The combination of battery-based energy storage and solar power already has some electric utilities worried.
They believe consumers' ability to store energy harvested by home solar arrays for later use could be a threat to their business model.
Given that, they're probably not going to like this latest development in energy-storage economics.
DON'T MISS: Innovative Arizona Utility Program Rents Your Roof For Solar Power (Oct 2015)
Consumers with home solar power can already use reverse metering to sell excess power back to utilities.
But the ability to store energy in battery packs may also allow them to sell that power to third parties, through a process called "energy trading."
In theory, this could allow consumers to sell electricity directly to each other, and leave utilities out of the loop. One company is already taking a step in that direction.
Used Chevrolet Volt batteries for energy storage at GM facility in Milford, Michigan
This setup links homeowners' solar panels and energy-storage battery packs with management software, which monitors real-time usage patterns and weather conditions.
The ultimate goal is to create a network that supports "peer-to-peer" sales of electricity.
ALSO SEE: As Solar Power Spreads, Diverse Users Fight Utility Attempts To Penalize It (Mar 2015)
Sonnenbatterie isn't alone in pushing the concept of energy trading.
In The Netherlands, the Vandebron platform--which already has over 38,000 subscribers--lets consumers contract with a provider, who sets their own price.
The U.K. also has a similar scheme for commercial customers called Open Utility.
BMW DesignworksUSA solar carport
If energy-trading schemes like these succeed, they could represent another evolutionary stage of distributed renewable energy.
Home energy storage allows users to rely less on power bought from utilities, by letting them keep more of the energy from their solar arrays.
But if consumers could also buy electricity from other consumers, that would lessen they need for utilities even more.
Photovoltaic solar power field at Volkswagen plant in Chattanooga, Tennessee
Of course, the Germany company's scheme still relies on existing infrastructure to transmit power between users.
So while energy-trading may aim to make utilities obsolete, it still doesn't posit a way to replace their grids, it seems.