House near the University of Hawaii at Manoa with solar panels.

BY PANOS PREVEDOUROS PHD – With a flurry of proposals being floated around for renewable and other forms of energy, it is good to establish practical and realistic reference costs or price points.

In June 2011 COSTCO Wholesale through offered for the first time a home or small business rooftop photovoltaic system with a maximum power of 5060 Watt for a cost of $18,000, which includes shipping and handling.

Such a large and involved system requires a city permit for installation and an inspection by the utility. A licensed electrician is strongly recommended for the installation. All inclusive, this system installed would cost about $25,000 or just under $5 per Watt. (This does not include Federal and State tax credits which in Hawaii would total roughly $9,000.)

The system’s literature states that it will generate between 462kWh and 924kWh of electricity per month depending on placement, longitude, latitude and hours of sun exposure. By Hawaii standards, this system is big. For example, my home which houses 3 adults and 2 children consumed 420 KWh in 32 days, based on an April 2011 HECO bill. That’s why I have a 1,600 Watt PV system on the roof. My system cost $13,000 or $8 per Watt installed about a year ago. Indeed PV prices are coming down fast.

Remember this figure: $5 per Watt installed. Next time a politician, legislator, salesman or contractor makes you an offer that is substantially higher either for a residential installation or as part of a utility Power Purchasing Agreement, then you are likely being taken for a ride as a customer, taxpayer or ratepayer.(1)

It should be added that the system referenced above is not the least expensive one. One can find solar panels of Asian manufacture that are sold by the palette at an even lower cost.

UPDATE: Google creates $280-million solar power fund, Los Angeles Times, 6.14.2011.

Note(1): We need to be mindful of special circumstances such as shipping and labor costs in Hawaii, specific solar exposure at each location, etc. Careful design is needed and PV is sensitive to proper orientation and as little cloud cover as possible.




  1. So, for a system of 30 240 watt panels with micro inverters and related hardware, the total cost should be about $30K rather than the $40K I’m being quoted?

  2. From the author:

    (1) At $5.5 per Watt the installed cost is OK. Micro inverters are more expensive. That’s what I have at home.
    (2) Your proposed system is large and may be more cost effectively done in two annual installments to maximize your Fed and State tax credits. Have your provider run the numbers for a 2-phase installation.
    (3) Always remember that one needs to have more than $5,000 in tax liability on order to receive the maximum $5,000 tax credit.

    • Mr. Prevedouros should check his facts before writing such garbage.
      1) Fact is that P.V. panels are not coming down in price. The only ones that are getting cheaper is the junk coming out of China because they can not sell there junk in the U.S.
      2) Fact is that the price of $5.00 a watt is ill stated as well, because a solar P.V. system is not sold by the watt and any one buying a system by the watt has not done there home work. A P.V. system is rated and sold by the kilowatt per day of power that each panel will produce under normal hawaiian weather conditions based on an average daily output over an annual basis. There are a number of other technical factors that also play into the price and size of a P.V. system that are to technical for this site and Mr. Prevedourous is most likely not educated on base on his ill spoken facts.
      Aloha Solar Guy

      • Solar World 240 watt made-in-usa panels are $100 less today than Solar World 230 watt made-in-usa panels were a year ago. These are mainland prices. The fact that the local installers haven’t reduced their prices is the result of other factors. But the price of the panels has definitely gone down.

  3. (1) PV cost has been going down steadily. The trend started 10 years ago. Here is a sample 2009 reference:
    The recent announcements by Google and Costco further reduce costs.

    (2) KWh is another metric but Watt and KW is just fine too. In fact HECO tells me that my system is 1.6 KW and residential is limited to 10 KW in the net metering agreement.

    (3) The low cost pricing assumes an easy installation and minimal safety risk for the installation crew; i.e., one floor high structure. Many installations can be problematic, thus expensive.

  4. Why am I not surprised it costs that much just to have solar panels installed? On the bright side, though, it would still be cheaper in the long run, seeing as you don't exactly pay for sunlight itself.

  5. It stand to reason that, if you can afford to get solar panels, you can also get someone to install them on the roof for you. Then again, why spend extra when you can learn to do it yourself?

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