From 2002 through June 2013, 475 transmission projects, developed to serve the reliability of the entire New England region, have been placed into service, with an investment totaling about $5.5bn, and additional projects – proposed, planned or under construction – total about $5.7bn, ISO New England (ISO-NE) said in its “2013 Regional System Plan” (RSP13), released on Nov. 8.
ISO-NE said it and its regional stakeholders have made progress analyzing the transmission system in New England, developing “backstop” transmission solutions to address existing and projected transmission system needs and implementing those solutions.
Of those efforts, 15 projects have emerged and all are critical for maintaining transmission system reliability, ISO-NE added, noting that as of June 1, nine of the 15 major 345-kV projects have been placed in service, with two additional projects expected to be in service by the end of the year at a cost of more than $3.6bn, including:
- Two Southwest Connecticut Reliability Projects (Phase 1 and Phase 2)
- Northeast Reliability Interconnection (NRI) Project
- Boston 345-kV Transmission Reliability Project (Phase 1 and Phase 2)
- Short-Term Lower SEMA Upgrades
- Northwest Vermont (NWVT) Reliability Project
- Vermont Southern Loop Project
- Rhode Island components of the New England East-West Solution (NEEWS)
- Long-Term Lower SEMA Upgrades (in service by the end of 2013)
- Greater Springfield components of NEEWS (in service by the end of 2013)
Central Maine Power‘s (CMP) Maine Power Reliability Program (MPRP) is under construction and the Interstate Reliability Project component of NEEWS is in siting, ISO-NE said, noting that one new 345-kV project has emerged as a result of the Greater Boston study but is being reassessed. Also, the needs assessment is being updated for the last of the 15 projects – the Central Connecticut Reliability Project component of NEEWS.
CMP’s parent company is Iberdrola USA, which is a subsidiary of Iberdrola S.A.
ISO-NE said that the addition of the 345-kV substations across New England has improved the transmission system’s ability to meet load growth.
A reliable and well-designed transmission system is essential for complying with mandatory reliability standards and providing regional transmission service that provides for the secure dispatch and operation of generation, ISO-NE said. Furthermore, a secure transmission system also plays an important role in such functions as regulating voltage and minimizing voltage fluctuations, stabilizing the grid after transient events and facilitating the efficient use of regional supply and demand resources.
ISO-NE added that the New England transmission system consists of mostly 115-kV, 230-kV and 345-kV lines, which in northern New England generally are longer and fewer in number than in southern New England.
The New England area has nine interconnections with New York, including two 345-kV ties, one 230-kV tie, one 138-kV tie and three 115-kV ties. New England and New Brunswick are connected through two 345-kV ties. ISO-NE also said that New England has two HVDC interconnections with Quebec.
Northern New England
In discussing the June status of several transmission planning studies and projects, as well as the need for upgrades, ISO-NE said that the two most significant issues facing northern New England have been to maintain the general performance of the long 345-kV corridor, particularly through Maine, and to ensure sufficient system security to meet demand.
Over the past several years, ISO-NE said, the addition of generation in Maine and New Hampshire, in combination with the area’s limited transfer capability and limited transmission expansion, has increased the likelihood of many northern New England interfaces operating near their limits, creating restrictions on northern resources.
Study efforts are progressing in various portions of Maine, New Hampshire and Vermont, ISO-NE said, adding that in Maine, for instance, the long-term system needs of Bangor Hydro Electric (BHE) and CMP were identified in 2007. To improve the Bangor system’s performance, the Keene Road substation was completed and 115-kV upgrades have been placed into service. Also, CMP has planned 115-kV expansions in western Maine to address area thermal and voltage issues.
BHE is wholly owned by Emera.
In New Hampshire, a number of studies conducted have identified the need for additional 345/115-kV transformation capability and the need for additional 115-kV transmission support in various parts of the state. ISO-NE added that existing and midterm concerns of northern and central New Hampshire have been improved by closing the Y-138 tie with Maine and the addition of a second 345/115-kV autotransformer at Deerfield.
Vermont regulators require the Vermont Electric Power Company (VELCO) to develop a 20-year Vermont Long-Range Transmission Plan every three years. Collaborative efforts among ISO-NE, VELCO, National Grid plc subsidiary National Grid USA and Northeast Utilities (NYSE:NU) have continued assessing the reliability of Vermont and New Hampshire’s transmission system, ISO-NE added.
The Vermont/New Hampshire Transmission System 2011 Needs Assessment identified several areas of weak performance and showed certain transmission system needs, including that the combination of key line contingencies causes some thermal overloads and many low-voltage violations on the underlying 115-kV system.
ISO-NE also said that projects that have been identified that address issues with transmission system performance, either individually or in combination include the MPRP, which addresses such inadequacies as insufficient 345-kV transmission support for Portland and southern Maine and insufficient transmission infrastructure in the western, central and southern Maine regions.
Southern New England
On southern New England, ISO-NE said that while recent improvements have been made, the system continues to face thermal, low-voltage, high-voltage and short-circuit concerns under some serious conditions. The most significant concerns involve maintaining the reliability of supply to serve load and developing the transmission infrastructure to integrate generation throughout the area.
Several needs, originally identified for various upgrades associated with the NEEWS studies have been reconfirmed, including three of the four NEEWS components: the Rhode Island Reliability Project, the Greater Springfield Reliability Project and the Interstate Reliability Project.
The Rhode Island Reliability Project and the Greater Springfield Reliability Project are expected to be in service by the end of this year. ISO-NE also said that because of a reassessment, certain upgrades included in the original Interstate Reliability Project are no longer needed, including adding a 345-kV circuit breaker at the Killingly substation.
On the Greater Boston area, ISO-NE said that a long-term reliability needs assessment has been completed for the area and solutions have been developed to address certain criteria violations. The preferred transmission solution for the northern area includes such elements in Massachusetts as a new 345-kV circuit from Tewksbury to Woburn and a new 345/115-kV autotransformer at Woburn.
The Southeast Massachusetts/Rhode Island study is in its needs assessment stage and will identify short-circuit needs in the SEMA/RI area.
ISO-NE also said that a long-term reliability needs assessment for 2018 has been completed for the Southwest Connecticut area and solutions are being developed to address the criteria violations. For instance, the preferred solution for addressing the needs in the Bridgeport area include reconductoring and rebuilding of the 115-kV transmission lines between the Baird and Congress substations, while the preferred solution for addressing the needs in the New Haven subarea include relay upgrades at the North Haven 115-kV substations.
On southern New England projects, ISO-NE noted that siting has been approved for the Springfield and Rhode Island components of the NEEWS project, expected to be completed by the end of this year. The Rhode Island components in service include a second West Farnum-Kent County 345-kV line and the Springfield components, expected to be fully in service by the end of 2013, include construction of a new Ludlow-Agawam-North Bloomfield 345-kV line.
Other projects that ISO-NE highlighted include the Salem Harbor-Railyard Cable Replacement project. ISO-NE noted that the replacement of the underground cables between the Salem Harbor and Railyard substations is scheduled to be completed in 2016.
Changes in generation
ISO-NE also noted that in a little more than a decade, the region has seen a major shift in its generation fleet, moving from a more balanced mix of oil, coal, nuclear and natural gas generators to a system where 51.8% of the electric energy produced in the region is by natural gas power plants, representing 43.0% of the region’s capacity.
The region’s future fuel mix will show continued dependence on natural gas-fired generation and the addition of intermittent renewable resources. ISO-NE added that as more coal- and oil-fired generators in the region retire, the primarily natural gas-fired generation and wind resources units in the ISO generator interconnection queue will likely replace them.
ISO-NE said that further increases in the use of natural gas-fired generation will likely occur, resulting from the loss of other types of generation subject to risks, such as nuclear and hydro units that may not be relicensed. Additionally, the region is beginning to experience the addition of photovoltaic (PV) resources, and future growth in that generation source is expected.
Several studies have quantified potential shortfalls in natural gas supply to electric power generators and additional studies are underway. Results of one study that ISO-NE commissioned showed that the natural gas system is adequate to meet the region’s expected summer peak conditions through 2020 and is able to supply local distribution company (LDC) demand, but the existing natural gas infrastructure may not be able to meet the electric power system demand during peak winter conditions.
Also, ISO-NE said it has immediate and growing concerns about the availability and flexibility of generating resources – particularly natural gas and oil-fired resources – to reliably serve the daily, round-the-clock demands of the region’s electricity consumers.
Working with the New England states and its stakeholders, ISO-NE said it developed interim measures outside the usual ISO wholesale electricity markets to improve reliability for winter 2013/2014, as well as during the transition period until the market design changes being considered by the ISO and its stakeholders become effective. The measures involve maintaining oil inventories, increasing access to demand resources and verifying the reliability of switching fuels by dual-fueled generators.
ISO-NE also said that short-term improvements to the wholesale electricity markets have been implemented, including accelerating the timing of the ISO’s day-ahead energy market and associated reliability commitments to more closely match them to existing natural gas trading and nomination cycles and provide additional time for generators to secure fuel from the gas market.
Furthermore, ISO-NE said it is working with stakeholders to address medium- and long-term fuel supply issues through wholesale electricity market developments that would increase the economic incentives for generators to perform when and where needed. Potential improvements to system reliability involve having more generators with dual-fuel capability to protect against fuel shortages, increasing the procurement of noninterruptible fuel supplies, improving staffing levels and personnel training and enhancing start-up capability that would reduce performance deficiencies, ISO-NE said.
Other plan highlights, including distributed generation
As noted in a Nov. 8 ISO-NE statement, other highlights of the plan include that as the amount of wind power in the region continues to grow, ISO-NE is on track to implement a wind power forecast for use in daily system operations later this year.
Also, to address the potential effects of high levels of distributed generation (DG) on grid reliability, ISO-NE recently convened a Distributed Generation Forecast Working Group, which will gather information about DG resources in New England and eventually develop a forecast of future DG growth to be incorporated into the long-term planning process. It is expected that more than 2,000 MW of DG, mostly from PV resources, will be installed region-wide by the end of 2021, up from about 250 MW of PV at the end of last year.
ISO-NE also highlighted smart grid efforts, noting that in June, in partnership with several New England transmission owners, it completed installation of 40 phasor measurement units (PMUs) on the high-voltage transmission system throughout the region. The PMUs are a streaming data to ISO-NE and transmission owners, which are using the data to analyze system disturbances and to develop tools for system operators.
Among other things, ISO-NE said energy consumption, unadjusted for energy efficiency programs, is projected to grow an average of 1.1% annually through 2022, while summer peak demand is expected to grow by 1.4% per year.
“[M]any factors are converging that will change the way the grid is operated and planned for in the future – and the RSP will continue to serve as a valuable reference document for all stakeholders to use as we move forward to solve these challenges,” ISO-NE President and CEO Gordon van Welie said in the statement.