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INL analysis of 5 large-scale PEV and charging projects finds public charging infrastructure not needed everywhere to enable PEV adoption

Idaho National Laboratory has released the voluminous findings from its analysis of five large-scale PEV and charging infrastructure projects funded by the American Recovery and Reinvestment Act. Collectively, these projects represent the largest-ever deployment, data collection and analysis, and reporting of PEV and charging infrastructure petroleum reduction benefits. The results will be used to support and refine activities of the US Department of Energy’s EV Everywhere Grand Challenge.

The key finding of INL’s assessment of the results was that public charging infrastructure is not needed everywhere to enable PEV adoption. Instead, the results suggest that charging infrastructure should be focused at homes, workplaces and public “hot spots” that serve multiple venues.

The five projects and technologies researched were:

  • ChargePoint America: charging infrastructure
  • Chevrolet Volts: extended range electric vehicles (EREVs)
  • Chrysler Ram Pickup: plug-in hybrid electric vehicles (PHEVs)
  • The EV Project: charging infrastructure, Nissan Leafs, Chevrolet Volts and Car2Go Smart EVs
  • SCAQMD/EPRI/Via Motors: PHEV vans and pickups

Combined, ChargePoint America and The EV Project alone formed the largest PEV infrastructure demonstration in the world. Between 1 Jan. 2011, and 31 Dec. 2013, this combined project installed nearly 17,000 alternating current (AC) Level 2 charging stations for residential and commercial use and more than 100 dual-port direct current (DC) fast chargers in 22 regions across the United States.

More than 8,000 privately owned Nissan Leafs and Chevrolet Volts and more than 300 Smart ForTwo Electric Drive vehicles in Car2Go car-sharing fleets were enrolled in the project.

A commonly cited barrier to PEV adoption is the lack of public places for PEV drivers to plug in their vehicles. To reduce this barrier, DOE set out to answer a set of critical questions: How many and what kind of charging stations are needed? Where and how often do PEV drivers charge? How many electric vehicle miles are traveled and what level of petroleum reduction can be achieved?

Beginning in 2009, several resulting projects—Charge Point America project, Chrysler Ram PEV Demonstration, General Motors Volt Demonstration, South Coast Air Quality Management District/Via Motors PHEV Demonstration, and The EV Project—installed roughly 17,000 charging stations and deployed approximately 8,700 PEVs across the US. The DOE Office of Energy Efficiency and Renewable Energy provided half the funding for the five projects, and INL researchers collected and analyzed the resulting data.

Data collected from all five projects captured nearly 130 million miles of driving and 6 million charging events, providing the most comprehensive view of PEV and charging usage to date.

INL found that PEV private owners performed an average of more than 85% of charging at home. About half the project participants charged at home almost exclusively. Of those who charged away from home, the vast majority favored three or fewer away-from-home charging locations, and one or more of these locations was at work for some drivers.

This is not to say that public charging stations are not necessary or desirable. Many DC fast chargers (all of which were accessible to the public) experienced heavy use to support both in-town and inter-city driving. Also, a relatively small number of public AC Level 2 public charging sites saw consistently high use. This begs the question: what is it about the small number of highly used charging sites that led to their popularity?

There was some correlation between public charging location characteristics and utilization. Public Level 2 charging stations installed in locations where vehicles were typically parked for longer periods of time often were, in fact, among those most often used. These locations included shopping malls, airports and commuter lots, and downtown parking lots or garages with easy access to a variety of venues.

—INL report

The study also found that drivers adjust their charging habits based on conditions such as fees and rules for use. When privately owned Volts are charged frequently, they achieved better than 120 mpg in normal consumer use patterns. Also, workplace charging was found to enable significant electric range extension. Project participants with access to charging at work were observed to drive 25% more on electricity alone than the overall group of vehicles in the project.

The project also illuminated other aspects of PEV use.

  • Public and workplace charging infra-structure enabled drivers to increase their electric driving range.

  • Drivers of the Chevrolet Volt, an extended-range electric vehicle, tended to charge more frequently and to more fully deplete their vehicle’s battery than drivers of the Nissan LEAF BEV. This allowed the overall group of Volts studied to average only 6% fewer electric vehicle (EV) mode miles traveled as the LEAFs in the project, despite the LEAF’s much larger battery pack.

    INL suggested two reasons for this: first, Volt drivers tend to deplete their batteries fully, while LEAF drivers favored recharging with significant charge resident in their batteries. Second, Volt drivers plugged in more oftern than LEAF drivers.

  • There are opportunities to use pricing structures and other policies to manage demand for PEV charging, both in terms of charging station through-put at charging hot spots and electricity demand on the electric grid.




The study is obviously correct. If one uses simple reasoned analysis it becomes apparent. However, the perception of the public is formed by media opinion, which has often stated that more range and more charging are necessary before plug-in cars will become viable. This media opinion may simply be ignorance as what we call journalists these days are simply teleprompter readers who have no real input to the words, and as such it just may be the simple following of standard human ignorance, or, it may be the message desired by the owners of media outlets who seem to want to stop change since they and their partners are already making all the money. There is risk in change, but mostly in who controls markets and make the money. Standard American corporations are risk averse since the CEOs are short timers only interested in their own enrichment and thus long term change even when likely inevitable is to be avoided for their own best interests (getting filthy rich). The bottom line is that regardless of whether large amounts charging infrastructure is actually necessary, public perception is that it is, and as unthinking as the typical person is, that means it is likely to be necessary if for no other reason than to convince the average person that the plug-ins are viable. This is similar to the cost of ownership argument. What I mean is that a number of EVs save consumers already on a total cost of ownership basis, but the average person will only look at the initial cost of vehicles and they will never understand that they can save with an EV if they use it correctly. But then that is all just too much work.


Practicality and initial cost of PHEVs and BEVs may be the main reasons why the majority is still reluctant to buy.

The e-range of early PHEVs was not sufficient but may soon reach the bare minimum of 100 Km. The higher initial cost is already offset in most States with subsidies.

The e-range of early BEVs was grossly insufficient and may not be addressed before 2020 in most cases, when it will reach about 500+ Km. The initial purchase price is still too high and much higher subsidies will be required to convince more potential buyers to make the move.

Subsidies will help bridge the gap, but as soon as battery costs fall below the threshold that makes the EV power plant price competitive with ICEs, any manufacturer selling EVs will have a permanent competitive advantage.

That threshold will be crossed much sooner if, like Tesla and Nissan, more manufacturers develop a charging network and bundle (and finance) some or all of the future fuel costs.

The most important insight of the INL study is that chargers must be placed in optimum sites. Only Tesla has done a really good job on this so far. It will be a significant competitive advantage over the next several years, if not longer.


When electrification reaches about 5% of light vehicle miles driven, and is growing about 20% per year, the price of oil will be permanently suppressed to such a point that the market will keep ICEs, because oil will be very cheap (like $28 per barrel cheap). There will be an equilibrium of electrification market share that then won't increase robustly.

The only way to reach the scenario you're describing is a fuel tax (or unrealistically large carbon tax) to keep fuel costs higher.


With well positioned charging stations, we can solve both the range and inital cost issues (smaller batteries). I would buy an EV tomorrow if the cost was low enough and I could get to work everyday then charge at work. We have two cars, so one can be available for longer trips, at least for a couple of more years. I believe others would make the same type of decision if they could.



I have a 100 mile EV (Fiat 500e) and I'm able to charge at work (my wife can too at her work); it is a significant upside for its viability for me. I live and work in Silicon Valley, however - it will be a while before other parts of the USA catch up to being as EV-friendly.


EVs have a $7500 tax credit when bought, how about a $2500 annual deduction every year you own and operate?


That could be done with variable (negative and positive) annual rgistration fees based on GHG and pollution created and distance travelled.

Since our e-grid is supplied with 100% REs and all liquid fuels are imported, it could be a win-win solution?


@ NP

The beauty is that not all areas have to have chargers at once. Silicon Valley now, but other areas can be added incrementally. We don't require a nationwide network to make EV's attractive locally.

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