Denali solar

PV is a term commonly used to describe a Photo Voltaic system which generally consists of modules and inverters that produce electricity.

The term array is used to describe a cluster of modules installed in the same physical group and connected to the same inverter.

PV modules are made in many different shapes and sizes, but for commercial and residential use the most common are rectangular and approximately 3 feet by 5 feet.

Unfortunately there is no way to predict how many modules are needed for any particular installation without a thorough usage and site investigation. That said, most residential systems though tend to consist of 14 to 48 modules. Commercial and industrial systems generally start at around 100 modules, and no limit.

Modules are connected to one another in series. These “strings” tend to run 7 – 12 modules long and must be balanced with other strings if connected to the same inverter, and must maintain the same slope and orientation. If they’re integrated into a micro inverter system, each module is connected directly.

An inverter converts the DC electricity produced by the modules into AC electricity which can then be fed into the host building’s electrical system or upstream into the municipal power grid.

More than one central inverter may be required if the overall size of the system is too large for one to handle alone, or if there is more than one array and the arrays are facing different directions or consist of different modules. Some systems use micro inverters, which are sometimes slightly more expensive, but have none of the limitations of central inverters.

There are many variables that must be considered when choosing an inverter location, but most of the time it is ideally installed in a place that is on close proximity to the main electrical panel, in a cool, dry place, and out of direct sunlight. Micro inverters are placed directly below the module they’re connected to.

Most residential installations can be completed in as little as a few days. Commercial and industrial installations can be completed within 2-3 weeks, or take months on a larger scale.

PV modules start producing electricity immediately upon receiving light. A system can produce electricity as soon as the wiring is completed. Power is fed into the host building and potentially into the grid as soon as interconnection agreements and inspections are complete. All paperwork and inspections are generally completed within a week of physical completion.

Although PV is only starting to become main-stream which in the minds of many people equates with technological advance, there have been few major advances in PV over the past 30 years and there are not likely to be many soon.

Most “news breaks” about solar PV target the production of more efficient modules. Unfortunately, most of these highly efficient modules are made using rare materials in laboratory setting are not practical to installation in large scale. Major advances are always possible, but unfortunately are not likely to happen soon.

Most of the recent advancements in solar electricity production have been made in inverter technology. Higher conversion efficiencies and the physical combination of smaller inverter mechanisms into one centrally controlled unit which allows more production time per day have been the main targets. The integration of micro inverters may be the latest addition to the market.

Currently, the state of California offers an incentive program that is applied per watt installed or kWh produced. The federal government offers a 30% income tax credit which can be applied to the purchase price after the state incentive is applied. If the installation is for commercial purposes it can often also be depreciated.

A cost per square foot does not apply to PV well. There are many variables such as module efficiency and inverter type that can alter the square foot price dramatically. Furthermore, most people who start with square footage rather than historic or anticipated consumption either greatly under or overestimate their needs.

The ideal size of a PV system is dependent on several factors. If the system is to be installed for purely environmental reasons, it is generally designed to produce 100% of the host’s power. If however, financial motivations come into play, a smaller system targeting a specific point on the utility’s tier structure which can be balanced with the cost of money invested often returns a better compound rate of return.

Most modules are warranted for 25 years. Most inverters are warranted for 10 to 15 years, and Denali Solar offers a 10 year labor warranty. Micro inverters can be warranted for as long as 25 years.

In a perfect world every roof mounted installation in the Northern Hemisphere would face due South. This is of course not the case, and PV can be installed facing in almost any direction. South is the best, West is generally better than East, and North is generally not recommended. There are specific efficiency reductions for every orientation and slope.

There are ways to install PV on a North facing roof, but if another direction is available it is normally preferred.

Most modules weigh about 40 to 45 pounds and occupy about 15 square feet. Most racking systems are 1 to 2 pounds per square foot. Total system weight is generally about 3 lbs/sq ft.

It is possible to enter into a power purchase agreement with most utility companies; however, most installations are coupled with a net metering agreement. Under a net metering agreement, a utility customer can accumulate credits for extra power produced at a one-for-one value that can then be used to offset underproduction at another time. However, most credits expire in one year and cannot be exchanged for cash. Think of them as a retail “store credit”.

Solar can be installed on any type of roofing, whether the roof is existing or new. There are specific “standoffs”, or feet, which are specific to each type of roof.

If there are any apparent deficiencies in your roof they should be addressed before the Solar system is added. If the roof has a limited remaining lifespan it may behoove you to replace it before or during installation. That said, it is possible to disconnect the PV system and address roofing issues even after its installation. You must call a licensed PV contractor who is well versed in your specific type of system to do any work on it.

No. In the ideal situation, a PV system is added in conjunction with the new roof. This allows the connections to the roof to happen in a neater, cleaner fashion, which generally produces a better looking final product. Integrating the installations can also help save some foot traffic on the new roof. Denali Solar is fully licensed to handle your roofing and Solar needs.

Once your contract is signed, Denali Solar will handle all of the paperwork that happens in conjunction with its completion. This includes all permit paperwork.

In every situation the installation of onto a traditionally constructed building requires a permit.

A full set of plans, including electrical and structural engineering is included in installation package offered by Denali Solar.

The Federal Income Tax Credit is offered across the board and is available to every tax payer. However, it is up to you to discuss the matter further with your accountant to find out how it specifically applies to your situation.

Residential systems can occupy as little as 150 square feet of roof space, or up to a few thousand, depending on historic usage and the size of the system purchased. Commercial systems can occupy many thousands on square feet.

Generally, your PV system will connect to your existing electrical system through a new 240v circuit breaker added to your main breaker panel.

As long as local regulations allow, your inverter can be installed inside. In fact, when installed inside an inverter is generally kept cooler and dryer which may prolong its lifespan.

There is always a display that will tell you what is happening with your system. The most basic is a simple LCD display, generally on the inverter, with a simple readout. Systems can also be fitted with wireless displays that show the activity of the system wherever the display is installed, or connected to a building’s broadband or computer system allowing more complex readings to be viewed on a connected computer or around the world via your broadband connection.

Although Solar PV systems are generally almost maintenance free and rarely stop working, it’s a good idea to put an eye on the status display every couple of days if you don’t have internet based monitoring. If you have a web based monitor the system will send out emails in the event of an issue.

Always call Denali Solar to address any concerns with your new PV system. PV systems are complex and operate at much higher voltages than normal household and commercial electronics. Do not allow any contractor who is not licensed and factory trained to work on your system.

PV modules can be installed vertically on a wall; however, vertical installations are not generally as specifically efficient as sloped installations. Additional benefits sometimes outweigh the loss of specific efficiency though. When an ample amount of roof space is not available, walls provide a viable alternative. Often, the loss of solar heat gain, which is provided when a sun-facing wall is cast in the shadow of a newly installed array provides substantial benefit.

PV Modules can be installed on a flat roof. There are many racking options for installation methods and include penetrating and non-penetrating, ballasted systems.

PV Modules can be installed flat, however, is generally best to install modules with some slope. This not only increases efficiency, but allows water and dust to naturally slough off of the modules.

PV installation will not shorten the life of a roof. In fact, because once the new PV system is installed the roof is cast in the shade; it is generally thought to lengthen the life of the roof.

Ground mounted PV systems are not only possible, but common.

Since it can take up to a couple of months to process paperwork anyway, its best to get the ball rolling. Once rebate paperwork is approved the level of the rebate is held for up to one year, and Denali Solar is sometimes able to help with special short term financing that can make installing sooner a reality.

Most systems that are financed are financed through a traditional home equity loan. However, Denali Solar can often help with special Solar Loans or short term loans that can be used to cover the entire cost of the system or to offset the ITC until such time as your taxes can be filed. Denali Solar can also lease you the system through one of our partners for as little as zero down.

Denali Solar has partnered with several lease providers and can offer leasing solutions with as little as zero down.

Sometimes there is not enough space in the ideal orientation available. In these cases, we look to other slopes or to the ground. If there is no alternative space available, sometimes the system must be installed smaller than what hoped, but generally still provides a great consumption offset.

There are DC pool pumps that can be powered directly through a PV system. However, there are several drawbacks to installing a system in this fashion and after careful consideration most people choose to install a traditional pump and a grid connected PV system.

PV will not heat a pool directly. Solar Thermal Collectors specifically designed to heat a swimming pool will heat a pool and are also available through Denali Solar.

Installing PV is not likely to significantly affect your natural gas bill.

Most PV systems reach payoff in 5-7 years. Your Denali Solar representative can calculate a very specific forecast as to when your system will reach cash payoff during your first meeting.

Most PV systems require almost no maintenance. The only thing generally required is that the array be cleaned a few times a year, and that the vents on the inverter be also cleaned about once a month.

You can contract with Denali Solar to clean your modules on a regular basis, or on a once-per-call basis.

Most modules are a multi-crystaline silicone film covered by thin plastic on the backside and tempered glass on the front. They are then framed with aluminum channel, and held together with stainless steel hardware. Most racking systems available are aluminum and stainless.

Although your PV array will hold your weight, it is generally not a good idea to walk on the modules.

Since the topsides of the modules are tempered glass it is unlikely that a baseball will crack the surface of a module. Generally, if it wouldn’t break the average car’s windshield it will not damage a PV module.

Most modules are white plastic on the bottom, a few are black. In almost every case some wiring is exposed on the bottom side.

BIPV, or building integrated photo voltaic modules are available. These modules are generally designed to be integrated into a flat tile roof.

Your system will produce on a cloudy day; however production may be less than a sunny day.

Shade can have a very dramatic effect on the productivity of a PV module. Solid object shading is considered the worst. Filtered shading such as that from trees can be dramatic or slight.

PV can be installed on any building as long as the engineering allows the additional weight.

Generally, the paperwork involved with the installation of a PV system takes four to eight weeks. However, there are cases when it can take much longer. Contact your Denali Solar representative to discuss your proposed timeline.

The earlier Denali Solar can be involved in a project the better. When we’re onsite before the building is complete it sometimes allows us to hide wiring better and to take advantage of space that may otherwise be unreachable.