Solar energy is the most popular form of renewable power in the world, followed by wind and hydroelectric in a distant second and third. Although it’s useful for some small-scale applications, a large panel system with powerful batteries unlocks its full potential. Investing in a solar-plus-storage system is worthwhile because you can save money, help the planet, and have a feeling of true accomplishment.
Here’s everything you need to know about solar-plus-storage systems.
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How Solar Batteries Work
Solar batteries have a simple purpose: to stockpile the extra energy panels produce. Panels without batteries are only valuable when exposed to sunlight. They also don’t store the energy you don’t use, instead sending it back to the utility grid. This problem is one of the main reasons people hesitate to invest in solar energy.
Batteries solve the deficiencies of solitary solar panels, storing any power you don’t use for the future. They enable you to use all the energy they collect, powering your devices even when they stop taking in sunlight. That means you have enough to get through the night and on cloudy days when the panels are less efficient.
These new systems are often called solar-plus-storage systems to distinguish them from regular standalone panels. Solar batteries have a wide range of capabilities, storing anywhere from 100 to 1,000 amp-hours, depending on their size. Multiple batteries can also connect to the same panel, enabling you to store even more power.
Benefits of Solar-Plus-Storage
Homeowners have many good reasons to invest in a solar-plus-storage system. The most obvious is the opportunity for unlimited, round-the-clock access to a renewable energy source. Here are some other benefits of switching to solar:
- Cost-effective: Many homes waste significant amounts of energy on lights, charging electronics and air conditioning. Their electric bill rates can also change without warning based on local demand. Solar storage eliminates both problems, reserving power until you actually need it and keeping your rates low because you have your own supply.
- Easy to monitor: Solar systems have monitoring features that allow you to track the energy expenditure of various appliances. You can identify which ones are wasting power or consuming too much.
- More self-sufficient: The system takes you one step further off the grid. You don’t have to completely rely on local utilities to provide electricity and have energy reserves in case of a power outage. Only homes with the largest solar batteries are 100% self-sufficient, but smaller batteries at least provide a limited supply of off-the-grid energy.
- Eco-friendly: Solar energy helps reduce humanity’s carbon footprint, reduces nonrenewable resource consumption and enables you to invest in other eco-friendly appliances, such as electric vehicles.
Solar panels hit the mainstream because of their eco-friendly nature, but they bring much more to the table than reduced emissions. A solar-plus-storage system can be the perfect power source for families looking to bring more value and independence to their homes. First, let’s go over the essentials.
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The 4 Key Components of Solar-Plus-Storage
To fully understand how a solar-plus-storage system works, homeowners must know their way around the four key components: solar panels, the inverter, the battery type and the system’s controls. Here’s what you need to know about each of these elements.
1. Solar Panels
Solar panels are the most well-known parts of a solar-plus-storage system. They are flat silicon slabs usually stationed in yards or on roofs for maximum sunlight exposure. Sunlight reacts with the silicon’s chemical properties to produce a small electric charge. Thousands of these equate to a substantial amount of energy that can power homes and appliances.
The energy panels generate is called a direct current. It’s measured in kilowatts (kW), while consumed power is measured in kilowatt-hours (kWh). Homeowners need to know these metrics to accurately estimate how much energy their solar-plus-storage systems are gathering and expending.
The average house with a few standard 6-by-6-foot solar panels consumes 25 to 30 kWh daily. The property’s size and the number of electronic appliances can cause this number to fluctuate, but 30 kWh is a good total to keep in mind.
The solar inverter is the straw that stirs the drink. The direct current (DC) electricity panels produce doesn’t work on household appliances. The inverter transitions DC into applied current (AC) electricity, making it usable. Inverters also maximize the amount of energy each panel produces and detect unstable currents, keeping the system intact.
Inverters can be located inside next to the battery, wiring and controls or outside attached directly to the solar panels. Solar-plus-storage systems usually have these four types of inverters:
- String inverters: This technology is the oldest type of inverter that works with solar panels wired together with strings. The DC electricity travels through the strings to the inverter, turning it into usable AC electricity. Shade impacts string inverters more than the other types because all the panels are connected. If one is blocked from the sun, the output from the others also decreases. They’re more easily compromised, but they’re also easier to fix.
- Microinverters: Microinverters are small devices attached to the back of solar panels. They’re more efficient than string converters because they monitor each panel independently without influence from the shade. However, since they’re attached, two essential parts of the system are exposed to the elements. You might want to add some sort of protective covering if you use microinverters.
- Power optimizers: Power optimizers add an extra step to the energy inversion process. They’re attached to the panels just like microinverters, but they send the DC electricity to other string inverters instead. This setup eliminates the shade problem of string inverters while having the same efficiency as microinverters. The main downside is that a broken power optimizer requires you to shut down the whole system to fix it, but they’re easily replaceable.
- Hybrid inverters: Hybrid inverters are the best options for solar-plus-storage systems. They convert DC to AC electricity like the other models, but they can also reconvert AC back to DC to charge the battery bank. They also come with charge controllers, enabling you to redirect power to the storage system, home appliances or back to the local grid.
These inverters might look and operate differently, but they fall into the same technological category as module-level power electronics (MLPEs). According to a survey conducted by UC Berkeley Labs, 94% of solar power systems utilized MLPEs in 2020. You can pursue unorthodox options like standalone inverters, but the above four options are the most practical.
3. Battery Type
Solar energy storage batteries act as reservoirs. Like any other device that runs on batteries, its life cycle can deteriorate from improper use. The depth of discharge (DoD) is the exact percentage of the battery’s power you need to monitor. Charging the battery past the manufacturer’s recommended level will negatively affect its performance.
A solar battery’s DoD is usually around 70%. If it has a charging capacity of 10 kWh, you shouldn’t drain the battery by more than 7 kW. Once it passes that threshold, you must recharge the battery or risk reducing its capacity. This preventive maintenance is crucial for maximizing its life span.
Solar storage batteries can have three different types of chemical compounds:
- Lithium-ion: Batteries in all electronic devices have similar lithium-ion chemical compositions. This compound can maintain high energy levels even at small sizes and light weights, making it highly versatile. SolarMetric says these batteries are the best overall options for solar-plus-storage systems.
- Lead acid: Lead acid batteries are the cheapest and most fragile options. They’re compact and stackable, enabling you to store massive amounts of energy. This feature makes them a popular choice for off-the-grid living. They won’t explode or catch fire if mishandled, but they will deteriorate over time and likely die within 10 years. Be prepared to make periodic replacements if you use them.
- Saltwater: These types of batteries use a saltwater electrolyte solution to store the energy taken from solar panels. The technology is relatively new and unproven compared to the other two options, but it’s also the most eco-friendly. Homeowners looking for a minimalist solar energy system should consider saltwater batteries.
Solar energy systems may be able to use self-sustaining fuel cells instead of batteries in the future, but for now, lithium-ion batteries are your best option.
4. Integration and System Controls
The solar-plus-storage system’s wiring and controls are the small details that hold it together. It’s important to look for a system that has strong controls that help you manage the system to meet your property’s needs. SolarMetric recommends getting a system designed to work together and finding an installer experienced with solar storage systems.
It can be difficult to pinpoint the source of the problem if something goes wrong, potentially leaving you unable to collect power for several days. Having a trusted partner that can make quick emergency repairs is a necessity.
Most systems have solar charge controllers that regulate the voltage from the panels to the battery to make monitoring and controlling things easier. These controllers utilize maximum power point tracking to speed up or slow down the charging process, which helps keep things in stable condition.
Solar Battery Storage Costs
Now that you understand the benefits of going solar and the essential parts of a solar-plus-storage system, it’s time to address the difficult part: costs. This can be a stumbling block for many people, but it doesn’t have to be.
A residential system with less than 10 kWh storage capacity costs between $10,000 and $20,000. Most people don’t need a system that powerful, so you should expect your number to be closer to $10,000. If you’re looking to go off the grid, a system with greater energy storage capacity costs between $25,000 and $30,000. These are the main factors that influence the final number.
1. Solar Battery Manufacturer
The energy storage battery manufacturer you choose can significantly impact your system’s full price. Popular companies like Panasonic, LG and Tesla make solar batteries in the $10,000-$13,000 range, while more niche manufacturers like the German brand Sonnen have luxury batteries that cost over $30,000. Installation charges are included in these numbers.
2. Battery Chemistry
Lithium-ion batteries are better options than lead-acid or saltwater versions for most homes. However, they’re also more expensive. Lead-acid batteries are cheap and easily replaceable, while saltwater batteries are also inexpensive because of their basic chemical compositions. It depends on which factor you think is more important: short-term savings or long-term sustainability.
3. Number of Batteries
Solar storage batteries come in many sizes, but the average energy storage capacity is 10 kWh. If you’re looking for batteries with a similar range, your property will need at least two or three. Those who want to take their electricity off the grid sometimes need up to a dozen batteries. It all depends on the property’s size, the types of appliances and your long-term goals.
4. Type of Inverter
String inverters are the cheapest types by a notable margin, but they’re also the least efficient. Microinverters and power optimizers can range from $100-$1,000 depending on their size and durability – two important qualities you need to keep in mind. Micro hybrid inverters cost only a few hundred dollars, but full-sized inverters can reach over $3,000.
Your state’s taxes, weather and market conditions will partly determine the cost of your solar-plus-storage system. Currently, the cheapest are Georgia, Kentucky, Pennsylvania and Louisiana. The most expensive places are New York, California, Nebraska and most New England states.
A Basic System Layout
For a basic solar-plus-storage system, SolarMetric recommends looking for panels covering 70% of your daily energy usage. Many factors play into this number, but the average American home needs about 16. One 5-kW lithium-ion battery with at least 10 kWh storage capacity is enough for 16 panels.
Most homeowners can expect the battery to add about 25% to the final cost. For example, a pv system estimated to cost $4 per watt would increase to $5 per watt with the addition of a battery.
An Advanced System Layout
People with large homesteads or high energy requirements might want to install a more advanced system, especially if they need a reliable backup power source. SolarMetric estimates that these types of systems need to produce 120% of the property’s daily energy needs. The battery storage must also be able to work completely independently from the local power grid.
Because of the battery’s off-grid requirements, SolarMetric recommends two energy storage batteries for advanced systems. This will ensure homes with higher energy requirements have enough daily power plus sufficient supplies left over.
Tax Credits and Incentives
Each state also has its own incentives for homeowners who switch to solar energy. Most have a 30% tax credit for the whole project, with other perks like $200- or $300-per-kilowatt rebates. However, the extra incentives in many states are declining as they get closer to reaching their solar capacity goals.
As part of the recently passed Inflation Reduction Act, a solar-plus-storage system might also make the owner eligible for a 30% federal tax credit on top of the state credit. Systems over $20,000 receive an additional $6,000, so it pays to invest in one.
However, it’s important to note that the 30% federal tax incentive will drop to 26% in 2034, 22% in 2035 and disappear in 2036. You can realistically save over $10,000 on the project if you start planning now.
How to Get Started
Ensure a successful project by working with an installer with experience with solar plus storage solutions in your area. Your home has many unique qualities and needs, such as the architectural design, wiring, zoning and inspection requirements. You can contact solar installers in your area and research them on SolarMetric.com.
Solar Energy Storage: A Worthwhile Investment
A full solar-plus-storage system with batteries, inverters and all the rest might be an intimidating investment. The many pieces of equipment, installation process and preventive maintenance may overwhelm you, but that’s part of the experience. Sustainable, self-sufficient living is supposed to be a daily challenge. That’s what makes it so fulfilling.
Solar energy storage is a worthwhile investment for any homeowner looking to help the environment or take another step off the grid. If you have the money saved up, don’t waste another day.