Commercial property solar: the questions before a proposal

Confirm the site and electrical constraints

Roof condition, structure, shading, usable space, tenure, service capacity, and interconnection affect feasibility. Ground or parking installations have their own constraints. A tenant needs appropriate property permissions and a plan for lease changes. Qualified design should address structural, electrical, fire, and utility requirements. A satellite image or generic production estimate is an early screen, not final engineering. Clarify roof replacement, removal, maintenance access, insurance, and ownership responsibilities before committing to a long-lived installation.

Match generation with actual tariff value

Solar output varies by hour and season. Self-consumed generation may avoid different charges from exported output, and fixed or demand charges may remain. Net-metering and export rules are account-specific and can change. Use interval load and a suitable production model such as PVWatts with stated assumptions. Model losses, degradation, curtailment, and operating costs where relevant. A simple annual production times blended bill rate can overstate benefits when it assigns full retail value to all exports or ignores demand rules.

Understand financing, attributes, and resilience

Ownership, leases, and on-site PPAs allocate cost, maintenance, tax, credit, and termination differently. Verify current incentives with qualified tax advisers rather than rely on an outdated percentage. Confirm who owns RECs and what claims the business can make. Ordinary grid-tied solar should not be assumed to operate during outages without appropriate controls and equipment. Storage and islanding require separate qualified design, permits, utility coordination, and a critical-load plan.

Hypothetical value split

An illustrative project produces 100,000 kWh annually. If 70,000 kWh offsets qualifying purchases at $0.10/kWh and 30,000 exports at $0.04/kWh, the simplified energy value is $7,000 + $1,200 = $8,200. Multiplying all output by $0.10 would give $10,000 and overstate this modeled value. Real tariffs and charges can differ. This example excludes project cost, demand, taxes, incentives, maintenance, and financing and is not a solar payback estimate.

Practical review checklist

• Verify tenure, property permissions, roof or land suitability, engineering, and interconnection requirements.
• Model hourly or otherwise suitable production against actual load and self-consumption or export rules.
• Compare full installed and financing economics with verified current incentive assumptions.
• Document REC ownership, maintenance, removal, transfer, and any separately designed backup capability.

Questions & answers