Solar power, large-scale energy storage, all linked together by a smart grid architecture that keeps power flowing and balanced. Duke Energy (NYSE: DUK) wants to do it all – and it's brought on Integral Analytics to help make it all work.

The Cincinnati-based startup is working with the utility on its McAlpine Creek project, a "virtual power plant" made up of grid electricity, renewable energy, a big battery and the very homes of its customers.

First off is the 50-kilowatt solar array Duke has installed at its McAlpine substation in south Charlotte. That can feed into the grid or power up a 500-kilowatt zinc bromide battery that Duke hopes to install in the coming weeks (for more on zinc bromide, click here).

Then there are about 100 households, picked from among the 8,300 in the area that have received smart meters from the utility, that will participate in a test of a residential energy management system.

The idea is to hook up air conditioners, heat pumps, water heaters, dryers and other appliances via wireless networks so they can be powered down or turned off to save energy and help the utility curb peak power demands (see The Smart Home, Part I).

Integral Analytics is tasked with getting all those things to work together, said Michael Ozog, vice president of economic valuation. Integral makes software that "can choreograph appliance demand across all these customers," he said.

"By doing that, we can reduce total peak demand that the utility sees without actually curtailing demand," he said. That is, it can get a lot of appliances and air conditioners and the like to respond to commands to turn their power use up or down slightly without a noticeable effect on the part of the homeowner.

Fine-tuning like this is made possible with the in-home devices feeding data to the utility, as well as sensors at the substation level. Working from those ends, Integral can do things like figure out which distribution feeder lines and transformers are under the most strain and turn down power demand from homes fed from them.

At the same time, it can also take into account homeowner preferences for how they'd like their energy managed, he said. For example, it can determine which customers said they're OK with having their air conditioners turned off versus those who want to keep them on, he said.

That's a complicated task even when one is only dealing with relatively stable grid power, Ozog said. Adding solar panels that can see power output sag and soar depending on cloud cover overhead only adds to the challenge, he said.

It's a similar challenge facing utilities across the country as they seek to incorporate growing amounts of intermittent renewable power into their transmission and distribution grids.

GridPoint is another software developer working on integrating these various parts of the smart grid, and is working with utility Xcel Energy on its $100 million SmartGridCity pilot project (see GridPoint Beefs Up Software, Lands New Marketing Deal).

Fort Collins, Colo.-based Spirae is doing similar integration work for the Department of Energy-funded FortZED project and another with Danish transmission system operator

As CEO Sunil Cherian explained earlier this month, integrating energy storage devices to help with grid stability operations like frequency regulation – keeping the grid humming at a steady 60 hertz, or cycles per second – is a tricky proposition.

That's because the microsecond lag times required to do that means that storage devices have to be embedded with the distributed intelligence to get them to interact with one another in a way that doesn't worsen the problem they were meant to alleviate (see Green Light post).

Ozog said that the Duke McAlpine project is currently getting data in one-minute intervals, but that such finer-tuned uses of its software could apply to future projects.

Integral Analytics started working with Duke when it did a 30-person smart meter pilot in Cincinnati last year, Ozog said. While it doesn't have any other utility projects at present, it is speaking with California utility Pacific Gas & Electric and others, he said.

Working with Integral Analytics is Aleri, a Chicago-based company that makes technology to analyze large amounts of data in real time.

As for who is providing the wireless networking for the McAlpine pilot, Greentech Media identified Sequentric Energy Systems as the company last week, though neither it nor Duke would confirm that fact.

The North Carolina-based company uses a proprietary wireless network to link appliances and home circuits to a gateway that communicates with the utility via broadband connections (see Sequentric Working on Duke Pilot Project).