How Does Solar Power Work For Your Home?

How solar works is simpler than you think. Once you’ve made up your mind to get off the utility company’s rate-hike roller coaster and embrace solar energy, switching to solar power is really pretty simple. You say “Yes!” to choosing solar energy and locking in your rate, and we’ll do the rest from home solar installation to maintenance and more.

But first, you’re wondering, “How does solar power work?” Glad you asked! It’s a good place to start when you’re thinking about how to go solar, because even though Sunrun takes care of everything from permitting to installation and flipping the on-switch, we want you to feel comfortable every step of the way. Understanding how solar panels work can help.

How does home solar power work?

Basically, solar panels work by converting solar radiation into two forms: electrical energy and heat. This solar energy conversion is primarily done by solar panels, which consist of numerous solar cells. These cells use the photovoltaic effect to transform sunlight into electricity. In simple terms, when sunlight hits these cells, it frees electrons, creating an electrical current. 

Additionally, some solar panels are designed to capture solar energy as heat. These are known as solar thermal collectors and are often used for heating water or spaces in buildings. 

The size and location of these solar panels can vary greatly, from small setups on residential rooftops to large arrays stretching across acres of rural land. Both small and large-scale installations contribute to harnessing renewable energy from the sun.

Solar panels

Solar panels work by generating electricity using solar radiation. They’re like sandwiches made of special materials, mainly silicon and glass, with a dash of metals like boron and phosphorous. These layers work together to create solar energy in the form of electricity. When the sun’s light, full of tiny particles called photons, hits these layers, it causes a reaction that frees up electrons. These freed electrons create an electric current. 

The silicon layers of each solar panel are charged differently—one positively with boron and the other negatively with phosphorous. With this setup, solar panels create an electric field. When photons enter this field, they push the electrons out. Metal plates on the sides of the cells then capture these electrons, allowing solar energy in the form of an electric current to flow through the panel.

Even on cloudy days, solar panels can still do their job because they use different parts of the sun’s light, not just the bright part we see. But their efficiency may diminish under heavy cloud cover, rain, or snow. Since solar panels produce direct current (DC) electricity, an inverter is necessary to convert this to alternating current (AC), the type used in most homes for running appliances, plugs, and lights​​.

Although low-maintenance, dust and leaves can block the sunlight and make panels less effective. So, a little maintenance goes a long way in keeping solar technologies working at their best.

Inverter

Inverters bridge the gap between the solar energy produced by solar panels and the energy we use in our homes. Solar panels produce DC electricity, but most homes and appliances run on AC electricity. An inverter’s job is to convert DC into AC electricity, making the solar energy produced usable for everyday purposes. If DC were to run directly into a home, it could potentially cause damage to appliances and electronics.

There are different types of inverters, such as standard string inverters, optimized string inverters, microinverters, and hybrid inverters, each with unique features and suited for different solar array setups:

Standard string inverters:

Commonly used for smaller solar technologies, solar string inverters connect a string of solar panels to convert the collective solar energy into AC. They are typically installed on the home, in a garage, or near the power meter. Their advantages include being the least expensive option and easy to maintain since they are not mounted on the roof. However, their efficiency at converting solar energy can be limited by complex roof designs or shading​​.

Optimized string inverters:

Optimized string inverters consist of two parts: the power optimizer and the inverter. The power optimizer conditions the DC power from each solar panel before it reaches the inverter. This setup allows for consistent energy flow and is great for complex roof designs where shading can be an issue. But they tend to be more expensive than standard string inverters and can require more labor for installation​​. Sunrun uses optimized string inverters for our solar- only projects to provide you with an efficient, yet affordable option.

Microinverters:

Installed at the panel level, microinverters convert solar energy to AC electricity right at the solar panels. This allows for optimization of energy conversion for each panel individually, making them suitable for complex roof designs and effective even in shaded conditions. They offer extended warranties but are more expensive than other types and can be harder to access for repairs​​.

Hybrid inverters:

Hybrid inverters are part of systems that include a battery backup. Hybrid inverters can manage energy from the solar panels, battery system, and even the grid. They are programmable, allowing for efficient energy management, and are ideal for systems where expansion or addition of battery storage is anticipated. However, they can be more limiting in terms of system design compared to microinverters and may reduce overall energy efficiency​​. Sunrun utilizes hybrid inverters for solar and storage projects to ensure a functional and optimized energy experience. 

Main electric service panel

Located typically in a basement, garage, or utility closet, the main electric service panel, or breaker panel, houses various breakers that distribute power to different parts of your home. Each circuit is designed to handle a specific electrical load, with larger appliances often having their own dedicated breakers. When solar panels are added, they become an additional source of electricity, feeding into this system, which can potentially overload an older or inadequate panel​​​​.

Upgrading to a solar-ready electrical panel is often necessary when installing solar panels, especially in older homes. A solar-ready panel has the capacity for the additional circuits required by a solar system and can handle the extra power load safely. This upgrade can also have financial benefits, as it might qualify for federal solar tax credits (if you purchase your home solar system), reducing the overall cost. Additionally, upgrading the panel can resolve issues like frequently tripped breakers and allow for future increases in household electrical needs, such as installing an electric vehicle charger or switching to electric appliances​​.

The cost of upgrading an electrical panel ranges from $800 to $2,500, with a standard 200-amp panel suitable for most homes costing around $1,300 to $4,000. Those who choose the Sunrun Subscription Plan can often have the cost of a breaker panel covered by Sunrun. An additional benefit to an upgrade is a SPAN Smart Electrical Panel which provides app-powered visibility and control and the circuit level. This modern electrical panel solution can also assist homeowners in battery backup management and solar energy system monitoring.

The upgrade process typically takes between 4 and 8 hours but can take longer if additional work like rewiring or moving the panel is needed. You’ll need to make sure the panel upgrade complies with the National Electrical Code and local codes—doing so often requires permits and an inspection.

Sunrun Meter

Your Sunrun meter monitors your system production and sends the information to Sunrun through a wireless signal. Since it tracks your energy production 24/7, it will automatically alert Sunrun if it detects problems or irregularities.

Net Meter

Net metering acts like a savings account for electricity. When your solar panels make more energy than you need, this extra solar electricity is sent to the electric grid. Your meter tracks this and can give you solar credits depending on your utility's available programs. Then, when your panels aren’t making enough energy, sometimes during nights or on cloudy days, you can use these credits instead of buying electricity from the grid. It’s like banking the extra solar power you produce for when you need it later.

Your credits from net metering can roll over from month to month. This is handy because your panels will make more energy in the sunny summer months than in winter. At the end of the year, your utility might pay you for any extra credits you haven’t used. But if you use more electricity than your panels produce in a month, you’ll pay your utility for the difference.

There are different types of net metering. Some programs give you credits equal to the retail price of electricity, while others may pay a little to much less. Also, with Time of Use (TOU) rates, the value of the electricity your panels send to the grid can change based on the time of day. Energy is usually more expensive during peak hours, like evenings, so credits earned during off-peak times might not offset as much peak-time use. In some areas, the value of solar exports back to the grid is very minimal. By considering battery backup for your system you can store any unused solar energy for future use, allowing you to make the most of the energy your system is producing. 

FAQs

Can solar power be generated on a cloudy day?

Yes, solar power can be generated on a cloudy day. Solar panels can still gather solar energy and produce electricity even when it’s cloudy because they can absorb both direct and diffuse sunlight. Direct sunlight is the unobstructed light on clear days, while diffuse sunlight is scattered by clouds, haze, or dust. On overcast days, panels are exposed to this ambient diffuse light, which is less intense than direct sunlight but can still generate electrical current.  

The amount of electricity you generate on cloudy days will depend on several factors, including the thickness of the cloud cover, the type of cloud, time of the year, location, and local weather patterns. Typically, solar panels generate electricity at a 100% efficiency rate on clear, sunny days when they receive direct solar radiation. On partly cloudy days, this efficiency drops to 50%–80%; on heavily overcast days, when solar radiation is much lower, the efficiency can be between 10%–25%.

Do solar panels still work at night?

Technically, no. Solar panels do not produce energy at night. The photovoltaic cells in solar panels need solar energy to generate electricity. However, solar panels can still indirectly support energy needs at night through two methods: net metering and solar battery storage. Net metering allows you to use credits earned from excess solar energy produced during the day, while solar battery storage lets you use stored solar energy at night. These methods ensure you can still benefit from your solar panels even when they’re not actively generating power​. Please note that the benefit of net metering is dependent on your utility and may not provide you with significant solar credits. 

Conclusion

So now that you’re a solar energy expert, the next time somebody asks you, “how does solar power work?” you can give them the lowdown on solar energy. And when you go solar with Sunrun, it couldn’t be easier to sit back and take control of your electricity bill and lock in your rate. So what are you waiting for? Go solar today!