Vehicle-to-Home (V2H)

Vehicle-to-Home (V2H) is a bidirectional energy technology that allows an electric vehicle (EV) to supply electricity directly to a residential building, using the EV battery as a backup or supplemental power source. Instead of only charging from the grid or a rooftop solar system, the vehicle can discharge stored energy to power household loads during outages, peak pricing periods, or low solar production.

In modern solar designing and home energy system planning, V2H plays a growing role in energy resilience, self-consumption optimization, peak shaving, and backup power strategy. When integrated with residential solar systems, solar inverters, and smart energy controls, V2H turns an EV into a flexible energy asset—not just a transportation device.

Key Takeaways

Vehicle-to-Home allows EVs to power residential buildings directly
Enhances backup power, self-consumption, and peak load management
Requires bidirectional chargers and compatible EVs
Complements rooftop solar and battery systems
Improves energy resilience without fossil fuel generators

What It Is

Vehicle-to-Home is a localized bidirectional power flow configuration where electricity flows from an EV battery into a single home, rather than back to the utility grid. This distinction separates V2H from grid-interactive concepts like Vehicle-to-Grid (V2G).

In real-world residential solar engineering, V2H enables homeowners to:

Use stored EV energy during grid outages
Reduce grid imports during peak tariff hours
Increase on-site solar self-consumption
Offset or delay investment in a stationary battery energy storage system

For solar designers and installers, V2H must be considered during solar layout optimization, load analysis, backup sizing, and long-term electrification planning.

How It Works

A V2H system relies on bidirectional charging hardware, intelligent energy management, and compatible EVs.

Step-by-Step Operation

Energy Generation or Charging: The EV battery is charged using grid power, rooftop solar, or both—often planned using a Solar Panel Sizer or Battery Size Calculator.

Bidirectional Inverter / Charger: A bidirectional charger converts DC energy stored in the EV into usable AC electricity for household loads.

Home Energy Management System (HEMS)A smart energy management system determines when the EV should discharge energy based on:

Grid availability
Electricity pricing
Household demand
Solar production forecasts

Power Distribution: Energy is routed through the home’s main panel or a dedicated backup loads panel to supply critical circuits or the entire home.

Recharge Cycle: When solar generation increases or grid prices drop, the EV battery is automatically recharged.

This workflow must be modeled alongside shadow analysis, load forecasting, and financial assumptions used in solar proposals.

Types / Variants

1. Backup-Only V2H

The EV powers the home only during grid outages, acting as a clean alternative to diesel generators.

2. Load-Shifting V2H

The EV discharges during peak pricing hours and recharges during off-peak periods or high solar production.

3. Solar-Optimized V2H

Excess rooftop solar is stored in the EV during the day and used at night, improving self-consumption and reducing grid reliance.

4. Partial-Load V2H

Only critical circuits—lighting, refrigeration, internet, HVAC essentials—are powered to extend battery runtime.

How It’s Measured

V2H system performance is evaluated using power, energy, and duration metrics:

Discharge Power (kW): Maximum instantaneous power the EV can supply.‍
Usable Energy Capacity (kWh): Portion of the EV battery allocated for home use.‍
Backup Duration: Time the EV can support household loads.‍
Round-Trip Efficiency (%): Energy retained after charge-discharge cycles.‍
Depth of Discharge (DoD): Limits applied to preserve EV battery health.

These values are key inputs when calculating savings and resilience benefits using the Solar ROI Calculator.

Practical Guidance

For Solar Designers

Analyze household load profiles before enabling whole-home V2H.
Co-size solar and EV storage using Solar Panel Sizer and Battery Size Calculator.
Validate production assumptions with Shadow Analysis to avoid overestimating recharge potential.

For Installers

Verify EV and charger compatibility for bidirectional operation.
Install dedicated backup or critical-load panels.
Coordinate electrical assumptions with Stringing & Electrical Design.

For EPCs & Developers

Position V2H as an alternative or complement to stationary batteries.
Integrate V2H scenarios into Solar Proposals for resilience-focused homeowners.
Apply conservative discharge limits to protect battery lifespan.

For Sales Teams

Emphasize blackout protection, energy independence, and fuel-free backup.
Translate technical benefits into savings using the Solar ROI Calculator.

8. Real-World Examples

Residential Example

A homeowner with rooftop solar and an EV uses V2H to power essential loads during outages, maintaining lighting, refrigeration, and internet for two days.

Commercial-Residential Hybrid

A home office uses V2H during peak tariff hours, reducing grid imports while maintaining business continuity.

Microgrid-Ready Community

In a solar-equipped housing cluster, V2H-enabled homes reduce demand on shared backup infrastructure, improving overall system resilience.