The US patent application describes this vehicle as "a two-rear-wheel electric vehicle configured to lean a vehicle body frame thereof when turning." It's not clear exactly how much power its electric motors would produce, but the design appears to be quite similar to the Yamaha EC-03 electric scooter that's already available in Europe, according to Visor Down. That little cycle uses an electric motor with 1.88 horsepower and 7.08 pound-feet of torque to power its single, rear wheel, but it weighs just 123.5 pounds.
According to the document from the US Patent and Trademark Office, Yamaha seems to have been working on this concept for a little while. The application says that it first filed for patents on this idea years ago. However, the US only received the documents recently, and they were published in late August. That might indicate that the company is serious about bringing this electric trike to market here. If you really want all of the details about Yamaha's patent, it can be viewed as a PDF, here.