The CHAdeMO fast charging protocol is an interesting beast. Developed by the Tokyo Electric Power Company (TEPCO) along with Toyota, Nissan, Mitsubishi and Fuji Heavy Industries (Subaru), CHAdeMO is a DC fast-charging protocol for electric vehicles. What's unusual is that any company can use CHAdeMO without paying royalties or any other fees to the developers. Hiroaki Takatsu, TEPCO's executive director, spoke about the technology at the 2010 Driving Sustainability conference in Reykjavík, Iceland this weekend.
By TEPCO's calculations, a standard gasoline-powered vehicle emits 120.8 grams per kilometer. By comparison, an electric car can emit just 33 grams. This is a number TEPCO wants to support, and Takatsu said that, "standardization of charging infrastructure is essential for EV dissemination."

Aside from being one possible fast-charging standard, CHAdeMO is also quite safe. Takatsu said that some say CHAdeMO is even overdesigned for safety. The fast-charging has no impact on battery life, he said, because the CHAdeMO protocol only controls the charging process. The electric vehicle decides the optimal charging current based on its battery condition.

Takatsu wanted to make it very clear that, while CHAdeMO was formed in Japan, it had very little help from the government there and currently has many European and North American partners. It is truly a private – not public – effort, he said. The developers created the product they wanted and found a balance between the benefits of AC slow charging (low cost) and DC fast charging (speed).

So far, TEPCO's private tests have shown that CHAdeMO makes electric mobility a very easy pill to swallow. Before a quick charger was installed at TEPCO in October 2007, the monthly mileage of the company's electric test vehicle was 203 km. Afterwards, it was 1,472 km. Drivers also returned the car after each trip with a much higher state-of-charge (like 80 or 90 percent) than they did before the charger was available. Fear kept them from using the vehicle's full potential, and, "Even a small number of quick chargers relieve drivers' range anxiety," Takatsu said.

Since CHAdeMO is an open standard, TEPCO only gets money from it when the technology is used in the Tokyo metropolitan area. The good news for TEPCO there is that there are 153 chargers in TEPCO's area and 254 total in Japan. By 2020, there should be 5,000 chargers installed throughout the country. How will CHAdeMO fare in the rest of the world? We'll have to keep watching to find out.


Our travel and lodging for this coverage were provided by the event organizers.

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