special wireless charging pads. Sweden is studying four different dynamic charging technologies that allow buses and other vehicles to charge while driving on roads and highways. The four tested technologies are overhead wires, in-road rail, on-road rail, and in-road inductive coils. The first solar powered microgrid for charging electric buses in the US is under construction in Montgomery County, MD, and scheduled for completion in fall of 2022. Capacitors Buses can use capacitors instead of batteries to store their energy. Ultracapacitors can only store about 5 percent of the energy that lithium-ion batteries hold for the same weight, limiting them to a short distance per charge. However ultracapacitors can charge and discharge much more rapidly than conventional batteries. In vehicles that have to stop frequently and predictably as part of normal operation, energy storage based exclusively on ultracapacitors can be a solution. China is experimenting with a new form of electric bus, known as Capabus, which runs without continuous overhead lines by using power stored in large on-board electric double-layer capacitors, which are quickly recharged whenever the vehicle stops at any bus stop (under so-called electric umbrellas), and fully charged in the terminus. A few prototypes were being tested in Shanghai in early 2005. In 2006, two commercial bus routes began to use electric double-layer capacitor buses; one of them is route 11 in Shanghai. In 2009, Sinautec Automobile Technologies, based in Arlington, VA, and its Chinese partner, Shanghai Aowei Technology Development Company are testing with 17 forty-one seat Ultracap Buses serving the Greater Shanghai area since 2006 without any major technical problems. Another 60 buses will be delivered early next year with ultracapacitors that supply 10 watt-hours per kilogram. The buses have very predictable routes and need to stop regularly, every , allowing opportunities for quick recharging. The trick is to turn some bus stops along the route into charging stations. At these stations, a collector on the top of the bus rises and touches an overhead charging line. Within a couple of minutes, the ultracapacitor banks stored under the bus seats are fully charged. The buses can also capture energy from braking, and the company says that recharging stations can be equipped with solar panels. A third generation of the product, will give of range per charge or better. Such a bus was delivered by Chariot Motors in Sofia, Bulgaria in May 2014 for 9 months' test. It