Compare EV Charging vs. Solar: Quick EV-Solar Calculator for Homeowners

Compare EV Charging vs. Solar: Quick EV-Solar Calculator for Homeowners

What it is

A concise tool that helps homeowners compare the costs, emissions, and payback of charging an electric vehicle (EV) from the grid versus charging from a home solar PV system. Designed for quick inputs and fast, actionable outputs.

Key inputs

• Location (zip/postal code): grid electricity price and solar irradiance estimate
• Current grid electricity price: \(/kWh (or use local default)</li> <li><strong>EV efficiency:</strong> kWh per 100 miles (or miles per kWh)</li> <li><strong>Average monthly driving:</strong> miles/month</li> <li><strong>Solar system size or budget:</strong> kW (or leave blank to size for EV load)</li> <li><strong>System cost & incentives:</strong> \)/W installed, local tax credits or rebates
• Battery storage (optional): kWh and round-trip efficiency
• Charger type & schedule: Level ⁄₂, time-of-use rates (if relevant)

Outputs provided

• Monthly and annual kWh needed for EV charging and share supplied by solar vs. grid
• Estimated monthly cost charging from grid vs. solar (with LCOE for solar)
• Simple payback and ROI for adding solar sized to EV needs (years)
• Upfront cost comparison (solar system + battery vs. continuing grid charging)
• CO2 emissions comparison (grid vs. solar-powered charging)
• Sensitivity scenarios (with/without storage, different electricity rates)

How it helps homeowners

• Quickly shows whether installing solar (with or without storage) is cost-effective specifically for EV charging.
• Highlights the impact of time-of-use rates and incentives on payback.
• Provides a recommended solar size or the additional panel capacity needed to cover EV charging.

Typical assumptions for a “quick” mode

• Use average local solar insolation from location input.
• Use national or local default installation cost and incentive rates unless overridden.
• Prioritize simplicity: assume daily charging evenly spread unless user selects TOU schedule.

Implementation notes (for product teams)

• Include defaults but allow overrides for accuracy.
• Show a clear single-number recommendation: “Install X kW solar to cover Y% of EV charging — payback Z years.”
• Offer exportable results and brief guidance on financing and installers.