Introduction: Beyond Simple Capital Cost

In industrial energy planning, capital cost alone rarely determines the true value of a technology investment. Decision        makers must assess total lifecycle cost, ongoing operational savings, delivered energy value, and long-term reliability.        Traditional solar evaluation often focuses on PV electrical output only, while mechanical heat supply is left to boilers        fired by fossil fuels or electricity. The result is a bifurcated energy system: one handling electricity, another handling heat.

This article compares two approaches for industrial buildings that need both electricity and hot water/low-temperature heat:        (1) PVT hybrid solar system, and (2) separate PV array + conventional boiler. We quantify financial differences,        payback periods, and economic risk factors.

1. How ROI Should Be Calculated For Dual-Energy Systems

Return on Investment (ROI) in energy systems is not simply the ratio of savings to capital cost. For systems that deliver        both electricity and heat, ROI must account for:

• Capital cost of installed system (equipment, installation)

• Operational savings on electricity and fuel

• Lifecycle maintenance cost

• System reliability and performance degradation

• Forecasted energy price escalation

A holistic ROI calculation compares *total lifetime energy value* against *total lifetime cost* including maintenance        and replacement parts.

2. Industrial Case: PVT vs PV + Boiler Breakdown

Consider a manufacturing facility with a consistent thermal load for process water and daily electricity demand. Two        energy system options are evaluated:

From this example, the PVT hybrid system has slightly higher upfront cost but delivers both electricity and usable        heat without additional fossil fuel consumption. In contrast, the separate PV + boiler solution requires ongoing fuel        cost and distinct maintenance cycles for each system.

3. Sensitivity: What Happens When Energy Prices Rise

Industrial energy plans must account for future energy price volatility. In markets where electricity and fuel costs        rise steadily, the value of on-site renewable production increases proportionally.

In contrast, the PV + boiler scenario is exposed to fuel price volatility, which increases operational risk and        uncertainty in long-term payback.

4. Net Present Value and Total Lifecycle Cost

Net Present Value (NPV) considers time value of money. Under standard industrial discount rates (e.g., 7–10%), a system        with stable cost avoidance often outperforms systems with unpredictable fuel expenditure. In our comparison:

• PVT yields stronger NPV when fuel escalation is considered

• Lower maintenance burden improves long-term cost profile

• Single integrated system reduces logistical and administrative expenses

Real-world financial decisions are influenced by tax incentives, depreciation schedules, and financing terms. Accounting        for these can further benefit renewable systems with dual outputs.

5. Key Factors That Influence ROI