1. MPRP Northern Route Alternatives N5 versus N1 NEPOOL Reliability Committee March 17, 2009

2. Agenda
Provide a recap of primary northern route alternatives for the MPRP
Describe basis for selected route N5
Overview of analyses performed
Description of process followed
Respond to questions from recent RC and TCA Stakeholders Meetings, including a Present Value analysis comparing N1 and N5

3. MPRP Northern Routes Alternatives Assessment
Developed 5 Northern Solutions (N1 thru N5)
Dropped N4 - Weakest Electrical Performance; Highest Cost
Analyzed 4 Solutions (N1, N2, N3, N5) in detail
Performance Evaluation
Compliance with reliability criteria for N-1 and N-1-1
Year 2017 Summer 90/10 peak load
18 base cases (6 dispatches, with 3 transfer conditions)
Electrical performance evaluation based on:
Longevity
115-kV Operability
Loss Savings
Transfer Capability

4. Assessment Criteria (Cost & Performance)
Electrical Performance Ranking based on:
Longevity Evaluation
Reliability assessment analyzed 15- and 20-year N-1 analysis for each alternative and compared both voltage and thermal reliability criteria violations
115 kV Operability Evaluation
Evaluated N1 & N5 alternatives with a limited number of single 115 kV line outages
Loss Savings Evaluation
Average of the loss savings for the 18 cases for each alternative
Transfer Capability Evaluation
Analyzed steady-state thermal transfer capability of Orrington-south interface in north-to-south direction
Other considerations:
Renewable integration
Design factors to mitigate the risk of Extreme Contingencies & Conditions

6. MPRP Transmission Alternatives Assessment Longevity Analysis – Thermal Results N-1 (First Contingency)

7. MPRP Transmission Alternatives Assessment Longevity Analysis – Voltage Results N-1 (First Contingency)

8. Western Area – Post-Contingent Thermal Loading
MPRP Transmission Alternatives Assessment Longevity Analysis (N-1) – Local Area Review
Western Area – Post-Contingent Thermal Loading
N1, N2 and N3 show overloads for line and / or autotransformer contingencies
N5 shows overload for autotransformer contingency only
Location of autotransformer at Gulf Island (N5) is preferred over Kimball Rd (N1 and N2) or Livermore Falls (N3) to reduce loading concerns on Section 62 and to eliminate need for new 115 kV line into the Lewiston area
Central Area – Post-Contingent Thermal Loading
Alternative N1 shows overload for Section 67 contingencies before the 15-year time frame
Alternative N1 shows overload on Section 84 for several contingencies before the 20-year time frame
Alternative N5 displayed reliable thermal performance at the 20-year time frame due to the Albion Rd. 345/115 kV autotransformer
Autotransformer Longevity
All Alternatives provide 12 to 16 years beyond 2017 before the outage of the Western autotransformer caused overload on Surowiec autotransformer
Alternatives N1 and N5 provide the best longevity overall

9. MPRP Transmission Alternatives Assessment Longevity Analysis Summary
Voltage Performance (N-1)
Fifteen Year # of Violations 23 13 11
Twenty Year # of Violations 79 65 74 34
Voltage Ranking 4 2 3 1
Thermal Performance (N-1)
Western Area Auto Contingency Ranking
Western Area Line Contingency Ranking
Central Area Contingency Ranking
Southern/Central Line Contingency Ranking
Thermal Ranking
Auto Transformer Loading
Overloads on Existing Autotransformers

10. MPRP Transmission Alternatives Assessment Longevity N-1 Analysis Conclusions
Alternative N5 Provides the best longevity solution
Only option with no violations in 2022 (15 yrs)
Option with the fewest violations in 2027 (20 yrs)
Alternative N5 requires only limited upgrades for 20-Year Solution
N5 Alternative only requires 2nd autotransformer at new Larrabee Road Substation
N1 Alternative likely requires addition of new 115 kV lines in both Central and Western Maine, along with other reinforcements
Overall, Alternative N5 moves the next Year of Need out about 5 years
While not studied, it was clear that there would be significant added costs to expand Alternative N1 to provide comparable longevity to Alternative N5

11. In Central region, several 115 kV outages were analyzed
MPRP Transmission Alternatives Assessment N1 vs. N5 Operability Analysis Scope
Operability is defined as the ability to operate the system under various scenarios
Operability comparison conducted on N1 vs. N5 in Central and Western Maine regions
N1 Autos are at Maxcys (Coopers Mills) and Kimball Road
N5 Autos are at Benton (Albion Rd) and Gulf Island (Larrabee Rd)
In Central region, several 115 kV outages were analyzed
Section 67, Section 83, and Section 84
In Western region, several 115 kV outages were analyzed
Section 62, Section 64, and Section 87

12. MPRP Transmission Alternatives Assessment N1 vs
MPRP Transmission Alternatives Assessment N1 vs. N5 Operability Analysis Results
Central Area - N5 provides more support with Benton (Albion Rd) autotransformer for both N-1 and N-1-1
Section 67, Section 83, and Section 84
Under N-1-1 conditions, voltage collapse and severe overloads for Alternative N1.
Under N-1-1 conditions, no violations of reliability criteria for Alternative N5
Recommend new 115 kV transmission line (26 miles) from Maxcys to Winslow for equivalent Operability
Western Area - N5 provides more support to load pocket with Gulf Island (Larrabee Rd) autotransformer for both N-1 and N-1-1
Section 62, Section 64, and Section 87
Recommend eliminating 345 kV line from Gulf Island to Kimball Road and moving autotransformer to Gulf Island for equivalent Operability

13. MPRP Transmission Alternatives Assessment N1 vs
MPRP Transmission Alternatives Assessment N1 vs. N5 Operability Analysis Conclusion
Both N1 and N5 meet reliability standards per MPRP scope.
However, there is a major difference in how these alternatives perform under N-1 and N-1-1 conditions.
In many cases, local area voltage collapse in N1 following the second contingency reinforces the conclusion that N5 is more robust electrically and will serve the load in the Western and Central Maine areas the longest during both normal and emergency conditions.
The effect of moving the N1 autotransformer location and additional 115 kV reinforcement is an additional $27M.

14. Reduction in losses due solely to changes in Maine
MPRP Transmission Alternatives Assessment N1 vs. N5 System Loss Savings
All dispatch scenarios and transmission alternatives were compared against the base system without upgrades in 2017
Reduction in losses due solely to changes in Maine
N5 had the highest average loss savings of 21.8 MW
The average loss savings of N1 is 20.6 MW
N5 average loss savings are 1.2 MW greater than N1 14

15. N5 (and N2) had the highest thermal transfer capability at 1975 MW
MPRP Transmission Alternatives Assessment N1 vs. N5 Transfer Capability Analysis
Summer Peak load assessment of first contingency thermal transfer limit on Orrington-South interface
Existing limit is 1200 MW due to loss-of-source limit for single contingency
N5 (and N2) had the highest thermal transfer capability at 1975 MW
N1 was the next highest at 1925 MW.
50 MW incremental transfer limit for N5 over N1 15

16. MPRP Transmission Alternatives Assessment Comparison Summary
ROUTE ALTERNATIVES N1 N2 N3 N5
Electrical Performance 3 2 4 1
Longevity
Loss Savings
20.6 MW
21.3 MW
19.8 MW
21.8 MW
Thermal Transfer Capability
1925 MW
1975 MW
1725 MW
Total Estimated Cost
$905M
$1,037M
$979M
$1,001M
Estimate to Achieve Similar Operability
$27 M
Estimated Cost for Similar Operability
$932 M
$1,001 M

17. MPRP Transmission Alternatives Assessment Selected Alternative: N5
MPRP Northern Alternative N5
Best Electrical Performance
Best Longevity
Best Operability
Best Loss Savings
Highest Thermal Transfer Capability
Additional 345 kV Transmission Corridors
Fewer 345 kV lines in common Rights-of-Way and more 345 kV substation reinforcements at different locations
Stronger Reinforcement of Central Maine – 345 kV transformation closer to major generation & load centers
Relies on fewest static capacitors to achieve reliable performance
Better integration of wind and/or Canadian resources to the north
Concurrence from ISO-NE
The above advantages of N5 over N1 were not quantified in a Net Present Value (“NPV”) analysis as part of CMP’s selection process

18. Process for Alternatives Assessment & Choice
N1 vs. N5 Evaluation
CMP MPRP project team met several times in fall 2007 with ISO-NE technical staff & senior management to review alternative analysis and basis for decision
CMP & ISO reached consensus on N5 vs. N1 performance difference and N5 as the best choice for MPRP
ISO-TO System Planning Group reviewed the N5 vs. N1 analysis & decision and accepted it subject to TCA review
N5 was presented as CMP’s choice to PAC in January 2008
N5 was studied and reviewed with the NEPOOL Reliability Committee task forces through the PPA process
The selection of northern route N5 has been thoroughly vetted with ISO-NE and stakeholder groups
No opposition to the selection from any stakeholders

19. Questions from Recent Meetings
After the January 29th TCA Stakeholders Meeting, ISO-NE asked CMP for an “NPV analysis of N5 versus N1”
CMP’s Approach
Express the Costs of N1 and N5 in NPV Revenue Requirements
Longevity – The entire scope of added projects & costs of N1 are unknown
Operability – Estimate the Added Costs to Provide Comparable Operability
Losses – Estimate the impact on regional LMP cost to load
Transfer Capability – LMP effects included in the estimate on Losses
CMP and ISO original decision making process
Recognized these benefits qualitatively
Only Operability costs were estimated at that time

20. MPRP N1 vs. N5 NPV Analysis Costs of N5 versus N1
Base N5 costs $96 million more than N1 (in 2012$)
That difference decreases to $69 million with equivalent operability
Multiply by annual carrying charge factor and add O&M costs to estimate incremental revenue requirements
NPV in 2008$ of incremental revenue requirements for N5 is $52 million

21. Energy market simulations performed assuming N1 instead of N5
MPRP N1 vs. N5 NPV Analysis Evaluated Benefits of Losses and Transfer Capability
N5 has 50 MW higher transfer capability for Orrington-South interface, compared to N1, based upon thermal analysis
N5 has higher loss savings (21.8 MW) than N1 (20.6 MW) at the peak hour, based upon an average of all dispatch and transfer scenarios.
Energy market simulations performed assuming N1 instead of N5
NPV of Benefits in 2008$
With N5, NPV of regional energy costs are $11 million to $63 million lower than with N1
Above NPV savings exclude benefits from N5’s greater longevity and superior operability

22. MPRP N1 vs. N5 NPV Analysis La Capra Northeast Market Model
Based upon the PROSYM simulation software
NE system representation based upon latest CELT and RSP databases
Benchmarked against latest year of historical LMP data
Renewable energy build-outs assumed to comply with RPS
Convention build-outs when necessary to achieve resource adequacy
Maine modeled as three energy zones
BHE, central Maine, southern Maine

23. MPRP N1 vs. N5 NPV Analysis NPV Summary
ROUTE ALTERNATIVES N1 N5
N5 – N1
Total Estimated Capital Cost, 2012
$905M
$1,001M
$96M
Estimate to Achieve Similar Operability, 2012
$27M
($27 M)
Total NPV of Revenue Requirements, 2008$
$698M
$750M
$52M
Estimate of Energy Cost difference due to Losses & Thermal Transfer Capability, 2008$
$11 - $60M
($11 - $60M)
Total Estimated Net Cost NPV, 2008$
$ M
$41M
- ($8M)