Understanding System Performance
Understanding Your Solar System
Going solar allows you to produce clean, renewable energy directly from your home. Consider the factors below to help understand and maximize the benefits of solar.
Power vs. Energy
Power, measured in kilowatts (kW), is the maximum amount of electricity your solar panels can generate at any given time. Your solar system rating is in kilowatts.
Energy, measured in kilowatt-hours (kWh), is the total amount of power used over time. Using one kilowatt of power for one hour equals one kilowatt-hour of energy. Your solar system's production, and energy to and from the grid, are measured in kilowatt-hours.
Think of the kilowatts of your system like the speed rating of your internet, and the kilowatt-hours the total amount of data used.
Understanding Your System Production
The Tesla app allows you to monitor your solar generation in real time from anywhere. Under ideal conditions where your system receives consistent sun exposure through the day, you can expect to see a solar generation graph that resembles a wave - increasing from early morning with a peak at noon, and gradual decrease to the end of day as the sun sets.
You will see changes in your system’s production throughout the year corresponding with your location and sunlight hours. The amount of energy your system produces is impacted by a number of factors, including some that you cannot control such as amount of sunshine and cloud covering. Shade from tree growth or extended periods of time with accumulated dust, snow or debris on your solar panels may also reduce your total energy production.
We recommend maintaining your system to get the most out of solar. If you see a significant change in energy production, follow the troubleshooting steps for your system.
Winter Energy Production
In the winter, it is typical for your system to produce closer to 50% of its power potential at noon, versus up to 100% in summer. Winter solar production is impacted by the following factors:
Winter months have less daylight hours than summer months. As a result, your solar system produces less power.
Clouds and Snow
Winter can bring increased cloudy weather and snowstorms. Clouds block sunlight from reaching your solar system, significantly reducing production. If a thin snow cover forms on your solar system, it may still be able to turn on and produce a small amount of power when the sun comes out. A larger buildup of snow may prevent your system from producing power until your roof is cleared.
If you system receives intermittent sun exposure through the day, you may see drops in production on the solar generation graph in your Tesla app.
Angle of the Sun
The position of the sun changes significantly during the winter — even at its midday peak, the sun is much lower in the sky than in the summer. This results in less direct sunlight hitting your solar system during the winter months, decreasing peak output and total power production.
The most accurate way to evaluate your home consumption is by the kilowatt-hours (kWh) of electricity used per month. Your daily home consumption typically varies with the seasons and weather.
Understanding Your Inverter Selection and Performance
Your solar inverter makes the power generated by your rooftop solar system (direct current) useable for your home (alternating current). Inverter selection is calculated using equipment ratings, solar panel orientation, stringing and efficiency. Your design is carefully optimized for the best overall lifetime system efficiency, reliability and cost.
Overdriving is when the solar panels have a slightly higher rating than the inverter. This can result in the inverter reaching maximum output capacity, while the solar array can produce more. This is commonly referred to as ‘clipping.’
Since system production is significantly less in winter compared to summer, carefully calibrated overdriving allows your system to produce more total power by trading some production during summer for more during spring, summer and winter. This is a common best practice in the solar industry. It can also avoid expensive and lengthy electrical upgrades and does not affect the durability of your system.
Powerwall and Solar
Powerwall will provide electricity to your home during an outage. When paired with Powerwall during an outage, your solar panels will also produce power when the sun is shining. The more power you produce and store, the longer your backup runtime. Under the right conditions, off-grid runtime is possible. Learn more about Powerwall best practices during an outage.
Your backup type is determined by the number of Powerwalls you have installed and your electrical configuration.
Whole Home Backup
Powerwall will back up all appliances in your home during a power outage.
Partial Home Backup
Powerwall will back up essential loads such as lights and outlets and leave out larger loads you select such as air conditioners and dryers. When the grid is operational, you will be able to use and monitor all appliances. When the grid is down, only the loads you deem essential will be usable.
To allow your system to continue to function during an outage or while in Self-Consumption mode, when your Powerwall is full your solar system will only produce enough to power what your home is using.
This process is known as curtailment, and will show as an abrupt stop or start in energy production in the solar generation graph of your app.
Solar panels are an investment for your home and can continue to provide you with clean energy savings well into the future. Homes with solar panels rely less on the utility and capture energy directly from the sun. By installing a solar system, you can take control of your energy sources and minimize your electricity costs. Learn more about how Tesla saves you money.
The Tesla app is the centerpiece of the ownership experience as it shows real-time and historic energy production of your system and your home’s consumption. This allows you to time when you do laundry, dishes, run pool pumps and more to when your solar system is producing the most, maximizing the value of your energy production and increases the percentage of self-powered, clean energy you consume directly. The use of high efficiency appliances and light fixtures allows you to use less energy in your home.
Pairing your solar system with Powerwall unlocks Time-Based Control mode, which uses your rate plan info and machine learning to optimize when you export and import energy from the grid. It will time exports to when you get the highest value, and store energy when you get the lowest, maximizing your financial benefit.
Additionally, understanding your utility rate plan is key for taking advantage of your Net Energy Metering (NEM) credits and reducing energy consumption during higher time of use (TOU) rate plans. Each utility rate plan is unique. Learn more about your utility bill after solar.
Maintaining Your Solar System
Tesla solar panels are designed to produce clean energy for decades. There are several best practices to get the most out of your solar system.
Keep Your Solar Panels Clean
You can maintain system performance by occasionally cleaning your panels to remove accumulated dust, pollen and leaves. Cleaning once or twice a year is typically sufficient, however, more frequent cleaning may be necessary during drier seasons as dust tends to collect on the panels. Ordinarily, you can rinse off panels with a water hose from ground level to remove accumulations. Rinse only the glass cover of the panels; do not rinse wiring or areas underneath panels. For safety and performance reasons, rinse panels only when the sky is overcast, or when the sun is low in the sky, as panels can become hot under intense sunshine. If you have excessive soiling, such as bird droppings, you may wish to hire a local solar panel cleaning service.
Prevent Shade on Your Solar Panels
Shade on your solar panels significantly reduces electricity production. Keep trees or other tall plants trimmed to prevent shade on your solar panels.
Monitor Your Solar Panel Production
The Tesla app allows you to manage your Tesla products from anywhere. By providing you with a comprehensive view of your energy ecosystem, the Tesla app helps you monitor day-to-day operations and understand the flow of energy in your home. Learn more about monitoring your system.