Why running your dishwasher overnight is a form of climate action – and saves money

Running electricity-thirsty appliances like dishwashers and laundry dryers in the middle of the night is a form of climate action – especially during heat waves like those swamping Michigan in recent weeks.

Energy experts say there’s a way climate-conscious people can organize their home chore routines to ease demands on the power grid and minimize harmful greenhouse gas emissions. It’s a matter of running appliances that require large amounts of electricity when overall energy demands are at the lowest. It can even result in lower electric bills.

Time-delay functions on appliances like dishwashers and laundry dryers help to spread out strains on the electric grid and reduce the need for power providers to fire up gas peaking plants that only run during periods of high demand. The same goes for setting lower temperatures for air conditioning during overnight hours.

“Utilities have a bunch of different power plants, and some of them are running all of the time, and some of them are only running for a few hours a day, or in some cases, even just a few hours a year,” said Lee Shaver, senior energy analyst for nonprofit Union of Concerned Scientists.

Typically, daily peak demand happens between 5 and 7 p.m., he said.

“You’ve got tons of businesses and offices that are still using air conditioning to cool their space. They haven’t closed down for the day yet. And at the same time, people are getting home and starting to use their AC at home, which causes this huge spike in demand for energy,” Shaver said. “That’s when the utilities start turning on these gas peaker plants to meet that demand.”

The energy analyst said gas peaking plants are less efficient and create more greenhouse gas emissions than gas plants that run 24/7. But the advantage is those peaking plants are designed to begin generating electricity in a matter of minutes – a fast response to sudden spikes in demand.

Wolverine Power Cooperative provides wholesale electricity to six power co-ops in rural areas of Michigan, and it also operates seven gas peaking plants across the state.

Eric Baker, Wolverine’s president and top executive officer, said balancing the constant swings in energy demands requires a complicated system unlike other business sectors.

“The electric industry is the only industry I know of that has an absolute need to balance load and supply every second. We don’t get the privilege of building an inventory and using extra warehouse space to supply a peak load,” Baker said. “We have to balance it every second on the grid with large generators that that can go up and down and constantly balance this.”

He said when power customers schedule appliances like dishwashers and laundry dryers to operate during times of low energy demand, it helps to stabilize the grid and reduces the need to fire up gas peaking plants.

“It helps utilize resources that are already on the grid. And so fewer resources have to run during the daytime,” Baker said.

Additionally, experts say turning down the temperature on air conditioning overnight provides further grid stabilization and climate benefits.

“If you cool your house off a little bit more at night, it ends up getting less hot during the day, and then you’re AC is not running during those less efficient times when it’s hotter out,” Shaver said.

He said another way to achieve that is with demand response programs offered by many utilities. Shaver said his smart device thermostat is connected to such a program at his home in Madison, Wisconsin.

“When the utility knows that they are going to need to reduce my usage during a certain time of the day, the thermostat will actually cool my house down ahead of time, and then I use less power during those two to three hours of the demand response event,” he said. “The house will get a little bit warm, but not too warm, and then it comes back on right afterwards.”

Electricity also literally costs more during peak demand times.

Michigan’s largest power provider, Consumers Energy, often appeals to customers’ pocketbooks to encourage fanning out some of their energy uses to the overnight hours.

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Brian Wheeler, Consumers spokesperson, said the company encourages shifting energy use away from the middle of the day – specifically between 2 and 7 p.m. on weekdays – during summer because electric rates are lower at “off-peak” times. It makes for lower electric bills, he said.

“Our summer rate reflects the fact that energy is generally more expensive at peak times. Shifting energy use to other times of day prevents energy providers like us from having to build more power plants that are used only occasionally or pay for more expensive energy on days, for example, when Michigan faces a heat wave,” Wheeler said.

“Ultimately, we encourage people to shift their energy use because it reduces bills for everyone.”

Shaver underscored there are bigger picture benefits to this type of shifting electricity use to overnight hours. Utility planning can be influenced, he said.

“Obviously, if you do it tonight, that’s going to reduce carbon emissions tonight. But if you and 10 or 20 of your neighbors and friends all start doing this, then there’s going to be a trend where people are using less power during those peak hours,” Shaver said.

“Maybe (utilities) are planning to build those peaker plants less often, or maybe they’re planning to decommission some of them a little bit sooner. So, it can make a long-term difference too.”