Usually GreenBiz's coverage of Johnson Controls Inc. focuses on its work on energy efficiency in buildings, and lately so has our coverage of General Electric.

However, developments in other lines of business for the companies also hold promise for sustainability by offering energy efficient and emissions-busting power solutions.

Johnson Controls plans to build a $100-million factory in China for making stop-start batteries for high-efficiency cars. The investment detailed yesterday by JCI, which dominates the auto battery market, is part of the firm's $520-million global commitment to the technology over the next four years. That commitment includes a nearly $140-million project to retool a factory in Ohio (announced in July) and a $280-million investment to boost manufacturing capacity in Germany.

Also yesterday, GE took the wraps off the latest addition to its portfolio of aeroderivative gas engines: a turbine called the FlexAero that runs on natural gas and doesn't need water to cool it or reduce emissions. GE's aeroderivative turbines, developed from their aviation engines, run on natural gas or biofuels and represent a burgeoning business for the firm. The company's orders for aeroderivative and heavy duty gas turbines amount to $1 billion so far this year in North America.

In a sense, the stop-start batteries and the new engine offer complementary solutions with the batteries serving a growing market in the developed world and the turbine providing an energy solution for the developing world.

Stop-Start Batteries

Stop-start technology switches off a car's engine when the vehicle is stopped and idling, say at a red light or in a traffic jam. A stop-start battery powers the auto's lights, radio and electrical systems in the meantime and makes it possible for the engine to restart when it's time to resume driving. Johnson Controls says its stop-start batteries can make that happen in a fraction of a second.

Stop-start cars, also called micro-hybrids and idle-stop vehicles, currently are most popular in Europe, where two dozen models are available, and so far have a small following in the U.S., where three models can be found, according to Pike Research. Pike expects the worldwide market will take off in a few years, rising from 3 million stop-start cars on the roads today to more than 37 million by 2020.

The advantages include lower emissions and better fuel economy -- a 5 to 10 percent improvement in both according to Pike, and as high as 12 percent, Johnson Controls says of its product. Pike points out that the stop-start vehicles are also easier on the wallet than hybrid electric vehicles. Globally, SSVs are expected to outsell HEVs 3.5 to 1 this year, says Pike, which predicts that ratio to climb to 16 to 1 by 2017.

Johnson Controls is looking to build on its stronghold in the industry. Through its VARTA brand, JCI is the leading supplier of stop-start batteries in Europe and produces 11 million of the batteries a year in its factories in Germany. Its plant conversion project in the U.S. is expected to add 6.8 million units of capacity and the new factory in China, slated to start production in 2013, is expected to have a capacity of 2.4 million stop-start batteries a year.

Next Page: A look at the FlexAero turbine.