PUB00037

• Year: 1988
• Title: Colorado Joint Planning Study Economic Potential of Pumped Storage
• CWCB Section: Interstate & Federal
• Author: Colorado Water Resources and Power Development Authority
• Description: Assessment of whether pumped storage facilities are economically attractive to Colorado utilities
• Publications - Doc Type: Water Resource Studies

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5.0 SENSITIVITY ANALYSES

Because of the uncertainty about future economic conditions and power demands, the
variability of the base resource plan is normally tested. In developing the least-cost
plan, utilities perform sensitivity analyses on all major independent variables including
load forecasts, capital and fuel costs, price escalation rates, power source availability,
transmission costs, cost of money, and others. Variations in these factors are often
combined into scenarios to calculate the associated revenue requirements and
evaluate each scenario using risk anaiysis. In this study, only one of the variables, the
forecast of demand and energy, was tested.

As mentioned in Chapters 2.0 and 3.0, each utility provided a low and high estimate
for peak demand and energy growth in addition to the medium forecast. Table 5-1
shows the assumed low growth rates for the state; Table 5-2 shows the high growth
rates for peak and energy. When combined into a statewide total the low forecasts of
peak load and energy were in the 1.9 to 2.0 percent compounded growth range, while
the high forecasts ranged between 2.5 and 2.6 percent compounded growth rate.
Figure 5-1 illustrates the medium, low, and high peak growth rates for the state. The
load growth rates in the state has been 2.6 percent compounded annually over the last
seven years.

The same methodology and assumptions were used in the sensitivity analyses as
were discussed in Chapters 3 and 4. Under the case for the low load forecast without
pumped storage, little new thermal capacity (744 MW) was needed through 2007.
However, in the case for the high peak load forecast, almost four times as much
thermal power, (2,802 MW) was needed compared to the low forecast, and 1,224 MW
of additional capacity over the medium case would be needed in the statewide system.
The 744 MW included the coal and CT additions plus the planned units. The capacity
additions for the low and high load forecast analyses without pumped storage are
shown on Tables 5-3 and 5-4.

5-1