As the only supplier of solar-electric hybrid vehicles in the United States, Cruise Car Inc. is often asked when it makes sense to purchase a solar-electric hybrid for business use or as a second vehicle. There are a wide variety of factors, both economic and environmental, that must be considered in answering this question. A quick overview of the progress that has been made by the automotive industry to control contaminant emissions is a good place to start.

Over the past 50 years, vehicle manufacturers have continually produced more sophisticated emission control systems to reduce harmful tailpipe discharges. Fuel, ignition and exhaust designs have all been modified to dramatically reduce emissions of hydrocarbons, carbon monoxide, and oxides of nitrogen, the primary chemicals linked to smog. In response to growing concerns over CO2 emissions and global warming, recent efforts have been focused on improving fuel economy using electronic fuel injection, computerized engine control systems, and gas-electric hybrids. Design efforts have also focused on the production of zero emission vehicles (ZEVs), many powered by electricity stored in batteries. Due to inherent power limitations of available batteries, current designs of electric vehicles have been categorized as low-speed vehicles (LSVs) or neighborhood electric vehicles (NEVs) due to their limited speed (<25 mph) and range (<50 miles). These vehicles are not technically zero emission vehicles because the power plants producing the electricity still discharge CO2. Solar electric hybrids represent the next step in the advancement of zero emission vehicles. By charging the battery with the sun’s energy, the goal of zero emissions comes closer to reality.

Understanding the advantages and disadvantages of solar-electric hybrids to NEVs, gas-electric hybrids and fuel-efficient vehicles is crucial in assessing when a solar-electric vehicle is the right choice. Towards this end, Table 1 was prepared to present the environmental benefits and cost of ownership of a Toyota Camry, a Toyota Camry Hybrid, a gas-powered golf cart produced by Club Car called the Precedent, an NEV produced by Chrysler called a GEM e2, and a solar electric NEV produced by Cruise Car called the Sunray Solar Vector. The comparisons begin by assuming the vehicles will be driven either 1,000 or 5,000 miles per year, and progress by estimating the capital and operation and maintenance costs along with the resulting CO2 emissions. The footnotes on the last page provide documentation for all assumptions used in preparing this table.


Initial Costs and Capabilities

Reviewing the initial costs, it is quickly evident that the Precedent and the NEV’s are much cheaper to purchase. The Precedent, GEM and the Sunray Solar Vector are all less than $8,500, while the Camry and Camry Hybrid list for $20,000 to $25,000. At $8,500 and $8,300, capital costs for the GEM and Vector are approximately the same. However, because the Sunray Solar Vector is a solar-electric hybrid, its solar portion qualifies for a $1,000 tax credit, which makes the net capital cost of the Sunray about 15% less than the comparable GEM and 4% less than the Precedent.

Range is the obvious limitation of the NEVs. The miles/Kwh assumed for the GEM and Sunray come from a report prepared for the California Energy Commission (CEC) and represents a realistic estimate of performance under average driving conditions. It should be noted that chargers are available (for $3,000 to $9,000) that effectively extend the range by allowing the batteries of the NEVs to be 80% recharged in 1-4 hours. The range of electric vehicles is significantly impacted by the terrain. For example, the Sunray can travel over 50 miles on flat terrain, but will average 34 miles based on the CEC findings. The additional range of the Sunray compared to the GEM reflects the additional power from the solar panels, which on a summer day can add an additional 5 miles.

Speed limitations are the other limitations of NEVs and the Precedent golf cart. Under federal law, NEVs and golf carts have a maximum speed of 25 mph and are not allowed to travel on public roads with speed limits greater than 35 mph. Thus, if your second vehicle driving needs will routinely require travel on 40 mph or greater roads, NEVs or golf carts would not be a good choice.

Yearly Operating Costsgraph2

Yearly operating costs from Table 1 are summarized in the chart to the right and show that the yearly cost of operation is of Precedent and NEVs are about one-third the cost of a Camry or Camry Hybrid. On average, the

Precedent and NEVs were approximately $4,000 less to operate each year. Much of this difference is directly related to the annualized purchase cost in the form of finance charges and depreciation. It is important to note however that even with the elimination of the finance and depreciation costs, the Precedent and NEVs were still one-third as expensive to operate as the Camry and Camry Hybrid. Fuel, maintenance, insurance, and registration costs for these vehicles were all significantly less than the Camry and Camry Hybrid, reflecting their lighter and simpler design. As gas prices continue to climb, the NEV savings will accelerate in comparison to all gasoline powered alternatives.


GEM e2 versus the Sunray Solar Vector

A comparison of GEM e2 and Sunray Solar Vector annual operating costs shows that the Sunray Solar Vector is approximately 20% less expensive to operate than the GEM e2. These savings are directly related to the following factors:

  • • The availability of a 30% federal tax credit for the solar portion of the Sunray
  • • The initial battery cost for the Sunray Solar Vector is less
  • • The solar charging of the batteries extends the useful life of the batteries
  • • The solar charging of the batteries reduces the electrical demand

The value of solar power is particularly apparent in the 1,000 mile per year scenario, where total fuel charges (i.e. electrical bill) for the Sunray Solar Vector are estimated at only $8 per year.

Environmental Factorsgraph3

Table 1 includes estimates of the total pounds of CO2 discharged per year. These estimates have been graphically displayed on the right. Using the 5,000 miles per year scenario, the Precedent and Camry will have the highest emissions, discharging over 3700 pounds of CO2 per year, followed by the Camry Hybrid, which will discharge about 900 pounds less CO2 than the Precedent or Camry. Average NEV CO2 emissions are significantly lower, approximately 1500 pounds less than the Camry Hybrid and 2400 pounds less than the Camry and Precedent. These estimates are based on the average CO2 emissions per kwh from US power plants in 2000 and would vary regionally depending on the percentage of fossil fuels used for power generation.

Because the Sunray Solar Vector derives a portion of its power from solar energy, CO2 emissions are less than the from the GEM e2. The difference on a percentage basis becomes greater as the number of miles driven decreases. At 1000 miles per year, Sunray Solar Vector CO2 yearly emissions of 105 lbs. are approximately one-third of the GEM e2 emissions.

When Choosing a NEV Makes Sense

Clearly there are economic and environmental advantages to selecting a NEV for business use or as a second or third car. Significantly lower CO2 emissions and potential savings of up to $4,000 a year have been demonstrated in the preceding sections. A gas-powered Precedent offers similar savings but with no reduction in CO2 emissions. Persons or corporations considering a NEV must first determine if they can routinely utilize the NEV on roads with speed limits of 35 mph or less and a daily travel distance of less than 30 miles. If not, then a NEV is not the right choice. However, for large corporate or institutional campuses or people living in downtown areas, on private roads, or retirement communities where routine NEV use is a viable option, a NEV supplemented with an occasional car rental may provide an ideal solution. Cars can typically be rented for $25 to $50 per day, so a $4,000 a year NEV savings could be used for 80 to 160 days of rental car usage. Rent a pick-up for hauling, a van for transporting guests or a convertible for a romantic weekend getaway. NEVs let you get more bang for your transportation buck while helping to fight global warming. In addition to being fun to drive and easier to park, many states/communities now have free parking for zero emission vehicles.

Electric versus Solar-Electric

Solar-electric vehicles represent the next step toward the goal of zero emission vehicles, replacing CO2 emissions from power plants with pollution free power from the sun. Federal tax credits and battery/electrical savings from the solar panels make the cost of ownership of a solar electric vehicle about 20% less than a regular NEV.

Cruise Car Inc. offers a wide variety of solar-electric vehicles to choose from, starting with the 2 seat Sunray Solar Metro or Vector to a 14 seat Tram. They also offer Sunray Solar Canopy conversion kits to turn your existing golf cart into a solar-electric vehicle. Do something for your pocketbook and your planet, go solar-electric!


Capital Cost (a)                                Capital costs represent the manufacturer’s suggested list price excluding taxes, insurance, and registration and delivery charges

Solar Tax Credit (b)                     A 30% tax credit is available for the solar portion of the solar-electric vehicle, which includes the solar panel, batteries and charge controller. This credit is currently set to expire on December 31, 2016.

Net Capital Cost (c)                     The net capital cost is the capital cost minus the tax credit

Miles/Gallon or KWH (d)       The miles per gallon for the Camry and Camry Hybrid is the average of the EPA estimated mileage for city and highway driving. The miles per kwh for the GEM and

Sunray come from a July 1, 2002 report prepared for the California Energy Commission titled “Demonstration of Neighborhood Vehicles (NEVs)”.

Range (Miles) (e)                            The range for the Camry, Camry Hybrid and Precedent is simply the fuel capacity (gallons) times the miles per gallon. For the GEM and Sunray, the range is the battery capacity (in Kwh) times the miles per kwh referenced above. The range of electric vehicles is significantly impacted by the terrain. For example, the Sunray can travel over 50 miles on flat terrain. The additional range of the Sunray compared to the GEM reflects the additional power from the solar panels, which on a summer day can add an additional 5 miles to the range.

Fuel (Gas-Electricity) (f)          Fuel costs were based on an assumed gas price of $5/gallon and an electricity cost of $0.10/kwh.

Maintenance (g)                              Maintenance costs for the Camry and Camry Hybrid are based on a 2006 report by AAA which showed maintenance and tire costs for a mid-size sedan to be approximately $0.06/mile. Because of the simplicity of power train and design of the Precedent, GEM and Sunray, maintenance costs were assigned a value of $0.03/mile.

Batteries (h)                                         Battery costs for the Camry Hybrid, GEM and Sunray were obtained from the manufacturers. For the Camry, the annualized cost was obtained by dividing by the 8 year warranty period. For the GEM, a battery life of 3 and 4 years was assumed for the 5,000 and 1,000 mile categories, consistent with the manufacturers published information. Sunray battery life was assumed to be 20% greater than the GEM to reflect the smaller battery drawdowns resulting from solar recharging.

Insurance (i)                                       Insurance costs were based on the lowest quotes from three insurance companies for full coverage on public roads. Only one insurance agency (Allstate) had special rates for NEVs. NEV insurance drops to less than $100/yr for private road use only.

Registration (j)                                  Registration costs vary from state to state. This table assumes registration fees based on 1% of vehicle value.

Depreciation (k)                               Vehicle depreciation of 10%-20% per year is generally regarded as a reasonable estimate. This table assumed a 10% per year depreciation based on age and the potential for an additional depreciation of 10% for 30,000 miles driven, pro-rated to the actual miles.

Finance (l)                                             Interest only charges on net capital cost at 7% interest

Lbs. CO2 Discharged (l)           Estimates of CO2 emissions for the Camry were based 19.3 lbs. of CO2 per gallon of gasoline used. C02 emissions for the GEM and Sunray were based on the estimated kwh times 1.34 lbs. CO2 per kwh. This number represents the average CO2 emissions per kwh in the United States from 1998 to 2000, as published in a March 2002 report prepared for the Energy Information Administration titled “Updated State and Regional Level Greenhouse Gas Emission Factors for Electricity”.