Load Analysis
Load Analysis is the process of evaluating a building’s electricity consumption patterns to determine how much energy is needed and when it is used. In solar design, load analysis is essential for sizing PV systems, batteries, inverters, and backup power solutions. It helps solar professionals understand daily, monthly, and seasonal energy demand so they can design systems that reduce utility bills, maximize ROI, and meet customer expectations—whether for residential, commercial, or industrial projects.
Load analysis is a foundational step in solar planning and is often integrated directly into advanced platforms like Solar Designing and financial tools like Solar ROI Calculator to improve system accuracy and proposal performance.
Key Takeaways
- Load Analysis determines how much energy a building uses and when it uses it.
- Essential for sizing PV systems, batteries, and inverters accurately.
- Helps optimize utility bill savings, demand charge reduction, and TOU strategies.
- Residential, commercial, and industrial sites require different modeling approaches.
- Integrates seamlessly with solar design, proposal, and financial tools for better accuracy.
What Is Load Analysis?
Load Analysis is a detailed study of how electricity is consumed within a property. It includes:
- Total daily energy usage
- Peak power demand
- Time-of-use consumption patterns
- Seasonal variations
- Circuit-level vs whole-building loads
- Backup power requirements
- High-load appliance behavior
For solar designers, load analysis ensures the PV system is engineered to:
- Offset energy bills
- Reduce peak demand charges
- Support EV charging
- Size battery backup correctly
- Comply with inverter and battery limits
Related concepts include Energy Modeling, Inverter Sizing, and DC/AC Ratio.
How Load Analysis Works
The load analysis process includes several key steps:
1. Collect Consumption Data
Solar professionals gather information such as:
- Utility bills (kWh consumption)
- Smart meter reports
- Time-of-use breakdown
- Demand charges
- Sub-metering data (for commercial sites)
- Historical seasonal consumption
2. Understand Appliances & Load Drivers
Includes equipment such as:
- HVAC systems
- Water heaters
- Refrigeration
- Motors and pumps
- Industrial machinery
- EV chargers
3. Identify Peak Demand
Peak demand determines:
- Minimum inverter size
- Required battery discharge rate
- Backup power requirements
See Solar Inverter for inverter loading considerations.
4. Analyze Daily and Seasonal Patterns
Solar output varies over seasons—so must the design.
5. Model Offset Strategies
Load analysis helps determine:
- How much solar can offset usage
- Whether a battery reduces peak demand
- If TOU rate optimization is required
Load analysis is also connected to proposal tools like Solar Proposals for accurate financial modeling.
Types / Variants of Load Analysis
1. Basic Load Analysis
Uses historical utility bills and monthly averages.
2. Time-of-Use Load Analysis
Breaks down consumption by hour-of-day and tariff periods.
3. Peak Demand Analysis
Focused on maximum instantaneous power usage.
4. Load Profile Analysis
High-resolution data (5–60 minutes) to evaluate:
- Load shape
- Variability
- Peak load probability
5. Backup Load Analysis
Identifies critical vs non-critical loads for battery design.
Includes:
- Fridge
- Lights
- Router
- Fans
- Medical equipment
- Sump pumps
- Essential business circuits
6. Commercial/Industrial Load Analysis
Includes demand charges, power factor, machinery cycles, and shift-based loads.
How Load Analysis Is Measured
1. Energy Consumption (kWh)
Monthly or annual total usage.
2. Peak Power Demand (kW)
Highest demand spike recorded during a billing cycle.
3. Load Factor
Indicates how consistently energy is used:
Load Factor = Average Load / Peak Load
4. Time-of-Use (TOU) Load
Consumption broken into peak, off-peak, and shoulder periods.
5. Critical Load Percentage
Portion of loads that need backup.
6. Seasonal Variation Index
Indicates how much energy consumption fluctuates across seasons.
Typical Values / Ranges
Residential
- Daily usage: 8–30 kWh
- Peak demand: 2–8 kW
- Backup load: 1–3 kW
India/Asia values tend to be lower; North America values are higher due to HVAC usage.
Commercial
- Daily usage: 100–5,000 kWh
- Peak demand: 20–300 kW
- Demand charges are often the largest savings opportunity.
Industrial
- Daily usage: 5,000+ kWh
- Peak demand: 100 kW–2 MW+
- Variable loads based on machinery and shift cycles.
Practical Guidance for Solar Designers & Installers
1. Always collect at least 12 months of utility data
Seasonal variance greatly affects system performance.
2. Identify high-load appliances
These determine system limits and battery requirements.
3. Match inverter sizing to peak demand
See Inverter Sizing.
4. Use TOU modeling for accurate savings calculations
Especially in California, Australia, Europe, and India.
5. Use design automation tools
SurgePV integrates load analysis into:
- Energy modeling
- Proposal generation
- Financial forecasting
Explore Solar Designing and the Solar ROI Calculator.
6. Use load analysis to size batteries
Use the Battery Size Calculator for backup or load shifting.
7. For commercial sites, prioritize demand reduction
Batteries + solar can significantly lower demand charges.
Real-World Examples
1. Residential Home in India
Daily usage: 12 kWh
Peak demand: 3.2 kW
Result: A 5 kW system + small battery meets 80% of annual consumption.
2. U.S. Commercial Office Building
Daily usage: 380 kWh
Peak demand: 52 kW
Result: Solar offsets energy use; battery is added to reduce demand charges during peak afternoon hours.
3. Manufacturing Plant
Daily usage: 6,500 kWh
Peak load: 540 kW
Result: Load analysis shows three spikes tied to machinery cycles → system designed with:
- 1.2 MWp solar
- 750 kW / 1.5 MWh battery
- Load shifting strategy
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