Policy DMM-4 Guidance For Photovoltaic Solar Projects At Closed Solid Waste Landfills

I. Summary

The New York State Department of Environmental Conservation (Department) Division of Materials Management is supportive of solar projects located at closed solid waste landfills, which align with the Climate Leadership and Community Protection Act mandate of 6 gigawatts of photovoltaic solar generation by 2025. While not every closed landfill in the state is suitable for placement of a photovoltaic (PV) solar array system, landfills with preferable site characteristics have the opportunity to generate clean, renewable energy and to create revenue from land that has limited opportunities for reuse. The feasibility of siting a PV solar array system on a landfill depends on numerous site-specific characteristics which may include: final cover configurations; pre-existing engineered cover systems; condition of vegetative covers; landfill grades and topography, stability and anticipated settlement; waste composition; storm water management systems; erosion control systems; and leachate and gas collection and treatment systems. This policy describes the procedure and considerations to be used by Department staff when reviewing PV solar projects located at closed solid waste landfills and identifies the required information that must be provided for review and approval of these projects.

II. Policy:

The Department supports the use of renewable energy and the development of alternative end uses at closed solid waste landfills. End uses such as wildlife habitats, parks, or golf courses at closed solid waste landfills can provide benefits to surrounding communities and the environment. Use of the closed solid waste landfills for PV solar projects is a practical end use that also yields renewable energy.

This policy has been established to ensure consistency in the review and approval of the construction, installation, and operation of a PV solar array on a closed solid waste landfill or on any adjacent property used for monitoring or environmental control systems. This policy will also ensure that the integrity of the existing cover system at the landfill will continue to be maintained during construction pursuant to the end use provisions of 6 NYCRR 363-9.7.

III. Purpose and Background:

Pursuant to the end use provisions of 6 NYCRR 363-9.7, the Department has review and approval authority both during and after the post-closure period over planned end uses at closed solid waste landfills that may disturb the integrity of the final cover, liners or any other components of the containment system or the function of the monitoring or environmental control systems. This approval authority includes the installation of PV solar array system on a closed landfill, or on adjacent property used for monitoring or environmental control systems. In reviewing these projects, the Department must be assured that the integrity of the existing cover system at the landfill will continue to be maintained. As described below, the project documents must demonstrate that the PV solar array will not interfere with the function of the existing landfill cover system or with access for site maintenance and will not result in increased potential for erosion or unauthorized release of landfill gas.

IV. Responsibility:

The responsibility for implementing, interpreting, and updating this policy lies with the Bureau of Solid Waste Management in the Division of Materials Management (DMM). DMM program staff are responsible for implementing this policy with input from other involved Department Divisions (e.g., Office of General Counsel).

V. Procedure:

Prior to commencement of installation of any project components, the owner of a closed solid waste landfill, referred to hereinafter as the landfill owner, seeking to install a PV solar array system on the closed solid waste landfill must submit a written request for Department approval to the Regional Materials Management Engineer located in the Department Region in which the landfill is located. It is suggested that a pre-submittal conference be held as early as possible in project development to discuss the project and to become familiar with the major items that need to be addressed.

All engineering plans, reports, manual modifications, drawings, and specifications must comply with the requirements of section 7209 of the New York Education Law and all appropriate provisions of the 6 NYCRR Part 360 Series. Engineering plans, reports, drawings, specifications, programs and manuals submitted to the Department must be certified by an individual licensed to practice engineering in the State of New York.

The written request for Department approval must contain, at a minimum, the following elements:

1. Modification of any Existing Post-Closure Monitoring and Maintenance Manual

Modification of any existing Post-Closure Monitoring and Maintenance Manual for the landfill to address any changes to the maintenance or monitoring of the final cover system or landfill site resulting from construction of the PV solar array system. Landfills that do not have a Post-Closure Monitoring and Maintenance Manual must submit a report that includes sufficient information to demonstrate that cover integrity, vegetation, drainage and drainage structures, gas venting structures, and any other related system will be maintained after construction and during operation of the PV solar array.

1. The modified manual or report must detail how maintenance of the final cover system, including vegetation around all PV solar array structures, will be addressed, including measures for replacement of vegetative cover should the PV solar array cause erosion or damage due to shading or concentrated water flow from PV solar array panels.
2. The modified manual or report must also include a plan for maintenance of the PV solar array and any increased site evaluation that may be associated with the secondary use.

2. Construction Level Drawings and Plans

Construction level drawings and plans including cross-section details of the PV solar array that provide sufficient detail to allow for evaluation of the solar module design. Drawings and plans must include, at a minimum, support frames, electrical equipment and components, rubber and concrete sleepers, ballast anchoring system, and electrical conduit as they relate to the landfill final cover system. The drawings should also provide locations of all temporary and/or permanent access roads.

3. An Engineering Report Addressing, at a minimum:

1. PV solar array design. The report must include a detailed description of the array system, including the number of panels and rows, design of the rack and ballast system, and wiring conduit systems.
   1. Grounding electrodes must be located outside of the landfill footprint.
   2. Design of the array system must allow for maintenance of the final cover system. This maintenance includes vegetation maintenance and mowing, gas system repair, and site monitoring and inspections.
2. Settlement, slope failure, and slippage. The report must include a stability analysis demonstrating that the placement of the PV solar array will be geotechnically stable. The report must include calculation of the maximum anticipated load from the PV solar array system.
   1. The stability analysis must include any additional load of items utilized during construction such as heavy equipment.
   2. The settlement analysis must include concrete pads and racking systems that are placed on the landfill cover system.
   3. The report must address potential differential settlement that is a particular risk to array piers, footings, and electrical conduits and that can alter the position of solar panels in relation to the sun.
3. Stormwater control and erosion. The design must evaluate precipitation from a 25-year 24-hour storm event at the landfill location. Stormwater runoff calculations should be included for drainage ditches, swales and retention ponds. The report must also include a discussion of any changes in stormwater management practices as a result of solar panel construction.
4. Landfill gas management. The report must address potential gas migration pathways and the impacts, if any, of the array on the landfill's gas management system.
   1. Buildings, electrical equipment, and subsurface utility conduits can become landfill gas receptors and accordingly all buildings must be designed to prevent the accumulation of gas within the structure.
   2. Utility lines in close proximity to the landfill should be located above ground when feasible. Buried utility lines should be designed to minimize the potential for landfill gas to enter the conduit and create a safety (e.g., explosion, fire) or health hazard. An updated gas survey must also be provided.
   3. For conduits placed aboveground, placement of conduits on stone should be considered to reduce maintenance issues related to mowing and trimming vegetative growth. It is the Department's experience that placement of invertors at the end of rows and running all wires on racks minimizes the number of conduits on or underground and may also minimize maintenance efforts.
5. Wind and snow. The report must include wind uplift calculations to confirm the solar panel ballast design will prevent components from blowing over and damaging the final cover system. Wind and snow accumulation increase the loads placed on array components and can increase the stress applied to the support structures. Designs at solid waste landfills that are located in areas prone to significant wind or snowfall may need to consider the use of solar panels and mounting systems that are certified for higher mechanical loading.
6. Construction techniques.
   1. The report must include a discussion of construction techniques that will be utilized to protect the final cover system.
   2. Equipment used during construction must not exert loads that exceed 10 psi. If loads greater than 10 psi cannot be avoided during construction, the report must include a demonstration that the cover system can withstand the increased loading without damage.
   3. The report should also address the use of temporary roads, utilization of boot systems for punctures that cannot be avoided, flagging of gas vents and monitoring wells, utility burial precautions, etc.
7. Contingency plan. The contingency plan in the Post-closure Monitoring and Maintenance Operations Manual must be modified as necessary to include responses to potential problems such as erosion or construction-related damage to the final cover system, and detection of unsafe concentrations of explosive gas. If a contingency plan does not currently exist, one addressing these and other potential issues must be prepared.

4. A Copy of the Agreement between the Landfill Owner and the Owner or Operator of the PV Solar Array System

A copy of the agreement between the landfill owner and the owner or operator of the PV solar array system that ensures that the integrity of the cover system is maintained throughout the operation of the solar panel system and that the PV solar array system will not interfere with post-closure or custodial care monitoring and maintenance of the landfill, if applicable.

Department Review of PV Solar Project Submissions:

1. The Department will review the project submissions to be reasonably assured that construction, operation, and maintenance of the project will not compromise the final cover system of the landfill, will not interfere with access for site maintenance, will not result in increased potential for erosion, or will not result in the unauthorized release of landfill gas.
2. The Department has jurisdiction over the landfill owner related to 6 NYCRR 363 requirements. If the integrity of the final cover system is compromised for any reason, including actions of the owner or operator of the PV solar array system, the landfill owner is responsible for any necessary actions including timely and adequate repair.
3. The Department will notify the landfill owner of approval in writing, and may include conditions on the approval such as notification requirements or a Professional Engineer certification that the construction and installation was in accordance with the approved plans and documents.
4. Department approval will not relieve the landfill owner and the owner or operator of the PV solar array system from their obligation to comply with any other applicable federal, state and local laws and regulations.
5. Landfill owner and the owner or operator of the PV solar array system must recognize that disruption of electric generation may be required if repair of the cap system is necessary.
6. The Department retains the right to inspect the facility pursuant to 6 NYCRR 360.7.

VI. Related References:

• 6 NYCRR Part 360 Series, November 4, 2017
• Section 7209 of the New York Education Law