Chapter 13 - Energy

What Does This Topic Include?

This chapter discusses the policy and procedures regarding energy analysis, including when an Energy Analysis Report is required for a proposed project.

Energy Analysis Report Decision Tree

View Energy Analysis Report Decision Tree (PDF)

Energy Policies and Regulations


NEPA (42 U.S. Code Part 4332) requires the identification of all potentially significant impacts on the environment, including impacts on energy resources. Guidance for evaluating energy impacts of transportation projects subject to NEPA is outlined in FHWA's Technical Advisory 6640.8A (Technical Advisory). The Technical Advisory energy analysis requirement applies to projects for which an Environmental Impact Statement (EIS) is prepared. The Technical Advisory indicates that documentation should discuss energy requirements for construction and operation, and the overall conservation potential for each of the project alternatives. The relationship of the project alternatives to applicable state or regional energy plan should also be documented. Additional conservation measures, such use of high-occupancy vehicle incentives and other measures to improve traffic flow should also be identified.

Other measures to improve energy efficiency in the transportation sector have been implemented at the federal level. In recent years, the United States Environmental Protection Agency (U.S. EPA) and the National Highway Traffic Safety Administration (NHTSA) issued Final Rules governing Corporate Average Fuel Economy (CAFE) standards and other improvements to fuel economy to new vehicles.

Further Reference

Department of Energy, Energy Information Administration

Department of Energy

National Highway Traffic Safety Administration, Corporate Average Fuel Economy


On December 28, 2018, the Governor's Office of Planning and Research and the California Natural Resources Agency updated the CEQA Guidelines to require that an Environmental Impact Report (EIR) include an analysis of a project's potential for significant environmental effects resulting from wasteful, inefficient, or unnecessary use of energy; or wasteful use of energy resources (Guidelines § 15126.2(b)). Appendix F, Energy Conservation, of the CEQA Guidelines outlines requirements for the evaluating energy impacts of projects subject to CEQA. The appendix outlines criteria to consider in reviewing potential impacts, and places particular emphasis on avoiding the "inefficient, wasteful, and unnecessary consumption of energy." An Initial Study must also examine potential energy impacts to determine if those impacts could be significant.

The State has passed several bills directing state agencies and entities such as the California Energy Commission (CEC) and the California Public Utilities Commission to implement renewable energy portfolio targets and energy efficiency measures to reduce energy consumption and GHG emissions in the state.

Further References

California Energy Commission, Fuels and Transportation Division

California Public Utilities Commission, Energy Efficiency


Every activity results in some kind of energy consumption. Energy is either used for work (kinetic energy) or stored (potential energy). Kinetic energy is the amount of work necessary to move an object. In transportation, thermal energy from fuel combustion is converted into kinetic energy to propel vehicles. Electrical energy is used to power facilities such as highway lighting, and converted to heat and power for buildings.

The transportation sector consumes energy for all modes of transportation for people, goods, and services, such as automobiles, trucks, buses, trains, aircraft, and marine vessels. Transportation energy is generally described in terms of direct and indirect energy.

Direct energy:

In the context of transportation, direct energy involves all energy consumed by vehicle propulsion (e.g., automobiles, trains, airplanes). This energy consumption is a function of traffic characteristics such as vehicle miles traveled (VMT) (volume X distance traveled), speed, vehicle mix, and thermal value of the fuel being used. Some projects may also include features such as new or replacement roadway lighting or other features requiring electricity which is an ongoing and permanent source of direct energy consumption. The one-time energy expenditure involved in constructing a project is also considered direct energy.

Indirect energy:

Fuel consumed by equipment required for periodic maintenance of the physical system associated with a project is considered indirect energy. The use of highway maintenance equipment and landscaping involve indirect consumption of energy after a facility is built.

On a much larger scale, many sources contribute indirectly to the energy consumption of a transportation system, but these are difficult to reliably quantify at the individual project level. These sources include refining raw materials into products such as vehicles or roads; exploring for and refining oil into various fuels; constructing and maintaining dams, power plants, transmission lines, fuel distribution systems, train stations, and airports; and many others. Such factors are often studied in energy life cycle or carbon footprint analyses. These considerations are important to acknowledge; however, attempting to characterize or quantify these factors at the project level is generally speculative and of little use to decision makers. As such, these factors are outside the scope of the project-level transportation energy analysis.

Transportation infrastructure in the United States developed during a period of easy access to relatively inexpensive fossil fuels. The shock of an oil shortage in 1973 contributed to an awareness of petroleum as a finite resource that is ever diminishing as petroleum-based fuels are consumed around the world. Combustion of fossil fuels has also been linked to climate change. The dual concerns of potential energy shortages and environmental impacts of climate change have spurred legislative action at the federal and state levels as well as innovation geared toward conservation of existing fuel supplies, development of renewable fuels, and energy efficiency measures. A notable legislative act was the introduction of federal Corporate Average Fuel Economy (CAFE) standards in 1975 to mandate fuel efficiency improvements in motor vehicles.

Energy use in the transportation sector accounted for 29% of total U.S. energy use in the year 2017, second only to the industrial sector (U.S. Energy Information Administration 2017). In California, the transportation sector accounts for 39% of total energy use in the state (U.S. Energy Information Administration 2016). California has the highest number of registered motor vehicles among the U.S. states, but in 2013 ranked 41st in vehicle miles traveled per capita (Bureau of Transportation Statistics), and ranked 39th in 2014 (Federal Highway Administration Highway Statistics 2014). California is the second-highest energy consumer in the U.S., which correlates with its status as the country's largest economy and most populous state, estimated at 39.8 million as of 2018 (California Department of Finance 2018). However, California ranks 48th in total energy consumed per capita (U.S. Energy Information Administration 2017).

Energy efficiency efforts in California have dramatically reduced statewide per capita energy consumption relative to historical averages. California's per capita energy use is the third lowest in the nation. This statistic is partially attributable to the state's continuous pursuit of policies to reduce energy consumption, promote renewable energy, and reduce reliance on fossil fuels. California's net taxable gasoline sales in 2016 were below 2002 levels (California Board of Equalization 2017), despite a population growth of at least 15% during the same time period (California Board of Equalization 2013; U.S. Census Bureau 2018). Furthermore, gasoline consumption in the state decreased by approximately 2.2% between 2005 and 2017, even as VMT increased by 7.5%, from 329 billion in 2005 to 354 billion in 2017 (California Department of Tax and Fee Administration 2018, FHWA 2018). These improvements are due in large part to a more fuel-efficient vehicle fleet (U.S. Energy Information Administration 2016). Annual trend lines of statewide gasoline consumption and VMT are shown in Figure 1.

Figure 1. California Annual Gasoline Consumption and Vehicle Miles Traveled, 1998-2017

Trends of California annual gasoline consumption and vehicle miles traveled


California's transportation energy consumption has become increasingly efficient due to technological growth, environmental policies, and innovation. Gasoline and diesel represent the largest fraction of fuel consumed by the transportation sector in California. However, it is anticipated that CAFE regulations, renewable fuel uptake, and zero-emission vehicle regulations will gradually displace gasoline-propulsion systems in favor of more energy-efficient systems with lower GHG emissions. As of 2014, renewable fuels represented a growing fraction of transportation energy consumption at 6.2%, with ethanol representing 4.5% and other renewables representing 1.7% of total transportation energy consumption (U.S. Energy Information Administration 2016).

Energy Versus Greenhouse Gas Emissions

Activities that consume energy also generate by-products. Greenhouse Gases (GHGs) are the most closely studied by-products of energy consumption because they are linked to climate change. Combustion of fossil fuels such as gasoline and diesel produces GHGs such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and smaller amounts of other GHGs, which contribute to atmospheric warming.

Project-level analyses of energy and GHG emissions use similar data to derive project emissions or energy consumption. However, energy and GHG emissions are distinct resource areas accounting for different types of environmental impacts. Energy in a resource context generally pertains to the use or conservation of fossil fuels, which are a finite resource. GHG studies, on the other hand, describe the potential of a project to contribute to climate change. Because each of these resource areas address different environmental concerns, both are studied in evaluation of overall environmental effects. The Climate Change Annotated Outlines contain separate guidance for assessing effects and quantifying construction and operational GHG emissions at the project level.

Interagency Coordination

Caltrans has primary oversight of the energy analysis for both state-only projects and federally-funded projects. For further guidance, see SER Volume 1, Chapter 38, NEPA Assignment.

Most Metropolitan Planning Organizations (MPOs) or Regional Transportation Planning Agencies (RTPAs) will conduct their own energy analysis as part of the environmental document prepared for their Metropolitan Transportation Plans (MTP) or Regional Transportation Plan (RTP) and Sustainable Communities Strategy (SCS), as applicable. Cities and other jurisdictions prepare climate action plans and energy-efficiency plans that may contain strategies and measures to reduce transportation energy consumption.

Information contained in the environmental document for an MTP/RTP/SCS and other local plans will be needed to determine that a proposed project does not obstruct or conflict with a state or local plan for renewable energy or energy efficiency.

Energy Analysis Report

Determining the Need for a Separate Energy Analysis Report

For NEPA, an energy technical study will only be required when an EIS is prepared and the project is a large-scale project with potentially substantial energy impacts. For an EIS that is not a large-scale project with potentially substantial energy impacts, a memo to the project file documenting this may be sufficient. If an Energy Analysis Report has been prepared to comply with CEQA, the results of that study can be included in an Environmental Assessment or EIS prepared for NEPA.

For CEQA, both an EIR and an Initial Study/Negative Declaration/Mitigated Negative Declaration (IS/ND/MND) require a discussion of energy impacts. An Environmental Impact Report (EIR) must include an analysis of energy use and must provide mitigation for significant effects if the project has the potential for a significant effect related to energy.

The level of effort for the energy analysis should be based on the anticipated impact the project will have on energy use. A very brief report would likely be needed for an auxiliary lane that is 1.2 miles in length while a longer, more detailed report may be needed for a new, multi-lane facility, or the widening of an existing facility over many miles. Projects that relieve congestion or increase capacity require an Energy Analysis Report. For all other project types, a qualitative discussion of energy impacts in the environmental document will be sufficient in most cases.

Congestion relief and capacity-increasing projects will require separate, quantitative assessment of energy impacts. Examples of congestion relief or capacity-increasing projects that would require a quantitative analysis include the following.

  • New Roadway or Facility: Bypass, new or extended highway, new interchange
  • Additional Lanes: HOV lanes, general purpose/mixed flow lanes, managed, express, and toll lanes
  • Interchange Reconfiguration: ramp widening or increased through lanes on bridges
  • Auxiliary lanes more than 1 mile in length

Energy studies should evaluate direct energy from vehicles using the facility (i.e., fuel consumption) and ongoing uses of energy such as roadway lighting, as well as energy consumption from new facilities (e.g., transit centers or maintenance stations). Construction emissions are a temporary and one-time direct source of energy consumption and should be evaluated as well. Vehicles and equipment associated with maintenance of the facility are considered permanent indirect sources.

Preparer Qualifications

There are no specific preparer qualifications for an Energy Analysis Report. Because of the overlap in data needs between the Air Quality Report (AQR) and the energy study, the Energy Analysis Report may be best prepared by an environmental engineer.

Timing of Studies with the Environmental Process

Information from the Energy Analysis Report (or memo to file) will be summarized in the draft environmental document; therefore, the Energy Analysis Report (or memo to file) must be completed prior to completing the draft environmental document. To the extent that the proposed project is modified or new information is obtained after circulation of the draft environmental document, the energy analysis may need to be revised prior to completion of the final environmental document.

Report Content

The Energy Analysis Report describes the proposed project's regulatory and environmental settings, the environmental consequences, and measures to avoid, minimize, and/or mitigate adverse impacts of the project on energy resources.

An Energy Analysis Report should be organized as follows.

  • Chapter 1, Introduction, introduces the Energy Analysis Report and describes the purpose, scope, and content of the report.
  • Chapter 2, Project Description, describes the project's characteristics, including location, purpose, need, and the alternatives.
  • Chapter 3, Affected Environment, provides background information on state and local energy resources and usage, as well as current federal, state, and local energy regulations, policies, and legislation. This section should also include a description of existing conditions in the project area that affect energy usage. For example, what are the existing traffic conditions? What mix of vehicles is currently using the facility (particularly if the project is expected to substantially change the vehicle mix)? Are there existing traffic management system (TMS) elements in place? What is the condition of the existing pavement surface? A poor driving surface can contribute to an increase in fuel consumption. Is there existing highway lighting and what type is it?
  • Chapter 4, Study Methods, describes the method used to analyze project-level energy effects.
  • Chapter 5, Environmental Consequences, presents the results of the energy analysis and discloses potential energy effects, including project consistency with applicable federal, state, and local energy regulations, policies, and legislation. This section should also include any energy-saving or conservation measures specifically incorporated into the design of the project. This section should also discuss any required avoidance, minimization, and/or mitigation measures. The analysis in this section is subject to the rule of reason and shall focus on energy use that is caused by the project—a full "lifecycle" analysis that would account for energy used in building materials and consumer products will generally not be required.
  • Chapter 6, References Cited, lists the printed references and personal communications used to prepare this report

There are no formalized processing requirements for the Energy Analysis Report. However, the draft Energy Analysis Report should be reviewed by the environmental generalist, the project manager, and the project engineer at a minimum. Following the Caltrans internal review of the draft, the Energy Analysis Report may be finalized.

Recommended Analysis Method for Congestion Relief and Capacity-Increasing Projects

Congestion relief and capacity-increasing projects affect the ability of a transportation facility to accommodate existing and future traffic demand. This results in changes to direct energy consumption (i.e., fuel usage) by vehicles using the facilities. Congestion relief and capacity-increasing projects require construction, which is a one-time direct energy source that ceases to consume energy once work is complete. Some projects may also include new buildings or more roadway lighting, which are an ongoing and permanent sources of direct energy consumption. Maintenance and landscaping activities would result in long-term indirect energy consumption through the use of equipment required to maintain the facility and associated facilities. Electricity usage can generally be discussed qualitatively, as can the energy requirements of long-term maintenance of the facility.

Direct Energy (Mobile Sources): The basic procedure for analyzing direct energy consumption by mobile sources is to calculate fuel consumption using CT-EMFAC2017. CT-EMFAC2017 is an emissions model developed by Caltrans that calculates project-level emissions and fuel consumption using data from the California Air Resources Board's EMFAC model. The fuel consumption can be easily derived from the CT-EMFAC model run prepared for the criteria pollutant and GHG emissions analyses.

Direct Energy (Construction): The basic procedure for analyzing direct energy consumption from construction activities is to obtain fuel consumption projections in gallons from the Caltrans Construction Emission Tool (CAL-CET). CAL-CET outputs both emissions and fuel consumption based on project-specific construction information. If CAL-CET-derived fuel consumption data is not available, fuel consumption converted from CO2 emissions generated by diesel and gasoline powered equipment may be estimated. These CO2 emissions can be obtained from the AQR or GHG analysis, where they have been quantified using any of the following models: the Sacramento Metropolitan Air Quality Management District's (SMAQMD) Road Construction Emissions Model (RCEM), the FHWA Infrastructure Carbon Estimate (ICE), or the CalEEMod emissions model.

It is preferable to break out construction fuel consumption by diesel and gasoline sources, as the carbon content differs between the two types of fuels. Typical gasoline sources are employee commute vehicles (e.g., light duty automobiles and trucks) and smaller construction equipment pieces (e.g., tampers and mowers). Typical diesel sources are off-road construction equipment (e.g., graders, dozers).

If construction emissions are not apportioned by fuel type (i.e., diesel and gasoline), a conservative analysis assumes 100% diesel equipment, as diesel equipment and exhaust typically represent the majority of overall construction emissions.

Indirect Energy (Maintenance): Maintenance and landscaping activities would result in long-term indirect energy consumption through the use of equipment to maintain the project and associated facilities. Roadway construction projects will require new periodic maintenance, which could result in indirect energy consumption from equipment and vehicles. Generally, these impacts can be discussed qualitatively as attempting to estimate fuel data or CO2 emissions for these activities, the frequency of which is unknown, would be speculative.

Recommended Analysis Method for NON-Congestion Relief and Capacity-Increasing Projects

For projects that require an EIR or an Initial Study but are not congestion-relief or roadway capacity projects, a qualitative discussion of energy usage will normally suffice or a combination approach can be used. Energy consumption used during construction may still be calculated using any of the tools noted above, especially for projects that may have a particularly long construction period.

Many non-capacity increasing projects may contribute to roadway improvements that would reduce emissions. For example, a pavement project may result in smoother pavement surfaces, which would improve vehicle operations, reduce emissions, and reduce energy consumption. Transportation Management Systems (TMS) infrastructure including Intelligent Transportation Systems (ITS) components such as traffic signals, ramp meters, changeable message signs, and real-time traffic monitoring can improve traffic flow without increasing the capacity of the highway. If traffic data is available for a project incorporating TMS elements, direct energy consumption from mobile sources may also be assessed qualitatively across project alternatives. Traffic data could include average vehicle speed, vehicle delay, level-of-service, volume-to-capacity ratios, and idling time. A comparison between these factors could allow for an evaluation of relative fuel consumption levels between alternatives, depending on how efficiently vehicles would be able to travel through the system.

The effect of the speed of vehicles traveling through a roadway system may also be appropriate to consider in a qualitative analysis. Average fuel economy as a function of speed is shown in Figure 2 below. In general, there is an optimum traveling speed that will allow vehicles to perform at a more efficient fuel economy. Projects that improve traffic flow during peak travel demand periods or reduce stop-and-go conditions would improve vehicles' fuel economies, and thus affect project energy consumption.

Another important consideration is that for operation of a project over the long term, newer and more fuel-efficient vehicles will enter the fleet, resulting in an overall lower potential for an increase in energy consumption due to vehicle traffic. Additionally, projects that include elements that would reduce VMT, such as transit improvements or providing facilities for pedestrians and bicyclists, would generally offset some of a project's potential energy usage. Projects that directly support the use of electric vehicles, such as the installation of charging stations, would also reduce energy usage. Fuel economy as a function of speed is shown in Figure 2.

Figure 2. Fuel Economy by Speed
(Model year 2008 Fuel Economy Guide (PDF), U.S. Department of Energy and U.S. Environmental Protection Agency, updated March 31, 2016.)

Fuel economy by speed

Information for Environmental Documentation

The Environmental Consequences section should specifically address whether the project may result in wasteful, inefficient, or unnecessary consumption use of energy, or wasteful use of energy resources. The guidance in section 15126.2(b) and Appendix F of the CEQA Guidelines, Energy Conservation, should also be considered. Note that there is a focus on energy efficiency, savings, and conservation in the CEQA guidance. This is a good place to demonstrate a project's long-term potential for energy savings and to document conservation measures to be employed during the construction, operation, and maintenance phases.

A discussion of environmental consequences should consider changes in total direct and indirect energy consumption under project build alternatives relative to existing conditions and the no-build alternative(s). For example, a transportation improvement energy study is very likely to indicate that construction of the improvements would result in a temporary increase in energy consumption. However, this may be offset over time by improvements in the form of altered traffic patterns or traffic flow, resulting in overall reduced energy consumption relative to the no-build condition.

Many projects will result in energy savings. As noted above, projects that make roadway improvements or that smooth existing traffic flow may result in reduced energy consumption. Projects that reduce VMT or incorporate active transportation elements may also lower or partially offset energy consumption. Replacing older highway lighting with newer energy efficiency lighting can result in energy savings over the long term. Projects that reduce out-of-direction travel can also lessen energy consumption. Indirect energy savings through reduced maintenance needs (roadway, culverts, etc.) should also be discussed.

Another factor to discuss in the context of environmental consequences is future energy efficiency improvements in the vehicle fleet due to gradual implementation of federally-mandated fuel efficiency standards. This would result in a net reduction of energy consumption over time. The analysis tools that quantify fuel and emissions from vehicles and equipment account for legislatively adopted vehicle fuel efficiency standards.

A discussion should include any energy-saving measure specifically incorporated into the project design. This could include reduction in grades and curvatures, and use of renewable energy sources in construction and operation of the project. Other examples might include the use of recycled materials, LED lighting[1], solar power, or the installation of TMS elements.

The discussion of environmental consequences must also describe the applicable Regional Transportation Plan (RTP) and other planning documents in order to demonstrate that the project does not obstruct or conflict with a state or local plan for renewable energy or energy efficiency.

Information Needed for Project Delivery

Project Initiation Document

Consideration of potential energy impacts should begin as early in the project development process as possible. In current practice, the energy analysis is often overlooked until the writing of the draft environmental document commences.

Projects on the State Highway System (SHS) – The need for an energy study should be determined at the Project Initiation stage and discussed in the Preliminary Environmental Analysis Report (PEAR). When preparing the energy portion of the PEAR, points to consider include: 1) whether an energy analysis is needed for the proposed project; and 2) if an energy analysis is needed, what would be the proper scope of the analysis?

Energy Analysis Report

As discussed above, the Energy Analysis Report (or memo to file) must be completed prior to completion of the draft environmental document and draft project report. The potential energy impacts of each alternative should be analyzed and discussed in the environmental document along with any proposed avoidance, minimization, and/or mitigation measures.

The Energy Analysis Report may be revised after circulation and public comment on the draft environmental document. To the extent that the proposed project is modified or new information is obtained after circulation of the draft environmental document, the energy analysis may need to be revised prior to completion of the final environmental document.

Permit Requirements

There are no permits required with respect to potential energy impacts.

[1] LED lighting is a type of lighting that uses "light-emitting diodes."