Agenda - Council Work Session - 04/11/2023

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o Investor interest o Equity considerations o Ecological co -benefits Two criteria received significant discussion among the agency team participants: GOBs and landfill cap age. A brief description of the issues and approach during scoring and ranking follows: • GOBs are an important criterion. However, in our geospatial analysis GOBS were considered a binary factor for CLP sites and not a physical characteristic. Whole landfill sites were considered bonded or not bonded, even when some "bonded" landfills had parcels not restricted by bond appropriations. The study, as described in the scope of work, is intended to identify the top five sites with GOB restrictions and the top five sites without GOBs. Our ranking identified the top sites irrespective of GOB status and then applied the GOB criteria as a means to narrow down the top five sites with and without GOB restrictions. The GOB issue is complex and adds significant restrictions to the use of parcels at sites where GOB funds were used to improve or close the site. There are ways to address or remove these restrictions; however, they are complex and not well tested in the context of solar development on CLP sites. • Cap age was also considered as a criterion for our geospatial analysis. As mentioned previously; the CLP caps are soil material meeting certain design specifications and there may or may not be a barrier layer of man-made material (plastic) incorporated below the earthen material. The cap is designed to minimize or eliminate infiltration of rainwater and manage stormwater runoff rate and minimize erosion. The MPCA has records of cap construction and provided data regarding the age of the soil cap. Settlement is often an issue with soil caps during the first few years after construction and is dependent on the relative consolidation of the waste material, the characteristics of the soil used to construct the cap and the construction techniques used to install the cap. A specific age, after which settlement is considered minimal, is difficult to determine and there is no clear consensus. Ten years was discussed as a conceptual age; however, there are only five sites with caps less than ten years old, (Flying Cloud, Hopkins, Washington County, WLSSD and East Mesaba). Regardless of the age of the cap, it is likely that the cap construction documentation will be reviewed, and a geotechnical survey completed to verify the status of the cap prior to solar development. 3.4 Ranking Method Our GIS analysis provided data for each landfill site which we scored to rank the sites and identify the top five GOB -restricted and top five non -GOB -restricted sites. For each of the criteria described above we used a simple scoring system. The range of values for a criterion was divided into equal parts and a score (five being high and one being low) was assigned for each landfill. The criteria were weighted based on our assessment of importance: cap generation capacity 20%, buffer generation capacity 20%, site generation capacity 40% and distance to nearest substation 20%. The weighted scores for each criterion were added together to create a composite score for each site. The limited number of criteria and 14