You asked for information regarding proposals to bury transmission lines in Maine and Vermont.

SUMMARY

In Maine, a proposal by Central Maine Power (CMP) to build a 69 kilovolt (kV) line in the southern part of the state was modified to address concerns of local residents and affected towns. While the vast majority of the line, as modified, will be overhead the crossing at York River will be placed underground and under a highway bridge.

The Vermont Electric Company (VELCO) has applied to the Vermont Public Service Board (PSB) to build a new 345 kV line and upgrade an existing line to 115 kV in the northwestern part of the state. The proposal does not call for any undergrounding. Several participants in the proceeding have argued that the proposal raises concerns regarding electric and magnetic fields (EMF), aesthetics, and property values, among other things. They propose that approximately two miles of the 345 kV line and somewhat longer segments of the 115 kV line be placed underground to address these concerns. These proposals have been criticized by VELCO and the Department of Public Service, which serves as the ratepayer advocate, on reliability and cost grounds. In addition, the Independent System Operator (ISO)-New England, which operates the regional transmission grid, has raised similar concerns regarding the undergrounding proposals.

MAINE

In 2002, CMP proposed to build a new overhead 69 kV transmission line in the southern part of the state. In late October 2002, 10 CMP customers asked the state Public Utilities Commission to open an investigation regarding the proposal. They asserted that the company had failed to respond to various inquiries regarding the need for the line and the customers’ environmental, aesthetic, and safety concerns. The Office of the Public Advocate (the equivalent of Connecticut’s Office of Consumer Counsel) also asked for an investigation, asserting, among other things, that CMP had not considered conservation or distributed generation as an alternative to the new line.

The commission opened an investigation in January 2003 and found that (1) there was a question as to the need for the line, (2) CMP had not demonstrated that even if there was a need, the line would be the best solution, and (3) even if a line was the best solution, CMP had failed to demonstrate that it was reasonably sized or located and that the proposed route was safe. The commission directed its staff to review the relevant information.

During subsequent proceedings, consultants retained by the Office of the Public Advocate and the town of York proposed an alternative route for the line. At a May 2003 public hearing, a substantial majority of those testifying supported the alternative route. The commission then held a technical conference in which CMP and the other parties participated.

In July 2003, CMP filed a stipulated agreement that was signed by the Office of the Public Advocate, several of the customers, York and two other affected towns. The agreement was a modification of CMP’s original proposal. While the vast majority of this route would be overhead, the agreement called for placing the line under a highway bridge where the line crossed the York River, with adjacent segments being placed underground. The modifications increased the cost of the project by about $ 1 million (about 10%), primarily for the burial of the line. The settlement calls on CMP to design another segment in York so that it could be placed underground, if requested by town and at its expense. The parties also agreed to cooperate in obtaining the federal, state, and local permits needed for the projects.

The commission approved the agreement in August 2003. It found that the added costs of the York River modification benefited the state as a whole because of the potential negative impacts of above ground lineson tourism, and allowed CMP to recover their costs from ratepayers. In contrast, it noted that the aesthetic effect of the other York segment was less likely to be of concern to the state as a whole.

Please note that this line is designed to operate at much lower voltages than the proposed 345 kV Norwalk-Middletown line, and thus subject to different engineering and reliability constraints.

VERMONT

VELCO has proposed building the “Northwest Reliability Project,” which would involve, among other things, (1) building a new 345 kV line from West Rutland to New Haven and (2) upgrading an existing transmission line from New Haven to South Burlington to 115 kV. The proposal, which does not call for any undergrounding, is currently before the Public Service Board, which has received extensive testimony.

Several of the participants in the proceeding have recommended placing several short segments of the 345 kV and 115 kV line underground to address local concerns.

In addition to the positions discussed below, several participants in the proceeding argue that it makes sense to bury distribution lines at various street crossings in the transmission line corridor. This would allow the transmission lines to be placed on shorter poles when they cross over the distribution lines, decreasing the visual impact of the transmission lines.

Proponents of Undergrounding

Towns of Charlotte and Shelburne. The towns believe that the VELCO proposal:

A landscape architect retained by Shelburne argues that the proposed line would create an adverse visual impact, because its towers would be 20 to 30 feet taller than the existing towers. She notes that the planting proposed by VELCO to mitigate the line’s visual impact would not provide adequate screening for at least ten years. Another consultant argues that the proposed 115 kV line will harm wildlife habitats, wildlife, wetlands, and the environment in general.

The Charlotte town planner and the Shelburne Selectboard chair (i. e. , first selectman) question whether VELCO has made a realistic estimate of the costs acquiring rights of way for the overhead line. The Selectboard chair notes that burying the line would reduce the cost of acquiring rights of way as well as associated permitting costs.

The towns have developed alternative proposals that would bury segments of the line near scenic viewsheds and densely populated residential areas (two segments totaling 3. 3 miles in Shelburne and a 3. 7 mile segment in Charlotte). The proposals also call for (1) using shorter poles in segments where the line would run overhead, to reduce its visual impact and (2) rerouting part of the line to avoid sensitive areas.

An engineering consultant for the town of Shelburne asserts that it is very feasible to bury segments of the line and that there are many examples of burying 115 kV to 400 kV lines. The consultant recommends the use of cross-linked polyethylene (XLPE) insulated cable. He asserts that this type of cable has an excellent reliability history and is environmentally friendly. He estimates that this type of cable is approximately 4. 6 times as expensive to build per mile as overhead lines. He also asserts that an underground line requires a narrower right of way than an overhead line. The consultant notes that placing the lines underground eliminates the dangers of overhead wires being downed on to people or structures. He believes that underground lines have less impact on property values than overhead lines and lower maintenance costs.

Local Institutions. A spokesman for the Lake Champlain Waldorf School, which has campuses in Charlotte and Shelburne, raises several concerns regarding the proposal, including:

the threat to the continued economic viability of the school posed by the perceived health risks of the line,

The spokesman requests that the board order VELCO to place a segment of the line in Charlotte underground or, if unwilling to do this, order the company to reroute the line away from the school.

The Shelburne Museum, a major tourist attraction, believes the VELCO proposal would degrade views from the museum. This would reduce the quality of visitor’s experience and reduce the museum’s ability to attract special events, potentially costing the region several million dollars in lost tourist revenue annually.

A Shelburne land trust (Meach Cove Real Estate Trust) endorses the town’s proposal. But it argues that the line must be buried, whether rerouted or not, in order for the trust to agree to allow VELCO to use of its land.

Addison County Regional Planning Board. A consultant for the board recommends that the existing 115 kV and the proposed 115 kV and 345 kV lines be buried in three locations in the county, for a total of approximately 2. 7 miles.

Opponents of Undergrounding

VELCO opposes undergroundng primarily on reliability and cost grounds. The project manager believes that there could be long-term outages if an underground line failed. He believes that an underground line costs five to eight times as much as an overhead line, although maintenance costs would be somewhat less. He argues that the entire project can be placed overhead without undue harm to aesthetics using a variety of mitigation techniques.

A VELCO engineer notes that the use of underground lines can contribute to significant capitance in the system, leading to difficulties in maintaining acceptable voltage. This can stress equipment on the system. Changing the design of the system would also have to be approved by ISO-New England, leading to implementation delays. The engineer also argues that if the state required undergrounding, the added costs would be borne solely by Vermont ratepayers, rather than being spread across New England. In contrast, as discussed in OLR memo 2004-R-0816, the costs of projects that provide economic or reliability benefits to New England can be spread across the region.

A VELCO consultant estimates that burying the short segments of the 345 kV line would cost $ 18. 4 million to $ 31 million, including the stations needed to transition from overhead to underground lines. (The consultant took the upper estimate from Connecticut Light and Power, which he characterized as being at “the high end of the scale with regard to both reliability and cost. ”) In contrast, the cost of an overhead line for these segments would be less than $ 800,000. The engineer asserts that (1) there has been no installation in the United States of XLPE cables at 345 kV or higher voltages in lengths exceeding 2,000 feet and (2) the splicing technology for these cables has not been field tested.

An archeologist retained by VELCO believes that undergrounding segments of the line will increase (1) the potential and actual impacts of the project on archeological resources and (2) the time needed to complete archeological studies.

ISO-New England. ISO-New England operates the transmission system in New England. Building a new transmission line or rebuilding an existing one requires its approval. It decides, subject to review by the Federal Energy Regulatory Commission, how the costs of such projects are allocated.

The organization’s chief operating officer raises reliability and cost concerns regarding the idea of placing parts of the line underground. He also asserts that placing the line underground does not appear to have operational or implementation benefits, and that as a result the added costs of placing the line underground would likely be borne solely by Vermont ratepayers.

Department of Public Service (DPS). The department serves as the ratepayer advocate in PSB proceedings, among other things. In the proceedings, the department’s chief engineer made the following arguments against putting any segment of the line underground:

A consultant retained by the department asserts that there has been sufficient experience with 345 kV and higher voltage XLPE. But he recommends that to reduce reliability concerns (1) the line have four, rather than three, cables and (2) the line be placed in an underground duct rather than being buried directly in the earth. He estimated that it would cost between $ 4. 1 and $ 5. 1 million for a one-half mile, buried 345 kV line in Middlebury.

DPS engineers found that VELCO’s estimates of the costs of undergrounding the Charlotte and Shelburne segments were reasonable. They found that using a four-cable design for 115 kV lines would result in circuit restoration times comparable to overhead lines. However, an underground line would not have the capacity that overhead lines do to restore service instantaneously under certain circumstances, e. g. , after lightening strikes. The engineers did not support the use of underground lines for the project.

Department of Health

While the state Health Department did not take a position for or against undergrounding, two agency staff members provided testimony on the department’s behalf regarding the EMF implications of burying part of the 115 kV line. They found that the buried line would not pose a health threat to adults. But, the magnetic field emanating from the line could pose a threat to children directly over the line when it operates at maximum load. They suggest that this risk could be mitigated by (1) restricting use of the right of way to uses other than bike paths or other recreational areas, (2) siting recreational areas at least ten feet away from the center of the line, or (3) inserting a layer of metal shielding in the duct containing the line.

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