Agenda - Council Work Session - 04/11/2023

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thumb, closer is better and results in lower connection costs. However, the other variables associated with the connection to local transmission/distribution systems can have a significant impact on costs and information regarding these variables is not easy to acquire for all sites and therefore they were not investigated as part of this study. In this case the barrier is the uncertainty about the costs to connect to nearby electrical infrastructure. To illustrate the uncertainty, we provide some feedback from developers and utilities. Several utilities and developers discussed the importance of distance to grid infrastructure. Qualitatively speaking, if a project is very large then it can be further from grid infrastructure to make it cost-effective. That said, predicting the weight of the distance criteria is difficult. One developer said: "In rural areas, sometimes the distance can be farther than you'd expect. I have connected a 5MW [solar on landfill] project to a substation located 2 miles away, for very reasonable cost. 1 have also connected a 30MW project with the substation located on the same parcel at a very high cost. Utilities are hard to predict!" Another developer seemed to say it was difficult to predict the weight of the distance criteria. She said, "Most of the smaller projects (from less than 1 to over 70 megawatts) can be tied into the nearest 3-phase distribution line, even if the line has to be extended to the site for some distance at a cost to the project... Most of these sites have little on -site load and may only have a single-phase pole at the site. Therefore, extending the line could be a significant cost. But interconnection is always costly, and the additional cost will not likely be overly burdensome relative to typical ["greenfield" or undeveloped sites] interconnection costs. " The solar project developer typically bears all costs associated with interconnection. Therefore, it is critical to understand what is required and the costs for interconnection. The voltage rating for a distribution line may dictate the largest size project that can be installed in a given location. Some rules of thumb from developers include that a 5 kV transmission line can support only a few hundred kW of intermittent renewable generation capacity. A 13 kV line can typically only support up to 3 MW of renewable generation capacity. A 23 kV line may support up to 6 MW of renewable generation capacity. There are many factors that influence what a given transmission or distribution line can support. Finally, a large- scale solar array will require three-phase power. To address this uncertainty, we recommend performing an interconnection survey for the top ten sites (five bonded and five non -bonded). We are not advocating for a complete interconnect study as required under state siting requirements; however, contacting utilities and collecting information to identify information about the critical characteristics of local electrical infrastructure would provide some level of certainty about the costs required to connect. Uncertainty Related to Site Suitability and CLP Program Responsibilities. Generally, landfill caps provide a clear, engineered surface on which to install solar equipment; however, they also present unique technical and engineering challenges which result in increased costs (when compared to greenfield solar installations). Specific issues include age of cap, use of lighter weight installation/construction equipment, presence of steep slopes, presence of leachate and gas collection systems, potential for cap maintenance activities and a general restriction from penetrations of the cap. Steep slopes and the presence of leachate C