Net-Zero? Yes, Electricity. Yes, Fuels. Yes, Infrastructure.
This is the second blog in a series examining net-zero energy systems, drawing upon the results of our Meta-Analysis of U.S. Economy-Wide Decarbonization Studies (Meta NZ).
Net-zero energy systems rely on electricity. Net-zero energy systems rely on fuels. And net-zero energy systems rely on vast infrastructure networks to move and store those electrons and fuel molecules, delivering energy where it’s needed, when it’s needed.
I have recently written about net-zero energy systems, building upon the findings of our Meta NZ report and a dialogue with some of my Meta NZ colleagues. In this post, I dive into the role of electricity, fuels, and infrastructure in achieving economy-wide, net-zero emissions.
In the U.S. today, 18% of the energy consumed by end-use customers is supplied as electricity — the other 82% is supplied as a gaseous, liquid, or solid fuel. In net-zero energy systems, the share of electricity grows substantially. This growth coincides with increasing adoption of electric vehicles (especially light duty), electric space heating (e.g. electric heat pumps), and electrification of some industrial processes. Across the 23 different net-zero scenarios contained within the five net-zero studies evaluated in our meta-analysis,* electricity accounts for between 36 and 59% of final energy.
Fuels are ubiquitous in today’s energy systems. Fuels continue to be ubiquitous in net-zero energy systems, supplying roughly half of all energy consumed by end-use customers. Fuels continue to be used for transportation (especially for heavy-duty, long-haul service), building heating, and heavy industrial processes. Across 23 different net-zero scenarios, the share of energy delivered to end-use customers as fuel ranges from 41 to 64%.
Fuels also play an important role in supporting the expanded electricity demands in net-zero energy systems. Fuel-based power generation provides firm capacity to balance renewables variability and demand fluctuations, especially over multiday or seasonal timescales. When accounting for fuel-based electricity, fuels underpin the majority of energy consumed by end-use consumers in most net-zero energy scenarios. Across 23 different scenarios, the share of end-use energy consumption underpinned by fuel ranges from 42 to 81%.
Why do fuels have such an enduring role in net-zero energy systems?
The results of each of the 23 different scenarios presented here were developed by solving for least-cost pathways to achieve economy-wide, net-zero emissions under differing set of inputs and assumptions. Considering that wind, solar, and battery technologies are becoming increasingly cost competitive, it’s not surprising that these solutions are widely adopted across these scenarios. But why do fuels continue to have such an enduring role in net-zero energy systems? Why is it that fuels consistently arise as part of a least-cost pathway to achieve economy-wide, net-zero emissions?
Part of the answer to this question lies within the intrinsic qualities of fuels. Fuel molecules are energetically dense, which means they can hold a large amount of energy in a small space. Fuel molecules are also stable, which means they can store energy for long periods of time. Those qualities make fuels well suited for moving and storing energy, allowing energy to be delivered where it’s needed, when it’s needed.
The other part of the answer to this question lies within infrastructure. Fuels are ubiquitous in today’s energy systems, and so are the vast infrastructure networks built over decades of investment to move and store those fuel molecules. For example, today’s natural gas and petroleum storage infrastructure capacity is capable of meeting average U.S. demand for more than seven weeks.** That means that if production stopped today, today’s energy systems could continue to support the roughly three-quarters of the U.S. economy that rely on these fuels for nearly two months. In 23 net-zero scenarios evaluated across five independent studies, these infrastructure networks are consistently leveraged as part of least-cost pathways to net-zero. This infrastructure is available today. By blending low-carbon fuel substitutes and/or applying carbon capture and sequestration to abate emissions from fossil sources, today’s fuels infrastructure can be leveraged to support net-zero energy systems.
Yes, and.
Net-zero energy systems are “yes, and” energy systems. Yes, to the expanded role of electricity. Yes, to the enduring role of fuels. And yes, to the at-scale infrastructure needed to move and store electrons and fuel molecules in net-zero energy systems.
* Net-Zero 2050: U.S. Economy-Wide Deep Decarbonization Scenario Analysis | An Open Energy Outlook: Decarbonization Pathways for the USA | Annual Decarbonization Perspective 2022 | Net-Zero America: Potential Pathways, Infrastructure, and Impacts | Pathways to Net-Zero Emissions
** Based on EIA data. Additional discussion available here.
