Can water heaters store energy captured by wind turbines and solar panels? A startup called GridMobility thinks so.

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Is the answer to helping integrate solar and wind into the power grid the humble home hot water heater? That’s one of the things that startup GridMobility is looking to find out, and the company has built software and connected hardware to enable utilities to use hot water heaters (and other energy consuming appliances) as on-demand grid storage in conjunction with local clean power when it’s available.

The problem with wind and solar is that they’re variable power sources, so they only work when the sun shines and the wind blows. Adding more energy storage technology — like batteries — to the grid could help with this problem, but many batteries are too expensive to produce at a grid scale right now. As a result, some startups, like GridMobility, Clean Urban Energy and EcoFactor, are developing new ways to use IT to manage HVAC systems, buildings and water heaters as sort of thermal batteries.

GridMobility chose hot water heaters as a main target for its technology because hot water heaters can be turned up and down slightly — commonly between 135 amps and 120 amps — and consumers generally tend not to notice the change all that much, explained James Holbery, President of GridMobility. Hot water heaters are also pretty ubiquitous in homes and buildings, so they offer a massive opportunity; the company is shooting to one day integrate hundreds of megawatts, or even a gigawatt, of clean power which would otherwise be shed or compromised.

Holberry calls that act of storing thermal energy in a fluid medium the low hanging fruit of energy storage for the power grid. Think of the water heater as having a similar type of grid storage capacity as having a Nissan LEAF in the driveway, says Holberry.

The GridMobility system works like this: the company installs a connected box next to a traditional hot water heater, which wirelessly connects the heater back to the utility and enables control of the device’s power consumption. The startup’s algorithms then can turn up and down water heaters to consume energy when clean power is available.

For example, in a 100-home pilot project with the power agency the Bonneville Power Administration (BPA), GridMobility linked home water heaters with nearby wind farms. When the wind blows strongly the hot water heaters can consume the excess clean power capacity, and when there is no clean power available they can switch down into the conservation mode.

The innovation is really in the software system, and the company’s algorithms can also intelligently control other connected building devices. Holberry says the next-generation of water heater tech will be connected — like GE’s smart water heater — and in that future GridMobility will supply the software and services while other hardware makers supply the connected heaters.

For a company that has been working on this tech for just three years, GridMobility has some sizable power partners. Beyond BPA, GridMobility is also working with Mason County PUD and transmission agency PJM. In addition, Holberry tells me that the company is working with electric car makers and plans to announce a pilot program in Texas soon, and is working on a smart grid project in the Bay Area, too.

To date, GridMobility is self-funded, but joined this year’s Cleantech Open competition, and is looking to raising funding shortly.

http://www.reuters.com/article/2011/07/24/idUS81078628820110724