An electrical connection: houses help the grid
By Tim Ledbetter
Researchers at the Pacific Northwest National Laboratory (PNNL) have developed a control system that could make most U.S. homes more capable partners in managing the nation’s electrical resources.
The control system effectively transforms existing home heating and cooling units and water heaters into smart devices that can manage their electricity usage in ways that help the grid coordinate supply and demand. The system could benefit around 120 million households.
“From the start, our goal has been to develop a solution that is inexpensive, simple to install and use, and puts residents in charge of its operation,” said Michael Brambley of PNNL, who is leading the development of the control system. . “In exchange for grid support, households should receive an incentive, such as a more favorable electricity tariff.”
Work on the control system was funded by the Department of Energy’s Office of Building Technologies (BTO) as part of a connected homes project.
What is a connected home?
A connected home contains smart devices with communication and control capabilities, which allow devices to automatically respond to information from an electric utility. Examples include smart and connected thermostats, which connect heating and cooling systems, and specially equipped water heaters. Some newer homes already have these types of appliances, but most homes don’t.
Experts believe that connected homes will play a key role in the United States’ transition to a future low-carbon energy system, one that relies less on traditional, non-renewable energy sources and more on clean solar and wind power.
Because solar and wind power are “variable”, i.e. their power output fluctuates with the rise and fall of the sun and wind, the grid must sometimes quickly pivot to other types. power generation or manage demand to bypass the grid. instability and meet electricity needs economically. Generating sources currently helping to fill the gap are, in general, fossil fuel power plants, which increase carbon dioxide emissions and contribute to global climate change.
Connected homes can help cope with the variable nature of solar and wind power as well as other conditions on the grid. Appliances with smart controls that take into account occupant comfort preferences, working with utilities and the grid, can quickly and automatically change their electricity demand to help even out variations and ultimately reduce the amount of greenhouse gases entering the atmosphere.
This “flexible demand” capability, if realized in tens of millions of homes, would give the grid more leeway to coordinate supply and demand at times when clean energy may not be available. Analysis by PNNL and others shows that this flexibility can also reduce costs for bill payers and utilities.
“Connected homes are becoming more and more mainstream, whether due to consumer demand or updating building energy codes,” said Marc Costa, director of policy and planning at The Energy Coalition. . Costa served on a BTO peer review committee that assessed the progress of PNNL’s control system.
“As customers try to save money on their bills, replace major appliances, or are simply interested in convenient ways to interact with their home, there is a major need for objective research in this area. The PNNL’s work is key to understanding potential impacts and solutions for consumers and for the decentralization of our energy system,” Costa added.
The control system offers a connected home solution
Households use more than a third of the country’s electricity and represent a huge opportunity to achieve flexible demand.
“We believe that an efficient and inexpensive control system installed in existing homes is not only good for the operation of the network, but also for providing energy at a lower cost to households. Our solution is designed for the millions of households that could benefit from this method but do not prefer or cannot afford to purchase smart devices,” said Brambley. “Our retrofittable system should allow them to take advantage of emerging programs that offer favorable electricity rates and other incentives for households that meet grid needs.”
PNNL worked with BTO to create a development strategy for the control system and partnered on the project with two smart technology companies – ecobee and Shifted Energy – as well as the University of Oklahoma.
The control system handles four types of devices
The researchers focused on four appliances in existing homes: electric resistance furnaces, electric resistance water heaters, heat pumps and air conditioners. The control system uses a software platform designed to help connect devices to the network and manage their demand.
During the tests, the results of the water heater and the air conditioning were particularly promising.
- For water heaters, the control system has demonstrated the potential to reduce electricity demand by 34-83% over seven hours, depending on hot water usage levels.
- The control system helped air conditioners maintain cool temperatures and reduce electricity consumption. In one example, electrical demand was reduced by up to 46% during four-hour tests in which cooling was maintained within a three-degree range considered acceptable for occupants. This was based on a 20 degree difference between indoor and outdoor temperatures. The reductions will be greater for greater temperature differences.
Electric oven testing has also resulted in demand reductions of 25%. By having the control automatically preheat the house three degrees above the usual thermostat setting just before a peak grid period, the reduction can be increased to almost 46% over a four hour period.
In 2022, the project team will prepare the control system for deployment in occupied houses. “Ideally, our findings will attract industry partners and lead to a commercial product that can be used nationally,” Brambley said.
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