Sarah Davis
Energy Delivery, PSE
Last Revised: 2/2/2016
2017 IRP – Montana Wind DRAFT
Legend
BPA, Losses = 1.9% + Formula losses on Townsend-Garrison
PSEI, Losses = 2.7%
Wind Project, Assume Losses = 2.7%
PSEI.SYSTEM
A
Judith Gap
C
B
Townsend
Ne
w
75 Line
Mi
New
Lin
Garrison
75 M
i
e
BPAT.PSEI
Broadview
Colstrip
Estimates of Interconnection Costs and Transmission Rates
Options
A - Colstrip 1&2 Retired, 300MW, 75 Miles Away to Broadview Sub
B - Colstrip 1&2 Retired, 300MW, 75 Miles Away to Colstrip Sub
C - Colstrip 1&2 Retired, Above 300MW Wind, 75 Miles Away to Broadview Sub
$
$
$
Interconnection Costs
Transmission Rates ($/KW-Year)
52,200,000 $
80.16
51,800,000 $
80.16
52,200,000 $ 80.16 + Impact of Capacity Increase on Rate
Wind Site Statistics
Assumptions and Scope of Estimates:
 Transmission capacity freed up by retiring Colstrip 1&2 is currently unknown.
 Costs to mitigate transmission impacts of retiring Colstrip 1&2 are currently unknown.
 Interconnection costs and transmission facilities costs are estimates based on previous
NorthWestern Energy (NWE) studies that assume Colstrip 1&2 are not retired.
 Costs exclude costs to build generation.
 Costs exclude overheads.
Estimated Wind Capacity
Percentage
MT Wind Capacity Factor
46.00%
Loss Factor
7.30%
Wind Capacity Net of Losses
42.64%
Transmission Rate Breakdown
Transmission Rates
$/KW-Year
Colstrip to Townsend (PSEI)
$
31.83
Townsend to Garrison (BPA)
Garrison to PSEI (BPA)1
$
7.36
$
21.62
Estimated Wind Integration Costs 2
$
19.34
Impact of Capacity Increase on Rate
$
Uncertain
1
Rates from BP-18 Initial Proposal
2
2016 year average of NWMT Energy Imbalance Prices
Sarah Davis
Energy Delivery, PSE
Last Revised: 2/2/2016
Breakdown of Estimates of Interconnection and Transmission Capital Costs
Name
Assumptions for New Montana Wind Plant
Estimated Interconnection Costs
Estimated Transmission Costs
1. Colstrip 1&2 are retired, 300MW Wind Plant
Scenario A
2. New 75 mile 230kV line from Judith Gap to Broadview Substation
(Wood Frame Poles)
$
44,700,000
-
3. Broadview Substation upgrades to accommodate new 230kV line bay,
assuming existing step up transformer capacity is available 1
$
1,800,000
-
4. Fiber communication between Judith Gap and Broadview Substation
$
5,700,000
-
5. Other Potential Costs: voltage support equipment, overdutied
equipment, RAS, relay upgrades, communication upgrades, etc. 3
$
Uncertain
$
Total Scenario A:
$
52,200,000
$
Uncertain
-
1. Colstrip 1&2 are retired, 300MW Wind Plant
2. New 75 mile 230kV line from Wind Farm to existing Colstrip Substation
$
(Wood Frame Poles)
Scenario B
44,700,000
-
3. Colstrip Substation upgrades to accommodate new 230kV line bay,
assuming existing step up transformer capacity is available 2
$
1,400,000
-
4. Fiber for communications between Wind Farm and Colstrip Substation
$
5,700,000
-
5. Other Potential Costs: voltage support equipment, overdutied
equipment, RAS, relay upgrades, communication upgrades, etc. 3
$
Uncertain
$
Total Scenario B:
$
51,800,000
$
Uncertain
-
1. Colstrip 1&2 are retired, Above 300MW Wind Plant
Scenario C
2. New 75 mile 230kV line from Judith Gap to Broadview Substation
(Wood Frame Poles)
$
44,700,000
-
3. Broadview Substation upgrades to accommodate new 230kV line bay,
assuming existing step up transformer capacity is available 1
$
1,800,000
-
4. Fiber communication between Judith Gap and Broadview Substation
$
5,700,000
-
5. NWE Facility Study - Upgrades required from Broadview to Garrison to
increase line capacity 4
1
-
6. Other Potential Costs: voltage support equipment, overdutied
equipment, RAS, relay upgrades, communication upgrades, etc. 3
$
Uncertain
Total Scenario C:
$
52,200,000
$
73,000,000
$
Uncertain
$
73,000,000
Refer to NWE Facilities Interconnection Study for Project #207 completed in August 2016. This study assumes Colstrip 1&2 are not retired.
Refer to NWE Revised System Impact Study Report for Project #164 completed in January 2016. This study assumes Colstrip 1&2 are not retired.
3
Additional costs may be identified in an interconnection study or transmission service request that are currently unpredictable.
4
Refer to NWMT Transmission Service Request Facilities Study Report completed for Gaelectric LLC in January 2014 for additional 550 MW of capacity. This study assumes
Colstrip 1&2 are not retired.
2