PR is the ratio of actual energy output to the theoretical energy output. It indicates overall system efficiency.

PR = Actual Energy Output (kWh) / (Irradiance (kWh/m²) × System Size (kWp))

Standard PR Values in Bangladesh: Rooftop (industrial) = 0.75 – 0.82, Rooftop (residential) = 0.70 – 0.78, Ground-mounted (utility scale) = 0.78 – 0.85

Pnom refers to the nominal or rated capacity of a solar panel or array under standard test conditions (STC).

Pnom Ratio= Installed Capacity (kWp) / Annual Energy Yield (kWh)

Typical Pnom Ratio in Bangladesh: Pnom (kWh/kWp/year) for Dhaka & Central Zone = 1,350 – 1,450, Southern Coastal Zone = 1,400 – 1,500, Northern Zone = 1,300 – 1,400. Rule of Thumb: Use 1,400 kWh/kWp/year as a planning benchmark for well-optimized systems in Bangladesh.

System sizing involves calculating the number of panels, inverters, and other equipment based on load, irradiance, and system goals.

Soiling, shading, mismatch, temperature, wiring, inverter efficiency, and degradation.

Annual Yield = System Size (kWp) × Specific Yield (kWh/kWp)

It’s the annual energy generation per kWp installed (e.g., 1,460 kWh/kWp/year considering average daily production 4KWh/KWp)

They determine how much sunlight a panel receives and hence impact energy yield. For Bangladesh Tilt Angle ≈ 15° to 25° and Optimum azimuth = 180° (facing South), Deviation ±10°–15° is acceptable with minor performance loss.

Use degradation rates (e.g., 0.5%-1%/year) to reduce yearly energy projections.

LCOE is the average cost per kWh of electricity generated over the system’s lifetime.

LCOE = Total Lifecycle Costs (CAPEX + OPEX) / Total Lifetime Energy Production (kWh)

It helps compare the cost of solar to grid electricity or other technologies on a per-kWh basis.

ROI (%) = (Net Profit / Total Investment) × 100

Payback Period = CAPEX / Annual Energy Savings or Revenue after opex

The present value of all future cash flows (positive and negative), discounted to today’s value.

NPV = Σ(Ct / (1 + r)^t) - C0, Where Ct = cash flow in year t, r = discount rate, C0 = initial investment.

The discount rate at which NPV becomes zero. It’s used to evaluate project profitability.

Usually 6-10%, depending on risk, financing, and market norms.

CAPEX: Customer owns the system. OPEX: System is leased or power is purchased (PPA model).

Irradiance variability, equipment failure, regulatory changes, currency risk, inflation.

A long-term contract to buy electricity from a solar provider at a fixed rate.

It allows exporting excess energy to the grid, improving ROI and reducing payback time.

Typically 25-30 years for panels; 10-15 years for inverters.

Include annual O&M as a percentage of CAPEX (typically 2–3%).

Reduction in CO₂ emissions can be monetized in voluntary or compliance carbon markets.