Addressing transmission reliability deficiencies fall into two broad categories of transmission-related solutions: substation upgrades and transmission line reinforcements. Substation upgrades typically involve adding a transformer, the reconstruction of the substation to a redundant design such as a ring bus or breaker-and-a-half, and/or the installation of capacitors and reactors to improve system performance. Generally, substation projects have minimal impact on surrounding communities because substations are typically built on properties that are acres in size. The other category of reinforcement is transmission line-related. Transmission lines are sometimes rebuilt to increase their electricity carrying capacity. Transmission line rebuilds typically involve the replacement of existing poles (or towers) and wire within existing rights of way. Certain reliability issues require construction of entirely new high-voltage transmission lines, and may impact multiple surrounding communities.

Planners have identified 25 potential transmission solutions in 22 locations where new transmission-related infrastructure upgrades would enable Vermont to comply with the transmission planning standards. The numbers on the map in Figure 3-3 are keys to the locations, type and timing of the proposed reinforcements shown in Figure 3-5.  

Figure 3‑3. Proposed transmission related project locations.

Of the 25 projects identified, six involve transmission lines; the rest are substation related. Of the six transmission projects, two of the projects are new lines, the others propose rebuilding existing lines to a higher capacity. The two new transmission lines are projects 3B and 19 in northwestern Vermont. Project 3B is a proposed new transmission line that is needed before 2018. This 115-kV line would run from Georgia to St. Albans at a distance of about 10 miles. Project 19 is a 230-kV line that would run from Plattsburg to Essex at a distance of about 30 miles. In the “base plan,” the timing of project 19 is scheduled for 2021 but may be needed by 2016. Project 19 may be undertaken sooner for reliability reasons or to facilitate access to renewable resources in New York State. Many of the listed projects are needed in 2009, based on existing loads and applicable reliability criteria. Most projects, however, will take several years to obtain the required approvals and to construct. The projects are therefore prioritized to help provide a sense of the order in which an application may need to be filed with the Board, the number of hours the criteria violation would exist, or the year in which the criteria violation occurs. All transmission reliability standards, however, must be met so the prioritization should not be interpreted as indicating discretion on whether or not to address the problem.

Figure 3-5 provides more details about the transmission solutions. Planners were required to project the year need each solution will be needed. Given the uncertainties associated with predicting future electric demand, planners also identified at what Vermont load level the projects become necessary. The load levels allow decision-makers and the public to evaluate these reliability issues in terms that can adjust to potential changes in the load forecast over time. Cost estimates in year 2008 dollars are illustrated and the figure indicates whether the project is a substation or transmission line modification. The deficiencies addressed by each individual project are listed. The description of the deficiency is available in Figure 3-1 according to the deficiency number listed. A brief description of the reinforcement, the distribution utilities that are impacted, and the local distribution utilities that will take the lead on coordinating the project are also provided in Figure 3-5.