Pink Fluffy Unicorns Ask Away Friday: DC or not DC?

By popular request, I hereby launch “Pink Fluffy Unicorns Ask Away Friday”!

Just ask me a question on a subject that has to do with electronics development, and you will read the answer on Monday. A question that’s asked a lot lately is: “Will the rise of electric vehicles and home batteries like Tesla’s Powerwall push us to DC in the home?”

The capacity of vehicle and home batteries has indeed come up to the point where it is feasible to power your home with it. The step to DC in the home (or “DC microgrid”) is obvious, since DC/AC conversion at the battery and AC/DC conversion in the appliance is less efficient compared to just DC/DC conversion in the appliance. Still, I think that DC in the home is very far away, I even doubt if it will ever happen.

The economic incentive for the Dutch consumers is aimed at buying solar panels. They can receive a VAT discount and the generated energy is the same rate as the consumed energy. Only when there would be a lower tariff for generated energy, an incentive arises for consumers to store their energy in a battery.

The growing number of solar panels ultimately poses a problem to electricity distribution companies due to peak energy generation. Only at that moment will the consumers be stimulated to store their energy themselves.

Though there is research being done to a good standard for DC in th home, there is no standard yet. Would there be a standard, it would have to be internationally supported. Until that time, appliance manufacturers will not begin to support DC supply of their appliances.

The payback period for DC in the home is currently long, around 40 years. The home battery accounts for around 75% of this period, the modification of the home installation to DC the rest.

When the application of home batteries becomes more common, the DC/AC converters will also become more efficient and cheaper. This further reduces the business case for DC in the home.

Conclusions

There is currently no economic incentive to buy a home battery in the Netherlands.

The benefits of DC in the home do not compensate the required investments by consumers and the electronics industry.

The benefits of DC in the home will erode by more efficient inverters once home batteries have become commonplace.

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