The Clean Energy Transition Institute (CETI) has collaborated with the University of Washington’s Program on Climate Change (PCC) and its Actionable Community-Oriented Research eNgagement (ACORN) program to provide UW graduate students the opportunity to analyze key state and federal energy data. This collaboration has enabled the development of data visualizations for the Northwest Clean Energy Atlas, which I encourage you to explore. These visualizations can help regional decision-makers in planning the clean energy transition.
As an ACORN fellow, I updated Atlas visualizations using energy data from the U.S. Energy Information Administration (EIA). In this blog, I examine the recent shift in the EIA’s approach to calculating the primary energy consumption of electricity generation from noncombustible renewables.
The U.S. Energy Information Administration (EIA) plays a central role providing energy data that tracks trends in the ongoing energy transition and shapes energy policy, particularly as the renewable energy sector expands.
Recently, the EIA updated its method for calculating the energy contribution of noncombustible renewables, which include hydroelectric, geothermal, solar, and wind energies and are defined as energy that can be extracted without burning or combusting fuels.
Since the EIA tracks energy from both fossil fuels and noncombustible sources, it needs a unified approach to convert these different energy types into comparable units to enable consistent comparison and analysis. Understanding this change in the EIA’s accounting method is important for tracking the progress of the clean energy transition, particularly with noncombustible renewable energy sources increasingly comprising a larger portion of the electricity generation pie.
Historically, the EIA has assessed the contribution of noncombustible renewable energy through the fossil fuel equivalency approach. This method quantifies noncombustible renewable energy based on a fossil fuel equivalency factor, i.e., how much fossil fuel heat would be needed to produce the same amount of electricity. For example, this method would compare the electricity output from wind or solar energy to the amount of heat that would be generated from burning fossil fuels to produce the equivalent amount of electricity.
To do this comparison, energy sources have traditionally been converted into common British thermal units (BTU), which allows different types of energy to be compared. Yet, because noncombustible renewable energy sources do not involve combustion, there is no direct conversion from physical fuel quantities (as there is with fossil fuel energy sources) into energy units like BTUs and therefore there are no established BTU conversion factors for noncombustible sources. Instead, the EIA calculated the BTU equivalent for noncombustible renewable electricity by estimating how much fossil fuel would have been needed to generate the same amount of electricity using an average heat rate.
The average heat rate assumes a constant level of efficiency for fossil fuel plants and does not account for differences in energy conversion processes and varying efficiency levels. Thus, while the average heat rate provides a way to compare the energy output of noncombustible sources to fossil fuels, it is an estimation tool rather than an established BTU conversion factor. This fossil fuel equivalency approach therefore may not accurately reflect the actual energy output and efficiency of noncombustible renewable sources and can overestimate the amount of energy produced by noncombustible renewable energy resources because they harness energy without combustion.
Starting in September 2023, the EIA switched to a new method called the captured energy approach. This method defines captured energy as the net energy used or available for direct consumption after noncombustible renewable energy transforms into electricity. This captured energy approach represents a significant shift in how renewable energy is measured.
Instead of comparing renewable energy to fossil fuels, this approach converts primary energy consumption of noncombustible renewables from kilowatt-hours (kWh) to BTUs using a standard heat conversion factor for electricity of 3,412 BTU per kWh. By reflecting the energy directly captured and converted into electricity, the captured energy approach is the preferred method by the UN International Recommendations for Energy Statistics (IRES).
A third approach is the incident energy approach, which is defined as the measurable mechanical, radiation, or thermal energy. For noncombustible renewables, incident energy is the gross energy used (called input energy) by an energy conversion device, such as photovoltaic cells for solar energy or wind turbines for wind energy. Noncombustible renewable electricity is then converted to BTU with consideration of energy losses. The EIA does not use this approach as accurate estimates of input energy are difficult to obtain.
Figure 1 below helps explain the importance of the EIA’s shift to the captured energy approach that converts electricity generation from noncombustible renewables into BTUs.
The left panel of Figure 1 shows that net generation by noncombustible renewable sources has been growing significantly since 2001, approaching approximately 0.6 trillion kWh in 2017. The middle panel shows that the heat content of electricity (related to the heat conversion factor used for the captured energy approach) has remained constant over time, whereas the weighted average fossil fuel-fired power plant heat rate (the conversion factor used for the fossil fuel equivalency approach) has decreased, which supports the need to shift approaches.
Finally, the right panel shows that the adjustment for fossil fuel equivalence has increased from around 2,800 trillion BTU in 2001 to 6,000 trillion BTU in 2017, while the heat content of net generation has risen at a significantly more modest growth rate.
The adjustment for fossil fuel equivalence is used to quantify the contribution of noncombustible renewable sources by comparing their energy output to the equivalent amount of energy that would be generated from fossil fuel combustion. The growing disparity between the heat content of net generation and the adjustment for fossil fuel equivalence indicates potential inaccuracies in accounting for the contributions of noncombustible renewable energy sources.
The captured energy approach better aligns with evolving renewable technologies by focusing on direct energy output rather than fossil fuel comparisons. While the fossil fuel equivalency method overestimated renewables' contributions, the new method provides a more accurate assessment of renewable energy efficiency, ensuring data remain relevant to modern advancements and consistent with IRES standards.
For example, in 2018, using the fossil fuel equivalency approach, noncombustible energy made up 15% of total energy consumption for utility-scale electricity generation. Using the captured energy approach, this value decreases to 6%. With the captured energy approach, we can better evaluate renewable energy progress and what further advancements are needed to meet climate goals.
As renewable energy consumption increases, the values calculated using the fossil fuel equivalency approach increasingly diverge from values calculated using the captured energy approach. The shift to this new accounting method offers policymakers clearer data on renewable energy output. This change also improves public discourse by moving beyond comparisons to fossil fuels and focusing on key issues like grid management and storage technologies.
You can explore where energy comes from and goes in Idaho, Montana, Oregon, and Washington, and check out other “energy resources and uses” visualizations using EIA data here.
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