Solar Energy: Solar Power Feasibility Assessment from Closed County Landfill and Transfer Station Sites

Background

Roof-mounted solar panels for facilities.

Hillsborough County (County) Solid Waste Management Division (SWMD) is exploring alternative energy sources to offset operations and maintenance costs at County-owned facilities. SCS Engineers (SCS) conducted a financial feasibility analysis for the County’s transfer stations and closed landfills in order to provide quantifiable recommendations based on current technological capabilities and market conditions.

The County manages and operates the South County Transfer Station Site (SCTS), which includes three buildings: the Transfer Station; the Administration Building; and the Scale House. SCS explored and provided recommendations to offset annual energy demand costs.

Challenge
SCS previously conducted a feasibility assessment for the placement of a ballasted photovoltaic (PV) system for electricity generation at the Hillsborough Heights/Taylor Road Landfill (HH/TR) and Northwest Landfill (Northwest). The previous assessment considered two scenarios: 1) maximize electricity generation for sale to a local utility; and 2) utilize generated energy at the subject site.

The analysis of HH/TR and NWTS demonstrated the economic benefit of selling generated solar power back to the utility grid exceeded the evaluated payback period of 20 years. Therefore, the SCTS solar assessment focused on a “grid-tied” system sized to meet the on-site energy demand and maintain a connection to the utility grid for back-up purposes.

Outcomes and Benefits
SCS provided recommendations and a path toward an energy-independent transfer station. The conceptual PV system evaluated was sized to offset the annual electricity demand of approximately 313,000 kWh/year, with an associated annual electricity cost of approximately $37,000.

Pro Forma Model financial results reflected a positive Net Present Value of approximately $22,000 with a payback period of approximately 13 years for the evaluated systems.