Smart grid wireless communications and software player SmartSynch has raised $25.6 million out of a planned $33.4 million round.

The world is expected to see $200 billion in smart grid investment by 2015. Startups like SmartSynch and major companies like Cisco and IBM are all looking to gain a foothold in growing smart grid markets like China, as well as government and utility-funded projects in the U.S. One aspect of the smart grid is enabling two-way, secure communication between smart meters and the utility, which allow users to track their energy usage and potentially save money with applications like time-of-use pricing.

SmartSynch has long championed using cellular networks for smart grid communications between the home meter and utility. The company has partnerships with the likes of AT&T, Qualcomm and Sprint, and recently introduced a new 3G communications platform. Other players opt to use proprietary networks or WiMax.

Cellular carriers, too, are moving aggressively to capture smart grid-enabled opportunities like home energy management.  AT&T and Motorola both made acquisitions last year that position them for moves into home energy markets.

SmartSynch isn’t alone in looking towards partnerships with cellular companies, though. Last year, Grid Net partnered with Sprint for a 4G offering, and AT&T also ironed out a wireless smart grid offering last year with smart meter company Elster.

Last month, SmartSynch debuted a plan for pay-as-you-go electricity, enabled by smart meters. The company raised $12 million in a third round of financing back in 2005. Its investors include Battelle Ventures, JPMorgan Partners, Siemens Venture Capital, Kinetic Ventures, Nth Power, Endeavor Capital, OPG Ventures, Lime Rock Partners, Cinergy Ventures and GulfSouth Capital.