Energy Modeling

Energy Modeling is the process of predicting how much electricity a solar PV system will generate under real-world conditions. It uses irradiance data, shading profiles, module characteristics, system losses, weather patterns, and site geometry to estimate annual and monthly energy output (kWh).

For solar developers, EPCs, installers, and designers, Energy Modeling is a core engineering function because it determines project performance, financial viability, customer ROI, and long-term reliability. In modern platforms like Solar Designing, Energy Modeling is tightly integrated with shading analysis, module layout, stringing, and inverter configuration to ensure accurate production estimates.

Key Takeaways

Energy Modeling predicts how much electricity a solar system will generate over time.
It accounts for shading, irradiance, weather, temperature, system losses, and layout.
Essential for engineering accuracy, financial modeling, and customer proposals.
Integrated into modern tools like SurgePV for fast, accurate design and analysis.
Helps reduce project risk, increase ROI, and improve system reliability.

What Is Energy Modeling?

Energy Modeling is the analytical process of simulating how a solar PV system will perform over time. It answers questions like:

How much energy will this system produce annually?
What will the month-by-month generation look like?
How will shading, tilt, azimuth, and weather affect yield?
Is the project financially viable?
How does layout optimization increase kWh output?

Solar professionals use Energy Modeling to design, compare, and optimize systems before they are built, preventing costly mistakes and improving bankability.

Related foundational concepts include POA Irradiance, Shading Analysis, and Solar Layout Optimization.

How Energy Modeling Works

Energy Modeling combines environmental data, equipment specifications, and system layout to simulate performance. The workflow typically includes:

1. Solar Resource Data

Using TMY datasets, irradiance maps, or satellite data.

2. Shading & Obstruction Analysis

Determines losses from trees, buildings, and roof obstructions using tools like Shadow Analysis.

3. Module Orientation & Layout

Tilt, azimuth, inter-row spacing, and array geometry affect solar exposure.

4. Electrical Configuration

Stringing, inverter loading, DC/AC ratio, and clipping determine electrical output.

See Stringing & Electrical Design.

5. System Loss Calculations

Includes:

Soiling
Mismatch
Wiring losses
Temperature impacts
MPPT efficiency
Inverter conversion losses

6. Hourly / Sub-hourly Simulation

Models energy generation using irradiance and weather patterns.

7. Final kWh Estimate

Outputs monthly, annual, and lifetime production estimates.

This data feeds directly into proposals via tools like Solar Proposal & Sales Hub.

Types / Variants of Energy Modeling

1. Hourly Energy Modeling

Uses hourly weather profiles for high accuracy.

2. Sub-Hourly / High-Resolution Modeling

Used for utility-scale or advanced grid-interactive projects.

3. 3D Energy Modeling

Incorporates terrain, roof shapes, and 3D obstructions.

4. Financial Energy Modeling

Ties energy output to ROI, payback, and savings.

Tools like the Solar ROI Calculator use this data.

5. Comparative Modeling

Used to compare different module types, layouts, or orientations.

How Energy Modeling Is Measured

1. Annual Energy Output (kWh/year)

Primary metric for evaluating system performance.

2. Performance Ratio (PR)

See Performance Ratio.

3. Specific Yield (kWh/kWp)

Measures system efficiency across climates.

4. Shading Loss (%)

Calculated using Shading Analysis.

5. System Losses Breakdown

Categorized into temperature, soiling, mismatch, inverter losses, etc.

Typical Values / Ranges

Actual energy output varies by shading, tilt, azimuth, weather, and system design.

Practical Guidance for Solar Designers & Installers

1. Use accurate shading data

Combine Energy Modeling with high-quality shading reports using Shadow Analysis.

2. Choose optimal tilt and azimuth

Use tools like the Sun Angle Calculator for site-specific optimization.

3. Pay attention to DC/AC ratio

Higher ratios increase clipping but may boost annual production—model both.

4. Model temperature effects

High temperatures can reduce energy output by 10–20%.

5. Validate inverter loading

Ensure that stringing and inverter selection (see Inverter Sizing) match the modeled design.

6. Model multiple layout scenarios

Auto-layout tools in Solar Designing allow fast scenario comparison.

7. Use modeling data in customer proposals

Integrate results directly through the Solar Proposal & Sales Hub.

Real-World Examples

1. Residential PV System

A 6.5 kW rooftop system is modeled using hourly irradiance data.

Shading loss = 4%

Annual output = 8,450 kWh

2. Commercial Flat-Roof System

A 300 kW array is modeled with 3D shade analysis.

Inter-row spacing optimized → Yield increases by 7%.

3. Utility-Scale Solar Farm

A 20 MW ground-mount project uses sub-hourly energy modeling to meet grid requirements.

Modeling predicts 34 GWh annual output.