Looking ahead, we've received intelligence from various sources in China, including indications from several of our customers, that wind farm installations both on and offshore can be expected to return to a more normal level within the next couple of quarters.
The current level was predicted last year by the consulting firm we engaged to assess business conditions and the direction of government policy in China, particularly as they relate to the wind and the bus markets. What we're hearing now is that issues relating to wind farm siting and permitting abuses have been addressed and technical fixes mandated to solve low voltage ride through problems have been implemented, clearing the way for return to more normal activity.
The new Chinese five-year plan sets forth aggressive targets for wind farm installations to help to satisfy China's ever growing appetite for electrical energy and Chinese wind turbine OEMs are now marketing their systems globally. So we've got a good reason to anticipate a significant upturn later in the year.
Turning to public transit vehicles, energy storage systems for recuperative braking and torque assist in fuel efficient, low emission hybrid electric transit buses were the primary drivers of ultracapacitor sales growth in Q4.Last fall, we announced a new supply agreement with Yutong, China's largest bus producer. Voith Turbo, a leading European heavy vehicle drive system integrator announced that it is introducing a Maxwell ultracapacitor-based hybrid system for buses in the North American market where we've had limited sales in the past. Obviously, this never keeps growing, but we now estimate that there are about 5,000 hybrid buses that are powered by Maxwell ultracapacitors in daily service around the world. According to our consultants, all of the 25 Chinese cities that are eligible for government subsidies for purchases of hybrid and electric transit vehicles are running behind their new energy vehicle deployment schedules. So we're seeing bus OEMs and drive system integrators continue to gear up to deliver more hybrid vehicles. Read the rest of this transcript for free on seekingalpha.com