Drive down car emissions with a jolt of sunshine

Do solar charging stations for electric cars and plug-in hybrid electric vehicles make sense?

At a recent Congressional briefing, the Environmental and Energy Study Institute (EESI) explored how a price on carbon might affect alternative vehicle fuels, including plug-in electrics. Guest blogger and former CAP staffer Alexandra Kougentakis recommends charging electric cars with power from the sun as a way to get off oil.

Solar energy and hybrid electric vehicles would be effective in achieving emission reductions both from transportation AND electricity generation. Solar-powered charging stations for cars that run on electricity are already popping up around the country. With hybrid vehicles becoming ever more popular, and even all-electric cars entering the market, transportation-related oil usage will be reduced. To avoid replacing gasoline carbon dioxide emissions with conventional electricity carbon dioxide emissions, an electric or hybrid car battery could utilize solar electricity .The conventional wisdom likely to raise objections against solar electricity charging stations is that solar energy is just too expensive. Yet photovoltaic (PV) technology prices have been falling since 2008 at extraordinary rates, with module prices dropping by 37.8%, wafer prices by 50% and polysilicon prices by 80%.

The capital investment for a carport structure topped with PV panels together with the actual charging unit may still exceed that of a conventional filling station. The high initial cost can be completely eliminated for the station owner, however, through an arrangement known as a solar power purchase agreement (SPPA).  Under an SPPA, the PV system is financed and owned by a solar project developer, and a property owner serves as a “host” for the array, purchasing all of the power that is produced at rates that are usually below local utility rates. Tax credits, grants and sales of solar renewable energy credits (SRECs) make it possible for the project developer to finance and profit from such a contract. This way, not only can solar electricity be used to charge hybrid and electric cars, but the electricity can be sold at rates competitive with that of oil, whose price will only keep getting higher. Notably, the 14-mW solar array at the Nellis US Air Force Base in Nevada employs an SPPA.

A carbon price for the transportation sector is a priority that Congress should include in any comprehensive climate change legislation, and by helping to stimulate renewable energy growth will result in substantial emission reductions. Further, a plan to more comprehensively integrate solar energy into the developing national infrastructure for electric vehicles would generate and support thousands of green jobs, both in the solar sector and in electric vehicle technology development. The economic growth that would result from the expansion of electric cars and the solar industry, and the gains that would come from saving billions of dollars every year on foreign oil, serve as strong arguments for a twin approach of solar powered charging stations for electric cars and a carbon fee for transportation.

Guest blogger Alexandra Kougentakis is a former CAP staffer and now regulatory analyst at Distributed Sun LLC, a Washington DC-based solar project developer.

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11 Responses to Drive down car emissions with a jolt of sunshine

  1. Raul says:

    Sounds nice, but are you sure that the consumer isn’t the one who is to take the all the moral glory for doing something progressive. Wouldn’t
    industry also benefit from steady employment rather than just waiting
    comfortably for weeks before they get the one job that pays well.

  2. Chris Dudley says:

    There is a bit of double counting in the article regarding SRECs. If those are sold, then the car is essentially using fossils for charging. But, there is not much point yet in hoarding SRECs though it may become a useful course of social action in the future. Because of the SRECs, where the solar panels are installed in unimportant. If it is cheap an convenient to cover parking areas, then that is a good place. If the building roof works out better, put them there. There are some utilities that are interested in putting them on otherwise unused land as well. That is less good environmentally sometimes, but it is not a very big deal usually.

  3. paulm says:

    “…with module prices dropping by 37.8%, wafer prices by 50% and polysilicon prices by 80%.”

    Can the price point be maintained if we ramp up production due to some of the rare materials used in PV’s?

    “The capital investment for a carport structure topped with PV panels together with the actual charging unit may still exceed that of a conventional filling station.”

    Theres also the tear down costs of a gas station which has to be cleaned up…this probably isnt that much though.

  4. GFW says:

    Any such station would have to be grid-tied, or it doesn’t make sense. With grid-tie, you can
    a) sell the unused power when no/few cars are present
    b) charge cars when the sun isn’t available

    I’m also thinking that the most sensible paradigm is not the “fill ‘er up” drive-in drive-out gas station model. Instead, it’s the Parking model. Shopping malls and other places with large parking lots could cover some fraction of the lot and charge for those parking spots. The user gets the benefit of a charge-up and shaded parking. The hitch would be if people park for much longer than the charge-up time, but that’s where grid-tie lets them sell the power rather than waste it.

  5. Bob Wallace says:

    We need both “fill ‘er up” and “park and charge”.

    Lots of cars sit all day and could be ‘smart charged’ as extra power appears on the grid. In fact, those cars could provide a very valuable function by helping with grid smoothing – sucking up spikes and giving back a little power to cancel short drops.

    Park cars under a solar carport for the day. Not only could you extend their daily range, you would also provide a cooler car thus requiring less energy for air conditioning.

    We are also going to need rapid charge points for people taking longer drives. The 200 mile range BYD e6 is expected to be able to take a 50% charge in 10 minutes. That’s a quick 100 mile range extender making a 400 mile driving day feasible with only two ten minute breaks.

    The Nissan Leaf is expected to take an 80% recharge in 30 minutes. That’s an extra 80 miles to it’s 100 mile range making the occasional longer trip feasible. It would not be unreasonable to take infrequent 300 mile trips in a Leaf if you could get a rapid recharge along the way.

    That sort of charge is not coming from a ‘carport roof’. It’s going to take some sizable input from the grid.

  6. Bob Wallace says:

    “Can the price point be maintained if we ramp up production due to some of the rare materials used in PV’s?”

    There are many different technologies used in making panels. Not all require hard-to-obtainiam. Thin film solar using dyes is one example.

    Another technology involves making super-efficient panels, but making them really small and then using collecting lenses to concentrate several ‘suns’ onto them. That gives a lot more power out per unit ‘rare stuff’.

  7. christopher yaun says:


    NO!, NO! AND NO!….Did I say “NO!”?

    Every project should be rated in $ per ton of carbon avoided.


    2000W of grid tied PV installed costs about $16,000

    and will generate roughly 3000kwh per year

    which converts to 10 million btu or 64 gallons of gasoline.

    Let us allow that the PV to electric car is more than twice

    as efficient as the gasoline car and estimate that the

    $16,000 investment in PV gains us the equivilant of 150 gallons of gasoline

    use that in a 50mpg automobile and we could drive about 7500 miles per year.

    That same $16,000 invested in weatherizing my house could reduce my

    fuel oil consumption by more than half or 500 gallons per year.

    The CO2 reduction would be proportional to the fuel saving.

    Solar powered electric cars are going to be very sexy.

    But the $$$ would be more effective in reducing our

    collective CO2 footprint invested in projects such as home weatherization.

    Home weatherization is not sexy but it is several orders of

    magnitude more effective use of our scarce financial resources.

  8. Christopher, above, is correct. Energy efficiency first. Using silicon PV is the most wasteful technology we can use to cut GHG. Notice that the writer of the article is making her income from selling PV systems and will find all kind of reasons to sell them. Her info about cost reduction of the components of PV system is twisted and incomplete. The reality is that PV vendors are reaping extra profit from the price drop since they do not pass it to the consumer. Go to the web and see the high install system prices, no drop in price or minimal drop. They count on misleading people by pointing the very high federal and state subsidies. The buyer care only about her final cost. However, we, collectively pay the high PV price and enrich PV vendors with negligible reduction in GHG.. Nature magazine just noted that the price reduction in Germany, the biggest user of PV,remains the same despite the drop in silicon panel prices.
    Energy efficiency is the key we need to start with. Also put high price on carbon [more than $50/ ton of CO2] to drive us in the right direction. Cap and trade would not bring us to the direction nature is dictating: cut GHG ASAP and as much as possible.
    See below how critical time is.

  9. catman306 says:

    Conversion to a charcoal-based, sustainable economy, requires that electric vehicles have charging stations. That electricity soon must come from renewable resources including PV, wind, tidal, and geothermal. Charcoal fired, highly efficient, steam turbine generators will replace gasoline engines as the power source for longer journeys than the batteries alone can provide. Those turbines will be computer controlled, with electric ignitors to start the charcoal fire, with temperature and air control finely tuned to prevent smoke and particulate pollution. Build charging stations and the vehicles will come. Those vehicles will evolve and our dependence on fossil fuels will diminish to zero. In time to save what’s left of our planet? We have to try.

  10. J.A. Turner says:

    PV should be installed where it make sense. A dedicated PV array for a charging station would require battery storage, which seems pretty wasteful. It seems better to me to use excess energy from the grid and let solar electricity just go into the grid when it’s available.

    My car is hardly ever around when my home’s solar panels are generating of power. I charge the car at night, off peak. Of course, if I could charge during the day, having that fed by renewable energy would be great.

  11. Dan K. says:

    I actually just completed my Master’s Project on this topic for my Masters of Environmental Management at the Nicholas School at Duke. Here is the link for those interested at the economics of such projects:

    “Electric Avenue: Two Case Studies on the Economic Feasibility of the Electrification of Transportation (Solar Charging Stations in CA & University Buses in NC)”

    Feel free to email any questions.