Power Conditioner Image

Failure Causes in Solar PV Systems

During the first 10 years in service, the chance of failure within a PV system is approximately 10%. Inverters and other electronic devices account for 85% of all those PV system failures. Only about 1 in 2000 modules will fail during their warranted 25-year life. The system components most likely to fail are the ones with complex electronic circuitry.  The graph below identifies this type of equipment as Power Conditioning; it includes monitoring equipment, inverters, PV optimizers & other DC to DC conversion devices. The causes of failure are from manufacturing defects, improper installation, operating stress and accidents. The first of these is out of the control of the installation and maintenance contractors and the last of these, accidents, is usually outside of their control; the second two, improper installation and operating stress, are not.

 

Failing Power Conditioning equipment will perform at a lower efficiency than warranted; failed equipment will stop performing its function. Failures due to improper installation and operating stress are both avoidable. Causes of these failures are: Inadequate wire terminations, undersized conductors, environmental conditions that are outside of the equipment rating, inadequate protection from surge voltage and inadequate protection from physical damage. Once the equipment is operational, an infrared camera can detect damage that is occurring from heat at the terminals and inside the equipment. Terminal temperatures should vary no more than 3°C from one to another under the same current load. The internal parts of the equipment should not exceed the max rated temperature listed by the manufacturer. If equipment is failing but still operating, the conversion efficiency can be measured by reading the (Volts x Amps) at the input and output of the equipment. The difference should be no less than the rated efficiency of the equipment. Test six months after installation and then annually thereafter.

Module failures get most of the attention since they don’t usually fail completely but continue to function at a lower output; the causes of failure are numerous. A module is considered failed when one of the following occurs: Breakage, delamination, burned solder joints, browning of a PV cell due to overheating, bad bypass diode or degradation in performance beyond the warrantied percentage. These are covered by the manufacturer’s warranty; depending on the failure mode, proof of failure can be verified with a standard photograph, infrared photograph or by inspection test with a calibrated meter such as an I-V curve tracer. A module is considered failing if it performs lower than other modules of comparable design and type. An IR camera may detect hot spots on PV cells that decrease performance –  an IV curve tracer can determine whether the module is operating below its warranted performance. Test with an IR camera annually, and with an I-V curve tracer for large commercial projects.

The most common long-term failures are: Hot spots due to manufacturing defects in the cells, hot cells caused by high current flow in a de-energized state, potential induced degradation (PID) caused by leakage currents to earth ground, low cell conversion rate due to cracks within the cell, delamination caused by extreme heat and humidity and current loss due to shorts (shunting) between cells where the module substrate is damaged by wind and dust or other natural causes. An I-V curve tracer and an IR camera can identify most of these problems. For residential and some commercial projects module level monitoring will identify problems; it is easy to compare each module performance to the others around it.

The other failure category shown in the graph is balance of system components (BOS). This is generally all the wiring, conduit, switchgear, junction boxes and module support structure. Failure is usually due to improper wire sizing or termination, galvanic corrosion with incompatible metals, materials installed in environments beyond their rating and improperly installed components. Prevention of failure includes testing conductor resistance before startup, capturing IR images at terminals when equipment is operating, measuring resistance to ground on all grounded metal parts and making a visual and torque inspection of all physical and electrical connections. Test six months after installation and then annually thereafter.

The most valuable tool for inspecting PV system performance is a module level monitoring system; most new residential and small commercial projects now have this level of monitoring. The next best tool is an IR camera; since there are now IR devices that connect to smart phones this is a very affordable option. The next best tool is an AC/DC volt-amp meter. You can take readings on the input and output of any equipment and determine the loss factor for that piece of equipment. If you are working on commercial systems, you will want a conductor resistance tester to measure the conductor insulation resistance to leakage currents at the maximum operating voltage. The I-V curve tracer is unnecessary for residential and small commercial projects. They are usually required for large commercial and utility scale projects.

Kelly Provence
Solairgen School of Solar Technology
IREC Certified Master PV Trainer
NABCEP Certified Professional Installer

Calculating Voltage Drop in PV Systems

Voltage drop (VD) is the loss of voltage in a circuit due to the resistance in the electrical circuit. To determine the amount of voltage lost in a circuit, we need to look at three parts: 1. Resistance of the conductor in Ohms (Ω), 2. The length of the circuit conductor, 3. The current flowing through the conductor. A forth component is to compare the VD to the operating voltage in the circuit to see the percent of voltage drop.

  1. The resistance of the conductor per 1000’ (Ω/kFT) can be found in Table 8 and 9 of Chapter 9 in the National Electrical Code (NEC). Table 8 is for DC and Table 9 is for AC. Divide by 1000’ to get the resistance of the conductor per foot (Ω/FT).
  2. The length of the conductor is the full circuit length; for DC and single-phase AC circuits, multiply the one-way distance by 2. For three-phase AC circuits, multiply the one-way distance by the square root of 3 (1.732).
  3. The amount of current flowing in the circuit directly affects the amount of voltage drop in the circuit; e.g. 2 amps of current will double the voltage drop of the circuit with 1 amp of current. Current is represented as intensity of current (I) in the formula.
  4. To determine the VD%, the operating voltage must be used. The operating voltage is dependent on the equipment and how it is connected. The PV source circuit voltage may be the product of modules connected in series or it may be controlled by DC-DC conversion devices and an inverter. The AC operating voltage is simply the nominal utility voltage at the premises.

DC and single-phase AC formula:  VD  =  I  x  Conductor length  x  2  x  Ω/FT

 VD%  =  VD  ÷  Operating voltage

Example: A PV source circuit operating at 9a and 400v using a #12 conductor in a circuit with 50’ of length one-way. Table 8 shows a #12 (7 strand) to have 1.98 Ω/kFT; 1.98   (.00198Ω/FT)

9a  x  50’  x  2  x  .00198  =  1.782 volts dropped or lost in the circuit (VD)

1.782v  ÷  400v  =  .004455  or  .44%VD

If you double the length of the conductor or double the operating current, the voltage drop would also double.

NOTE: This calculation is accurate using current and voltage data either from the PV module Standard Test Condition (STC) or the Normal Operating Condition (NOC). NOC test conditions represent the irradiance and cell temperature during the six critical sun-hours of the day. Both current and voltage are lower than STC. Since they are both lower, the VD% is close to the same as if you used STC current and voltage instead.

The AC side of the calculation is the same as The DC example above, however it may not be as accurate since the inverter rating can be sized from 80% of the PV rating to 135% of the PV rating. This affects the average operating current and the amount of voltage drop. We typically use the inverter’s listed max operating current if the PV array is sized 125% to 135% of the inverter rating. If the inverter is rated the same as the inverter, use 80% of the listed inverter max operating current.

Example: An inverter rated 6000 watts, 240v and 25a is connected to a 7200 watt PV array. The inverter AC output is located 30’ from the AC interconnection point. The conductor used is #10 copper rated 35a with resistance shown in Table 9 of 1.2 Ω/kFT   (.0012Ω/FT)

25a  x  30’  x  2  x  .0012Ω/FT  =  1.8 VD  ÷  240v  =  .0075 or .75%VD

The combined VD% of the DC and AC circuit is .44%  +  .75%  =  1.19%

If the inverter and PV array are the same size, multiply 25a  x  80%  =  20a. This reduced the VD by the same proportion.

We usually consider more than 3% VD in the entire circuit (DC and AC) to be excessive. Increasing conductor size reduces the Ω/FT and reduces the voltage drop in the circuit. The voltage drop percent is a loss factor with energy production. The example above reduces the PV system production by 1.2%.

Three-phase AC formula:  VD  =  I  x  Conductor length  x  1.732  x  Ω/FT

 

Kelly Provence
Certified Master PV Trainer
Solairgen School of Solar Technology

Is everyone a potential solar PV customer?

The short answer is yes since electrical utility companies generate a portion of their electrical energy from solar energy; indirectly everyone is a solar PV customer if they purchase electrical energy from one of these utilities. The better question is who is a direct customer of a solar energy system; the type that will offset or replace electrical energy that would have been purchased from an electrical utility. To clearly see who these customers are, we need to break them down into categories. The first breakdown is between residential and commercial electrical consumers. The second breakdown is stand-alone off-grid customers and grid connected customers. For this blog we will look at the residential customer, both grid-connected and off-grid.

Residential: To be a potential solar customer they must be owners of the property and they must have enough sun exposed space on the roof or ground to support the PV array relative to their level of electrical consumption. They must also have the financial capacity to purchase the system. The four basic criteria are, (1) ownership of the property, (2) extent of solar exposure for a PV array, (3) % of monthly/annual electrical consumption to be offset by solar and (4) the financial capacity to purchase. With evidence of ownership established, the sun exposed space is compared to their electrical consumption to determine the size of the solar PV system and the approximate electrical consumption it will offset. If a method of payment can be established, this is a potential solar customer. There are however four other factors that should also be considered (5 – 8), (5) utility interconnection limits, fees and purchase rates, (6) rate of financial return on investment and cash flow, (7) building covenants or restrictions and (8) understanding the customer’s motivations. Contact the customer’s utility company and find out all requirements, fees and rates that will be offset by solar electrical production; this affects the type of system, cost of the system and the return on investment. Find out about homeowner’s associations or local ordinances that may restrict or even prohibit the installation of the PV array where it is publicly visible. Most solar customers want to offset their energy bills and save money in the process but there are many other motivators such as environmental concerns with conventional energy, independence from the utility or to be gird connected but consume all the energy generated from the solar PV system and have some off-grid capacity during utility power outages. Look at all eight of these considerations to determine who is a potential solar customer.

Residential off-grid: These customers are typically located in rural areas without utility access. That being the case, we can eliminate considerations 5, 6, and 7 above but #8 become much more important. This customer needs a high level of self-reliance and independence with the solar system. Other forms of power generation should be considered as well such as wind, hydro and a fuel generator.

In a follow-up blog, we will look at the criterial of a potential commercial customer.

Kelly Provence
Solairgen School of Solar Technology

The Benefits of Achieving NABCEP Certification

Overall, the benefits of NABCEP certifications are to the industries they serve. The North American Board of Certified Energy Practitioners (NABCEP) was founded in 2002 as a 501(c)(6) non-profit organization with the stated goal to develop voluntary national credentialing programs that will promote renewable energy, provide value to practitioners, promote worker safety and skill, and consumer confidence in the industry. But how does certification help your career? Consumers need to be confident of their choices.

Consumers at all levels need to know as much as possible about the products they purchase. However, it’s next to impossible to know all that is necessary to make the best choice, so they depend on third-party grading and rating systems to help make decisions. This works out very well for the consumer if the grading/rating organization is doing the hard work of vetting the products and services provided, like NABCEP.

But it also works out very well for the product/service provider. This is especially true when it comes to certifications held by installation contractors. A certified installer’s high standards and achievements stand out so the consumer can see there is a quality difference with minimal research. NABCEP has done a great job of serving the solar industry by providing this credentialing and certification process and standard. They now offer several levels of credentials and certification.

The entry level NABCEP certification is the Associate Credential; the requirement to sit for this exam is to complete a solar PV course from a NABCEP approved training provider and then pay the registration fee through that provider. Achieving this NABCEP Credential provides the holder with more visibility in the industry to employers and potential customers. The credential holder’s name is placed on the NABCEP web page under NABCEP Associate Directory.

The highest level of certification is the NABCEP Certified PV Installation Professional. The minimum education requirements to sit for the exam are 58 hours of solar training with 40 of those hours being advanced level, solar PV specific, provided by an accredited school. A minimum 10-hour OSHA card is also required. Verifiable experience in PV design or installation is also required to sit for the exam. The value of this certification has many benefits in the solar industry and is often required by entities such as utilities or governments. Many developers will specify and require that the solar contractor must have this level of certification. Showing potential customers that you are a certified solar contractor will give you the advantage over a contractor who is not certified. The certification holder’s name is placed on the NABCEP web page under Certified Locator.

For professional sales people, the achievement is the NABCEP PV Technical Sales Certification. The education requirement varies widely from 0 to 60 hours of solar training depending on the person’s background. However, it would be a good idea to take some training courses to prepare for the exam. The first person a customer meets is usually the sales representative; if the sales person is certified, it provides the customer with confidence and an element of trust, elements that are an essential part of winning an installation contract.

NABCEP now has three Specialist Certifications: PV Installer Specialist, PV Design Specialist and PV Commissioning and Maintenance Specialist. Each of these require 24 hours of advanced training from an accredited school. Verifiable experience in each of these specialist categories is also required to sit for the exam. A minimum 10-hour OSHA card is also required. Each of these certifications is focused on the individual’s specific area of expertise. The greatest value to the individual holding the specialist certification is companies who employee certified specialists gain a level confidence with this individual and it also improves the company image to the potential customer.

Another level of certification is directed to building inspectors. Many of the building inspections are now contracted to professional inspectors. These inspectors are usually certified in as many fields of building construction as possible. The NABCEP Certified PV Inspector certification provides these inspectors with this credential that indicates they possess a sufficient level of knowledge and expertise with PV system inspection requirements. No training or experience is required to sit for this exam. However, it is highly recommended to sufficiently educate yourself prior to registering for the exam; it requires extensive knowledge of the IBC, NEC and PV system design.

Certifications are key to any industry’s growth and success. The solar industry is still young and it cannot afford failures due to poor quality installations. One effective way to guard against these failures is to support industry certifications. NABCEP has done a great job of providing their widely accepted certification program to many from different backgrounds. When you become certified at any level, you enhance your opportunities for personal success, you help raise the standards of the industry and you help provide consumers with the ability to make smart choices.

Solairgen PV specific training programs are NABCEP approved and IREC accredited solar PV training programs, designed in support of industry certification and professional excellence.

Kelly Provence
Solairgen School of Solar Technology
IREC Certified Master PV Trainer
NABCEP Certified PV Installation Professional
NABCEP Certified Technical Sales Professional
Master Electrician

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The Importance of Optimum PV Array Size for Solar PV Systems

Residential Solar PV Ground Mount SystemThe question of optimum PV array size is the first question to be answered when designing the PV system. There are several factors that have to be considered to arrive at the best size. The customer budget, the available area for the array and the purpose of the PV array are always primary considerations. The budget is usually the most flexible since the system can be financed. The second may be difficult to get around if the location options are limited and restrictive. The third part is where most mistakes are made. There are generally two types of systems, (1) stand-alone and (2) utility grid interactive.

The stand-alone system must be designed to serve the electrical loads throughout the year. The PV array is usually sized to serve the loads in the month with the highest ratio of electrical load demand verses available solar energy. As long as the electrical load demand is known and the solar resource is known, the calculation is made for each month of the year (Avg. daily loads kWh ÷ Avg daily insolation ÷ Power conversion efficiency % = ratio) The ratio is the exact size of the PV array necessary to offset 100% of the energy consumed in that critical design month. The hard part is usually determining the kWh of electrical consumption.

The stand-alone system can be off-grid with generator backup or grid supported. If it is grid supported a portion of the house electrical loads are served by the stand-alone system. The PV array is sized for the stand-alone portion of the house.

The graph below show a typical PV system output capacity compared to the electrical consumption for each month of the year. The PV array is exaggerated in size to cover the worst ratio months of the year.

Graph 1

Grid interactive systems must consider how much power can be fed into the electrical system and remain compliant with the utility interconnection agreement and the best power offset value. The most common interconnection agreement is Net Metering for the billing cycle. It is typically set to offset up to 100% of consumption with solar PV generation during the monthly billing cycle. Energy generation in excess of 100% is usually compensated at avoided cost, about 1/3rd the rate of retail. The obvious objective here is to not generate more than is consumed for each month of the year. The challenge is to project generation and compare it to consumption throughout the year.

The months that usually control the PV array size are in the spring and fall. We consume less energy during these periods because of the reduced need for heating and cooling. Coincidentally, these are usually the best two periods for solar PV generation because of clear skies and lower temperatures, April and May are typically the best generation months.

The graph below shows the typical electrical usage for residential customers. The PV system that is designed to offset 60% of the annual electrical consumption is generating 100% of that consumption during the month of April.

Graph 2

A third type of system is a self-consumption type system that requires energy storage and is designed to connect to the grid but not sell into the grid. The PV array size usually follows the same rules as the interactive guideline above, but it can be more complicated and requires a smart control system with consumption and generation metering to keep everything in check.

It is OK to oversize a stand-alone system but with interactive systems keep an eye on the low-consumption vs. high generation months.

Kelly Provence
Solairgen
www.solairgen.com

706-867-0678
info@solairgen.com

The Best Methods for Energy Efficient Solar Homes

Solairgen-Installation475x317Your home’s overall energy efficiency is not as exciting to think about as a solar PV system, but it is much more important in most cases. Solar PV systems are getting more affordable, but that doesn’t help much if the overall energy consumption is higher than it needs to be. An energy efficient home will require about half the PV system size as a home that is not energy efficient. There are several low cost improvements that can improve energy efficiency; there are also many improvements that require an investment but provide good return on the investment.

The division of energy consumption in a home looks similar to the following pie chart taken from the Energy Industry Administration report.

Pie Chart of Typical Energy Usage for
Legend for EE Pie Chart

Appliances, electronics and lighting make up 40% of the home’s energy consumption. The lowest cost improvement is changing the energy user’s behavior, e.g., turn off lights and appliances when not in use. Replacing old appliances with higher efficiency ones as they require replacement, such as LED bulbs in long-hour-use fixtures.

Water heating costs can be reduced by several methods; the lowest cost methods are listed first. Insulate the hot water pipes from the water heater to the point of reduced access to the pipe. Buy and install an insulated jacket for the water heater. If your water heater fails and needs replacing, replace it with a high efficiency one. There are models that use a heat pump as the primary source of heat generation with heat coils as backup. Another, but more expensive option is to install a gas tankless water heater.

Heating and cooling together account for about 40% of the home’s annual energy usage. The best savings for the investment is to simply seal all cracks from the exterior to the interior of the home. This would be at the foundation, around doors and windows, and fixtures and access-ways to the attic. The next best investment is to improve the quality of insulation in the attic. The best insulation improvement is to have spray-foam insulation installed in the rafters and vertical walls of the attic. If there is a basement, the walls should be spray-foam insulated as well. Replacing blown-in insulation with spray-foam insulation can reduce heating and cooling costs by up to 50%. That would reduce the home’s total energy consumption by 20%.

It takes some effort and some investment to make the home energy efficient but it will not be nearly as expensive as trying to offset that portion of inefficient energy usage with a solar PV system. A 2000ft² consumes about 1800kWh/month. With an investment in spray-foam insulation, water heating insulation and replacing old appliances with high efficiency ones, it is easy to reduce the home’s energy consumption by 30% to 40% and spend less than $6000. That is about ½ the cost of a PV system to offset the same amount of energy.

Reduce energy consumption first through energy efficiency and then look at offsetting the remainder with a PV system. You may even have some money leftover to include energy storage with the PV system.

 

Kelly Provence
Solairgen
www.solairgen.com

Jobs in the Solar PV Industry

Image of Solar Installer on Roof of a Virginia HomeThe solar workforce in the U.S. has grown by over 160% since 2010 for a little over 93,000 to well over 250,000. Solar accounts for less than 2% of all electrical energy generation in the U.S. However, the solar industry employs twice as many workers as the coal industry, almost five times as many as nuclear power, and about the same number as the natural gas industry.

The largest sector of jobs is in installation of the PV equipment and systems at 51%. The second largest sector is in manufacturing of equipment and materials at 16%. Project development is third at 14%, sales and distribution is fourth at 12%, and the remaining jobs are in various sectors at 7%.

These figures indicate that the best job opportunities will be in the installation sector and that would be correct. This will require a certain amount of training to make yourself attractive to an employer and the solar industry in general. The most difficult positions for employers to fill are, (1) Sales Professionals, (2) Electricians and (3) Installers. If it is possible to get retrained to fill the roll of one of these professional groups, your prospects for employment are very good.

It may also be possible that your present skill will be attractive to an employer in this industry. Every solar contractor or developer needs workers who possess a variety of skill sets. Aside from developing skills listed in the previous paragraph, here are some job skills that are always be required by some of the personal within each company:

  1. An understanding of IP and computer communication are necessary skills since all solar electronic equipment is now built to communicate within its own network and with the internet.
  2. A proficient understanding of computer programs and the ability to bridge computational and drawing programs with DOE and Google type programs is essential to most solar companies.
  3. Writing and editing skills are always necessary when communication with other people and groups is common; this is an undervalued skill that can can make a big difference in the success of a company.

The best way to get into this industry as an employee or as a contractor is to first look at the skills you now possess and see where you would fit in. The next step is to get enough training with solar sales and design to get you started and continue training as you move up the ladder to success.

Kelly Provence
IREC Certified Master PV Trainer
NABCEP Certified Professional PV Installer
Master Electrician

Solairgen School of Solar Training

The Good and Bad of Net Energy Metering

MeterRealities in Net Energy Metering (NEM)

The term net metering has several definitions and interpretations. There is one most of us agree on as the standard model – the owner of a solar PV system may offset up to 100% of their electrical energy usage during the course of any one-month period at the retail rate. This is the one that solar contractors and customers like but it is also the one that utilities would like to see go away. There can be some drawbacks for the customer under this NEM.

Monthly metering fees are usually added, monthly processing fees are sometimes added, some utilities require the customer to shift to time of use (TOU) metering under NEM agreements and occasionally the utility will raise the base rate for customers with NEM agreements. The actual rate offset by the PV system is usually less than it appears when these other costs are factored in. Producing energy above the NEM point would be compensated at a lower rate called the “avoided cost rate” or “possible not allowed”.

The average size of the installed PV system offsets at least 50% of the total energy consumed and sends at least 50% of that energy into the grid during midday hours. Without a NEM agreement, the digital meter will charge the customer for the energy sent back into the grid. Even though 50% of the usage is offset at the retail rate, the other 50% will be charged to the customer and the cost of the system will never be recovered.

There are other options but they are not necessarily optimum. Ideally all energy produced by a customer’s PV system should offset load demand and should not flow out into the grid. This can be achieved in one or more ways.

The simplest way is to design the PV system small enough so that the premises consumes all the energy produced. This is easier for a business to do because most of the energy is consumed during the day when the PV system is operating. A typical residence consumes most of its energy during the morning and evening hours (non-solar hours). Because of this, the PV system size should be restricted to offset only around 20% of the total energy consumed; a NEM agreement would not be needed and the monthly fee would be avoided.

Another option is to design the PV system with energy storage. The nice part of energy storage is having some electrical power during an electrical outage. The bad part is that it adds between 50% to 100% more cost to the PV system. The system functions as stand-alone with support from the utility and does not sell any energy to the utility so the NEM agreement and monthly fee is avoided. The big drawback to this type of system operation is that it restricts PV production during midday to prevent overcharge of the batteries.

Smart energy storage systems provide key benefits to NEM. These systems require a battery type that can be left in a partial state of discharge for prolonged periods without causing internal damage to the battery. The systems meter usage and production; energy produced during midday can be temporarily stored and released during the highest TOU rate periods of the day (afternoon and evening). Some smart energy storage systems can prevent the system from selling into the grid; in that case there is no need to participate in an NEM agreement with the utility and the monthly fees can be avoided. Smart energy storage PV systems will cost 100% more than an interactive PV system without energy storage.

Net metering values need to be calculated for each customer, and the effects and benefits will be different for every one of them. There are no one-size fits-all with PV systems and NEM.

Kelly Provence
Solairgen School of Solar Energy
www.solairgen.com

 

Solar Shingle

The Future of Solar PV Shingles

Solar shingles seem like the most logical application for the future of solar PV systems, serving two purposes – a roof and a solar PV system – by simply integrating the shingles into photovoltaic roofing. There are problems with the solar shingle system, slowing its mainstream marketability, but may work if the following obstacles can be overcome:

(1) The cost of solar shingles is not competitive with conventional solar electric PV modules. Costs might balance with high penetration into the photovoltaic industry, but that takes time.

(2) The physical constraints of solar electric roofing shingles do not allow for custom fitting to varying roof dimensions. This is an obstacle that is difficult and expensive to overcome.

(3) The solar roofing contractor’s training is limited to the narrow market of solar shingle manufacturers. The manufacturers will not train contractors in areas where sales are not profitable, so the solar shingle market restricts customers’ choices and is controlled exclusively by the manufacturer.

(4) Roof warranties can only be fulfilled by the solar roofing manufacturer and its own factory-trained solar roofers. Repairs may be delayed if there is not a trained contractor in the customer’s area. Roof damage not covered by the solar roofing manufacturer would be difficult or impossible to have repaired by conventional roofers who are not trained to work with solar shingles.

I would like to see this product succeed in the market, but no manufacturer has made a successful long-term run with residential solar roofing to date, and some who are attempting it have yet to make a profit in the photovoltaic industry.

Mainstream success of solar shingle roofing may happen, but it doesn’t appear to be coming in the near future.

 

Kelly Provence
NABCEP Certified Professional PV Installer
IREC Certified Master PV Trainer
Solairgen, Inc.
706-867-0678
info@solairgen.com

Image of a Poor Solar PV Installation

How to Prevent a Substandard Solar PV Installation

No one wants a poor PV system installation, but it happens from time to time. The good news is it’s 100% preventable but you should first understand the causes of a bad installation, and then learn how to prevent it. We tell you how.

Problem #1: The installer is unskilled and unknowledgeable about the correct installation process, but how do you determine that?

Solution: Screen the installer. Ask for references and evidence of their experience such as pictures, invoices, permits and inspection reports.  Ask how much training they received, and where they received it. You can even ask to see their graduation certificates. Inquire about industry certifications (NABCEP) and whether they have a contractor’s license.

If they can’t or won’t provide any of the above information, don’t contract with them no matter what they promise you. A reputable installer will be eager to provide their credentials.

Problem #2: A skilled and experienced installer wants to install a brand-new product that is not fully understood or tested in the industry. It is not uncommon in this industry for changes in PV products to outpace the contractor’s full understanding of them. Don’t be the guinea pig.

Solution: Insist on tried-and-true system components unless it’s just an improvement over a product that has been around a while. It’s best to see how those brand new products hold up during beta testing. Find out by going to the internet and doing some independent research. Don’t be afraid to tell your installer what you learned and that you prefer another product.

Problem #3: The contract price is too low for the contractor to make a profit. Incorrect bidding is common when a contractor is inexperienced, but underbidding occurs occasionally even for experienced installers.

Solution: It is best to find out the going price for the installation prior to accepting a bid. If you don’t know the going price, get more than one bid and then compare. Most companies will give you a generic bid without a problem.

Some Advice: If the installer you select has underbid the installation, it may save you money in the long run to offer a fair, renegotiated price. Some contractors are very honorable and will do the same good job even if they lose money, but some will not and that may cost you more down the road. And remember, a deal too good to be true is usually exactly that, untrue.

In summary, the real responsibility is on you, the customer. Take a day or two to learn about the PV products, the installation process and who the good contractors are. There are many organizations out there to help you. Here are a few links to get you started: American Solar Energy Society, Solar Energy Industries Association, NABCEP, IREC, and The Solar Foundation.

Finding skilled, experienced solar PV installers isn’t difficult, and eliminates the frustrating and very expensive future problems of a bad, or failed, solar PV installation.

Kelly Provence
IREC Certified Master Trainer
Solairgen School of Solar Technology