Colorado Lab Tests 'Smart Home,' Where Dishwashers Talk To The Grid

Nov 19, 2014

Bryan Hannegan is picturing the home of the future. In his imagination, it's not in outer space, or shaped like a giant geodesic dome. This home talks to itself, and to what's around it.

"The dishwasher could talk to the electric vehicle in the garage, it could talk to the solar PV system on the roof," said Hannegan, a scientist at National Renewable Energy Laboratory in Golden, Colorado.

These "talking" appliances can also read a weather forecast calling for a sunny afternoon. This tells them the rooftop solar will be making lots of power, meaning it's a great time to run the dryer and dishwasher.

You may be at work, but your "smart" home doesn't need you. When you pull into your driveway at the end of the day, the dishes are done and the clothes are dry -- all with power generated from your rooftop that afternoon.

NREL engineers are testing versions of this home of the future in their Energy Systems Integration Laboratory, where Hannegan is the associate director. Their goal: to maximize how homes use renewable energy, and minimize disruption to the grid.

Take houses with rooftop solar. Right now, they use the grid kind of like a battery. They make a lot of power when the sun shines, and if they don't need the power right then, they dump it onto the grid. These same houses also draw power from the grid when they need it -- a kind of push and pull scenario.

When only a few homes have solar panels, it's not a huge deal. But if your ideal future is a world with a solar panel on every roof and a community wind farm on every corner, this push and pull gets to be a problem.

"This put stresses and strains into the utility infrastructure where there is kind of a practical limit to how much solar PV or wind energy that you can bring into a given system," said Hannegan.

A smart home helps reduce that push and pull, because it manages its own energy demand. This creates less stress on the grid, and more space for renewables.

Making homes more efficient is a key part of reducing climate change impacts, said Dane Christensen, a senior engineer at NREL who works on the smart home project.

"Buildings are our nation's largest emission sources of global warming gases. They lead to more than transportation in terms of the overall climate impact. And so we really want to tackle that," he said.

At the lab, a cavernous bay with a dense network of pipes criss-crossing the ceiling, sit what look like three New York City-sized apartments, their appliances crammed together into about 400 square feet of space.

"So we have a refrigerator, a range, a dishwasher, a water heater, washing machine and drier, we have lighting controls, we have air conditioner system around the corner. And these are the major energy using devices in our homes," said Christensen.

Dane Christensen, an engineer with the National Renewable Energy Laboratory, in a laboratory where he simulates how "smart" homes might work under different energy scenarios.
Credit Stephanie Paige Ogburn / KUNC

With the three homes, each of which has varying degrees of "smartness" built in to its appliances, the NREL group can simulate a neighborhood, and different scenarios. They can mimic a hot August in Houston or a sun-soaked Colorado afternoon. They can see what it means if homes next to each other alternate turning on their air conditioning system, or if a lot of drivers with electric vehicles all try to charge their cars at once.

One day, they hope, the appliances in a home will be able to talk with each other to coordinate energy use -- but they also want homes to coordinate with other homes.

Many utilities do this now at a smaller scale. In Colorado, Xcel Energy customers can sign up for a program called "Saver's Switch," where the utility cycles a home air conditioner off-and-on to reduce demand during a few parts of very hot summer days. Customers who participate get a $40 per year credit. The Fort Collins municipal utility offers a similar program for both heating and cooling.

Homeowners also have the option of smart thermostats like Nest that allow them to better manage one aspect of energy use – home heating and cooling.

Hannegan's vision is of something similar, but much larger and more coordinated. Getting there, though, is a lot more challenging than buying the newest LG smart dryer and downloading a few apps, he said.

An ethernet connection for a refrigerator to talk to a network, in NREL's smart home laboratory.
Credit Stephanie Paige Ogburn / KUNC

"What's lacking is still is how all those pieces interact with one another to turn something into value for you, without you having to manage 20 different devices or 20 different apps on your phone. Where is the intelligence in that system?"

Leia Guccione is a manager at the nonprofit Rocky Mountain Institute, and works with business and industry on accelerating the development of renewable energy.

Big businesses and industrial users of electricity already work with utilities to manage their demand for power, and are charged different rates for using power at peak times, she said.

Doing this for homes is a logical next step – and it could happen soon, she said. The municipal utility in Fort Collins will discuss this option next spring, said Steve Catanach, light and power manager with the city. 

Catanach said with the Fort Collins utility already offering some incentives for energy management, it seems plausible they might offer a whole-home management system in the future. 

"That is much more sophisticated but I don't think it's out of the question."

David Goswick, the CEO of Houze, a company that builds net zero homes, calls this technology "incredibly disruptive."

"I think in five years it will be mainstream across the board," Goswick said.

Before utilities can get on board, they will need to understand the dollar value of what NREL is developing -- these technologies that manage consumer demand for electricity, said RMI's Guccione. State public utility commissions will also need to empower utilities to institute a system that allows customers to benefit from managing their demand.

"[There need to be] new rate designs that actually give customers the signals and create the economic incentive for homeowners to have these systems in the first place," Guccione said.

In some states, like California and New York, the commissions have done just that.

One way this may play out, said NREL's Hannegan, is similar to how phone service has changed in recent decades.   You used to just buy minutes of telephone time from your service provider. Now you buy a plan, and for $99.99 a month you get a range of services, from contact management to texting to picture sharing. No one counts your minutes. It just works.

That could be the future of the smart home. You pay the utility company a set monthly rate, and it -- or a third party -- manages your electricity use, he said.

"Maybe there's a new business model in there. Who knows?"