Laserfiche WebLink
and gas collection systems can reduce the buildable area available for solar installations. Using the GIS <br />tool developed for this project, we eliminated slopes on each cap greater than 15% when calculating <br />buildable cap area; however, we did not plot or estimate reductions associated with leachate or gas <br />collection systems. These features can also reduce the buildable area which reduces the site generating <br />capacity. <br />With respect to the age and maintenance activities associated with the cap, there is not good agreement <br />about the rate of settlement and corresponding appropriate age for installing solar on a cap. Based on <br />data provided by the MPCA, there are five caps in the CLP that are less than ten years old (Flying Cloud, <br />Hopkins, Washington County, WLSSD and East Mesaba). This does not mean they are unsuitable. It means <br />a geotechnical evaluation may be necessary to verify suitability. Future cap maintenance activities could <br />also impact a solar installation; however, a good method of predicting maintenance activities with any <br />precision is not available. Stormwater management is an especially important issue on a landfill cap. A <br />solar site design will be required to manage stormwater to prevent cap erosion. Developers indicated that <br />solar installations on landfill caps are inspected at a greater frequency than landfill caps without solar <br />installations. This tends to ensure erosion and other issues with the integrity of the cap are identified <br />earlier. In general, the cap issues described here represent a potential financial risk for the solar <br />installation during the economic life (approximately 25 years) of the site. This risk may be addressed with <br />additional insurance coverage at additional cost to the project. <br />Increased Construction Costs Associated with the Unique Features of Closed Landfill Caps. Based on <br />experience in other parts of the country, where solar installations on landfill caps is more common, <br />construction techniques and solar racking and cabling required for landfill cap installations is where the <br />significant increases in construction costs are associated. The cap must not be damaged by construction <br />activities/equipment and because the cap cannot be penetrated, ballasted racking systems are usually <br />employed. Smaller, lighter equipment results in longer construction schedules and ballasted racking <br />systems and above ground cabling are more expensive to purchase and install. <br />Investor owned and cooperative (co-op) utility stakeholders pointed out power pricing is a key issue for <br />them. Their goal is to provide customers the lowest priced electricity. There is a perception solar is not the <br />least expensive option and given the increased capital and construction costs (over greenfield sites), <br />utilities are skeptical these sites can be developed, and power purchased economically. <br />These barriers, and the resulting additional costs, cannot necessarily be changed but it might be possible <br />to reduce the real and perceived risk associated with them by collecting and providing some detailed <br />technical information about the sites. We recommend developing a guide for solar development on CLP <br />sites to help interested parties understand the opportunities and challenges associated with building solar <br />on MN CLP sites. We suggest this guide include technical details about the sites and more general <br />information about installing solar on the sites. <br />It is unlikely the state of Minnesota can directly impact the increased capital and construction costs <br />associated with solar installations on closed landfills; however, we recommend the state consider <br />a <br />