Publications

Idling Reduction for Personal Vehicles

5/7/2015

Fact sheet on reducing engine idling in personal vehicles. Idling your vehicle--running your engine when you're not driving it--truly gets you nowhere. Idling reduces your vehicle's fuel economy, costs you money, and creates pollution. Idling for more than 10 seconds uses more fuel and produces more emissions that contribute to smog and climate change than stopping and restarting your engine does.

Stop and Restart Effects on Modern Vehicle Starting System Components

4/28/2015

Many drivers of personal and commercial vehicles believe that turning the vehicle off and on frequently instead of idling will cause premature wear of the starter system (starter motor and starter battery). As a result, they are concerned that the replacement cost of the starter motor and/or battery due to increased manual engine cycling would be more than the cumulative cost of the fuel saved by not idling unnecessarily. A number of variables play a role in addressing this complex concern, including the number of starting cycles per day, the time between starting cycles, the intended design life of the starting system, the amount of fuel used to restart an engine, and the cumulative cost of the saved fuel. Qualitative and quantitative information from a variety of sources was used to develop a life-cycle economic model to evaluate the cost and quantify the realistic factors that are related to the permissible frequency of starter motor cycles for the average vehicle to economically minimize engine idle time. Annual cost savings can be calculated depending on shutdown duration and the number of shutdown cycles per day. Analysis shows that cost savings are realized by eliminating idling exceeding one minute by shutting down the engine and restarting it. For a typical motorist, the damage to starting system components resulting from additional daily start cycles will be negligible. Overall, it was found that starter life is mostly dependent on the total number of start cycles, while battery life is more dependent on ensuring a full charge between start events.

Authors: Windover, P.R.; Owens, R.J.; Levinson, T.M.; Laughlin, M.D.

What were the "Best Practices" Identified for Residential Charger Installations?

4/1/2015

This lessons learned white paper is based on data from the EV Project which enrolled 8,000 residential participants to install and use residential electric vehicle supply equipment. Along with background information and key conclusions, this paper describes observations regarding permitting practices and best installation conditions.

Building a Business Case for Compressed Natural Gas in Fleet Applications

3/19/2015

Abstract: Natural gas is a clean-burning, abundant, and domestically produced source of energy. Compressed natural gas (CNG) has recently garnered interest as a transportation fuel because of these attributes and because of its cost savings and price stability compared to conventional petroleum fuels. The National Renewable Energy Laboratory (NREL) developed the Vehicle Infrastructure and Cash-Flow Evaluation (VICE) model to help businesses and fleets evaluate the financial soundness of CNG vehicle and CNG fueling infrastructure projects.

Authors: Mitchell, G.

Clean Cities Alternative Fuel Price Report, January 2015

3/17/2015

The Clean Cities Alternative Fuel Price Report for January 2015 is a quarterly report on the prices of alternative fuels in the U.S. and their relation to gasoline and diesel prices. This issue describes prices that were gathered from Clean Cities coordinators and stakeholders between January 1, 2015 and January 15, 2015, and then averaged in order to determine regional price trends by fuel and variability in fuel price within regions and among regions. The prices collected for this report represent retail, at-the-pump sales prices for each fuel, including Federal and state motor fuel taxes.

Table 1 reports that the nationwide average price (all amounts are per gallon) for regular gasoline has decreased $1.04 from $3.34 to $2.30; diesel decreased 71 cents from $3.77 to $3.06; CNG price decreased 5 cents from $2.16 to $2.11; ethanol (E85) decreased 67 cents from $2.88 to $2.21; propane decreased 16 cents from $3.08 to $2.92; and biodiesel (B20) has decreased 63 cents from $3.81 to 3.18.

According to Table 2, CNG is $.19 less than gasoline on an energy-equivalent basis, while E85 is $0.82 more than gasoline on an energy-equivalent basis.

Authors: Bourbon, E.

Sample Workplace Charging Policy

3/2/2015

A sample workplace charging policy developed by the U.S. Department of Energy's Workplace Charging Challenge.

Authors: Workplace Charging Challenge

Effects of Regional Temperature on Electric Vehicle Efficiency, Range, and Emissions in the United States

2/11/2015

We characterize the effect of regional temperature differences on battery electric vehicle (BEV) efficiency, range, and use-phase power plant CO2 emissions in the U.S. The efficiency of a BEV varies with ambient temperature due to battery efficiency and cabin climate control. We find that annual energy consumption of BEVs can increase by an average of 15% in the Upper Midwest or in the Southwest compared to the Pacific Coast due to temperature differences. Greenhouse gas (GHG) emissions from BEVs vary primarily with marginal regional grid mix, which has three times the GHG intensity in the Upper Midwest as on the Pacific Coast. However, even within a grid region, BEV emissions vary by up to 22% due to spatial and temporal ambient temperature variation and its implications for vehicle efficiency and charging duration and timing. Cold climate regions also encounter days with substantial reduction in EV range: the average range of a Nissan Leaf on the coldest day of the year drops from 70 miles on the Pacific Coast to less than 45 miles in the Upper Midwest. These regional differences are large enough to affect adoption patterns and energy and environmental implications of BEVs relative to alternatives.

Authors: Yuksel, T.; Michalek, J. J.

Notes: This Environmental Science & Technology article is copyrighted by the American Chemical Society and only available by accessing it through ACS Publications.

Plug-In Electric Vehicle Handbook for Consumers

2/9/2015

This handbook is designed to answer a consumer's basic questions, as well as point them to additional information they need, to make the best decision about whether an electric-drive vehicle is right for them.

Fuel Cell Buses in U.S. Transit Fleets: Current Status 2014

1/29/2015

This report, published annually, summarizes the progress of fuel cell electric bus (FCEB) development in the United States and discusses the achievements and challenges of introducing fuel cell propulsion in transit. Various stakeholders, including FCEB developers, transit agencies, and system integrators, have expressed the value of this annual status report, which provides a summary of results from evaluations performed by the National Renewable Energy Laboratory. The annual status report tracks the progress of the FCEB industry toward meeting technical targets, documents the lessons learned, and discusses the path forward for commercial viability of fuel cell technology for transit buses.

Authors: Eudy, L.; Post, M.; Gikakis, C.

Supporting the Plug-In Electric Vehicle Market: Best Practices from State PEV Programs

1/14/2015

This paper captures best practices in state-sponsored plug-in electric vehicle (PEV) buyer incentive programs, DC fast charging programs, and PEV awareness initiatives, as presented at the Transportation and Climate Initiative's 2014 Plug-In Electric Vehicle Workshop.

Authors: Powers, C.

Notes: This copyrighted publication is available on the Georgetown Climate Center website

Clean Cities Alternative Fuel Price Report, October 2014

12/23/2014

The Clean Cities Alternative Fuel Price Report for October 2014 is a quarterly report on the prices of alternative fuels in the U.S. and their relation to gasoline and diesel prices. This issue describes prices that were gathered from Clean Cities coordinators and stakeholders between October 1, 2014 and October 15, 2014, and then averaged in order to determine regional price trends by fuel and variability in fuel price within regions and among regions. The prices collected for this report represent retail, at-the-pump sales prices for each fuel, including Federal and state motor fuel taxes.

Table 1 reports that the nationwide average price (all amounts are per gallon) for regular gasoline has decreased 36 cents from $3.70 to $3.34; diesel decreased 14 cents from $3.91 to $3.77; CNG price decreased 1 cent from $2.17 to $2.16; ethanol (E85) decreased 35 cents from $3.23 to $2.88; propane increased 1 cent from $3.07 to $3.08; and biodiesel (B20) has decreased 17 cents from $3.98 to 3.81.

According to Table 2, CNG is $1.18 less than gasoline on an energy-equivalent basis, while E85 is $0.73 more than gasoline on an energy-equivalent basis.

Authors: Bourbon, E.

Increasing Biofuel Deployment and Utilization through Development of Renewable Super Premium: Infrastructure Assessment

11/25/2014

A high octane fuel and specialized vehicle are under consideration as a market opportunity to meet federal requirements for renewable fuel use and fuel economy. Infrastructure is often cited as a barrier for the introduction of a new fuel. This report assesses infrastructure readiness for E25 (25% ethanol; 75% gasoline) and E25+ (more than 25% ethanol). Both above-ground and below-ground equipment are considered as are the current state of stations, codes and regulations, and materials compatibility.

Authors: Moriarty, K.; Kass, M.; Theiss, T.

Workplace Charging: Comparison of Sustainable Commuting Options

11/18/2014

Reducing greenhouse gas emissions (GHG) from employees' commutes, also known as Scope 3 emissions, is a top priority for many organizations interested in minimizing their carbon footprint. Scope 3 emissions are indirect GHG emissions from sources not owned or directly controlled by the organization but are related to their activities, including emissions from an employee's commute. Employers interested in investing in GHG emissions reduction efforts may want to compare the benefits of workplace charging to other commuter emission reduction investments such as subsidized public transportation or carpooling. The GHG emissions reduction benefit of workplace charging per dollar is comparable to, and in some cases greater than, other commuting options.

Authors: Brown, A.

U.S. Department of Energy's EV Everywhere Workplace Charging Challenge, Progress Update 2014: Employers Take Charge

11/17/2014

Through the Workplace Charging Challenge, more than 150 partner organizations are accelerating the development of the nation's worksite PEV charging infrastructure and are supporting cleaner, more convenient transportation options within their communities. Challenge partners are currently providing access to PEV charging stations for more than 600,000 employees at more than 300 worksites across the country and are influencing countless other organizations to do the same.

Using Recent Land Use Changes to Validate Land Use Change Models

11/14/2014

Economics models used by California, the Environmental Protection Agency, and the EU Commission all predict significant emissions from conversion of land from forest and pasture to cropland in response to increased biofuel production. The models attrib-ute all supply response not captured by increased crop yields to land use conversion on the extensive margin. The dramatic increase in agricultural commodity prices since the mid-2000s seems ideally suited to test the reliability of these models by comparing actual land use changes that have occurred since the price increase to model predictions. Country-level data from FAOSTAT were used to measure land use changes. To smooth annual variations, changes in land use were measured as the change in average use across 2004 to 2006 compared to average use across 2010 to 2012. Separate measure-ments were made of changes in land use at the extensive margin, which involves bring-ing new land into agriculture, and changes in land use at the intensive margin, which includes increased double cropping, a reduction in unharvested land, a reduction in fallow land, and a reduction in temporary or mowed pasture. Changes in yield per harvested hectare were not considered in this study.

Authors: Babcock, B.A; Iqbal, Z.