Frequently Asked Questions

Technology

Q: How does PV work?: Most PV modules are made of a semiconductor called polysilicon. (Hoku plans to manufacture this material in its Idaho production facility, beginning in 2009.) When the cells of the modules are struck by a photon of light, this material discharges electrons, creating direct current (DC) electricity. DC is then converted to alternating current (AC) in an inverter and it flows to power the building loads. Any excess goes back to the grid, turning the building's meter backward in the process.
Q: How long will a PV system last?: You should plan to have it on your roof for a while. PV modules have warranties that extend typically for 20 to 25 years. However, some PV panels have been known to function continuously for more than 40 years.
Q: Will it become obsolete in the next few years?: There is no apparent "Moore's Law" for PV. Improvements in the performance of the technology have been incremental, so there is little risk of obsolescence.

Q: How big of a system do I need?: Hoku will analyze your building load and roof area to custom fit a system for you. We have designed and installed systems as small as 2kW, a typical residential-sized array, and as large as 250 kW, a fairly large commercial system.
Q: How much does it weigh?: The racking systems and module frames are made of anodized aluminum and are lightweight, but strong. And, in almost every case, the building code covering residential and commercial roofs is more than sufficient to support a full-sized PV array. To be sure, though, Hoku provides a full set of engineering drawings, stamped by a mechanical engineer, before proceeding with the installation.
Q: Do I need battery back-up?: Most systems installed in Hawaii are grid-tied, and do not have battery back-up. As a result, if grid power goes down, the systems power down. (The utility needs to know the power lines are de-energized before troubleshooting any problems!) However, remote locations and other specialized applications frequently require an investment into battery backup. Hoku can work with you to evaluate your needs.
Q: What happens on cloudy days?: The array may still produce some electricity, but functions best in direct sunlight. On average, Hawaii locations see nearly 5 hours of productive sunlight, 365 days per year.

Q: How will Hoku select between different modules for my system?: We take into consideration the location and size of your facility and your desired power output to decide which equipment to recommend. For example, if space is restricted, we will likely recommend a very high-efficiency panel to maximize system output.
Q: How will Hoku decide what inverter to recommend?: Inverters are selected based on overall system size and design. Some inverters perform better with intermittent shading than others, so we will also consider the possibility of partial coverage.
Q: Who are some of the businesses that have selected Hoku Solar?: Click here to see some of our recent projects.

Q: Can I finance my PV system?: If you have a preferred lender, you may be able to obtain a tax-leveraged lease to finance your PV investment, though this will reduce your overall return on investment. Traditional debt financing, equipment leasing and power purchase agreements might also be a possibility. Hoku will be happy to help you evaluate your options.
Q: What tax incentives will I qualify for?: Most system purchases are eligible for either a 35% State Energy Tax Credit, or a 24.5% State Energy Tax Rebate, in addition to a 30% Federal Investment Tax Credit. You may also depreciate commercial systems according to a standard MACRS schedule, which further improves the performance of your investment.
Q: Do I have to take the tax credits all at once?: If you don't have enough tax liability to offset the credits, you may roll excess credits over until the next year or multiple years. However, Hoku is not a professional tax advisor, so it is advisable to consult with your tax advisor or accountant before purchasing.
Q: What is the typical payback for a commercial system in Hawaii?: 4-8 years, depending on system specifications and location.
Q: What is the typical payback for a residential system in Hawaii?: 6-12 years, depending on system specifications and location.

Q: Will a PV system void my roof warranty?: No. Hoku will work with your roofing company to ensure your warranty remains intact.
Q: How long does it take to install?: Depending on system size, it could take 1-2 days for a residential system, or up to 3 weeks for a commercial system. Typically, Hoku needs between 8-10 weeks from the time of contract signing until the systems are placed in operation.
Q: What kind of permits will I need?: Hoku will obtain a stamped building permit for the installation and coordinate the required inspections associated with grid interconnection.
Q: Will the system installation interfere with my normal business operations?: No. There should be no disruption of power with the exception of the final breaker test, which is a very brief validation of the system. In any case, Hoku will work closely with you to ensure we don't disrupt your routine business.
Q: I'm thinking about replacing my roof, should I coordinate the installations?: Yes, since the systems are expected to be on your roof for more than 25 years, it makes sense to think about coordinating the array installation with a re-roofing. We can help you think through this process.

Q: What kind of maintenance is required?: PV systems require minimum maintenance — Hoku recommends a freshwater rinse every 6 months, as required, to remove accumulated dust and dirt, and an annual check of the connections and racking systems. If you would like, Hoku does offer an operations and maintenance package and will be happy to provide this routine maintenance service for your system.
Q: How do I know the system is working?: You will be able to monitor the system power output, either at the inverter itself on smaller systems, or via a web-based software package for larger systems.
Q: Will I have to replace anything over time?: The inverters are normally covered by warranties for between 10-15 years. These will need to be replaced, normally between the 12-15 year mark in the system's service life.