Goals and Accomplishments

Clean Cities coalitions employ five strategies to advance affordable, efficient, and clean transportation fuels and technologies:

  • Evaluate transportation needs and energy choices to determine the most impactful and cost-effective vehicle options, fuels, technologies, and best practices that make sense for specific stakeholder applications
  • Shift to efficient and clean energy sources through the use of alternative and renewable fuels such as natural gas, propane, hydrogen, electricity, ethanol, and biodiesel
  • Improve fuel efficiency through state-of-the-art technologies and strategies
  • Reduce greenhouse gas emissions through idle reduction and other fuel-saving technologies and practices
  • Demonstrate and assess new mobility choices that maximize the return on investment for mobility systems in terms of time, cost, energy, and opportunity.

Discover how Clean Cities coalitions have contributed to significant transportation advancements through the years.

Impacts of Alternative Fuels and Advanced Vehicle Technologies

Since 1993, Clean Cities coalitions have steadily increased their energy use impact each year through diverse transportation projects for a cumulative impact equal to nearly 12 billion gasoline gallon equivalents (GGEs). Clean Cities coalitions have helped to place more than a million alternative fuel vehicles on the road and establish the fueling infrastructure to serve this growing market. They have also aided in the elimination of millions of hours of vehicle idling and have been instrumental in the entry of new transportation technologies into the marketplace.

Cumulative Energy Use Impact

The cumulative energy use impact of Clean Cities coalitions has reached nearly 12 billion GGEs since 1993 through alternative fuel use, fuel economy improvements, idle-reduction measures, and other strategies. Source: Clean Cities coalitions annual activity reports

Energy use impact is a metric that measures the quantity of conventional fuel that was shifted to clean, domestic, economical sources, such as alternative fuels, or saved through efficiency improvements. The metric used is gasoline gallon equivalents.

Cumulative Energy Use Impact
Year Annual Cumulative
2020 955000000 11853000000
2019 1063000000 10898000000
2018 1056000000 9835000000
2017 973000000 8779000000
2016 978000000 7806000000
2015 897000000 6828000000
2014 800000000 5930000000
2013 742000000 5131000000
2012 661000000 4389000000
2011 641000000 3728000000
2010 520000000 3087000000
2009 482000000 2567000000
2008 287000000 2085000000
2007 294000000 1798000000
2006 302000000 1504000000
2005 187000000 1202000000
2004 233000000 1015000000
2003 156000000 782000000
2002 133000000 626000000
2001 119000000 494000000
2000 92000000 375000000
1999 87000000 283000000
1998 67000000 196000000
1997 43000000 128000000
1996 45000000 86000000
1995 26000000 41000000
1994 15000000 15000000

Energy Use Impact by Technology Type

In 2020 alone, coalition projects resulted in a cumulative impact in energy use equal to 740 million gasoline gallon equivalents by using alternative fuel vehicles. Source: Clean Cities Coalitions 2020 Activity Report

* EVs include all-electric vehicles and plug-in hybrid electric vehicles, but not hybrid electric vehicles.

Energy Use Impact by Technology Type
Technology Type Million GGEs
Natural Gas 367.96
Biodiesel 125.22
Ethanol 73.15
Propane 45.25
Idle Reduction 44.11
Fuel Economy 43.49
EVs* 38.70
VMT Reduction 37.78
HEVs 35.61
Renewable Natural Gas 33.96
Off-Road 32.98
Renewable Diesel 19.68
Hydrogen 0.59

Clean Cities Alternative Fuel Vehicle Inventory


Coalitions have made great strides to integrate alternative fuel vehicles (AFVs) across the United States. In 2020, more than 1 million of the AFVs in operation were a result of Clean Cities coalition efforts. Source: Clean Cities Coalitions 2020 Activity Report

* Electric includes all-electric vehicles and plug-in hybrid electric vehicles, but not hybrid electric vehicles.

Clean Cities Alternative Fuel Vehicle Inventory
Fuel 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
Biodiesel 31922 52275 91584 98785 17222 2814 88726 99347 103106 98028 130540 189823 160763 150695 153380 163366 203839
Compressed Natural Gas 76257 49271 57458 55021 51121 44317 42911 48157 59521 79616 68479 107283 98388 97271 82266 100938 87392
Ethanol (E85) 47643 72899 221834 385671 524169 642520 403981 479706 197187 259337 275508 271996 457817 327865 263967 275216 268047
Hybrid Electric 10674 18553 43886 81987 101954 107585 30613 50503 141406 83339 82834 94330 129827 178011 178733 144875 157540
Hydrogen 23 42 72 86 75 74 62 118 50 46 49 95 97 116 402 691 413
Liquefied Natural Gas 0 1873 2271 1731 2053 2038 3410 4315 3411 3645 2992 3974 4924 5070 5100 4917 4510
Electric* 9241 7464 9481 5895 14135 4568 9223 10541 20455 32187 65042 96896 171011 162811 227854 263543 234277
Propane 31338 21117 25543 23628 22260 7937 13196 18793 16501 35554 17404 22762 23648 34753 25395 31985 30156
Renewable Diesel 0 0 0 0 0 0 0 0 0 0 0 3183 71066 7819 11174 13109 11807
Renewable Natural Gas 0 0 0 0 0 0 0 0 0 0 313 366 1157 1734 1677 4922 7229

U.S. Alternative Fueling Station Inventory


Today's drivers can find thousands of fueling stations across the country that provide natural gas, electricity, ethanol, and other alternative fuels. Source: Alternative Fuels Data Center

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In the past 29 years, the U.S. Department of Energy (DOE) has [funded hundreds of transportation projects nationwide](/partnerships/search/) through a competitive application process. Clean Cities coalitions have historically leveraged these federal dollars to produce almost 2:1 in additional matching funds and in-kind contributions from private and public sector partners. ## National Award Recipients DOE recognizes the accomplishments of Clean Cities coalitions and stakeholders through the [Hall of Fame](/hall-of-fame/).
U.S. Alternative Fueling Station Inventory
Fuel Type 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021
Biodiesel 0 0 0 0 0 0 0 0 2 16 79 142 176 304 459 805 633 660 615 633 690 832 783 713 716 704 680 611 712 730
Compressed Natural Gas 349 497 1042 1065 1419 1426 1268 1267 1217 1232 1166 1035 917 787 732 731 771 803 869 941 1155 1290 1495 1607 1730 1682 1621 1576 1549 1510
Electric 0 0 0 188 194 310 486 490 558 693 873 830 671 588 465 432 440 484 626 2100 6200 8100 10712 13696 17723 19792 22826 26959 31738 50054
Ethanol (E85) 2 7 32 37 68 71 40 49 113 154 149 188 200 436 762 1325 1699 1982 2296 2494 2519 2616 2840 3012 3095 3379 3627 3786 3946 4331
Hydrogen 0 0 0 0 0 0 0 0 0 0 7 7 9 14 17 33 51 63 58 56 58 53 51 35 58 63 62 64 63 67
Liquefied Natural Gas 0 0 0 0 72 71 66 46 44 44 36 62 58 40 37 35 38 37 43 43 61 84 103 117 140 137 129 118 106 103
Methanol (M85) 43 50 82 88 95 106 91 51 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Propane 3297 3297 3299 3299 4252 4255 5318 4153 3268 3403 3431 3966 3689 2995 2619 2331 2110 2420 2604 2551 2644 2967 2931 3749 3654 3510 3319 3176 2956 2805