PG&E Solar Power Calculator
Estimate your potential electricity savings by switching to solar energy in the Pacific Gas & Electric service area.
Estimated Monthly Savings
System Payback Period
Monthly Solar Production
Annual Savings
Monthly Cost Comparison
What is a PG&E Solar Power Calculator?
A PG&E Solar Power Calculator is a specialized tool designed to help homeowners and businesses in Pacific Gas & Electric’s California service area estimate the financial viability of installing a solar panel system. Unlike generic solar calculators, it uses inputs specific to the region, such as local electricity rates and average sunlight, to provide a realistic projection of savings, energy production, and the time it will take for the system to pay for itself (the payback period). This tool is essential for anyone considering a move to renewable energy and wanting to understand their potential return on investment. For more detailed financial planning, you might also find our NEM 3.0 calculator useful.
PG&E Solar Power Calculator Formula and Explanation
The calculator uses several core formulas to estimate your savings. The primary calculation determines your monthly energy production and translates that into dollars saved based on the electricity you no longer have to buy from PG&E.
Monthly Energy Production (kWh) = System Size (kW) × Avg. Daily Sun Hours × 30.4 × Efficiency Factor
Monthly Savings ($) = Monthly Energy Production (kWh) × PG&E Rate ($/kWh)
A 0.85 efficiency factor is used internally to account for real-world conditions like panel degradation, inverter inefficiency, and minor shading, providing a more conservative and realistic estimate.
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Monthly Electricity Usage | Your average energy consumption per month. | kWh | 300 – 1,500 |
| PG&E Rate | The cost per kilowatt-hour you pay. | $/kWh | $0.30 – $0.55 |
| System Cost | Total installed cost of the solar system after incentives. | $ | $12,000 – $30,000 |
| System Size | The total power output rating of your solar panels. | kW | 4 – 10 |
| Daily Peak Sun Hours | The equivalent number of hours the sun is at its peak intensity. | Hours | 5 – 7.5 |
Practical Examples
Example 1: Medium-Sized Home
- Inputs: 700 kWh monthly usage, $0.45/kWh PG&E rate, 6 kW system size, $18,000 system cost, 5.5 sun hours.
- Calculation: The system would generate approximately 841 kWh per month. Since usage is 700 kWh, savings are capped at the amount consumed.
- Results: This leads to estimated monthly savings of $315 (700 kWh * $0.45), annual savings of $3,780, and a payback period of about 4.8 years.
Example 2: Larger Home with Higher Usage
- Inputs: 1,200 kWh monthly usage, $0.48/kWh PG&E rate, 8 kW system size, $24,000 system cost, 6 sun hours.
- Calculation: The system would generate approximately 1,244 kWh per month.
- Results: This covers the full 1,200 kWh usage, resulting in monthly savings of $576, annual savings of $6,912, and a payback period of approximately 3.5 years. Learning about understanding your PG&E bill can further optimize savings.
How to Use This PG&E Solar Power Calculator
- Enter Your Energy Usage: Locate your average monthly usage in kWh from your most recent PG&E bill and enter it into the first field.
- Input Your Electricity Rate: Find your average cost per kWh on your bill. If you’re unsure, the default value is a recent statewide average.
- Estimate System Cost: Enter the total quoted cost for your solar panel installation, after applying any federal or state tax credits.
- Define System Size: Input the size of the solar system you are considering in kilowatts (kW). Your solar contractor will recommend a size based on your usage.
- Adjust Sun Hours: The default is a reasonable average for much of PG&E’s territory. You can adjust this up or down if you live in a particularly sunny or foggy area.
- Review Your Results: The calculator will instantly update your estimated monthly savings, payback period, and annual savings, giving you a clear picture of the financial benefits.
Key Factors That Affect PG&E Solar Power Savings
- Net Energy Metering (NEM) Policy: The current policy, NEM 3.0, significantly changed how customers are credited for excess energy sent to the grid. Savings are maximized by using the power you generate directly. Check out our guide to California solar incentives.
- Time-of-Use (TOU) Rates: PG&E’s TOU plans mean electricity costs more during peak hours (typically 4-9 PM). A solar system paired with a battery can drastically reduce costs by using stored solar power during these expensive periods.
- System Orientation and Shading: South-facing roofs with minimal shade from trees or buildings will produce the most power. An east or west-facing roof can still be very effective but may produce slightly less energy.
- Panel Efficiency and Degradation: Higher-efficiency panels produce more power from a smaller area. All panels slowly lose efficiency over time (degradation), a factor that should be included in long-term savings projections.
- System Cost and Incentives: The final price after accounting for the federal solar tax credit and any local rebates directly impacts the solar panel payback period.
- Your Energy Consumption Habits: Shifting heavy electricity usage (like charging an EV or running the AC) to daytime hours when your panels are producing allows you to use your own free power instead of buying from the grid.
Frequently Asked Questions (FAQ)
- 1. How accurate is this PG&E solar power calculator?
- This calculator provides a strong preliminary estimate based on the data you provide. However, a professional quote from one of the best solar companies in California will provide the most accurate numbers, as it will include a detailed analysis of your specific roof, shading, and local weather patterns.
- 2. What is NEM 3.0 and how does it affect me?
- NEM 3.0 is California’s current solar billing structure. It reduces the credit homeowners receive for exporting excess solar energy to the grid. This makes it more valuable to consume your solar power directly or store it in a battery for later use, rather than selling it back to PG&E.
- 3. Will I still have an electric bill with solar panels?
- Almost always, yes. You will still be connected to the grid and will likely have some monthly connection fees or taxes. You may also draw power from the grid at night or on cloudy days if you don’t have a battery, which will appear on your bill.
- 4. How is the payback period calculated?
- The payback period is the total system cost divided by the estimated annual savings. It’s the time it takes for the solar system to “pay for itself” through electricity bill reductions.
- 5. Should I get a solar battery with my system?
- Under NEM 3.0, adding a battery is highly recommended. A battery allows you to store excess solar energy generated during the day and use it during the evening peak-rate hours (4-9 PM), maximizing your savings and energy independence.
- 6. What size solar system do I need?
- The ideal system size aims to offset as much of your annual electricity usage as possible. A solar contractor can determine the optimal size by analyzing the past 12 months of your PG&E bills. This calculator can give you a good starting point.
- 7. How long do solar panels last?
- Most solar panels come with a 25-year performance warranty. They will likely continue to produce power for 30 years or more, with a gradual and expected decline in efficiency over their lifespan.
- 8. Does solar increase my home’s value?
- Yes, studies have consistently shown that homes with owned solar panel systems sell for more than comparable homes without them. It’s a significant, value-adding home improvement.