AutoGrid Systems, the startup that’s brought its grid data analytics chops to partnerships with U.S. utilities and Japanese building energy projects, has now landed a strategic investor with deep roots in Europe’s energy markets.

That’s German utility E.ON, which on Wednesday joined other strategic investors from the utility sector in a $12.75 million round C in the Silicon Valley startup. The money will go toward growing AutoGrid’s sales force, expanding its international presence and building new applications for its Energy Data Platform software, CEO Amit Narayan said -- including some as-yet-unnamed work underway with its new investor.

“With E.ON, we are already working on several projects,” Narayan told me in an interview last week, though he declined to give more specifics. But as a pan-European energy giant with business ranging from renewable and traditional generation to retail business in the continent’s deregulated markets, E.ON has plenty of venues in which to put real-time, cloud-based analytics capabilities to use, he said.

Those could include energy theft detection in E.ON’s Eastern European markets, demand response and customer acquisition and retention for its retail business units, and help in integrating its considerable wind power assets into Europe’s renewables-strained energy markets, he said.

E.ON, like many other European utilities, is also facing an existential threat to its traditional business models, as increasing amounts of renewable power and distributed generation continue to undercut its central fossil-fuel-fired power plants, eating into revenues. The Dusseldorf-based utility has been investing quite a bit into startups with technology to help merge the demand and supply sides of its energy business, including FirstFuel’s remote building analytics software and Bloom Energy’s fuel cells.

E.ON is also partnering with a set of demand response and energy management technology providers, ranging from large-scale commercial and industrial demand response with German startup Entelios, to home automation and energy management services with U.S. startup GreenWave Reality. It would be reasonable to expect that some of E.ON’s early work with AutoGrid will be in this area as well, given that its first commercially available application is focused on demand response.

AutoGrid’s Demand Response Optimization and Management System (DROMS) has been deployed by U.S. utilities including Palo Alto’s municipal utility, Sacramento Municipal Utility District (SMUD), Oklahoma Gas & Electric, and Austin Energy. In December, AutoGrid partnered with Texas-based Big Data Energy Services (BDES), which provides cloud-based services to retail energy providers, to develop demand response and energy management tools for Texas’ deregulated energy market.

AutoGrid’s platform is also being put to use by a growing list of smart grid vendors, including Silver Spring Networks for its UtilityIQ Demand Optimizer platform, and by grid giant Schneider Electric for its Wiser line of home energy management products. In Japan, IT giant NTT Data is developing new applications with AutoGrid’s via a joint R&D agreement.

There’s plenty of competition on the big-data-for-utilities front, of course, whether from rival startups like C3 Energy, Trove, Opower and Verdeeco, grid giants including General Electric, Siemens/eMeter and ABB/Ventyx, or IT giants like Oracle, IBM, SAS, Teradata, EMC and SAP. Where AutoGrid differentiates itself, Narayan said, is in combining a whole set of big data tools and methods with what he described as an in-depth expertise in modeling the physics of grid operations via high-performance computing.

Looking at demand response, AutoGrid’s ambitions are to calculate the complex interactions of grid power flows with analysis of how lots of customers react to demand response and energy pricing programs, both to manage real-time operations and to fine-tune utility approaches over time. That can be particularly important for deregulated markets, where retail energy providers have a lot more freedom in what kinds of different products and incentives they offer individual customers.

“We do have models for every customer, and based on the messaging and incentive, how much load they’re expected to drop,” he said. “That’s why deregulation, and deregulated markets, are important for us to target. Working with E.ON, we have an opportunity to move into one of the largest markets.”

Wednesday’s announced investment brings AutoGrid’s total funding to date to more than $25 million, including a $9 million Series B round in 2012 from investors Foundation Capital, Voyager Capital and Stanford University, a $2.87 million grant from the Department of Energy’s ARPA-E program, and a $1.2 million grant from the California Energy Commission.