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Save the Earth, Save Money—There’s No Need to Choose

The views expressed are those of the author and are not necessarily those of Scientific American.

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Earlier this year, I blogged about a new website set up to ease the chore of shopping for solar panels, EnergySage, and since then the company’s own blog has described two financial benefits of solar which I hadn’t thought about before. First, solar panels can help you save for retirement; in fact, it’s hard to imagine an investment that anyone who’s not a Russian oligarch could make for such a high return and such a low risk. Second, photovoltaic power can cut the cost of driving an electric car—which, mile for mile, is already a third or fourth of a gasoline car—in half.

My own panels have earned me about $2,000 a year in electricity savings as well as the tradable certificates I receive for each megawatt-hour of energy they generate. Considering how much I had to pay up front, that amounts to a return of just under 20%. That outdoes the stockmarket, not to mention the lower-yielding investments that many retirees rely on. The investment isn’t completely risk-free; you’re subject to the vagaries of weather, equipment failure, fluctuations in the certificate market price, and family members who evidently take the solar array as an excuse to leave all the lights on. At one point, we had a run of cloudy days and our array fell behind its expected monthly output. We later caught up, though. (I’m still working on the family members.)

I talked to Diane Hammond, a Massachusetts homeowner featured on the EnergySage blog, and she said she bought her solar array last year when one of her certificates of deposit matured and all the new ones were paying just 0.5%. “There just isn’t any place to put your money to get a return on it,” she told me. She, too, estimated her solar array has had an effective return of about 20%. “I’ve been so excited I’m not paying the electric company all that money,” she said. “It puts a little bit extra in my pocket.”

EnergySage’s CEO, Vikram Aggarwal, who has a background in financial planning, told me: “It’s one of the best financial products you can buy. All financial advisors should be promoting solar.” He also argued that the panels increase the resale value of a house, which I’m more skeptical about. I watched a few episodes of House Hunters on HGTV recently and got a sobering lesson in the irrationality of homebuyers—they’d routinely reject an entire house for want of a $100 bathroom fixture. So I doubt that a lifetime’s worth of free electricity will even register with them. But, realtors who are reading this, I hope you can prove me wrong.

Regarding the electric car, the EnergySage blog cited Neeraj Aggarwal (no relation to Vikram) and I contacted him to follow up. He told me he leased a BMW i3 at the same time he was preparing to install a solar array and decided to increase the array size from 8 kW to 10 kW. Working through the cost of charging the battery and the savings afforded by his array, he reckoned the electric car costs 2 to 3 cents per mile to operate. A equivalent gasoline-powered car might cost 20 cents per mile. Given the distance he typically drives, Aggarwal estimated he saves $250 a month, or half the cost of the lease.

Whenever the subject of electric cars comes up, people always ask about range. Aggarwal said he gets 80 to 100 miles on a full charge, which is just enough for his daily commute. He uses special mapping apps to get driving directions that take charging stations in account, so he can top off his battery over dinner. “You have to be a little more prepared or analytical in terms of driving the car,” he said. This minor inconvenience is offset by lessened routine maintenance—no oil changes, for example.

To take full advantage of the economics of solar, you do need to buy the array rather than lease it. Although leases save the upfront cost, they give you only a fairly small reduction in your electric bill. Fortunately, buying an array is easier than it used to be, because banks are now providing loans specifically for solar arrays. In my case, I was able to take advantage of a loan program run by my utility, PSE&G, which recently announced a renewal of the program.

It’s not often you can do good and do well at the same time. Take advantage of it while you can.

Photos courtesy of Neeraj Aggarwal and Diane Hammond

George Musser About the Author: is a contributing editor at Scientific American. He focuses on space science and fundamental physics, ranging from particles to planets to parallel universes. He is the author of The Complete Idiot's Guide to String Theory. Musser has won numerous awards in his career, including the 2011 American Institute of Physics's Science Writing Award. Follow on Twitter @gmusser.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. sault 12:46 pm 09/13/2013

    Excellent article! It will attract the usual crowd of pro-pollution trolls that frequent this site, but I’ll help to preemptively rebut their arguments, George.

    First of all, there will be a lot of irrational fearmongering about the clean energy solutions described in this article. Wildly inaccurate numbers concerning the “real” costs of solar power and electric cars will probably be trotted out even though they have been debunked time and time again. What these folks never understand is that the specific examples highlighted in this article are working today, in the real world. People paid real money to buy these systems and get them installed. If these wildly unimaginable costs were anywhere close to real, somebody would be going broke. However, this is not the case, and since these unrealistic cost estimates are mostly based on junk numbers cooked up by those that stand to lose financially from the adoption of clean energy, they are clearly not credible.

    Secondly, the more rational objections will probably concern the tax incentives and credits that helped to lower the cost of these solar arrays. What people making this argument fail to realise is that dirty energy enjoys massive subsidies that are much larger than the paltry tax credits directed towards wind, solar, etc. These massive subsidies have been government policy for decades longer than tax breaks directed at clean energy as well. To top things off, dirty energy makes us deal with the negative impacts of their pollution while not paying a dime themselves. This is a massive indirect subsidy that is not incorporated into the cost analysis of people objecting to clean energy tax breaks.

    Hope this limits the irrational posts made on this article, but I doubt it…

    Link to this
  2. 2. syzygyygyzys 12:58 pm 09/13/2013

    Rats! So, according to the news rules the first troll wins?

    Well played.

    Link to this
  3. 3. sault 1:24 pm 09/13/2013


    Congratulations! You win!

    Link to this
  4. 4. rkipling 1:29 pm 09/13/2013

    Mr. Musser,
    If the assumptions used to estimate the 20% ROI are available, it would be useful to publish them. With that level of return there will be a wave of installations all across the country.

    Most people wouldn’t want to plan their lives around making an electric car work for them. If this guy is happy with his purchase, it sounds like an EV works for him.

    The 2 to 3 cents per mile compared to 20 cents per mile is fuel cost only.

    Link to this
  5. 5. sault 11:55 am 09/14/2013


    The array generates $2,000 in electricity each year. It cost around $10k up-front, ergo, it has a 20% annual return. And this return is in straight-up cash, which is much better than paying dividends in the form of shares that may go up or down in value over the life of the investment.

    As for your assertion about electric cars, it is totally unfounded and blatantly silly in light of the high sales of electric vehicles already on the market. They make great commuter / errand vehicles and 80% of people drive less than 40 miles a day anyway. And did you happen to catch the part about the mapping apps that help Aggarwal plan his daily trips so he doesn’t even have to worry about his electric vehicle’s range?

    If an electric car doesn’t work for you, then by all means, don’t buy one. However, don’t go making blanket assertions that can easily be disproved by the 10′s of thousands of electric vehicles already on the roads. Please stop spreading all this FUD, especially when you don’t even bother to read the article. And claiming that people wouldn’t bother making an EV “work” for them is just silly. How about all the oil changes, gas station visits, smog checks, tune-ups, filter changes, transmission maintenance and all the other upkeep that a regular car needs? How disruptive to people’s lives are all these expensive maintenance items?

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  6. 6. EnergySage 11:34 am 09/16/2013

    RKipling– This EnergySage blog on electric cars provides some of the math you are looking for.

    Link to this
  7. 7. EnergySage 11:37 am 09/16/2013

    This one has the financials for Diane and her retirement strategy. Hope this is helpful to you.

    Link to this
  8. 8. rkipling 5:44 am 09/17/2013

    Interesting. The SREC was the piece I was missing.

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  9. 9. rkipling 3:11 pm 09/17/2013

    If I read it correctly, Diane would get $10,000 to reduce the initial purchase and installation costs. In addition she would get 15,000 over 10 years.

    So, if every household in Massachusetts went solar the total cost would be in the range of $70,000,000,000 or $7 billion per year or back to the $25,000 per household. With an annual budget of $32 billion, can they afford it? It would be up to state voters, but if they increase taxes to pay for it, the subsidies effectively go away, don’t they?

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  10. 10. George Musser in reply to George Musser 3:36 pm 09/27/2013

    @rkipling: Yes, the subsidies are unsustainable in the long term. But no one is talking about keeping them indefinitely (as, for example, fossil fuel subsidies have been). They are meant to provide a crucial bridge for the technology to achieve parity with fossil power prices. I see the subsidies as an investment that we will later recoup.

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  11. 11. maralora 12:08 am 11/2/2013

    Installing solar panels requires a big initial investment. Before you make this investment you should check to see if the money you will save by installing solar panels will pay for this investment. This website provides you an opportunity to examine how much money you will actually save if you install solar panels.

    Link to this
  12. 12. Radovan Skriba 7:42 am 11/20/2013

    To spend any money into solar technology and calling it investments is foolish,new technologies are for people who are rich and happy to play and for smart people who are making profit by wrapping these things into nice customer packages, do you really think that energy companies with such a lobby in relevant places would be allowed some profitable deals for somebody without their share in it? It is a bit same like e-cigarettes,same people who making real fags also making nicotine patches,nicotine mist,nicotine chewing gum,e-cigarettes it is only an different way how to sell a bad product on fancy way. Enjoy your solar.

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  13. 13. jerryd 7:59 am 12/4/2013

    I’d like to suggest a lower cost way to get PV.

    Go online to find the big PV sellers like sunelec to buy the parts/kits and have a local electrician install it on an hourly basis. It just doesn’t take long.

    Panels are going retail for well under $1/wt of first quality ones so now fairly easy to buy the parts for around $1.7k/kw ongrid and $300/kw to install means just $2k/kw, far lower than most installs.

    Now prices are so low I’m thinking of plug and play units like a 1.5kw shed or patio already wired, just needing an outlet to plug into.

    PV is now in the $.02-.04/kwhr range so economically it’s a no brainer.

    My problem is I use so little power for more home, business, lightweight EV’s because of the base fees, etc my effective power costs are $.25/kwhr.

    So by going offgrid I save these fees and can use lower cost inverters that with 3kwhr of batteries, only costs $1.2k/kw. Thus my effective cost is under $.02/kwhr. Just the utility base fee savings pays pays off the system in 5 yrs!! So they make it not worth hooking up to the grid in smaller systems.

    But that is not all. Solar CSP and wind in home, building sizes once in real mass production like PV be even more cost effective.

    The US grid has shrunk the last 3 yrs and that will continue and people find out making their own power is far lower in cost.

    Link to this
  14. 14. BrianEdwards 2:40 am 02/22/2014

    I was able to save thousands of dollars on my solar panel kit and installation by using By entering my zip code, I got free quotes from the best solar installers in my area. I hear they serve all of North America so if your looking to go solar, I advise you check them out. Here’s their link:

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  15. 15. JeneeVie 10:50 pm 03/7/2014

    I also have seen a site before about Solar Power. It encoureges me to install Solar Panels at home.

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  16. 16. shakawat 4:03 pm 07/5/2014

    Solar energy is cheaper and cleaner than regular utility energy. To install a solar power system in California, Oregon, Colorado, and Arizona; No hesitation !!!

    SolarCity can install a solar power system on your home for free and sell you the energy it produces for less than you currently pay. This is your chance to save for years to come.

    for more information about solar for your home click here:

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  17. 17. drsolar 4:05 am 09/5/2014

    Going for an alternative source like renewable energy is really a good thing. If we use solar energy for our daily needs its saves a lot of penny for sure. May be the initial investment is high, but it will compensate later. You can get many solutions from here

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  18. 18. bryanmason01 5:28 am 10/6/2014

    We can use SUN energy and save our earth and our electricity bills also. Solar energy is renewable and SUN provides it totally free of cost. We provide best services for installing solar planes in homes and office also.
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  19. 19. rosariobondsr68 2:54 am 02/25/2015

    If you want to get helpful information on solar panels, its cost, installation and other stuff then you better get it from the best, right? For more info please visit:

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