Car Power – Used for the House?


One of the problems with an electric car is the cost of building up the right amount of power. With home electricity sky-rocketing people might wish they could run their house off the car’s battery in a pinch, but that cannot be done just yet.

For a second let’s suspend the fact that you buy your car so you can drive it, not run the battery dead powering your house.

When power is shut down, nothing in the house will work. And there are hundred reasons for a power outage: wild fires, seasonal winds and so on. So there is a market for alternatives.

The technical name for such power is a bi-directional battery, one that works with two objectives in mind. It gives the customer more choice, but it does ramp the prices up.

There is enough electricity in a car to power a house but getting it out is the problem. The difficulty is that houses are so plugged into the grid that it becomes the default setting; creating any generator that would power the house outside the main system would present a difficulty.

The power company would treat a power line as a cut, even if the house is simply switched over to battery for a time, and someone would try and repair it. It seems overzealous but the reality is that generators are set to kick in when the grid is down, so the houses aren’t built to toggle back and forth from grid to local generation.

There’s a problem with the current too. The battery is DC powered and the grid is AC powered, so you need a way to convert this (also known as inverting this). Some nerd needs to come up with a way for a car to discharge its power to act as a battery back up to a house in an emergency.

In recent years we’ve seen people go to their car to charge their cell phones when the grid is down. Why isn’t this possible on a slightly larger scale? Why couldn’t your hybrid act as a whole house generator?

There’s an access conflict too. Only a certain number of people can access the electricity grid and any new rules need to be regulated fairly. There are laws on the books that say if your home generation system, think solar panels on the roof, generate more power than your home is using, that the local PUD must buy the excess from you. So it’s possible to sell back power.

So for emergencies it might be a nice option and there are number of players who are looking at the concept. The people at Nissan are looking at developing a project in Copenhagen and there is an office in Chile actually pulling power from a car to conduct business. It’s just doing it on a large scale which is the headache.

Enter the experimental Den Do Drive House by Mitsubishi. The company’s goal is to create a more efficient electric ecosystem, where power can be generated locally when possible and off grid when not, then stored in a house battery or the cars battery as needed. So there would be times when the car would be feeding power back to the house to avoid buying grid power. Why? Well the grid gets its energy from a number of different sources. Some more cost effective and some which are deemed “renewable.” The cost per KW hour varies because power is sourced in response to demand.

The local power company currently negotiates rate in bulk and then resells the power to users at a consistent price, but in the bulk market electricity is bought and sold based on demand and availability. In the past, availability was steady from sources like nuclear power or coal plants, and seasonal from dams. However, wind power varies continuously and unpredictably. The thing most users don’t understand is that there is no giant battery out there storing up wind energy for the times the wind isn’t blowing. Why not? Because the laws of physics prevent such a device from working.

Enter the Mitsubishi Dendo Drive House. If entire developments were to each have local generation and local storage of power, its possible for rate payers to share in the hourly rate swing of power costs and using their smart home, sort of game the system to minimize their liability. It would pay for itself over a number of decades. It just isn’t a short term solution to cheaper electricity bills. The installation of the house will all be done by Mitsubishi and is cost inhibitive unless some sort of government grant enters the scene.

So the while the Dendo Drive house may be a long-shot, only practical in a true energy crisis, a bidirectional switch with local house battery storage could come in handy when the grid goes down. It could let your keep the lights on in your home for a few hours…until your gas tank runs dry.



Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.