
Off-System Sales Sales of electricity from generation owned or contracted
by the company that is over and above the amount required
to serve retail customers and traditional wholesale
contracts.
Purchased Power - Firm Load Power purchased from wholesale market sources used to
serve regulated retail demand and traditional wholesale
contracts. Measured in gigawatt-hours.
Purchased Power - Marketing and Trading Power purchased from wholesale market sources used to
serve marketing and trading sales not served by
company-owned generation. Measured in gigawatt-hours.
Realized and Mark-to-Market Components Marketing and trading gross margin, before income
taxes, for off-system sales and for sales and purchases
of electricity and other commodities by the company in
the wholesale market, summarized by the period of
delivery and whether the margin is realized or
mark-to-market. Realized margins relate to commodities
that have been delivered. Mark-to-market margins
relate to commodities that have delivery dates in
future periods.
Retail Customer Growth Percentage growth over the prior year in the number of
retail customers.
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Retail Electricity Usage Total retail sales for a period divided by the
average retail customers for the same period.
Measured in kilowatt-hours per average customer.
Retail Load Hedge Management Wholesale sales to liquidate electricity purchases
originally intended to meet firm load during peak
times, which purchases were not needed ultimately for
firm load. These sales are made to other electric
companies, power marketers, or public entities for the
purpose of resale. Measured in gigawatt-hours.
Retail Sales Sales of electricity made directly to retail customers or
ultimate customers. Residential retail sales are sales to
households. Business retail sales include commercial,
industrial, irrigation, and streetlighting sales. Measured
in gigawatt-hours.
System Peak Demand The demand for electricity during the one hour of
highest use each month. Measured in megawatts.
Traditional Contracts Wholesale sales resulting from unique cost-based, long-term
contracts held by the company with various entities for the
supply of electricity at agreed-upon prices.
Weather Normalized Adjusted to exclude the effects of abnormal weather patterns.
Wholesale Sales of Electricity All wholesale sales of electricity not accounted for in sales
under traditional contracts or retail load hedge management.
These sales are made to other electric companies, power
marketers, or public entities for the purpose of resale.
Measured in gigawatt-hours.