How Does A Solar Battery Work? | Energy Storage Explained
A solar battery can be an important addition to your solar power system. It helps you store excess electricity that you can use when your solar panels aren’t generating enough energy, and gives you more options for how to power your home.
If you’re looking for the answer to, “How do solar batteries work?”, this article will explain what a solar battery is, solar battery science, how solar batteries work with a solar power system, and the overall benefits of using solar battery storage.
What is a Solar Battery?
Let’s start with a simple answer to the question, “What is a solar battery?”:
A solar battery is a device that you can add to your solar power system to store the excess electricity generated by your solar panels.
You can then use that stored energy to power your home at times when your solar panels don’t generate enough electricity, including nights, cloudy days, and during power outages.
The point of a solar battery is to help you use more of the solar energy you’re creating. If you don’t have battery storage, any excess electricity from solar power goes to the grid, which means you’re generating power and providing it to other people without taking full advantage of the electricity your panels create first.
For more information, check out our Solar Battery Guide: Benefits, Features, and Cost
The Science of Solar Batteries
Lithium-ion batteries are the most popular form of solar batteries currently on the market. This is the same technology used for smartphones and other high-tech batteries.
Lithium-ion batteries work through a chemical reaction that stores chemical energy before converting it to electrical energy. The reaction occurs when lithium ions release free electrons, and those electrons flow from the negatively-charged anode to the positively-charged cathode.
This movement is encouraged and enhanced by lithium-salt electrolyte, a liquid inside the battery that balances the reaction by providing the necessary positive ions. This flow of free electrons creates the current necessary for people to use electricity.
When you draw electricity from the battery, the lithium ions flow back across the electrolyte to the positive electrode. At the same time, electrons move from the negative electrode to the positive electrode via the outer circuit, powering the plugged-in device.
Home solar power storage batteries combine multiple ion battery cells with sophisticated electronics that regulate the performance and safety of the whole solar battery system. Thus, solar batteries function as rechargeable batteries that use the power of the sun as the initial input that kickstarts the whole process of creating an electrical current.
Benefits of battery storage
By shifting your excess solar generation to peak periods, you’re reducing your carbon emissions and the demand on the electric grid, putting us closer to our goal of reaching zero carbon emissions in our power supply by 2030 – the most ambitious goal of any large utility in the United States.
A battery storage system lets you store excess solar energy generated during the day. You can use this excess energy during peak hours, when electricity is most expensive. This reduces the typical customer’s electric bill, but doesn’t factor in the cost of leasing or purchasing the battery. Learn more about our Time-of-Day rates.
In the event of a power outage, battery storage systems can provide power and reliability. Unlike backup generators, battery storage can power critical appliances like your refrigerator.
Start your estimate
If you’re considering battery storage, use our solar system estimator, which includes a battery storage option, to help you determine the benefits of installing battery storage. Let us serve as your trusted advisor to help you make the choice that’s right for you.
We have a variety of battery storage incentives available for residential customers.
Join SMUD’s new voluntary program, My Energy Optimizer SM. and earn financial incentives for making your battery storage unit an even smarter device.
When you partner with SMUD, your battery will reduce energy usage during the hours when demand is highest and clean energy resources are scarce. This could include shifting the time when your battery is used to power your home. The interactions would be seamless to you and no extra effort is needed on your part.
To be eligible for the program, you must have a battery storage unit installed at your home and participate in SMUD’s new Solar and Storage Rate.
If you’re adding a new solar system with battery storage or a battery storage system only, there is a one-time fee to connect to SMUD’s grid to recover the cost of providing interconnection service. The interconnection fee will be applied to all new systems starting March 1, 2022. Your solar installer should already be aware of this new fee. If you’re adding battery storage to an existing solar system, an interconnection fee does not apply.
All levels of participation include a one-time incentive of up to 5000,500 that is paid after the interconnect application reaches a project complete status and enrollment onboarding process is completed. The Partner and Partner program levels have ongoing performance payments. See details below.
Levels of participation
Starter (50/kWh up to 500)
Set your battery to optimize with SMUD’s Time-of-Day (5-8 p.m.) Rate. Your battery is most likely already operating in this mode so you can set it and forget it. This one-time incentive is paid after the interconnection application reaches a project complete status.
Partner (150/kWh up to 450,500)
My Energy Optimizer Partner level allows SMUD to optimize your battery storage system to respond to Peak Events during summer months, when energy demand is highest. SMUD will communicate Peak Events in advance and your battery will respond automatically.
When you join My Energy Optimizer Partner, you’ll participate in our Critical Peak Pricing rate. This rate is in addition to your current Time-of-Day (5-8 p.m.) Rate and gives you a discount on energy throughout the summer in exchange for higher energy during Peak Events. Customers with storage and/or solar will also receive 50 per kWh for energy sent back to the grid during a Peak Event. You’ll have battery capacity reserved for back-up power needs.
Once enrolled, you don’t need to reconfigure your battery storage system. SMUD has partnered with the industry to make your household’s response to Peak Events seamless. The program will ensure your battery is at full charge prior to a Peak Event and that your battery discharges during the Peak Event, with no extra work on your part.
Learn more about My Energy Optimizer programs and incentives for thermostats.
Partner (250/kWh up to 5000,500)
The most engaged level of participation. Instead of the summer-only Peak Events in the Partner level, Partner optimizes your Tesla Powerwall year-round. The battery will continue to be available for customer use, such as back-up power needs in the event of an outage. Customers in the Partner level will receive ongoing performance payments in addition to the enrollment incentive.
Once enrolled, you don’t need to reconfigure your battery storage system.
For this incentive level, you must own and have installed a Tesla Powerwall.
The Partner program is under development and will launch this summer. Check back soon.
How to enroll
Enrolling in one of our My Energy Optimizer programs is easy. Once you’ve installed a battery storage system, or if you already have battery storage at your home, simply use the button below to apply for the program. After receiving your application, we’ll be in touch with further instructions.
How does a battery storage system operate? Battery storage systems are a way of storing and releasing electrical energy in a chemical manner. Battery storage systems store the energy in batteries. An inverter converts the battery’s DC energy to AC energy your home can use.
The battery is charged using energy from your solar PV system or the electric grid. The battery is discharged to offset energy use during more expensive peak times of the day. This is to reduce your electric bill or for back-up power in the event of an outage.
What is the lifespan of a battery storage system? Lithium Ion (Li-Ion) battery systems usually last about 10 years. The warranty period for batteries is set by your battery system manufacturer.
Do all battery storage systems provide backup power? Many battery storage systems can provide backup power if they are configured to do so. A battery can be configured to provide backup power for critical items or your whole home. Be sure to communicate with your contractor about how much, if any, of your battery capacity you want dedicated to backup power.
Is battery storage safe? Safe installation should follow:
- National Electric Code (NEC)
- SMUD’s Electrical Service Requirements
- Any additional requirements of your local building permitting agency
Follow manufacturer’s care, use and service criteria to ensure safest possible operation.
Battery storage for your home
How long will a battery storage system power my home during an outage? Without solar, batteries usually provide backup power for about 2-3 hours at their peak rated output. When paired with solar generation, the backup period can be extended. The number of appliances powered during an outage will impact the backup power duration.
What size battery system should I consider for my home? Your battery installation contractor can help you decide what battery system size is right for you. The typical residential battery storage system installed in SMUD territory is a 5kW / 10kWh unit.
Can I go completely off-grid with a battery storage system? While it is possible to go completely off-grid with a battery storage system, a modern home is not designed to be disconnected from the grid. A battery storage system is not a generator. It’s not realistic to permanently operate off-grid without substantial investment in larger solar and storage systems. Even with solar generation, a storage system would need to be significantly larger to provide enough electricity to power your home 24 hours a day, 7 days a week.
How can I learn more about battery storage systems? If you’re interested in learning more about battery storage systems, you can attend a SMUD class to get a better grasp of this new technology. Also, we recommend getting multiple bids before you sign a contract.
Does SMUD have any requirements on how I install my battery? SMUD requires that the battery storage system installation follows:
- National Electric Code (NEC)
- Requirements of your local building permitting agency
- SMUD’s Electrical Service Requirements for Distributed Generation
The interconnection process for battery storage is very similar to interconnection of solar PV systems. Battery storage systems are processed through the SMUD PowerClerk portal. This step-by-step web tool will make your interconnection process easy and straight forward. Your contractor will most likely handle the process for you.
My Energy Optimizer incentives
Why join My Energy Optimizer program? Your participation in My Energy Optimizer reduces your household’s environmental footprint and helps our community achieve SMUD’s 2030 Zero Carbon Plan. The program makes it easy to conserve energy when the electricity grid is under stress. The program is also part of our efforts to reduce peak demand, avoid building new power plants and reduce the need to buy electricity from more expensive, less environmentally-friendly sources.
Am I eligible for My Energy Optimizer if I am currently in the process of installing a battery storage system at my residence? To be eligible for My Energy Optimizer Partner and Partner, you must own the battery storage unit installed at your home and participate in SMUD’s new Solar and Storage Rate (SSR). Leased battery storage systems only qualify for the Starter level. To confirm your enrollment in the program, email MyEnergyOptimizer@smud.org.
What about back-up power? Program participants will have full access to the amount of power available in their battery storage system during a power outage. If a customer has 80% of their battery charged, then 80% capacity will be available to back-up the home. For more information, please see the Do all battery storage systems provide back-up power? question above.
Solar power and storage
As a long-term operator of solar projects, we are experienced in developing high quality projects that benefit the communities where we operate. From the very first stages of development, we remain committed to using the highest quality standards in construction, equipment, and safety. We also ensure that communities see real benefits from the project.
High quality materials
We procure solar panels from trusted Tier 1 manufacturers, providing greater quality and reliability.
Local economic benefits
We prioritize using local workers and materials whenever possible.
Our construction standards minimize environmental impacts and preserve local habitats.
Community infrastructure investments
Our projects generate millions of dollars in revenue for communities that can be invested back into local priorities like schools, roads or emergency services.
We support educational efforts in these communities including Science, Technology, Engineering and Mathematics (STEM) programs that help develop career opportunities in the clean energy industry.
Solar energy and storage projects
Through an established execution model developed over decades of experience, our solar and storage projects generate clean, affordable energy.
Muscle Shoals solar farm is located in Colbert County, Alabama. The project generates 227 megawatts of solar power and includes a long-term power purchase agreement with the Tennessee Valley Authority. Muscle Shoals began commercial operations in September 2021.
The Permian Energy Center is located in Andrews County, Texas. The project generates 420 megawatts of solar power, enough electricity to power 80,100 homes. Permian Energy Center began commercial operations in May 2021.
Old 300 Solar Farm is located in Fort Bend County, Texas. The project generates 430 megawatts of solar power, enough electricity to power 74,600 homes. It will also provide millions of dollars in landowner payments and property taxes for local communities.
The Helena Energy Center is located in Bee County, Texas, and is comprised of co-located solar and wind generation. The project will generate 250 megawatts of solar power, enough electricity to power 50,000 homes. It will also provide tens of millions of dollars in landowner payments and property taxes for local communities.
Ørsted has office locations and projects across the U.S. to support our growing business, create skilled jobs, and meet the demand for clean, reliable energy.
Use our interactive map to see where we work across the U.S. and the rest of the world.
With the largest portfolio of offshore wind farm projects secured to date, we’re leading this rapidly growing industry in the U.S.
Offshore North America 399 Boylston Street, 12th Floor Boston, MA 02116
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The Ørsted vision is a world that runs entirely on green energy. Ørsted develops, constructs, and operates offshore and onshore wind farms, solar farms, energy storage facilities, renewable hydrogen and green fuels facilities, and bioenergy plants. Ørsted is recognised on the CDP Climate Change A List as a global leader on climate action and was the first energy company in the world to have its science-based net-zero emissions target validated by the Science Based Targets initiative (SBTi). Headquartered in Denmark, Ørsted employs approx. 8,000 people. Ørsted’s shares are listed on Nasdaq Copenhagen (Orsted). In 2022, the group’s revenue was DKK 132.3 billion (EUR 17.8 billion).
INCREASING ENERGY FLEXIBILITY RELIABILITY
EVESCO’s utility battery storage systems have a storage capacity ranging from a few megawatt-hours (MWh) to hundreds of MWh. We utilize the very best in battery technology within our battery storage systems designed for grid applications, which include lithium iron phosphate (LiFePO4) and valve regulated lead acid (VRLA). Our battery storage can be connected to power generation assets or transmission and distribution networks increasing flexibility in power systems and enabling optimal use of renewable energy sources.
The increasing share of renewable energy sources within the global energy mix calls for a more flexible and resilient energy system to make sure that renewable sources are integrated in the most efficient and reliable way. Power Sonic’s large scale battery storage solutions increase flexibility and reliability within the energy network enabling optimal use of intermittent renewable electricity sources. flexibility is delivered due to our battery storage’s unique ability to respond lightning fast to import, store and export electricity.
Let us guide you through your energy storage project
EVESCO understands the complexities of energy storage, contact one of our energy storage experts today.
UNLOCKING THE FULL POTENTIAL OF RENEWABLES
Large-scale battery storage is the most responsive and flexible asset available to network operators, it can solve the issue with network volatility caused by the intermittent nature of renewable generation within the network. As EVESCO’s battery storage solutions are bi-directional they can provide and absorb power from the energy network, smoothing out the intermittence of renewables by storing and distributing power when needed. Battery storage can be situated anywhere in the network to improve the flexibility and resilience of the entire network.
Integrating renewable energy sources, such as wind and solar, with EVESCO’s battery storage will enable you to capture all the energy generated and release that energy when it is needed. You are no longer forced to either use it or lose it. Grid-scale battery storage also enables you to do more with your renewables including capacity firming, power output smoothing, control ramp rates, and power absorbing during times of excess generation. With these capabilities, our lead-acid and lithium battery storage solutions will ensure cost-effective energy on demand.
SCALABLE ENERGY STORAGE SOLUTIONS
Unlike more conventional storage systems, such as pumped hydro storage, battery storage has a number of advantages including flexibility of location and sizing. This means battery storage systems can be deployed closer to the actual locations where flexibility and scalability is needed. Installation of pumped hydro storage, as an example, requires specific geographical conditions. Our battery storage systems are fully scalable in modules and can scale up to the hundreds of megawatt-hours.
Large scale battery energy storage currently dominates in terms of overall energy storage capacity, however deployment of smaller scale battery storage solutions and commercial battery storage have seen an increase in demand. Whatever size battery energy storage system you require and whatever the application EVESCO can help you discover the right solution for you.