Handbook of Energy Storage for Transmission or ... - W2agz.com

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cost/benefit analysis
Table 4-6. Cost/Benefit of AGC Applications
Base Case
Alternate
AGC (NYISO) GVEA Equivalent
Initial Installed Cost, M$ 23.0 27.2
Total Cost, M$ (Note 1) 37.1 43.9
Total Benefits, M$ (Note 2) 36.3 48.8
NPV, M$ (Note 3) (0.8) 4.9
Notes:
(1) Total Costs: Present value of initial capital, operating, replacement,
taxes and insurance costs
(2) Total Benefits: Present value of avoided costs and revenues
(3) NPV: Total Benefits minus Total Costs
4.2.4 Application 4: 20MW Wind Farm Stabilization (40 NAS PS Modules)
A wind generator business model based on forward contracts to supply on-peak energy at firm
rates is assumed, wherein shortfalls in wind generation are supplemented with purchased power
from the grid or auxiliary generation. It is also assumed that the wind generator commits to the
transmission capacity necessary to distribute the amount of power contracted. Wind generation
during other periods is sold at non-firm rates and no transmission tariff is charged because of
excess capacity during off-peak hours. When the wind farm incorporates energy storage, the
storage media is assumed to be charged during off-peak hours. If the off-peak wind resource is
inadequate, the amount necessary on a daily basis is also purchased. The electric rates shown in
Table 4-4 are assumed to apply.
Table 4-7. Electricity Rates & Business Model for Wind Stabilization
Rate Descriptor Time Period Explanation $/MWh
On-Peak Firm Energy (sell), 10am to 7pm Firm on-peak power sold via contract 120
On-peak power purchased to hedge wind
On-Peak Energy (buy),
10am to 7pm
deficiency 144
On-Peak Non-Firm Energy (sell) 10am to 7pm On-peak wind in excess of contract 60
Off-Peak Energy (sell), 9pm to 7am Off peak wind in excess of battery charge 20
Off-peak power purchased to hedge wind
Off-Peak Energy (buy),
9pm to 7am
deficiency required to charge 21
Semi-Peak Energy (sell),
Transmission Tariff, $/kW-mo
7 to 10am;
7 to 9pm
10am to 7pm
Wind during other hours 40
Tariff charged wind generator for on-peak
generation
The wind data summarized in Figure 4-1 illustrates the nature of the wind resource. This data
represents the power generated at a 20MW wind farm. It indicates that the maximum capacity of
the wind farm is reached at some point during each month, but that there was no wind resource
about 20% of the time. It also shows that the average annual capacity is about 5MW or 25%
rated capacity. This particular site is subject to pronounced seasonal variations as illustrated by
the difference between average summer and winter generation. Daily and diurnal variations in
the wind resource are also present (not shown).
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