Charted: Home Heating Systems in the U.S.
This was originally published on April 25, 2022, on Elements.
Fossil fuel combustion for the heating of commercial and residential buildings accounts for roughly 13% of annual greenhouse gas emissions in the United States.
Decarbonizing the U.S. economy requires a switch from fossil fuel-combusting heating solutions to renewable energy sources that generate electricity.
Currently, the majority of new homes in the U.S. still combust natural gas for heating through forced-air furnaces or boilers. Just like cars need to be electric, homes will need to switch to electricity-powered heating systems that use renewable energy sources.
The graphic above uses census data to break down the different heating systems and fuels that are warming the 911,000 single-family homes built in the U.S. in 2020.
Types of Home Heating Systems
Most American homes use one of the following three heating systems:
- Forced-air Furnaces: These typically have a burner in a furnace that is fueled by natural gas. A blower forces cold air through a heat exchanger which warms it up before it flows through ducts that heat the home with air as the medium.
- Heat Pumps: The most common type of heat pumps are air-source heat pumps, which collect hot air from outside the home and concentrate it before pumping it through ducts that heat the air inside. They are usually powered by electricity. During warmer months, heat pumps can reverse themselves to cool the home, transferring hot air from the inside to the outdoors.
- Hot Water/Steam: These systems typically work by boiling water (or generating steam) to the appropriate temperature using gas and sending it through a home’s pipes to radiators that heat the air.
How Home Heating Fuels Have Changed
U.S. home heating has been going through a transition over the last two decades. Electricity has steadily been replacing gas and biofuel/wood-powered home heating systems for new homes, and powers almost half of the heating systems in single-family homes built in 2020.
Here’s how the share of heat sources for new houses changed between 2000 and 2020:
|Fuel||2000 % of Heating for New Homes||2020 % of Heating for New Homes|
Percentages may not add to 100 due to rounding.
While electricity’s share has grown since 2000, most American homes are still heated with gas largely because of the fossil fuel’s affordability.
According to the U.S. Energy Information Administration (EIA), households relying on gas for space heating are expected to spend an average of $746 over the winter months, compared to $1,268 for electricity, and $1,734 for heating oil.
Heating in Newly-Built Houses Today
Of the 911,000 new single-family homes, 538,000 houses installed forced-air furnaces. Of these, 83% or nearly 450,000 homes used gas as the primary heating source, with 16% opting for electrified furnaces. By contrast, 88% of the 353,000 homes that installed heat pumps relied on electricity.
Here’s how the heating systems and fuels break down for single-family homes built in 2020:
|System Used||Houses Built in 2020||% Powered by Gas||% Powered by Electricity||% Powered by Other|
Percentages may not add to 100 due to rounding.
Fewer than 1% of new single-family homes used hot water or steam systems, and the majority of those that did relied on gas as the primary fuel. Around 1.3% of new homes used other systems like electric baseboard heaters, smaller space heaters, panel heaters, or radiators.
While gas remains the dominant heating source today, efforts to decarbonize the U.S. economy could further prompt a shift towards electricity-based heating systems, with electric heat pumps likely taking up a larger piece of the pie.
Visualizing U.S. Electricity Generation Jobs by Technology
Exploring U.S. electricity generation jobs by technology with a focus on renewable energy and workforce development.
Visualizing U.S. Electricity Generation Jobs by Technology
In 2021, 857,579 people were employed in the U.S. electricity generation sector.
To explore the distribution of this workforce, the above graphic by the National Public Utilities Council breaks down the number of jobs for each electricity generation technology using the U.S. Department of Energy’s Energy and Employment Report.
An Evolving Employment Landscape
The employment landscape within the U.S. electricity generation sector is continually evolving, driven by technological shifts, growing urgency towards decarbonization, and new policy initiatives.
Here are some interesting trends seen in 2021.
1. Solar Leads the Way with Significant Job Growth
The solar energy sector emerged as a shining star in 2021, witnessing substantial job growth compared to other electricity generation technologies. With a total of 333,887 jobs, solar not only topped the chart but also experienced a notable increase of over 17,000 jobs from the previous year.
This surge in solar jobs can be attributed to several factors, including advancements in technology, falling costs, and increased adoption of renewable energy sources across the country.
2. Advanced Natural Gas Employs More People Than Traditional
While renewable energy sources gained traction, advanced natural gas also played a significant role in the U.S. electricity generation sector with 69,113 jobs.
Advanced natural gas refers to the application of technologies that optimize efficiency and reduce the emissions associated with traditional natural gas.
As the fourth biggest employer on the list, advanced natural gas employed more people than traditional natural gas in 2021.
3. Renewable Energy Sector Outpaces Broader Sector Growth
Between 2020 and 2021, the renewable electricity generation sector experienced a robust growth rate of 4.4% in employment, outpacing the broader power generation sector’s growth rate of 2.9%.
The employment figures highlight the potential for continued job creation within the renewable sector as the transition to cleaner energy sources gains further momentum.
Getting Over the Workforce Development Hurdle
The employment figures in the U.S. electricity generation sector demonstrate promising growth in clean energy jobs. With that said, rapid decarbonization of the sector may still require a level of workforce development that hasn’t yet been seen in the United States.
As electric utilities and the nation at large strive to achieve their ambitious net-zero goals, investing more in workforce development can be an integral piece of the puzzle, specifically to help individuals transition smoothly from fossil fuel jobs to those in clean generation.
By addressing this challenge, the U.S. can ensure a well-prepared workforce that will drive the transition to a sustainable and net-zero future.
How Does U.S. Electricity Generation Change Over One Week?
This chart tracks U.S. hourly electricity generation over one week, with various sources producing electricity at different times of the day.
How Does U.S. Electricity Generation Change in a Week?
The U.S. has a dynamic electricity mix, with a range of energy sources generating electricity at different times of the day.
At all times, the amount of electricity generated must match demand in order to keep the power grid in balance, which leads to cyclical patterns in daily and weekly electricity generation.
The above graphic sponsored by the National Public Utilities Council tracks hourly changes in U.S. electricity generation over one week, based on data from the U.S. Energy Information Administration (EIA).
The Three Types of Power Plants
Before diving in, it’s important to distinguish between the three main types of power plants in the U.S. electricity mix:
- Base load plants generally run at full or near-full capacity and are used to meet the base load or the minimum amount of electricity demanded at all times. These are typically coal-fired or nuclear power plants. If regionally available, geothermal and hydropower plants can also be used as baseload sources.
- Peak load or peaking power plants are typically dispatchable and can be ramped up quickly during periods of high demand. These plants usually operate at maximum capacity only for a few hours a day and include gas-fired and pumped-storage hydropower plants.
- Intermediate load plants are used during the transitory hours between base load and peak load demand. Intermittent renewable sources like wind and solar (without battery storage) are suitable for intermediate use, along with other sources.
Zooming In: The U.S. Hourly Electricity Mix
With that context, the table below provides an overview of average hourly electricity generation by source for the week of March 7–March 14, 2023, in the Eastern Time Zone.
It’s worth noting that while this is representative of a typical week of electricity generation, these patterns can change with seasons. For example, in the month of June, electricity demand usually peaks around 5 PM, when solar generation is still high, unlike in March.
|Energy Source||Type||Avg. Hourly Electricity Generation, MWh
(Mar 07–14, 2023, EST)
|Natural Gas||Fossil fuel||175,967|
Natural gas is the country’s largest source of electricity, with gas-fired plants generating an average of 176,000 MWh of electricity per hour throughout the week outlined above. The dispatchable nature of natural gas is evident in the chart, with gas-fired generation falling in the wee hours and rising during business hours.
Meanwhile, nuclear electricity generation remains steady throughout the given days and week, ranging between 80,000–85,000 MWh per hour. Nuclear plants are designed to operate for long durations (1.5 to 2 years) before refueling and require less maintenance, allowing them to provide reliable baseload energy.
On the other hand, wind and solar generation tend to see large fluctuations throughout the week. For example, during the week of March 07–14, wind generation ranged between 26,875 MWh and 77,185 MWh per hour, based on wind speeds. Solar generation had stronger extremes, often reaching zero or net-negative at night and rising to over 40,000 MWh in the afternoon.
Because wind and solar are often variable and location-specific, integrating them into the grid can pose challenges for grid operators, who rely on forecasts to keep electricity supply and demand in balance. So, what are some ways to solve these problems?
Solving the Renewable Intermittency Challenge
As more renewable capacity is deployed, here are three ways to make the transition smoother.
- Energy storage systems can be combined with renewables to mitigate variability. Batteries can store electricity during times of high generation (for example, in the afternoon for solar), and supply it during periods of peak demand.
- Demand-side management can be used to shift flexible demand to times of high renewable generation. For instance, utilities can collaborate with their industrial customers to ensure that certain factory lines only run in the afternoon, when solar generation peaks.
- Expanding transmission lines can help connect high-quality solar and wind resources in remote regions to centers of demand. In fact, as of the end of 2021, over 900 gigawatts of solar and wind capacity (notably more than the country’s current renewable capacity) were queued for grid interconnection.
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