We’ve got some interesting ideas coming out of California’s utilities, including one aimed at converting San Diego apartment buildings into big smart-grid surrogates.

At this week’s Smart Energy International conference in San Francisco, San Diego Gas & Electric’s smart grid chief Lee Krevat dropped the news that his utility had placed a big order for smart appliances to put in new apartment buildings, with plans to start plugging them in next year.

I caught up with him afterwards and got some more details. General Electric is the key partner, and plans to supply its Nucleus home energy manager to property owners interested in installing some smart appliances -- smart thermostats, smart refrigerators and other such controllable loads -- in their newly built rental units, he said.

The idea is to make thermostats, fridges and other household power loads available for programs like automated demand response, or to make them responsive to the critical peak pricing SDG&E wants to start implementing for residential customers next year, Krevat said. While he wouldn’t say whose smart appliances would be going into the buildings, GE does make appliances that would fit the bill.

So far, SDG&E has about 120 rental units lined up for the pilot, which will run over SDG&E’s smart meter network. The project itself is part of the “Smart City San Diego” collaborative, which so far has emphasized microgrid and plug-in vehicle charging pilots.

GE has done pilots of its smart appliances in homes, but apartments offer different challenges. One obvious problem is that most apartments have their meters in the basement or outside the building itself. Smart meters equipped with low-power ZigBee radios aren’t going to be able to reach every apartment through all those floors and walls.

Krevat didn’t get into details on how the project might surmount such barriers, but options might include beefing up the wireless signal, using powerline carrier technologies to communicate via apartment wiring, or exploiting existing broadband connectivity. Apartment buildings are a big and tempting target for energy management, since they aggregate so many power users in one place, so finding a way to hook them up reliably to the smart grid could yield outsize benefits. This isn’t the first project to tackle multifamily housing. South Korea is a hotbed for apartment-smart grid linkages, with players like GE, IBM and Cisco working alongside Korean giants such as Samsung and LG.

In other news, Krevat also laid out more details on how California’s big three investor-owned utilities will work on a challenge from U.S. CTO Aneesh Chopra. Chopra wants utilities to devise a “green button” system that allows their customers to download and share their personal energy data in a standardized way, whether with one another (on Facebook, perhaps) or with third-party energy service providers.

Earlier this month, SDG&E, Southern California Edison and Pacific Gas & Electric agreed to try to deliver energy data to their customers by the end of 2011 using a common format based on a developing standard called Open Automated Data Exchange (OpenADE). The particular standard for that common format, known as Energy Services Provider Interface (ESPI), was just finalized in a 1.0 version earlier this month. The federal government wants to make it a national smart grid standard, and Chopra wants it to spread to utilities around the country.

California’s big three utilities are under more pressure than most to make good on that promise, since the California Public Utilities Commission is demanding that all three start sharing energy data with their customers as soon as possible.

Krevat noted that three months is a challenging timeframe for the project. Although all three utilities deliver some energy data to some customers, they do it in different ways, and only PG&E currently delivers data to all its smart metered customers via website. SDG&E, for one, has had to transition customers who were using Google’s PowerMeter platform to the utility’s own web platform, after Google pulled the plug on its nonprofit home energy sharing project.