Solar panel system basics

Net Energy Metering

The biggest reason to install solar is to eliminate, or drastically reduce, your electric bill. So how are we able to achieve this if solar only produces power during the day? It all starts with the initial site inspection and energy analysis. We determine your annual energy needs and design a system that can produce enough excess energy during the daytime to offset your day and night electrical consumption needs.

But wait, where does that excess power go? Until recently, battery storage wasn't a viable option to store the excess power production, so the utilities offered a process of tracking your annual solar power production called Net Energy Metering (NEM).

This process acts as a virtual battery by allowing for excess power to be fed back to the grid, literally spinning your meter backward, and storing energy credits, not the actual energy itself. With NEM in place, when you use electricity from the grid at night or during winter months when there is less sun, rather than a traditional charge on your bill the utility offsets the cost with your stored energy credit.

The goal for most homeowners and businesses is to design a system for which you produce just as much solar power as needed and at the end of a 12-month cycle you have consumed all your energy credits. No more, no less.

Solar Photovoltaic (PV) System Components

There are 2 main components to a solar PV system which include solar panels and an inverter.

With so many different brands and technologies available today, how do you choose what's best for you? The answer is step 1 in the "How to get started" section below. Schedule a free site inspection and energy analysis and we'll help you to determine your exact needs. There is no one size fits all solution, every project has site-specific conditions which may call for one product over another.

Let's explore the components below to help you make an informed choice.

Solar Panels

1. Energy Efficiency
2. Degredation Rate
3. Temperature Coefficient
4. Warranty
5. Price

There are 3 basic categories of solar panels: Economy, Standard, and Premium.  Depending on how they score in each metric will tell you which category of panels you are looking at.

Economy solar panels are typically cheap polysilicon modules still using a decade’s old technology providing lackluster performance and backed by a subpar warranty. Modernize Power DOES NOT install economy modules.  We stand behind the performance of our systems for 25 years and economy panels do not make the grade.

By using our easy comparison chart below you’ll be able to easily stay clear of these panels if you’re looking for an investment-grade module.

Your installation site-specific conditions and investment goal will determine whether a standard or premium panel is the right choice for you. When beginning your comparison, be aware some manufacturers carry both standard and premium models of solar panels. So, it is important to compare individual models against each other, not just brand to brand.

Pro Tip: A higher wattage rating does NOT mean a more efficient module. Many manufacturers are making panels in larger sizes (longer and wider) to achieve a higher nameplate rating for wattage without increasing efficiency. Compare efficiency percentage not the wattage of the panel.

Efficiency percentages range from the high teens to the low 20s encompassing economy, standard, and premium panels. The range is typically between 16% and 22%. The higher the percentage the better. When a solar panel has a higher efficiency percentage more energy can be produced per square inch than less efficient modules.  

This is particularly important when installation space is constrained like on some rooftops. A more efficient panel can reduce the number of total solar panels needed for your project.  If you are installing a roof mount system, then this also means reducing the probability of a leak with fewer roof penetrations.

However, looking at efficiency percentage alone can backfire.  If a high-efficiency panel has a poor temperature coefficient and degradation rate it will negate the efficiency advantage of that panel.  Use our easy comparison chart below to compare.

The Temperature Coefficient is a very important measure that is often overlooked. Simply defined, it means the amount of energy production loss at higher temperatures. The hotter a solar panel gets the less efficient it becomes. This might sound counterintuitive because solar panels need sun energy to produce power.

But indeed, it’s true. Solar panels perform better on sunny cold days than on sunny hot days. So, if you live in a region with sunny hot summers you may want to invest in a module with a lower temperature coefficient to maximize your production. A premium panel may have a temperature coefficient of .26% and a standard panel at .36%. The lower the number percentage the better.

‍Degradation rate is the amount of decrease in solar power output over time. It is usually expressed in an annual percentage. A solar panel with a .5% annual degradation rate degrades at a pace twice that of a panel with a .25% degradation rate. Here again, the lower the number the better.  

What does this mean in the real world? As your solar production diminishes over time your need for Utility power will increase.  This increase will equate to a rise in your utility bill.  Degradation rate may be the most important metric of the 5 we are comparing.  The lower the rate the longer you can keep the Utility at bay.

The Warranty is another important factor when choosing your module.  Be aware that the warranty is broken down into 3 subcategories: Product, Production, and Labor.

The production portion of the warranty is directly related to the degradation rate and how much power the manufacturer will warranty over time. Most manufacturers warranty that at year 25 minimum production will be at least 86%-92% of the original production, varying by brand. So here, you want the highest number possible if your wish is to maximize your investment and again keep the Utility billing at bay.

The product warranty is pretty straightforward. This is how long a manufacturer will stand behind its product against any defects. Typical warranty periods are 10-25 years.

The labor to replace a failed panel is covered by some, but not all manufacturers, and for varying time periods. The best of the best panels offer a full 25 years of coverage for replacing defective panels.

In Summary, after comparing the key metrics to determine the quality of the solar panels then pricing becomes more relevant in understanding one quote from another.

Here is an example of an easy comparison chart you can do.  Substitute economy, standard, and premium with the models of the panels you are comparing.  Clear the values in our example and look on the back of the module specification datasheet and fill in the corresponding values.  Then see which panel wins and is best for your needs. 

Inverters

Solar panels create DC energy from the sun, but homes and businesses use AC electricity. This is where the inverter comes in. The inverter converts the DC energy into usable AC electricity. There are 3 main types of inverters which are central string inverters, micro-inverters, and a hybrid inverter system that uses DC power optimizers. As with anything, there are pros and cons for each. At Modernize Power we typically install either the hybrid inverter with DC optimizers or micro-inverters, but again this depends on site specific conditions and/or customer preference.

Let us customize the perfect solution for your home or business, schedule a free estimate today!