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Another cut at US electric vehicle range requirements and usage patterns; fully-charged LEAF could handle 83-95% of all driving days

Daily
Cumulative distribution curve for daily driven distance by cars that were used on the Travel Day (representing 61% of all cars owned by the participating households). Data source: NHTS 2009. Click to enlarge.

In an effort to calculate what percentage of daily trips in the US could be covered with a fully charged electric vehicle, two Columbia doctoral candidates recently conducted a statistical analysis using the National Household Travel Survey of 2009 on distances driven by the US population. They projected the results on typical range bins seen in the portfolio of electric cars that are available as of 2011.

The second part of their study, Assessment of Electric Cars’ Range Requirements and Usage Patterns based on Driving Behavior recorded in the National Household Travel Survey of 2009, covers car usage patterns on an hourly basis for weekdays and weekends, which are in turn used to assess when cars are connected to the grid and available for charging.

Solar Journey USA project
This study was conducted as part of the Solar Journey USA project, an initiative to educate Americans about electric vehicles, solar energy and the synergy of Sustainable Driving that arises from the two.
In the summer of 2012, Rob van Haaren and Garrett Fitzgerald plan to make a cross-country trip powered strictly by solar energy, generated by a towed PV array. Each day, they will recharge the batteries in their electric car for the next leg of the trip, while giving presentations and workshops about the technologies.

The National Household Travel Survey (NHTS) includes data from 150,147 households gathered between March 2008 and May 2009 on four levels: household, person, vehicle and travel day. The dataset was downloaded from the NHTS website and imported into SPSS 18 for analysis.

Among the top-level findings of the study are:

  • 61% of all participating cars, SUVs, vans and pickup trucks were used on the Travel Day and they drove an average of 40 miles per day.

  • For individual trips (i.e., one-way), 95% are below 30 miles and 99% are below 70 miles. When driven distance is aggregated over the whole day, ~95% are below 120 miles and 99% are below 250 miles.

  • Car commuting distances were found to average 12.6 miles nationally, with 95% below 40 miles and 99% shorter than 60 miles. Assuming the electric car is charged overnight only, a Nissan LEAF with a 62-138 mile range would be able to satisfy 83-95% of all travel days, depending on driving conditions as described before. A 2011 Tesla Roadster would be able to satisfy >98.5% of travel days, assuming a minimum range of 0.85 times the EPA-labeled range.

  • Vehicles owned by households in districts constrained by area—such as Hawaii and District of Columbia—were driven shorter distances than others (~24 miles per day, compared to a national average of 39.5 miles per day). On the other hand, States with primarily rural areas and a large fraction of the population living in single dwellings or small towns (typically in the Midwest) averaged higher driven distances (up to 49 miles per day).

Perhaps the most important conclusion is that the majority of US households have the luxury to simply pick their gasoline car in case they plan on a long trip. 64% of households that own one or more cars have the luxury of owning a gasoline car besides their future EV (assuming the EV replaces a gasoline car). Think of it as owning both a two-seater and a sedan: would you choose the two-seater if you’re picking up three friends to go watch the football game? We’ve seen that 39% of all cars are not even used on the Travel Day. This gives rise to a new research question: “From all cars owned by members of a household, how many vehicles drive beyond a distance of x miles on the Travel Day?”

—Rob van Haaren

Resources

Comments

ai_vin

@AD

Actually, solar home owners have found "the colder it is, the clearer the skies."
http://www.solarhouse.com/index.php?option=com_content&view=article&id=61&Itemid=58
Also solar isn't the only form of clean energy, there's always wind - and winters tend to be windier.

As for the issue of heating: I have seen studies that suggest insulation of the battery box and passenger compartment together with preheating while the car is still plugged-in on the recharge as a solution.

LanceK

very quick charge 440/660 DC Volts stations at every shopping, eating, school, working places and roadway (Ex) gas stations etc will become common place
Back to reality pluging 440/660 in after John Q Public's kid stuck bubble gum in the end dosen't sound OSHA approved, Not to be a nea sayer.

ai_vin

Oh that is definitely 'nea saying.'

SJC

Nea you say, just realistic scenarios to keep the dreamer's feet on the ground.

HarveyD

Naysayers have not (yet) learned that foul/kid proof power interlocks have been around for almost 100 years. Even the power plug cover could easily be made foul/kid proof.

A basic simple $10 gas tank access cover has stopped John low IQ public and fouls/kids from stealing gas and/or putting sugar in your gas tank.

Let us not create problems where there are none. Future extended range EVs (with 100+ Kwh batteries) will use much higher voltage ultra safe DC and/or AC chargers. Who will even try to charge a 100+ KWh battery with 110 VAC?

HarveyD

AD...large (bus like) BEVs could have extra batteries or a small methane gas heater for extreme cold weather driving. Of course a 100+ sq. ft. high efficiency (30+%) solar panel mounted/glued on their very large roof/hood could keep the cabin warm enough.

HarveyD

Why so many seem to have limited faith into future developments, specially with regards to improved batteries, BEVs and wired and/or wireless quick charging stations? Are we going to wait for China and EU to do it and then import those products?

Darius

I rather bet on existing technologies, whichh are just waiting on the brink. Let's concentrae on remaining 5% range issue. Is it cheaper for that 5% installing fast chargers on every corner and invest into double capacity power grid, invest into large bateries or just bet on 30 kW 200 lbs range extender possibly fueled with synthic fuel? I think this is future: small, powerfull and cheep bateries, satisfying 90% our needs and small range extender based on synthetic fuel.

SJC

I agree, there has to be a middle ground, when you look at some of the range extendersdesigns you see what can be done. Biomass and natural gas can be made into synthetic gasoline cost effectively. This buys time to improve batteries and fuel cells, which would get rid of combustion. One step at a time, not all or nothing at all.

fred schumacher

Let's decouple single-purpose travel, i.e. commuting, from general purpose. We presently use multi-purpose vehicles for both tasks. This has been made possible by inexpensive, energy-dense portable fuel.

A BEV, at present stage of electricity storage development, does not fit in well with the multi-purpose vehicle paradigm, yet that is the vehicle morphology the industry has chosen, to date, resulting in high-cost, limited-range vehicles.

If a BEV were designed as a single-purpose machine made to service the needs of commuting, it could be greatly simplified and reduced in size and cost. Since nearly 7/8ths of the time we drive alone, a narrow, three-wheel, enclosed, two-seat BEV "motorcycle" could fulfill the task of commuting and could be built at less than half the cost of a multi-purpose 5-seat car.

ExDemo

Sorry. All the artificial recalculations in the world don't change the fact that EVs do nor yet have the range that is useful enough to all potential buyers.

When it is sufficient, the buyers will provide the proof.

"If wishes and wants were candy and nuts, we would all have a Merry Chrsitmas."

Brotherkenny4

I would like a BEV that goes exactly twice the distance of my daily commute. I will then use that for my daily commute and never over tax the battery. I will keep my 4 cylinder 5 speed manual transmission car for longer trips. A 300 mile range battery will only get used about 3% of the time and thus would be wasted money. It's cheaper just to have the second car. Really if the car companies would start building these thing in any kind of real quantity they could get the price down to where it needs to be, which is $20-25K. Of course if the price of gas goes up, and it will, then that number moves up. I believe that gas will go up this summer, but it's likely an attempt by the oil companies to anger voters in an election year.

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