CleanTechnica is the #1 cleantech-focused
website
 in the world.


Cars GM Volt.

Published on May 18th, 2013 | by Nicholas Brown

24

How Adding An Electric Car Cut Solar Payback Time In Half

Share on Google+Share on RedditShare on StumbleUponTweet about this on TwitterShare on LinkedInShare on FacebookPin on PinterestDigg thisShare on TumblrBuffer this pageEmail this to someone

May 18th, 2013 by
 
Do you think that buying an electric vehicle could reduce the payback time of a solar power system by 50%? Let us explore that.

GM Volt.

Chevy Volt.
Image Credit: GM

This is the story of a family in Pennsylvania who installed a 9.43 kW solar panel array to offset their electricity usage. They found themselves saving considerably more money than they originally would have.

The solar power system was installed in October 2011. It consists of 41 panels. Each of the panels can generate 230 watts DC.

The quoted cost of the solar system was $5.50 per watt of its generation capacity, which translates to $51,865. Yes, it is a very large system!

Their electric bill was $2,500 per year, and the financial payback time of the solar system after state and federal government incentives was estimated to be 11.7 years.

A year later, they replaced their 2007 Acura RDX with a 2013 Chevy Volt. They used the surplus electricity they generated to power the Chevy Volt, so they were able to eliminate their Acura RDX gasoline bill without incurring any new electricity costs, and now they have a solar-powered car!

They said this cut the payback time of the solar system in half, down to 5.96 years, but the purchase price of the Chevy Volt does not appear to have been factored in.



The Volt’s gas bill is up to $50 per month, while the RDX gas bill was $250 per month. The 2007 Acura RDX crossover achieves 19 MPG combined.

I should note that the gas bills for both vehicles are a bit high. The writer of the story said they added 7,228 miles to the Chevrolet Volt in “only” six months (they drive an average of 1,250 miles per month), and that they “racked up a lot of miles.”

5,255 of the 7,228 miles accumulated on the Volt were on electricity alone (72% of pure electric driving).

The writer of the story said that they fill the Volt’s 9 gallon gas tank “once, maybe twice per month.”

Average Miles Driven In US & UK

According to the DOT, the average American drives 13,476 miles annually, which translates to an average of 1,123 miles per month, so these people don’t drive that much more than average, only an additional 127 miles.

To be fair, Americans do tend to drive quite a bit. In the UK, for example, the average number of miles driven in 2010 was 8,430 miles, which is 5,046 miles less than Americans.

Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.

Print Friendly

Share on Google+Share on RedditShare on StumbleUponTweet about this on TwitterShare on LinkedInShare on FacebookPin on PinterestDigg thisShare on TumblrBuffer this pageEmail this to someone

Tags: , , , , , , , , , , ,


About the Author

writes on CleanTechnica, Gas2, Kleef&Co, and Green Building Elements. He has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is: Kompulsa.com.



  • Ray

    The writer of the original story says he leased the Volt and it was CHEAPER than the lease cost of the Acura.

  • Paul Blackwood

    I got the generous solar feed in subsidy of $0.68 per kilowatt hour, four years ago. I installed a 3.5 kW system which produces about 16kW a day on average. My energy consumption back than was around 25 kW a day, from then onwards I increased that level 60-70kW per day on average why eliminating natural gas supply and going all out on electric.

    Although I don’t produce 60-70 kW in a day, the feed in subsidy of $0.68 per kilowatt hour covers my energy costing, I have no utility bill costing for the last three years, and I’m in the planning to install an extra 3 kW so I can get a return on my investment.

    • http://www.facebook.com/people/Jouni-Valkonen/736198505 Jouni Valkonen

      note that you are talking that your energy consumption is 60-70 kWh per day. So you need to have 14 kW solar system. Which is pretty nice.

      I hope that the price of battery storage is getting down fast. Battery storage would make your solar array even more useful, because you do not need 14 kW peak power — expect perhaps for EV charging.

  • Uri Naor

    whow so given that you have a huge house and that you are wealthy this is a great solution

    • Bob_Wallace

      I’m not sure they have a “huge” house nor that they would qualify as wealthy. Sounds more upper middle class to me.

      Wealthy is more like owning nine homes and your wife owning a couple of Cadillacs at one of your houses.

      One could use what this family has done and see if it scales down to their situation. Perhaps as large a solar array wouldn’t be needed. I do fine with only 1.2 kW.

      And if you are going to buy a new car, and about 15 million Americans do that each year, you can buy a Volt (or a Nissan LEAF), pay some more money up front, but save money over the life of the car.

      The big thing – do the math. Solar and EVs/PHEVs are a lot more affordable than many people realize.

      • MacGregor

        How is that possible 1.2kw is a very small solar system, most people consume about 30kw-65kw a day, you need a big solar system to cover that modern energy equipments in the home these days’ dishwasher, hot water, plasma TV, dryer & air conditioning and what about central heating 40kw-100kw a day . There no way that I could live on 1.2kw, all the modern equipment which I quoted cannot be reduced in energy consumption, including my spa bath.

        • Bob_Wallace

          I live a fairly energy-conservative lifestyle.

          I wash my dishes by hand, it’s not much more effort than loading and unloading a dishwasher. My clothes dryer is a 50′ nylon cord strung between two trees. It’s worked fine for ten years with no repairs needed. And it makes no noise while in operation.

          I chose to live some place where one doesn’t need AC, I seldom need to turn on a fan. I heat with wood, which I find a lot more comfortable than central heat. Takes a couple gallons of gas a year to cut my firewood. And a half gallon or less of gas to power the pickup to haul it in.

          Haven’t watched TV (at home) since the 1980s. Radio/music stays on all day, as does my computer. I just light up the part of the house I’m using at night, not the whole thing.

          I use about five gallons of propane per month for cooking and water heating. (Haven’t gotten around to installing a solar water heater.)

          If someone else wants all that dryer/big TV/spa stuff, that’s fine. But they are going to have to install a larger solar system to cover their use. Continuing to power them with fossil fuel generated electricity is just not right.

          • Andrew

            What you said in your last paragraph, the attitude towards energy will never change especially with many in society. People boast about using more energy, been dependent on fossil fuel is their given rights, after installing renewable grid tied solar power to the utility company.
            I’m not in agreement with Macgregor’s or Paul lifestyle like many that uptake renewable energy for the very same reason.

            It’s my belief that some sort of limitation be imposed on people that use more carbon base fossil fuel energy with that attitude. Sure they can have the entire modern con, but there needs to be accountability on energy consumed from carbon based energy sources.

            I guess many in our society are not willing to change or concern about emission levels unless you place heavy hand taxes on them, for using more energy then before with a grid tide system.

          • Bob_Wallace

            I said absolutely nothing about it being OK that people depend of fossil fuels.

            My point is, people are unlikely to adopt a significantly conservative energy lifestyle. Most people simply won’t do that. They will not give up their TVs, clothes dryers and cars as long as they can afford them.

            Many people won’t stop smoking, exercise or invest for retirement when the impacts are going to hit them personally. They are even less likely to endure a decrease in how they want to live in order to minimize the impact on people generations from now.

            I don’t think we have the ability to tax people into using less electricity. The politicians who attempt to establish heavy energy taxes would simply be replaced with “no new tax” people during the next election.

            We need to find ways to lower people’s carbon footprints while not requiring significant changes in their lifestyle or budget.

            If someone wants to live a 40, 60 80 kWh per day lifestyle encourage them to install a large enough solar system so that they produce as much as they use.

            In large parts of the US they will pay less for their electricity than buying it from the grid as they are now doing. They’ll bring a large amount of new clean capacity to the grid, making it easier to shut down coal and natural gas generation.

            It’s an all around win. They get to live as they like and save money. We have less CO2 and coal pollution in the atmosphere.

        • Ronald Brak

          No country in the world produces enough electricity to allow households to use 30-65 kilowatt-hours a day per person. Some figure checking is in order.

          • John L.

            I live in Hingham, Massachusetts, USA and our local municipal electric utility states that the average residential load per month is 830 kWh. That is usage in a fairly affluent suburb of Boston. If we divide that by the average number of days in the month, 30.42 days, we come out with the figure of 27.3kWh average load of electricity per day.

            That does seem like a lot of power for people to be using. We have a 1700 sq. ft. house with an electric range used for all cooking, an electric dryer (used 1/3 of the year) and some fans used on the hotest days but no air conditioning. We shut TV and computer centers down with power strips at night to minimize phantom power usage. We don’t go extreme on electricity saving measures but only average 347kWh/month or 11.4kWh/day usage.

            We have 16 230Watt SunPower 18% efficiency panels in place, averaging 13.1kWh/day or 4778kWh/year production. The system puts out 114.7% of our power needs.

            We do this on 234 sq. ft. of roof space. If we end up buying a Chevy Volt and drive it 15,000 miles a year with no gasoline figured in and conservatively figure a full charge powering it 40 miles (in actuality 42-43 miles but less mileage if using the heat), it will only take a total of 30 230W SunPower panels to almost completely power the house and car. It would produce 8958kWh out of 9004kWh needed and only take up 439 sq. ft. of roof space.

            Unfortunately, we are in one of the worst towns in Massachusetts for solar power policy. We do get 8 cents/kWh for excess electricity we put out on the grid (not bad for a municipal power company but not equal to the 1 for 1 net metering required of the private electric utilities by state law). The kicker, though, is that we are charged 6.7 cents/kWh for power we produce and use (all on equipment we personally own!). When I tell people in the solar industry about this policy they are astounded and in disbelief.

          • Ronald Brak

            Thanks for that update, John. In Australia the average houshold of 2.4 people uses about 16 kilowatt-hours a day. And I’m very sorry to hear you have the grossest billing systems of all – gross metering. Basically you’re a solar serf. Solar electricity you generate by the sweat of your own PV panels doesn’t belong to you, it belongs to your fuedal lord, the power company. You have my sympathy. I hope your power companies stop abusing their power soon. If not, it’s time to look into home storage and a small generator.

    • arne-nl

      Hi, I live in a standard 140 m2 family home in the Netherlands. I started out with 1.1 kW a few years ago and added 2.5 kW recently. The cost for that last addition was about 2700 euros (incl VAT, after 15% subsidy, DIY).

      I now have 3.6 kW and still half my roof is empty. My reduced energy bill allows me to save up for that extra 3.5 kW that I will add a few years into the future, bringing my total to more than 7 kW. I expect to pay less than 2700 for that 3.5 kW.

      Wealthy? I think not.

      • Bob_Wallace

        Anne – why such a large array? Are you charging/planning to charge an EV in addition to running your house?

        • arne-nl

          Yep

  • http://www.facebook.com/people/Jouni-Valkonen/736198505 Jouni Valkonen

    note that in April 2013 the system cost of roof top solar was $1.7 per watt in Sydney. That is 3 times cheaper than US prices in October 2011.

    • Dimitar Mirchev

      From where did you get this number?

      Its really low.

      • Ronald Brak

        According to Choice PV Price Index for April the average price of a three kilowatt system in Sydney was $1.68 a watt. Without subsidy it would be $2.33 a watt. It’s good, it’s far cheaper than buying electricity from the grid, but we’re still being embarrassed by the Germans. But we’ll catch up, oh yes we will. Parts of the US are already closing in on where Australia is now, so it won’t take long for North America to see similar installation prices.

        • Dimitar Mirchev

          Thanks :)

          • Ronald Brak

            Sorry, a slight omission, that should be SOLAR Choice PV Price Index for April. (Sorry for shouting the word solar at you.)

    • Jenny

      You would think that low but I’ve seen one company advertising 50cent a watt installed, due to Federal government State subsidies.

    • http://www.facebook.com/patrick.jerome.37 Patrick Jerome

      To say it is 3 times cheaper is incorrect.
      It should read “That is 1/3rd of the cost in the US as of October 2011″

      • Ronald Brak

        Correct in Australia it is!

      • http://www.facebook.com/people/Jouni-Valkonen/736198505 Jouni Valkonen

        thanks for the correction. In my native language both ways are correct, hence the mistake, but good to hear that Australians prefer also this way.

Back to Top ↑