Vehicles running E85 corn ethanol have 30 percent lower CO2 emissions than the all-electric Tesla Roadster, study finds

In Florida, Biofuels Digest has found that cars running on E85 corn-based ethanol, at the proposed new Corporate Average Fuel Economy (CAFE) standards, will generate 30 percent lower CO2 emissions over an average car lifetime than a Tesla all-electric sports car using coal-fired power.

The findings, available via free download here, are based on the GREET model for corn ethanol lifecycle emissions, as published by the Argonne National Laboratory; e85 fuel economy figures as established in the most recent University of Nebraska study; Tesla’s reports on miles per KWh, Department of Transportation figures on auto lifespan, EIA data on electricity prices, E85 price data from e85prices.com, and EPA figures on emissions from coal-fired power generation.

The analysis also determined that the Tesla will create 21 percent higher CO2 emissions than a car running conventional gasoline (with up to 10 percent ethanol content), at the proposed CAFE standards.

The Digest report also found that, based on current ethanol prices, the total increase in cost of ownership for running an E85 vehicle in the US is $19 per year, compared to a non-flex fuel vehicle running conventional gasoline (with up to 10 percent ethanol content). E85 saves an average of 6 tons of CO2 emissions over the average life of a vehicle, when utilizing corn ethanol, and up to 36 tons of CO2 when running on cellulosic ethanol derived from waste biomass.

Results vary from state to state based on the cost of ethanol, gasoline and residential electric power. In New York state, the Digest found that, based on current prices reported by E85prices.com and the Energy Information Administration, running E85 corn ethanol decreases total cost of ownership by $57 per year compared to conventional gasoline.

The Digest also found that the annual operating savings, based on national average prices for residential power as reported by the EIA, and current E85 prices, that an all-electric Tesla owner will save $4,674 in energy costs over the lifetime of the vehicle by paying less for power than liquid transportation fuel, but pay $12,000 in additional cost of a lithium ion battery (Tesla’s battery replacement charge).

The Digest also found that, in New York state, the energy savings for operating an all-electric vehicle such as the Tesla are $1,424 compared to E85 corn ethanol, far less than the premium paid for the lithium-ion electric battery pack.

The Digest also found that cars running on E85 corn-based ethanol at the proposed new Corporate Average Fuel Economy (CAFE) standards will generate 10 percent lower CO2 emissions over an average car lifetime than a Chevy Volt running solely on electric power – although the Chevrolet is a hybrid engine that would routinely add gasoline into the mix. A Volt using a 50/50 mix of gasoline and electric power would generate 13 percent more CO2 than an E85 car running on corn ethanol.

The US Department of Energy recently provided a $465 million low-interest loan to Tesla to produce an all-elkectric sedan Model S. Production of the vehicles will commence in 2011. Gas2.org has stated that it believes the Tesla Model S will rate  4 mpKwh to the Chevy Volt. If that is the case, the federal loan to Tesla, which will empower the production of 20,000 sedans, would increase US CO2 emissions by up to 76,000 tons based on the metrics in the Digest’s analysis, compared to the emissions for 20,000 flex-fuel cars running E85 corn ethanol.

The Digest will make available future comparisons of other sources of power and fuel, but has chosen to focus on a comparison of “standard” sources for ethanol and power in choosing corn and coal. The substitution of natural gas, or cellulosic ethanol, would materially reduces CO2 emissions.

By permission, Biofuels Digest is including this report on the Tesla from Automotive Industries, authored by SAE member Bob Brooks.

At a recent rally event here of the Midwest Automotive Media Association, AUTOMOTIVE INDUSTRIES talked to Seneca Giese, sales representative for Tesla Motors Inc., San Carlos, California. Giese displayed a Tesla production  electric car and outlined a number of features of the $109,000 very small, carbon fiber, 2 seat roadster;155.4 inches long, 92.6 inch  wheelbase, 44.4 inches high…total weight with battery: 2700 lb. The electric motor is rated 240 HP 3 phase with rev limit of 14,000 rpm

The vehicle is powered by a 992 lb, 6800 cell, 400V, 53 kWh capacity, lithium ion battery mounted with the motor and electronic controls behind the 2 seats driving the rear wheels. Economic and operational factors explained by Giese follow:

When the vehicle is sold new, for an additional $12,000, the owner can purchase guaranteed future replacement of the battery after 7 years use if needed. If the original battery is still functional after 7 years, a portion of the $12,000 is returned to the car owner on a schedule basis that was not explained..

Driving range depends on car owner use(speed & acceleration) which Giese explains is not unlike conventionally powered vehicles. Battery life is similarly impacted. The Tesla car’s computer maintains information about speeds and acceleration which is both stored and goes to a instrument panel readout of battery energy remaining expressed on a count down basis as miles the vehicle can travel before charging is needed.

The vehicle can be programmed for best range of 244 miles which limits  power to about half for moderate speed and acceleration performance. Programmed instead for performance, range is cut to about 195  miles.

Battery charge is limited to between 90% and 10% of  full capacity . Outside these limits, battery life is  compromised.  Full charge up time on 240V 30 amp input is 3.5 hours or 24 hours on 15 amp 120V input. An important characteristic of the system is the need  to  maintain  battery temperature at 70F at all times.  For this reason vehicle owners are advised to keep the car plugged into an electric source whenever not in use  and whether charging is or is not needed. Cooling or heating of the battery is achieved with the vehicle’s on-board systems that draw current in proportion largely to ambient temperature impact on stand-by battery drain. If left unplugged with battery at low charge level and significant battery temperature maintenance required, severe damage to the battery can occur quite soon, perhaps in as little as one day.

Passenger cabin heating and cooling can be a byproduct to a varying degree of the need for battery temperature control depending on ambient and operational conditions.

Information was provided on an advanced Tesla “Model S” electric car planned for production in 2011 said to have  seating for 7 people, range up to 300 miles, 45 minute quick charge time and charging from 120V, 240V or 480V sources. Commercial 480V  is needed for quick charge and is anticipated at future charging stations perhaps where food and comfort facilities are available.  The Model S forecasted price is $49,900 said to include Federal tax credit of  $7500.  Add $12,000 for battery replacement insurance if that carries over from the current program.

Taken together, it is evident  that if the Tesla car is representative, owners of lithium ion powered vehicles will have to adjust to special requirements for overall operation. Not the least of electric car owner requirements is access to plug-in electric source whenever the car is not in operation or at least not for any length of time.

If  fuel  economy of the little roadster is in the ball park of 4 miles per  kWh,  this translates at 14 cents/kWh for recent Chicago total residential electric cost to about $1.00 per 30 miles whereas gasoline cost for a similar conventional small car  is close to  $3.00 per 30 miles. Whether this advantage offsets total lithium ion battery powered vehicle cost and use limitations, remains for consumers to decide.  Electric power has carbon emissions to be considered and the questions about road tax collection are unknown.

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