Solar power is becoming quite popular as energy costs continue to rise. Therefore, understanding the basics of solar system design is increasingly important. You may not know this, but there are various types of solar systems and various options that go into them.
Gaining knowledge of what works best for your situation and how to implement that is the key to success. As such, this article will provide that valuable knowledge so you don’t make a costly mistake. Now, continue reading to learn about solar system design and uncover how to do it right.
Uncover how solar power works
In many cases today, solar energy comes from self-sustaining home electrical systems that either connect to the local power grid or are completely independent. That means, they provide three sources of power: solar energy, a battery bank, and electricity from the grid. Now, let’s uncover all three in better detail.
Being the most important part of your solar system, your solar panel array converts sunlight into free electricity. Then, your battery bank stores excess electricity for future use. Finally, your local power grid connection provides two benefits: extra power and the ability to sell excess power back to the grid.
Now, watch the following video to see Eric Martineau, the founder of Just Get Solar, explain in detail exactly how solar power works as a system.
Two primary solar system design options
The distinguishing factor between the two primary solar system design options is your power grid connection. To explain, when not connected to the grid, your solar system design will be an off-grid solar system. If you plan to remain connected to your power grid, your solar system design will be a hybrid solar system. Hybrid solar systems are sometimes called a grid-tie solar system.
Another distinguishing factor between off-grid and grid-tie solar systems is power storage. Generally speaking, hybrid solar systems store excess power within the grid in the form of a credit. Then, you use that credit when your solar panels are not generating power at night.
When keeping your grid connection and using a process called “net metering,” your solar system is a hybrid solar system. But, a solar-energy household completely disconnected from the grid is an off-grid solar system. Both are self-sustaining, but off-grid solar is more complex and requires more attention.
Off-grid solar systems use a backup solar battery bank to store excess power generated during the day. Also, off-grid solar systems usually include a backup power generator. Generators provide power when during long periods of time without sunshine.
Using an off-grid solar system design
Over 300,000 homes use off-grid solar systems for solar energy independence around the world. They know that when connected to the grid, they’re dependent on an external supplier, the utility company, for all their power. And when that power grid goes down, so does their power supply.
When preparing your off-grid solar system, you must determine the amount of energy your household requires. As such, calculate your daily and yearly energy usage. The reason for this is simple: off-grid solar systems are inherently variable – day vs. night and sunny vs. cloudy.
Understanding the daily and yearly power rhythms or usage curves of your family’s energy consumption is essential when planning an efficient and reliable system. Using your household power usage data, solar component size determination for your entire solar system will be accurate and adequate.
Knowledge of how power is used by your household is critical. For example, water pumps eat power fast. That means, showers, toilet flushing, and washing dishes drain power quickly. The steps to take are small, but mindful. When you understand these factors, small changes make all the difference.
The benefits of hybrid solar system design
When referring hybrid solar assets, you’re talking about a self-sustaining household electrical system that is also connected to your local electrical grid. That means, this system provides three sources of electricity: solar power, battery bank power, and power from your local electrical grid.
Keeping your connection to your power grid allows you to receive unlimited electricity. That means, if you use big equipment or appliances, your electrical system will support it without fault. And if the summer heat steeply rises, use air conditioning to your heart’s content and stay cool throughout the day.
As mentioned, hybrid solar systems use solar net metering – they are self sufficient and tied to the grid. Solar net metering balances those seasonal differences in solar energy production throughout the year. Get a credit for the excess electricity your solar panels produce and use your credit at a later date.
With solar net metering, you’re only billed the net of what you take from the grid after using your credits. To simplify it, you supply the grid during the day when you’re at work. Then, you use electricity from the grid at night. When you use more than you supply, the difference becomes the net amount you owe.
Smart meters provide your net metering
As a replacement to your standard meter, a smart meter provides you with something called net metering. For an explanation, net metering analyzes and displays your local power grid’s electrical exports and imports to and from your solar system.
Smart meters manage additional factors too. To explain, they handle both the power generated by your solar system and your household power consumed. When exporting electricity, your meter spins backward. As a result, your electric bill receives applied credits each month.
Solar system design with solar panels
PV solar panels use semiconductor technology to convert energy from sunlight into DC electricity to power your home. So to explain how solar panels work, they take advantage of one of nature’s most powerful yet free resources. Also, solar panels generate clean, emission-free electricity to power your home all year round.
On top of being a clean technology, solar panels have a long life span. In fact, they usually last more than 25 years, making them a good long-term investment. Also, solar panels reduce your energy bills.
For a brief history, Alexandre-Edmond Becquerel first discovered how solar energy works in 1839. To explain, he saw the ability of some materials to create an electrical charge from light exposure – this is exactly how solar panels work! Then, Russell Ohl designed solar cells used in modern solar panels in 1939. He patented that in 1941.
After 1941, modern solar panels became a stable and effective technology for the marketplace. That means, they worked great and they haven’t changed very much since then. Although their efficiency has gone up a little, from 18% to 22% on the high-quality end, it means that the technology is quite stable.
Elements that make up solar panel technology
The silicon used in solar panels is a non-metal semiconductor. It is the material that absorbs and converts sunlight into electricity. The two main semiconductor silicon materials used in solar panel production are cadmium-telluride and copper indium gallium diselenide.
PV cells comprise two layers of semiconductor silicon. Each treated to create an electric field between the layers. This electric field forces electrons to flow through the solar cell and out of the silicon, generating a DC electrical current. Phosphorus and boron treat each layer prior to bonding them together.
Metal plates on the sides of each solar cell collect the electrons pushed out by the electric field. Then, the DC electricity created from that electric field transfers to connecting wires. At this point, the DC current flows through the wiring to a solar inverter and then throughout your home.
Solar battery system types
In the marketplace, you’ll find many different solar battery system types. But of course, most residential systems use either lead-acid or lithium-ion solar battery systems. Lead-acid batteries are the type used in automobiles and have been around a long time. Lithium-ion batteries are like those use in smartphones.
As you’ll find, there are two main lithium-ion chemistries used for solar batteries. The first is NMC or Nickel Manganese Cobalt. The second is LFP or Lithium Iron Phosphate. NMC batteries, like the LG Chem Prime, have been around a bit longer, making them slightly less expensive.
Many homeowners choose to use lead-acid batteries instead of lithium-ion batteries. The main reason for this is that they cost less. But, there are downsides to them. First, they usually have a shorter lifespan. Next they contain a lower power capacity. Finally, they require regular maintenance.
Lead-acid solar battery system performance
Traditionally, lead-acid deep cycle battery systems were the most common and reliable option for off-grid solar systems. Though a proven technology lasting over a decade, keep them at room temperature and don’t discharge them often.
To explain why room temperature is so important, both high temperatures and low temperatures degrade them over time. Also, when you fully drain lead-acid batteries damages occur internally. In fact, fully draining a lead-acid battery can cause it to completely die and no longer take a charge.
Lithium-ion solar battery system bank options
The best battery option for your solar system is a lithium-ion battery bank. It’s an advanced storage device optimized for long life, fast recharge, and high efficiency. But most notably, lithium-ion battery banks are quite popular for their high efficiency that ranges from 92% to 98%.
Next, lithium-ion batteries are lightweight, compact and scalable. On top of that, they provide flexible sizing for additional capacity down the road. In other words, install additional lithium-ion batteries in the future as you’re power needs increase. Or, add them to increase power storage for peace of mind.
An amazing advantage to lithium-ion batteries is their ability to sustain a low or partial charge level for long periods. To explain, there are no negative effects to sustained low or partial charge levels. Also, lithium-ion batteries provide high charge rates – charge times are up to 70% faster than lead-acid.
Using EV batteries for solar battery systems
There’s a new and emerging technology known as V2H or Vehicle to Home. In fact, it’s slowly being introduced and implemented into many next-generation EV’s or Electric Vehicles. EV’s are essentially a large battery on wheels that can store excess solar energy.
Power your home and charge your EV using a specialized charging system called a smart EV charger. These are bi-directional, so they can deliver power to your home or receive solar power for charging. Smart EV chargers require an add-on meter to measure the energy flow to and from your home.
Three types of solar power inverters
When connected to the grid, your solar inverter synchronizes the frequency of the grid and inverter power to match the frequency for smooth operation. Solar Inverters are generally classified as conventional transformer-less inverters or transformer-based inverters.
MPPT or Maximum Power Point Tracker inverter
The solar panel array has a limited DC supply and it varies throughout the day depending on the sunlight. To extract maximum possible power from the sun, a technique known as maximum power point tracking is used within your solar inverter.
MPPT is simply just a DC to DC converter. The MPPT circuit within your solar inverter constantly detects the solar panel array DC voltage and current. Then, it adjusts the setting to extract maximum power and drive your solar inverter at the maximum possible efficiency.
If the solar panels within your solar panel array are mounted across the roof area in different directions, multiple MPPTs are needed. This is due to the amount of sunlight falling on each panel being different.
MPPT solar inverters are classified as single or dual inverters. Dual MPPT inverters are advantageous as they connect two or more strings without the need for a combiner box. Also, they efficiently handle different tilt angles, azimuth angles, and voltage and power differences.
Transformer-less Inverters REVEALED
Today, transformer-less solar inverters are becoming popular. As no extra transformer is required, they decrease the extra weight, expense, and size. This sort of solar inverter is more productive as the misfortunes caused by the transformers are overcome – the efficiency is practically 97%.
This type of solar inverter uses a computerized multi-step process. As such, it converts the DC output of solar panel into high-frequency DC using a boost converter. Also, it’s converted into AC as per the grid and load requirement using an H-Bridge converter and oscillator.
Finally, the DC boost converter replaces the traditional step-up transformer. That means, it reduces the losses and space requirements.
Transformer-based Inverters EXPLAINED
A conventional solar inverters is built with a transformer to synchronize the voltage of the grid and your household load. Then, the generated DC is converted into AC with the help of an oscillator and metal oxide semiconductor field-effect transistor or MOSFETs. Finally, the AC power is matched with the frequency of the grid/load with the help of a transformer.
Traditional solar inverters suffer from transformer losses. That causes an efficiency decrease. Also, the weight of these inverters is high leading to increases in transportation and installation expenses. To overcome these losses transformer-less multi-mode inverters are gaining in popularity.
Do you need a solar backup generator?
Trying to determine whether you need a solar system backup generator can be frustrating. If you’re not sure you need one, you’ve come to the right place. The first question to answer is what type of solar system your home uses. Then, do you plan to achieve total energy independence?
Regarding the second question, a solar system backup generator certainly provides total energy independence. But, there’s a cost both upfront and during use. Running a solar system backup generator costs money in gasoline and it defeats the purpose of helping the environment.
Although a solar system backup generator has a downside, it is your last defense when two conditions occur. The first condition is lack of sunshine for extended periods of time. Then, the next condition occurs when your battery bank runs low while your solar panels are not producing power.
Solar system design for yearly power
With the right solar system designed for yearly power usage, it will generate enough power to match your total electricity use for a year. That means, your electricity will be completely free. As such, as your solar system generates excess electricity, you receive credits based on net kilowatt-hours sent back to the grid.
On the flip side, when producing less electricity than you use, you’ll be billed by your utility company. You must pay the net difference. In that case, you must pay for the electricity you use beyond the excess electricity your solar panels generate. In both cases, solar net metering handles the net difference.
Although your household energy demand varies throughout the year, start by calculating the basics in kWh. To begin, water usage, appliance usage, and general electricity usage is where to start. Keep in mind, only calculate water-usage if you use an electric water pump to provide water to your household.
Calculate each appliance individually. As such, use the wattage value for each of your own electrical appliances and products. This will provide the most accurate estimate. Then, add them all together to calculate your total annual energy consumption.
Estimate the number of daily hours each electric appliance and product runs at the most. For example, estimate the number of hours you use each electronic device. Examples include TVs, computers, gaming systems, home audio, and so on. Then, calculate each based on the wattage stated on each label.
Perform your household energy calculation
To determine your daily energy consumption, use the following formula:
(Watts × Daily hours used) ÷ 1000 = Daily kWh of consumption.
To calculate your annual energy consumption, use the following formula:
Daily kWh of consumption × Number of days used per year = Annual energy consumption.
This is a statement about annual electricity consumption in the U.S. by the U.S. Energy Information Administration:
“In 2020, the average annual electricity consumption for a U.S. residential utility customer was 10,715 kilowatthours (kWh), an average of about 893 kWh per month. Louisiana had the highest annual electricity consumption at 14,407 kWh per residential customer, and Hawaii had the lowest at 6,446 kWh per residential customer.”
Estimate your home appliance power usage
In the following article from Energy.Gov about estimating appliance and home electronic power usage, estimate the total electricity used by your appliances with the following four methods:
- Review each Energy Guide label to estimate the individual unit’s average energy consumption.
- Use an Electric Consumption Meter to uncover how much electricity each appliance consumes.
- Install a whole-house energy monitoring system to monitor your actual energy usage.
- Calculate your total annual energy consumption using the formulas shown below.
Use only highly-trained solar installers
You must be trained, experienced and certified to install a solar system. In other words, solar installation is not a DIY project. In fact, solar component installation and wiring requires an electrician and a construction contractor to do it right.
Installing a complete solar system is like installing a circuit breaker unit along with other major electrical systems. One primary component of a solar system is the solar power inverter, which powers your entire home. That means, safety and reliability is no different between the two.
The ability to perform construction is also necessary to install a solar system. Since solar panel arrays are typically secured on top of existing structures, the physical connections must be strong and reliable. Additionally, structures are sometimes built from the ground up to carry the load of your solar panel arrays sufficiently. Therefore, if you’re not familiar with construction, do not attempt solar installation.
To learn how to choose a great solar installer near you, check out this informative article:
SOLAR INSTALLERS NEAR ME: How to pick a solar installer to do it right
