How to Convert Your Old Coal Plant into a New Solar Farm

How to Convert Your Old Coal Plant into a New Solar Farm


Converting an old coal plant into a new solar farm can bring numerous benefits. As coal plants retire, their infrastructure can be repurposed for renewable energy generation. This allows coal communities to transition to the clean energy economy.

Converting a coal plant to solar requires extensive planning and work. But the end result is a renewable power source that creates jobs and generates clean electricity for decades to come.

In this guide, I will walk through the full process of converting a coal plant into a solar farm, from initial feasibility studies to ribbon-cutting day. I cover all the key steps and considerations in depth, using examples from real-world solar conversions.

Whether you are a utility, developer, or community leader, this guide will equip you with the knowledge needed to successfully transform your old coal plant into an economic engine for solar power.

Conduct Initial Feasibility Studies

The first step is to thoroughly assess the feasibility of converting your specific coal plant site into a solar farm. This involves both high-level viability studies and in-depth technical assessments.

Evaluate Overall Viability

Start by looking at the big picture viability:

  • Site size: How many acres of land does the coal plant site include? At least 50-100 acres are ideal for utility-scale solar.
  • Solar resource: Assess the quality of the solar resource using databases like NREL’s PVWatts. Locations with annual insolation of 4-6 kWh/m2 /day are best.
  • Transmission infrastructure: Examine if existing transmission lines and interconnections can be repurposed for solar energy distribution. This minimizes costs.
  • Zoning: Is the site properly zoned for solar farm development? If not, a zoning variance may be required.
  • Community support: Gauge if there is local community backing for a solar conversion. Community engagement is key throughout the process.

Conduct Technical Assessments

Once initial viability is confirmed, perform in-depth technical assessments:

  • Engineering audit: Engineers conduct a full audit of the existing infrastructure at the coal plant. They determine what can be reused vs. what must be retrofitted or replaced.
  • Environmental assessments: Evaluate if any land or water remediation is required to remove coal pollution. Some remediation is typical to make the site “solar ready.”
  • Interconnection studies: Utility engineers perform interconnection studies to integrate the solar farm into the grid. Any infrastructure upgrades needed are identified.
  • Permitting review: Experts assess all permits and regulations that will apply to redeveloping the site into a solar farm. The permitting process is mapped out.

These studies provide critical data to determine feasibility and accurately estimate project costs/timelines.

Assemble the Right Project Team

Converting a coal plant into solar is complex, requiring collaboration across many different partners:

  • Utility: The utility that owns the existing coal plant provides the site access and infrastructure. They are also the long-term power purchaser.
  • Developer: An experienced solar developer handles upfront planning, permitting, procurement, and construction.
  • Investors: Equity financing and tax credit investors provide capital and monetize tax benefits.
  • EPC contractor: An engineering, procurement, and construction (EPC) firm oversees system design, component sourcing, and installation.
  • Operations/maintenance: A long-term O&M provider operates and maintains the solar farm post-construction.
  • Local partners: Community colleges, nonprofits, and contractors help support the local labor force.

Assembling the right project team is crucial upfront. Look for experienced players with coal-to-solar expertise.

Design an Optimized Solar Layout

A solar engineering firm develops a tailored site design to maximize energy production. Key considerations include:

  • Available land: Design around areas with residual coal ash or contamination. Maximize use of open, usable acres.

  • Module locations: Optimize placement based on the movement of the sun. Avoid shading from buildings.

  • Access roads: Utilize on-site roads, designing new access as needed. Roads must support equipment and crews during construction.

  • Interconnection points: Connect to existing transmission infrastructure. New collector lines may also be needed.

  • Drainage: Management of stormwater runoff is critical. Design drainage channels, retention ponds, and erosion controls appropriately.

  • Perimeter fencing: Secure the site perimeter with tall fencing and surveillance systems.

The solar farm layout is iteratively optimized to generate the maximum possible energy yield within site constraints.

Manage Decommissioning and Remediation

Before solar system construction can begin, the existing coal plant must be decommissioned and any environmental remediation required must be performed.

Decommission Coal Plant Components

  • Remove hazardous materials like coal ash carefully. Deconstruct towers, turbines, and generators. Recycle components and scrap metal where possible.

  • Clearing and grading of the site may be required. Demolish and dispose of any unnecessary structures.

  • Work with local historical societies if certain buildings can be preserved versus demolished.

Conduct Required Environmental Remediation

  • Test soil and water for any contamination from coal ash or fossil fuel emissions. Remove and dispose of any contaminated elements.

  • Utilize proper protocols for erosion control and dust management during remediation.

  • Restore wetlands or streams on-site that may have been degraded during the coal plant’s operation.

  • Monitor air quality and utilize control measures as the coal plant is decommissioned.

Conducting remediation generates a clean slate for solar development.

Acquire Necessary Permits and Approvals

The project team engages with local authorities early to acquire all permits and approvals required to redevelop the site:

  • Zoning permits are updated to approve solar farm use. Additional hearings may be required.

  • Building permits must be secured for any new electrical buildings, substations, or grid connections.

  • Stormwater permits regulate drainage, retention ponds, and erosion control during and post-construction.

  • Close collaboration with the utility is needed to secure grid interconnection approvals and updated power contracts.

  • Environmental permits ensure compliance with standards for natural resource protection, waste disposal, and pollution controls.

  • Local incentives like tax abatements or rebates may be available to support the coal-to-solar transition.

Navigating the bureaucracy requires an experienced solar developer. Permitting delays can significantly impact project timelines.

Procure Solar System Components

The solar developer manages procurement of all key system components:

  • PV modules: Order mono- or poly-crystalline silicon modules rated for 320+ watts each from Tier 1 suppliers.

  • Inverters: Procure utility-scale string inverters or central inverters rated from 500 kW to 2+ MW. Optimize inverter sizing to match PV capacity.

  • Tracking arrays: Choose single-axis horizontal or vertical axis trackers to maximize output. Trackers follow the sun’s path to boost production by 15-25% versus fixed-tilt systems.

  • Balance of system: Source transformers, switchgear, monitoring systems, mounting structures, combiner boxes, and wiring.

Leverage expertise and economies of scale to procure top quality components at competitive pricing.

Install the Solar System Safely

System installation is complex and must be managed carefully by the EPC contractor.

Construction Preparation

  • Hold safety training and planning meetings for all subcontractors. Designate site supervisors.

  • Stage initial equipment and supplies on-site. Deliver materials according to installation schedule.

  • Hire local skilled tradespeople first. Provide solar job training where experience is lacking.

Step-by-Step Installation

  • Prepare site by grading areas, building access roads and drainage.

  • Install driven pile foundations for mounting structure supports or tracking anchors.

  • Attach and wire together PV modules into arrays on mounting racks.

  • Connect arrays via underground wiring collection runs to combiner boxes.

  • Install inverters, transformers and switchgear in electrical enclosures and shelters.

  • Construct interconnected collector lines to transmit AC power to substation.

  • Interface solar output to the grid per interconnection approvals.

  • Commission systems and monitoring equipment to complete the build.

Adhering to best practices for solar construction ensures a safe, high performing system.

Maintain and Operate the Solar Farm

Once construction completes, the project transitions to ongoing operations and maintenance (O&M):

  • Monitor energy output via a solar data acquisition system. Identify any production shortfalls.

  • Inspect electrical components and PV modules annually. Clean modules 2-4 times per year, as needed.

  • Maintain site vegetation by mowing and trimming. Keep access roads graded.

  • Service inverters, transformers, and trackers per OEM maintenance schedules.

  • Update software and cybersecurity measures periodically.

  • Technicians make any needed module/equipment repairs promptly.

  • Budget for inverter replacement every 10 years and PV module replacement every 25+ years.

Robust O&M ensures optimal solar farm output over its 30+ year lifetime.


Repurposing retired coal plants for solar energy is a win-win. Communities can continue to benefit from these sites, while generating clean, renewable power for decades to come.

Converting a coal plant into a solar farm is undoubtedly complex. But by following best practices for feasibility assessments, permitting, remediation, procurement, construction, and O&M the project can produce outstanding results.

What old fossil fuel plant in your community could be transformed into a new solar power beacon? With the right partnerships, planning and solar know-how, the possibilities are bright.