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Energy Management

Maximize Efficiency. Minimize Carbon.

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Energy Management

Maximize Efficiency. Minimize Carbon.

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overview Video

What we did
  • Solar power for zero energy living and transportation
  • DC microgrid to improve HEMS efficiency
  • Automatic response to support the electrical grid
How that worked out
  • Zero net was achieved, despite the efficiency being lower than expected
  • Home power backup works, though weather dependency makes it uncertain
  • Grid responses were managed in the background with no user involvement required
What we did
  • Solar power for zero energy living and transportation
  • DC microgrid to improve HEMS efficiency
  • Automatic response to support the electrical grid
How that worked out
  • Zero net was achieved, despite the efficiency being lower than expected
  • Home power backup works, though weather dependency makes it uncertain
  • Grid responses were managed in the background with no user involvement required

Zero Net Energy over a year

The Smart Home achieves zero net energy when summed over the course of the year. While it manages and smooths energy using the battery and the vehicle at every moment, the chart shows that it would need a lot more energy generation or storage to be able to achieve zero net energy every month.

Better Together

ACHIEVED MORE THAN 7 TONS OF CO2 REDUCTION PER YEAR

(compared to a conventional home and vehicle)

Meet the Brain of the Honda Smart Home

Our goal is to develop a future where every home can have clean energy, and every vehicle can produce zero emissions. To overcome the grid challenges of this future, our Home Energy Management System (HEMS) was the vision of one solution. As the home’s brainpower, the HEMS monitored all energy input, sent energy where it was needed, and kept the home comfortable and the Fit EV charged. It also worked to improve grid reliability by automatically responding to demand response signals and providing other grid services.

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How It Worked

The HEMS monitored electrical loads and communicated with the electrical grid to coordinate the home’s power consumption with the needs of the grid.

The roof mounted solar panels could produce up to 9.5kW of power that was sent to the DC-microgrid side of the management system.

The system could store DC power in its battery for later use, or send it directly to the battery of a plug-in electric vehicle.

In situations where DC power was not required, the energy could be converted to AC power and sent to the home or back to the grid.

What We Learned

Our experiment provided ample opportunity for real-world learning, some of which was unexpected.

1

Manual Not
Automatic

One of the early design decisions was to use a manual transfer switch (for backup power during a blackout) because an automatic transfer switch had too much standby energy consumption.

2

Critical Load May
Not Pass Through

Because our stove was inductive, we could not use a typical low-amperage panel for critical loads. Ultimately, we decided to manually select which circuits to use during a blackout.

3

Battery Management
Energy Is Significant

We discovered that our Battery Management System had higher standby loads than expected, so we changed our logic to put the batteries to sleep on most nights.

4

The Grid Is Stressed at Inconvenient Times

We responded to periods of grid stress by discharging the vehicle. Unfortunately, those events typically happened just before- or just after the occupants returned home.

5

Predicting Grid Carbon Intensity

Optimizing charge times for low-carbon grid power was more accurate using a simple time, instead of our complicated web scrapes and carbon calculation forecasts.

6

DC Efficiency

Our HEMS strategy would have been simpler with an AC system since our DC/DC conversions in the microgrid weren’t as efficient as we originally planned.

1

Manual Not
Automatic

One of the early design decisions was to use a manual transfer switch (for backup power during a blackout) because an automatic transfer switch had too much standby energy consumption.

2

Critical Load May
Not Pass Through

Because our stove was inductive, we could not use a typical low-amperage panel for critical loads. Ultimately, we decided to manually select which circuits to use during a blackout.

3

Battery Management
Energy Is Significant

We discovered that our Battery Management System had higher standby loads than expected, so we changed our logic to put the batteries to sleep on most nights.

4

The Grid Is Stressed at Inconvenient Times

We responded to periods of grid stress by discharging the vehicle. Unfortunately, those events typically happened just before- or just after the occupants returned home.

5

Predicting Grid Carbon Intensity

Optimizing charge times for low-carbon grid power was more accurate using a simple time, instead of our complicated web scrapes and carbon calculation forecasts.

6

DC Efficiency

Our HEMS strategy would have been simpler with an AC system since our DC/DC conversions in the microgrid weren’t as efficient as we originally planned.

Technical Resources

The Smart Home project was about generating insights for others to build upon. As you develop your next home, please use any of our specs, drawings and data to help create a more sustainable future.

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Performance Data

Download All Data (1.37GB zip file)

 

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Related Videos

Honda’s Experimental Home Energy Management System (HEMS)

Hear about the overall energy strategy and how the system worked.

Honda Home Energy Management System (HEMS) Technical Animation

Watch how AC and DC power are managed in different situations.

Addressing Solar Intermittency with a Home Energy Management System (HEMS)

Learn about the electric grid and the potential impacts of EVs and solar power.

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Take a tour of what made the Smart Home “Smart”

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