New Mexico Transmission Expansion Concepts For Wind Resources May 2008 Update Electric Services Transmission Operations
FOREWORD This document contains PNM s latest concepts for expanding the transmission system to interconnect large amounts of proposed wind generation in east-central New Mexico. The concepts depicted here take into account the proposed wind generator interconnection to the PNM system as well as regional transmission development that is currently under study. The transmission system expansion scenarios described herein should not be interpreted as commitments to build transmission, nor as PNM s plans to develop transmission facilities, nor as requirements for interconnection or locations of any specific proposed generator or group of generators. For more information, please refer to PNM s OASIS page at http://www.oatioasis.com/pnm/index.html, and select the folder News/Status of System Impact Studies.
INTRODUCTION As of May 2008, wind generation installed on the PNM transmission system totals 294 MW. PNM has entered into commitments to interconnect an additional 160 MW of wind generation. Interconnection Agreements are under negotiation for an additional 202 MW. All but 102 MW of this existing or committed wind generation is located east of the Sandia and Manzano Mountains. PNM s Interconnection Queue contains approximately 7,146 MW of additional proposed wind generator projects in study mode, of which 6,926 MW are located in east-central NM. These projects propose to interconnect to the PNM transmission system in the Guadalupe and Willard area. EPE and TSGT Interconnection Queues also have have significant amounts of proposed generation located in Gladstone area and in southern New Mexico. As a FERC jurisdictional transmission provider, PNM is required to develop a plan to interconnect each Interconnection Customer, pursuant to the Large Generator Interconnection Procedures (LGIP) in the PNM OATT. System reinforcements and associated cost required to interconnect each proposed project are identified through Interconnection Studies. Interconnecting large amounts of wind generation to the PNM transmission system in the Willard/Gladstone area would require substantial system reinforcements. Additional reinforcements are also needed to mitigate impacts to Affected Systems in New Mexico and to provide adequate delivery service to loads outside New Mexico. Additional studies are needed to fully assess the impact on Affected Systems within and outside New Mexico. The information contained in this document is intended to promote open discussions among stakeholders about the available options for interconnecting New Mexico vast wind resources to the transmission system. The transmission development Stages described in this document represent possible discrete transmission expansion projects that may be needed to interconnect incremental amounts of wind generation in east-central New Mexico. This particular sequence assumes that transmission development is initially driven by generation in the Willard area. Other transmission development scenarios are possible depending on the timing and location of specific projects.
MAY 2008 UPDATE A route analysis performed by PNM suggests that approaching Ft Craig from the Willard area (estimated 86 mile route) may be challenging due to present and planned environmental exclusion zones. The same study identified two alternative locations to access the West Mesa Arroyo 345 kv line. (1) New Engle 345 kv Station east of Elephant Butte. Compared to Ft Craig, this location provides for a shorter route to tap into the Springerville Luna line (23 miles), but much longer route to the Willard area (123 miles). (2) New Belen 345 kv station just north of the Valencia Socorro county line. Compared to Ft Craig, this location provides for a shorter route to Willard (61 miles), but a longer route to the Springerville Luna line. Currently, this alternative appears to be the most feasible. Recent generator interconnection studies conducted by PNM suggest that the least-cost, near-term alternative to interconnect generation in the Guadalupe area would be construction of 345 kv lines from the Guadalupe area to the BA area north of Albuquerque, roughly parallel to the existing line. Recent interconnection studies also show that the least-cost, near term alternative to interconnect additional generation in the Willard area would be construction of 345 kv lines from Willard to the Belen area (option 2 above). Interconnection in the Guadalupe area will require the development of a new 345 kv station east of Guadalupe (Guadalupe East). Future 345 kv transmission lines in the area would be terminated at the new 345 kv station. Economics of scale can be achieved by developing transmission to allow for interconnection of large amounts of wind generation. However, a reasonable staged approach to transmission development is required to make the projects viable from an economics and policy standpoint. In the figures that follow, Stage 0 represents upgrades that have been defined and could be pursued in the near term. Stages 1a and 1b represent transmission upgrades required to interconnect up to 1800 MW of wind generation in Eastern NM. Stages 1a and 1b could be pursued independently of each other. Stage 2 represents a longer term vision of transmission expansion to accommodate additional wind generation. Other transmission initiatives such as SunZia and HPX could allow for even greater amounts of wind generation development in eastern New Mexico.
Stage 0 Near Term Maximize use of existing transmission system Total Wind Guadalupe: 750 MW Willard/Duran: 100 MW Stage Cost ~$100M Gladstone 1200 Constraint Loss of Willard Belen 115 kv Overloads Willard Algodones 115 kv Guadalupe BA 345 kv at thermal limit BA Thermal limit on this line is approx. 1000 MVA. Commitments include 200 MW from the Blackwater HVDC converter at Clovis 200 Guadalupe 300 Willard Belen 100 New 345 kv line Existing 345 kv line Existing 115 kv line New station Existing station 250 Proposed wind project Existing or committed wind project Build new Guadalupe East station Add reactive compensation (SVC) on BB line Loop Four Corners West Mesa 345 kv line at Rio Puerco Expand or build new Willard 115 kv station Rebuild Willard Belen 115 kv (50 mi.) Upgrade Willard Algodones 115 kv line (70 mi.) Install 115 kv series reactors on Belen Socorro 115 kv line
Stage 1a - Guadalupe Wind Collector Interconnect Guadalupe Area Generation Total Wind Guadalupe: 1350 MW Willard/Duran: 100 MW Stage Cost ~$200M Gladstone 1200 Constraint Loss of one BA BA2 345 kv Overloads second BA BA2 circuit BA station at limit BA 200 Guadalupe 300 600 Willard Belen 100 New 345 kv line Existing 345 kv line Existing 115 kv line New station Existing station 250 Proposed wind project Existing or committed wind project Build new BA2 345 kv station east of BA Expand Guadalupe East station Re-terminate BA Norton and BA Guadalupe at BA2 Build double-circuit Guadalupe East BA2 (90 mi) Re-conductor BA BA2 circuits up to BA station limit (1200 MVA)
Stage 1b Willard Wind Collector Interconnect Willard/Duran Area Generation Total Wind Guadalupe: 750 MW Willard/Duran: 500 MW Stage Cost ~$150 Gladstone 1200 Constraint Loss of Belen West Mesa 345 kv Overloads Willard Algodones 115 kv BA 200 Guadalupe 300 Willard Belen 100 400 New 345 kv line Existing 345 kv line Existing 115 kv line New station Existing station 250 Proposed wind project Existing or committed wind project Build Belen 345 kv station Build Willard 345 kv and 115 kv stations Build double-circuit Belen Willard 345 kv line (61 mi) Install two 345/115 kv transformers at Willard May need to bypass Arroyo phase shifting transformer
Stages 1a & 1b Guadalupe and Willard Wind Hubs Total Wind Guadalupe: 1350 MW Willard/Duran: 500 MW Total Cost of Stages 1a and 1b ~$350M Gladstone 1200 BA 200 Guadalupe 300 600 Willard Belen 100 400 New 345 kv line Existing 345 kv line Existing 115 kv line New station Existing station 250 Proposed wind project Existing or committed wind project
Stage 2 - Wind Collector Expansion Longer-term vision of New Mexico wind collector system expansion alternatives Total Wind Guadalupe/Willard/Duran: Guadalupe: 1200 MW Willard/Duran: 2,500 4,000600 MW MW? Gladstone 1200 BA 200 Guadalupe 300??? Willard Belen 100??? Duran New 345 kv line Existing 345 kv line Existing 115 kv line New station Existing station 250 Proposed wind project VL Tap Existing or committed wind project Build additional 345 kv transmission infrastructure in central NM Build 345 kv or higher voltage connections to Arizona and/or Colorado
COST ASSUMPTIONS Cost assumptions used for the purposes of this report are outlined in the Table below. Please note that Interconnection Studies may use different cost assumptions and will reflect more detailed cost estimates. Component Cost Note 345 kv line, single circuit $ 1.0 M /mi Rural ROW 345 kv line, double circuit $ 1.5 M /mi Rural ROW 115 kv line, single circuit $ 0.25 M/mi Rural ROW 345/115 440 MVA transformer $ 11.0 M 345 kv line reactor $ 1.0 M Required if line >70 mi Greenfield 345 kv Station $ 10.0 M 3 terminations Additional 345 kv termination Additional 115 kv termination $ 3.0 M Greenfield 115 kv Station $ 3.0 M 3-terminations $ 1.0 M The preceding pictures show the system reinforcements associated with each Stage, the cost, and the maximum amount of generation that can be accommodated. The amount of wind generation shown in each stage includes 450 MW existing and committed wind generation already installed (or committed) at Guadalupe and Taiban Mesa. Determination of whether the system additions qualify as Network Upgrades for a particular project will be made in the context of Interconnection Studies. As stated before, the results are preliminary and based on the assumptions described earlier in this document.