Solar for Factories: A Practical Guide for Industrial Rooftop Projects

Introduction

Factories often have high daytime electricity consumption, large roof areas and predictable operating schedules. These factors can make rooftop solar worth evaluating as part of an energy-cost and sustainability plan.

However, an industrial solar project is not simply a larger version of a residential installation. It requires careful assessment of production loads, electrical infrastructure, roof condition, safety requirements, operating continuity and long-term maintenance.

Why factories evaluate solar

High daytime electricity demand

Many manufacturing facilities operate during daylight hours, which can allow solar generation to support a meaningful share of on-site consumption.

Large roof areas

Factories, warehouses and industrial sheds may have substantial roof space, but usable area depends on shading, roof condition, equipment, access and structural constraints.

Energy-cost pressure

Electricity is a recurring operating cost. A solar project can help businesses plan a portion of their energy supply, subject to generation, tariff, financing and system performance.

Sustainability requirements

Solar can support renewable-energy, carbon-reduction and ESG objectives when the project is properly documented and monitored.

Step 1: Review electricity consumption

Before discussing system capacity, collect:

• Electricity bills for the last 12 months, where available.
• Monthly units consumed.
• Tariff category.
• Demand charges.
• Maximum demand.
• Operating hours.
• Production schedule.
• Major equipment loads.
• Weekend and shutdown patterns.
• Future expansion plans.

A single bill may provide a starting point, but a 12-month consumption profile gives a more reliable picture of seasonality and operating patterns.

Step 2: Assess the roof and site

A factory roof should be evaluated for:

• Usable roof area.
• Orientation and slope.
• Shadow from nearby structures or equipment.
• Roof condition and waterproofing.
• Structural capacity.
• Access for installation and maintenance.
• Cable routes.
• Inverter and electrical-equipment locations.
• Fire-safety requirements.
• Drainage and roof protection.

A roof that appears large may have limited usable area because of ducts, skylights, water tanks, equipment, parapets, safety clearances or maintenance pathways.

Step 3: Understand the load profile

Solar generates electricity during daylight hours. A factory should therefore understand when electricity is consumed.

Review:

• Start and stop times.
• Continuous versus intermittent loads.
• Major machinery loads.
• Daytime base load.
• Peak demand periods.
• Seasonal production cycles.
• Weekend operations.
• Future production changes.

A system should be designed around actual consumption and expected operating conditions—not only roof size.

Step 4: Choose the right project structure

CAPEX model

Under CAPEX, the factory funds the system and generally owns the asset.

Potential considerations include:

• Upfront investment.
• Financing cost.
• Asset ownership.
• O&M responsibility.
• Long-term savings after payback.
• Tax and accounting treatment.

OPEX or RESCO model

Under an OPEX or RESCO structure, a third party may invest in, own and operate the system, while the factory pays for electricity under an agreed arrangement.

Potential considerations include:

• Contract duration.
• Tariff or payment structure.
• Escalation clauses.
• Minimum purchase obligations.
• Roof-use rights.
• Performance responsibilities.
• Maintenance and replacement terms.
• Exit terms.

There is no universally better model. The right choice depends on capital availability, ownership preference, building tenure, risk appetite and long-term energy plans.

Step 5: Evaluate the technical proposal

A factory solar proposal should clearly state:

• Proposed system capacity.
• DC and AC capacity basis.
• Module and inverter specifications.
• Roof layout.
• Shadow analysis.
• Expected annual generation.
• Generation assumptions.
• Estimated energy offset.
• Electrical scope.
• Protection and safety systems.
• Monitoring arrangements.
• Commissioning process.
• O&M scope.
• Warranty details.
• Project timeline.
• Exclusions and commercial terms.

Do not compare quotations only on cost per kW. A lower quotation may exclude electrical upgrades, structural work, monitoring, approvals or commissioning.

Step 6: Plan electrical integration

Industrial sites may require detailed electrical planning for:

• Existing distribution panels.
• Transformer capacity.
• Cable routes.
• Protection systems.
• Earthing and lightning protection.
• Metering.
• Grid interconnection.
• Load balancing.
• Safety isolation.
• Monitoring and communication.

The electrical scope should be defined early because it can affect project cost, timeline and safety.

Step 7: Plan for O&M

A factory solar system should have a clear O&M plan covering:

• Module inspection.
• Cleaning schedule.
• Inverter checks.
• Cable and connector inspection.
• Mounting-structure checks.
• Monitoring review.
• Fault response.
• Safety checks.
• Performance reporting.

The Ministry of New and Renewable Energy’s rooftop-solar O&M guidance recommends regular cleaning and inspection, using water and a soft sponge or cloth while avoiding abrasive materials.

Common mistakes in factory solar projects

• Designing capacity from roof area alone.
• Ignoring production schedules and load timing.
• Using a single electricity bill for financial planning.
• Comparing quotations only on price.
• Ignoring electrical-infrastructure requirements.
• Failing to plan maintenance access.
• Accepting savings estimates without assumptions.
• Treating commissioning as the end of the project.

How to evaluate ROI

A factory should evaluate solar using project-specific assumptions, including:

• Project cost.
• Annual generation.
• Electricity tariff.
• Self-consumption.
• Export or net-metering treatment.
• O&M cost.
• Financing cost.
• Degradation.
• Downtime.
• Tax and depreciation treatment.
• Operating life.

Simple payback = Initial project cost ÷ Annual net savings. Use only documented tariff, generation and cost assumptions when calculating it.

Use this as an initial estimate, not a guaranteed result. A robust evaluation should disclose every assumption.

How Conservit can support

Conservit can support an initial factory solar discussion by reviewing:

• Electricity bills and load profile.
• Roof and site conditions.
• Electrical infrastructure.
• Solar generation potential.
• CAPEX or OPEX considerations.
• Installation and commissioning requirements.
• O&M and monitoring needs.