Cleantech Market Intelligence
In Korea, Wireless Charging Takes the Bus
Wireless charging is a technology that attracts more public attention than its actual use would seem to warrant. This week saw breathless reports that the Droid 5 might include wireless charging capability and GM plans to put a wireless charging mat into its 2014 models for mobile devices. In the electric vehicle (EV) market, Bosch introduced the first aftermarket wireless charger for EVs in the United States during July, the Plugless charging system.
In some ways, EV wireless charging seems superfluous. We already have good charging technology: the plug and cord. It works, it’s safe, it’s easy to use, and it’s affordable. It seems counterintuitive to replace that with more expensive technology when you’ve got a market already limited by high prices for the cars themselves – unless that extra cost gives you some significantly higher utility. As we have discussed earlier, developers argue that wireless charging can be a market enabler for EVs – by upending the range versus charging time dilemma. EVs would be charged frequently, throughout the day, allowing OEMs to downsize the battery without sacrificing performance. Once the initial investment in wireless capability has been made, adding new charge pads would be cheaper than adding more charging boxes. But, as noted in the Navigant Research report Wireless Charging Systems for Electric Vehicles, it will likely take many years for the plug-in EV (PEV) market to make this shift.
A new demonstration project in Korea presents another angle in the wireless charging argument. The Korea Advanced Institute of Science and Technology (KAIST) is running two electric buses equipped for wireless charging … while operating. KAIST engineers built a 7.5-mile charging mat on a 15-mile transit route at a cost of $4 million. The two buses reportedly have batteries that are just one-third the size of a regular electric car battery.
In this case, the argument is that wireless charging can extend the effective range of battery buses while lowering the cost of the buses, since they use smaller batteries. Range and cost are serious limitations for battery buses, more so than in the passenger car market. As forecast in Navigant Research’s report, Electric Drive Buses, battery buses will constitute well under 1% of transit bus sales for the next several years, with sales in the thousands from 2014 on. Key reasons for this are the higher price, lower passenger capacity, and reduced range, all of which limit the utility of battery buses for transit operators.
In effect, the KAIST wireless system would be like having a light rail or trolley line, only without the overhead lines that many consider an eyesore. The drawback is that the wireless charging equipped bus is tied to an exact route. The transit operator loses the flexibility that a battery bus can provide, compared to a trolley or light rail system. For the near term, the best application may be on well-established transit routes that are not likely to shift over time – for example, routes in urban centers where cities want to reduce emissions and noise, such as downtown malls. The technology may eventually be incorporated in the planning process for new roadways, allowing widespread deployment of the wireless charging that would give transit operators more flexibility in designing routes. But this seems a long way off. In the meantime, KAIST says it will add 10 more buses to the route in 2015, if this first trial is a success.