UCS Hybrid Scorecard Methodology
UCS created the Hybrid Scorecard to give consumers a comprehensive comparison of hybrid models on the market today. Our scorecard provides three primary ratings: Environmental Improvement Score, Hybrid Value, and Forced Features. Below is more detailed information about the methodology used to determine each rating.
The Environmental Improvement Score is a measure of environmental performance the manufacturer is achieving by applying hybrid technology to a specific model. The score incorporates two separate environmental attributes. One is based on global warming emissions and the other is based on particulate and smog-forming emissions(1).
Global Warming Emissions Reductions
The first component of a hybrid’s Environmental Improvement Score is based on the global warming emissions reductions achieved by the hybrid over a comparable non-hybrid model (see “Choosing Comparison Models” below for more information). It is not a measure of the vehicle’s overall global warming emissions performance relative to the average vehicle on the road, but rather a measure of how much better the hybrid is compared with its conventional-technology counterpart. This provides a way to compare the implementation of hybrid technology in different vehicles, regardless of which class they are in.
Global warming emissions reductions are calculated as a percent reduction based on the combined city/highway fuel economy ratings for both the hybrid and non-hybrid models as they appear in the Environmental Protection Agency’s (EPA’s) fuel economy guide (online at www.fueleconomy.gov) (2). The hybrid with the largest percent reduction in global warming emissions is assigned a 10, while the hybrid with the smallest reduction is assigned a zero. A linear scaling is used to assign values to models that fall in between these two end points.
Since the global warming emissions scale is based on the hybrid models on the market as of April 2011, new hybrid models added to the scorecard after April 2011 may score above 10 or below 1 if they are better or worse than the 2011 Lincoln MKZ Hybrid or the Volkswagen Touareg Hybrid, respectively. A recalibration of this scale may be necessary in the future as hybrid performance continues to change.
Particulates and Smog-forming Emissions
The second component of a hybrid’s Environmental Improvement Score is based on particulate and smog-forming emissions (a combination of carbon monoxide, hydrocarbons, and nitrogen oxides) from the tailpipe. The EPA’s air pollution score for model year 2011 and 2012 vehicles, which ranges from 0 (worst) to 10 (best), is used as the smog-forming emissions score for each hybrid model. This score is based on the actual emissions certification level of the hybrid rather than an improvement over the base model.
The EPA’s air pollution score rates vehicles’ certification levels under both federal and California emissions standards, but the Hybrid Scorecard uses the scores based on California’s certification levels (see the table below) because they represent the full potential of clean fuels and smog-forming emissions control technology to reduce tailpipe pollution. Since all light-duty vehicles including SUVs, pick-up trucks, and small and large cars are subject to the same tailpipe emissions standards, the scores can be compared across all classes.
Combined Environmental Improvement Score
To determine the final Environmental Improvement Score, the values for global warming emissions reductions and tailpipe emissions are averaged and rounded to the nearest tenth. As an example, the 2011 Lincoln MKZ Hybrid achieves a 46 percent reduction in global warming emissions compared with the conventional Lincoln MKZ. This is the largest percent reduction achieved among all hybrids and therefore the MKZ Hybrid earns a global warming emissions score of 10. The MKZ Hybrid is also certified in California as a Partial Zero Emission Vehicle, earning it an EPA air pollution score of 9.0. Combining these two scores results in an overall Environmental Improvement Score of 9.5.
Hybrid Value is a measure of how cost-effectively manufacturers are obtaining environmental improvement with their hybrids. Specifically, it is a measure of how much it costs for each percent reduction in global warming emissions. The Hybrid Value rating helps determine whether a manufacturer is offering a good bang for consumers’ climate bucks with a particular hybrid model.
Each hybrid is evaluated by dividing the estimated cost of hybrid technology used in the vehicle (see “Estimating Hybrid Technology Cost,” below) by the percent reduction in global warming emissions achieved over the conventional model. The hybrid models are then assigned a rating based on the resulting incremental cost, as shown in Table 2. In cases where the hybrid achieves a better smog certification level than the conventional model, the cost of additional emissions controls is included in the estimated hybrid technology cost. The break points in our scale are based on the assumption that we would expect an approximately normal distribution of the data as shown in Figure 1.
As an example, the Ford Fusion Hybrid achieves a global warming emissions reduction of 31 percent. Based on comparison of a similarly equipped conventional Fusion model, we estimate the hybrid technology cost for the Fusion Hybrid is $4,190, resulting in an incremental cost of $126 per percent reduction in global warming emissions. Based on this cost, the Fusion earns a “Very Good” Hybrid Value rating.
Estimating Hybrid Technology Cost
The hybrid technology cost is an estimate of how much the manufacturer is charging for technology that boosts fuel economy and cuts global warming emissions, plus any costs for technology that reduces smog-forming emissions. Getting the figure is not as simple as calculating the difference in MSRP (manufacturer’s suggested retail price) between the base model and hybrid model because there are various options and features that are considered add-ons for the non-hybrid model but are often forced on hybrid buyers as standard equipment (see “Forced Features” below).
For example, the Honda Civic sedan comes in the DX, the base-model, as well as the LX, EX, and EX-L versions. The Civic Hybrid features most closely match the EX (e.g., power doors and windows, a better stereo system), rather than the DX, though not all features are identical (the EX comes with a moonroof while the hybrid does not).
To estimate hybrid technology cost, the difference in MSRP between a hybrid model and its non-hybrid counterpart with the most closely matching features was calculated. This cost difference was then modified to reflect any further differences in features between the hybrid and non-hybrid models.
The resulting cost is an estimate of the price the manufacturer might set if the hybrid system were offered as a stand-alone option. This assumes the automakers are setting hybrid vehicle prices with the same profit margin on extra features as they have set for conventional models. It is possible, however, that some automakers are adopting a different pricing strategy where they accept lower profits on the “forced features” as a way of disguising the cost of a hybrid system. In such cases, we would be underestimating what they might charge for the hybrid system alone.
The cost of the different features was estimated from options pricing data on manufacturers’ websites and calls to dealerships. For some vehicles, cost information for every feature was not available. Therefore, the hybrid technology cost represents a best estimate based on publicly available information. Greater information from manufacturers on the cost of individual options could improve estimates of hybrid technology costs and forced features in the future.
For a typical conventional vehicle, manufacturers offer a base model along with models that include more expensive options such as premium audio packages and upgraded seat covers. Consumers often don’t have the option of simply adding a hybrid system to a base model; instead, many hybrid models come with premium or upgraded features as standard equipment. These “forced features” inflate the cost of the hybrid, making it less economical to buyers.
To estimate the cost of forced features, UCS calculated the difference in MSRP between the base model, with no upgrades, and the hybrid model and then subtracted the estimated hybrid technology cost (as described above).
Each hybrid model is assigned a Forced Features rating based on the resulting cost estimate, as indicated in table 4.
For vehicles with no forced features, there is no added cost for the vehicle beyond the hybrid system. These vehicles are assigned a rating of “None.” Vehicles that have $6,000 or more of forced features are assigned the maximum of “$$$$$.” The scorecard lists the full set of forced features for each hybrid model; we recommend visiting the manufacturers’ websites for more information about these features.
To compare hybrid models with conventional models that come with different engine options, we used the engine option that most closely matches the acceleration performance of the hybrid. For large SUVs and trucks, torque and horsepower are also considered in selecting the closest conventional vehicle match.
Some hybrid vehicles are not based on the platform of an existing model, making a comparison more challenging. In situations where no conventional model exists, a vehicle from the same manufacturer is chosen that most closely matches the hybrid vehicle in size and acceleration performance. For example, the Toyota Prius is compared with the Toyota Matrix.
Final scorecard results are separated for luxury and non-luxury brands. Luxury vehicles as a segment traditionally focus on high-end features and performance, meriting a separate listing for the purpose of more accurate consumer comparisons. The luxury market accounts for roughly 12 percent of total light duty vehicles sales(3).
This scorecard covers only new Model Year 2011 and 2012 hybrids sold as of April 2011. The Hybrid Scorecard also excluded the plug-in hybrid Chevrolet Volt. While this hybrid does have a conventional model against which to compare (the Chevy Cruze), there are a variety of factors that affect plug-in hybrids’ environmental performance. For example, the resources used for generating electricity (to charge the vehicle) vary widely in their environmental impact; electricity generated from fossil fuels such as coal and natural gas have higher global warming and smog-forming emissions than electricity generated from renewable resources such as wind and solar. Driving habits, including how often the vehicle is plugged in and the number of miles driven on electricity alone, can also affect the overall emissions benefits of plug-in hybrid vehicles.
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(1) Global warming emissions refer to carbon dioxide and other heat-trapping gases generated from producing and burning motor vehicle fuel. Particulate and smog-forming emissions are emitted from internal-combustion vehicles and contribute to urban ozone and unhealthy air quality.
(2) We did not account for the global warming impact of different fuels as all hybrids use gasoline. We also did not account for the impact of improved air-conditioning systems, which run more efficiently, reduce leaks, and/or use refrigerants that generate less global warming emissions compared with conventional air conditioning refrigerants. These systems are installed on some hybrid models; however, detailed emissions data are not currently available.
(3) Based on model year 2010 sales data from Ward’s U.S. Light Vehicle Sales by Segmentation September 2010