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 Costco.com 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. Given Hawaii's cost premium "substantially higher" in Hawaii (for residential installations under 4 KW) is over $7 per watt, assuming an easy installation; see note below.
Note(2): The low cost pricing assumes an easy installation and minimal safety risk for the installation crew; i.e., one floor high roof. Installations can be problematic, thus expensive.