Batteries

Published on March 3rd, 2017 | by Steve Hanley

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Tesla May Drop DC Powerwall 2 Option In Most Markets

March 3rd, 2017 by  

According to Ronald Brakels, a longtime CleanTechnica reader and blogger in Adelaide, Australia, the DC version of the Tesla Powerwall 2 will not be offered Down Under. Only the AC version with a built-in inverter will be available and even that will not be offered until sometime later this year, possibly in June.

Tesla Powerwall 2

Brakels reached out to Tesla for a comment and got this reply from an unnamed person at the company who he refers to as Secret Sauce. (Those Aussies have a wicked sense of humor.)

“Tesla is committed to the development of industry-leading technology and ensuring we always provide our customers with the best products possible. The AC Powerwall includes a Tesla built-in inverter, offering customers the greatest value, flexibility, and ease of installation, regardless of whether they’re pairing Powerwall with new solar, retrofitting, or using the Powerwall for backup. As a result, we will no longer be offering the DC Powerwall, which was the same price and size of the AC Powerwall but did not include an inverter.

“When Tesla originally launched Powerwall 2, we announced we would offer an AC Powerwall and a DC Powerwall. Both variants cost $8,000 and are identical in size. The only difference is that the AC Powerwall included a built-in inverter, offering customers the greatest flexibility for retrofits, standalone, back-up, or new solar without the need for an external, compatible inverter. The DC Powerwall would only be used for customers who already had an existing compatible inverter and therefore didn’t need an integrated inverter.”

Our curiosity aroused, we contacted Tesla ourselves and were told much the same thing, also by a person who told us the information was on background and not attributable to any one person at the company. Apparently, the AC version of the Powerwall 2 will be offered in Australia, Asia, and Europe. The AC and the DC versions will be offered in the North American market, apparently — although, that information does not appear to be written in stone.

What’s the big deal? Solar panels generate direct current. The electrical grid runs on alternating current for reasons that date back to the days when Thomas Edison and George Westinghouse were still inventing how electricity would be harnessed to power the world.

Edison was a proponent of DC because at the time there were no AC electric motors. Edison envisioned zero-emissions subways running deep underground, which meant DC motors were the only choice. But DC requires thicker, heavier cables to move electricity over long distances. Under Edison’s plan, generating plants needed to be in the middle of the cities they served.

Westinghouse favored AC because it could be sent over longer distances using thinner wires. Ultimately, Edison won the subway battle but Westinghouse won the distribution war and AC became the standard for electrical grids everywhere.

Now more than a century later, the echoes of those early battles between the two pioneers are still reverberating. Solar systems make DC. Homes run on AC. Inverters are what convert one to the other and back again. Unfortunately, no inverter is 100% efficient, so a tiny bit of electricity is lost every time the conversion is made.

That’s what has modern-day DC fans upset. If DC is coming down from the rooftop solar system and is being converted first to AC for use in the home, and then back to DC to be stored in a battery, and then back to AC later when the stored electricity is used to power the house after the sun goes down, that adds up to a lot of conversions and a lot of tiny losses that soon add up to some pretty significant losses.

The beauty of having both versions of the Powerwall 2 available was that electrical engineers were free to design different systems with different performance characteristics depending on the needs of the individual customer. Now that flexibility will not be available (in Australia, Asia, and Europe), at least not using Tesla equipment.

Our unnamed source at Tesla essentially confirmed everything Brakels’s source (sauce?) told him, except they used the US price for the system, which is $5,000 USD. Essentially, we were told that a battery and an inverter for that price was better than just a battery alone, so the company has decided to focus solely on the AC system.

At US$5,000, the company feels the AC version with built-in inverter is an excellent value for customers who live in the US, but the Australian dollar is only worth 70% of the US dollar.

We were not able to confirm the June release date. Will let you know if I hear more on this topic.

Note: This article has been modified slightly since publishing to provide greater clarity.

Source: Solar Quotes


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About the Author

writes about the interface between technology and sustainability from his home in Rhode Island. You can follow him on Google + and on Twitter.



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