336
translates into substantially larger life cycle energy and GHG benefi ts, even if you
consider that BEVs have signifi cantly larger cradle-to-gate production energy inputs
and GHG emissions than equivalent ICVs (Campbell et al. 2009 ). However, one
major drawback of any sun-to-wheels transportation pathway based on biomass is
that the energy conversion effi ciency of photosynthesis is typically below 1 %
(Blankenship et al. 2011 ). This means that vast areas of land are needed to harvest
signifi cant amounts of solar energy (McDonald et al. 2009 ). A much more effi cient
alternative would be direct photovoltaic conversion into electricity. Such a PV-BEV
system is orders of magnitude more land use effi cient than even the most optimistic
biomass scenarios and has equal or higher energy and GHG benefi ts (Geyer et al.
2013 ). PV-powered BEVs are conceptually appealing but have some technical and
operational challenges, one of which is the timing of PV power supply and EV
charging demand.
3 Powertrains
Electric vehicles had all but vanished by 1920, apart from some niche applications
such as the iconic British milk fl oat. The modern era of the EV began when General
Motors (GM) unveiled a BEV prototype called Impact at the 1990 Los Angeles
Auto Show. This was encouraging news for the California Air Resources Board
(CARB), which had been working on a low-emission vehicle (LEV) program to
help areas such as Los Angeles meet federal air quality standards (Collantes and
Sperling 2008 ). CARB had come to the conclusion that improvements in conventional powertrains alone would not achieve the required emission reductions. As a
result, CARB added a so-called zero-emission vehicle (ZEV) mandate to the LEV
program of 1990. The mandate specifi es that car sales of the major manufacturers
had to be composed of at least 2 % ZEVs by 1998, 5 % by 2001, and 10 % by 2003.
A ZEV is defi ned as having no tailpipe emissions of air criteria pollutants. CARB
clearly had BEVs in mind, but since its regulation has to be technology neutral, it
pointed out that fuel cell vehicles (FCVs) would also meet the defi nition. The ZEV
mandate is arguably the single biggest driver behind the emergence of alternative
powertrains. It is interesting to note that it emerged from concerns over air quality
and not oil resources or climate change. In the United States, fuel economy can only
be regulated at the federal level. After a White House proposal to increase fuel
economy standards failed in congress in 1992, the Clinton administration started the
Partnership for a New Generation of Vehicles (PNGV) with the goal to develop
dramatically more fuel-effi cient powertrains (Malakoff 1999 ). The research collaborative, which was cancelled in 2001 by the Bush administration, focused on dieselelectric hybrids and FCVs rather than BEVs.
In late 1997 Toyota’s Prius, the fi rst mass-produced hybrid-electric vehicle
(HEV), went on sale in Japan. A few years later, Honda and Toyota started selling
HEVs in the United States. In contrast, only a number of concept vehicles were created under the PNGV program. Measured in ZEV sales, California’s ZEV mandate
R. Geyer
translates into substantially larger life cycle energy and GHG benefi ts, even if you
consider that BEVs have signifi cantly larger cradle-to-gate production energy inputs
and GHG emissions than equivalent ICVs (Campbell et al. 2009 ). However, one
major drawback of any sun-to-wheels transportation pathway based on biomass is
that the energy conversion effi ciency of photosynthesis is typically below 1 %
(Blankenship et al. 2011 ). This means that vast areas of land are needed to harvest
signifi cant amounts of solar energy (McDonald et al. 2009 ). A much more effi cient
alternative would be direct photovoltaic conversion into electricity. Such a PV-BEV
system is orders of magnitude more land use effi cient than even the most optimistic
biomass scenarios and has equal or higher energy and GHG benefi ts (Geyer et al.
2013 ). PV-powered BEVs are conceptually appealing but have some technical and
operational challenges, one of which is the timing of PV power supply and EV
charging demand.
3 Powertrains
Electric vehicles had all but vanished by 1920, apart from some niche applications
such as the iconic British milk fl oat. The modern era of the EV began when General
Motors (GM) unveiled a BEV prototype called Impact at the 1990 Los Angeles
Auto Show. This was encouraging news for the California Air Resources Board
(CARB), which had been working on a low-emission vehicle (LEV) program to
help areas such as Los Angeles meet federal air quality standards (Collantes and
Sperling 2008 ). CARB had come to the conclusion that improvements in conventional powertrains alone would not achieve the required emission reductions. As a
result, CARB added a so-called zero-emission vehicle (ZEV) mandate to the LEV
program of 1990. The mandate specifi es that car sales of the major manufacturers
had to be composed of at least 2 % ZEVs by 1998, 5 % by 2001, and 10 % by 2003.
A ZEV is defi ned as having no tailpipe emissions of air criteria pollutants. CARB
clearly had BEVs in mind, but since its regulation has to be technology neutral, it
pointed out that fuel cell vehicles (FCVs) would also meet the defi nition. The ZEV
mandate is arguably the single biggest driver behind the emergence of alternative
powertrains. It is interesting to note that it emerged from concerns over air quality
and not oil resources or climate change. In the United States, fuel economy can only
be regulated at the federal level. After a White House proposal to increase fuel
economy standards failed in congress in 1992, the Clinton administration started the
Partnership for a New Generation of Vehicles (PNGV) with the goal to develop
dramatically more fuel-effi cient powertrains (Malakoff 1999 ). The research collaborative, which was cancelled in 2001 by the Bush administration, focused on dieselelectric hybrids and FCVs rather than BEVs.
In late 1997 Toyota’s Prius, the fi rst mass-produced hybrid-electric vehicle
(HEV), went on sale in Japan. A few years later, Honda and Toyota started selling
HEVs in the United States. In contrast, only a number of concept vehicles were created under the PNGV program. Measured in ZEV sales, California’s ZEV mandate
R. Geyer