Energy Time Machine

Lyn Stoler

Electricity is a restless resource. It won’t wait for us the same way that natural gas, coal, or petroleum can, sitting patiently in barrels and pipes and tanks. Instead, electricity races from power plants, through our energy grid, and through the wires in our home, looking for appliances and electronics to power. If it finds a place to go, it will happily power our electrified lives. Otherwise, it keeps along its merry way, following the path of least resistance until it finds a place to be useful or eventually dissipates.

So when it comes to electricity, we use it or we lose it. This means that electricity needs to be used in nearly the same exact moment that it is generated, distributed, and delivered to our homes. Whatever isn’t used immediately is effectively lost to us.

Timing Matters

The need to use electricity at the same time that it’s generated means that when we use energy matters a lot — especially for those of us who are interested in cutting our energy bills and minimizing our carbon footprint.

Let’s start with our energy bills.

When you sign up to receive electricity from your local utility, you’re usually presented with several pricing plans. As energy efficiency has gained more attention, “Time of Use” plans have become increasingly popular. Under these plans, consumers access low-cost energy during off-peak hours in exchange for higher rates during peak hours.

Time-of-use hours based on the PG&E Time of Use Rate Plan E-TOU-C.

With the right planning and scheduling, signing up for a Time of Use plan can help reduce your household energy bill every month. But peak hours are called peak hours for a reason; for most households, the afternoon and evening peak hours are when they most need energy as they return home from work, turn on their air conditioning or heaters, run laundry, or prepare dinner. The way we live our lives shows up in our grid: electricity demand is consistently highest from around 4 PM to 10 or 11 PM.

This graph shows energy demand data from 9/19/2023 to 9/21/2023 for the California Independent System Operator, as reported by the US Energy Information Administration.

This is especially true for households that have leaned into electrification. Unfortunately, this means that many electrified households can’t take advantage of lower electricity rates during off-peak hours. For a lot of people, though, this trade-off is worth the positive climate impact that they’re able to make through electrification. It is worth it… right?

Digging deeper into our carbon footprint.

Home electrification has been hailed as one of the highest-leverage actions a person can take to reduce their carbon footprint. And it seems obvious: rather than literally burning fossil fuels in your home to cook your food or heat your bedroom, you can pull electricity from the grid to accomplish those tasks while creating fewer emissions.

Don’t get us wrong — home electrification is a huge and important step towards reducing your carbon footprint. But there’s a small catch: our electricity is only as low-carbon as the fuel that we use to generate it.

In the United States, there are a few fuel sources that power our electrical grid. Renewable sources include hydro power, nuclear power, solar power, and wind power. High-emissions sources include coal, natural gas, and petroleum.

Solar and wind are currently the dominant sources of renewable power in the US, and they generate huge amounts of electricity during the day time, say from around 8 AM to 6 PM for much of the year. In states like California and Texas, renewables could soon generate enough to meet or surpass electricity demand during the daytime.

But, any excess renewable energy that we don’t use to power or charge our devices during the day often can’t be saved. So as we start using more electricity as afternoon turns to evening, the grid turns to other, high-emissions fuel sources.

This graph shows energy supply data, by type from 10/17/2023 to 10/20/2023 for the California Independent System Operator, as reported by the US Energy Information Administration. For clarity, we grouped solar, wind, nuclear, and hydro power under "renewables", and petroleum, natural gas, and coal under "non-renewables".

The fall out? As Grist reports, the average home cook using an electric stove actually has almost the same exact carbon footprint as a home cook using a gas stove: about 0.95 pounds of CO2 each day. Over the course of a year, that's the same amount of carbon you'd emit by driving a Chevy Malibu from Santa Barbara to Phoenix. Ouch.

Batteries Keep The Promises Of Electrification

Over the long term, the best way for us to reap the benefits of electrification — reliable, affordable, and low-carbon energy around the clock — is to decarbonize the electrical grid. That’s projected to take a long time (like, at least a decade), but batteries can help us accelerate the timeline.

We're not talking about the pack of AA batteries you have in the junk drawer, to be clear. We're talking about large-scale batteries — everything from classic lithium ion to innovative solid state batteries. These batteries can potentially store massive amounts of energy, meaning that whether it's on the utility scale or at home, batteries increasingly serve as energy time machines. In the short term, they allow us to store energy at one time of the day, and use it at another. In the grand scheme of things, they help us leapfrog decades of grid improvements and energy infrastructure investments, getting to a clean energy future faster. 

At the scale of the electrical grid, utility-scale energy storage startups and industry leaders like Form Energy or Key Capture are deploying new and traditional battery technologies to store excess renewable energy during the day for later use during peak demand hours. On the demand side, startups like Antora are developing thermal energy storage to help decarbonize industrial heat and power.

This graph shows renewable energy supply data, by type from 10/17/2023 to 10/20/2023 for the California Independent System Operator, as reported by the US Energy Information Administration. For clarity, we grouped solar, wind, nuclear, and hydro power under "renewables". Recommendations on when to charge, and when to use battery power are based on earlier discussions of peak demand hours as well as Time of Use rates.

And finally, some of us — Impulse included — are working on bringing battery technology home. Companies like Swell and Leap are helping consumers sign up for virtual power plant programs, which use a combination of demand response, energy generation, and storage to decarbonize homes while stabilizing the grid. Other companies, like Haven, simply provide home battery products. All of these companies, alongside Impulse, have the opportunity to help keep the promises of electrification. By putting batteries in your home, you get the magic of an energy time machine: collect and store electricity when it’s cheap and clean, and use it when you need it. 

Energy Time Machine