Rooftop solar panels with battery storage give homeowners access to clean energy. While they’re great for providing clean backup power, solar-plus-storage systems also help homeowners lower bills by supplying free stored electricity when utility rates are high. And as global energy prices surge, homeowners increasingly search for ways to keep costs down and the lights on.
Maximizing the power generated by your solar panels and stored in your battery ensures that your free source of electricity goes farther and works harder for your household. This is where home energy management systems (HEMS) are invaluable, automatically analyzing reams of energy data to keep your home comfortable and your bills low.
A HEMS comprises hardware, such as a smart panel, and software usually accessed via an app. These systems monitor your home’s energy requirements by analyzing household data such as energy usage and the energy consumption of appliances, as well as external data, such as the weather forecast and utility energy prices. A HEMS uses these data points to automate decisions and make recommendations — such as minimizing home energy usage on cloudy, rainy days where there’s lower production from your solar panels — to ensure that your solar panels provide as much of your electricity as possible.
Without an energy management system in place, you must pre-select which appliances can be supplied by your battery. While you can’t use all your appliances at once from a single battery, a HEMS lets you choose between appliances, rather than limiting you to preselected choices.
“This means that if you want to use your air conditioning, you will be given the choice of which loads to turn off so this can happen,” says Mukesh Sethi, director of solar and energy storage at Panasonic. “These choices give flexibility to shut loads on and off, so you could have your AC on for 30 minutes and then turn it off and switch on other loads, like your tea kettle.”
In this way, a HEMS can act on your behalf to coordinate appliances and systems, balancing the energy demands of different devices with the energy supply available from your panels and battery. A HEMS can help you prolong the running time of your battery, an invaluable resource in a power outage and during times of peak demand, when utility energy rates are at their highest.
A HEMS learns trends and patterns in your household’s energy behavior to make decisions and predictions on future usage. Here’s a closer look at some of the data-led ways it can help you.
1. Saves energy
A HEMS monitors the energy consumption of each of your appliances, collecting data on how quickly they drain your battery. The system also learns your household's energy patterns and combines this data to make real-time forecasts and decisions on where you can save energy.
2. Accounts for weather fluctuations
A HEMS automatically adjusts your solar-plus-storage system according to the weather to ensure your household energy requirements are met. “Solar production can be low during a storm, or in clouds and rain, so a HEMS will minimize your energy usage to save you money,” says Sethi.
3. Extends battery run time
A HEMS shows you how long your battery can supply power to single and groups of appliances. It can then automate which appliances receive power based on your priorities, or share recommendations on which ones you should switch off to prolong battery capacity.
4. Determines the best time for stored energy
A HEMS can determine when it’s ideal to use your stored solar power based on local energy prices, automatically switching your home from the grid to your battery when prices hike, thereby maximizing the potential of your free solar electricity to keep bills down.
5. Prioritizes energy
“A smart panel knows which loads to feed and which loads not to feed, and how to make those decisions of which are critical and which are not,” says Sethi. By monitoring how much energy remains in your battery and how many appliances it can supply with that power over how long, a HEMS can prioritize which appliances receive power, while also accounting for your preferences.
A HEMS achieves in real time what humans cannot: It analyzes vast swaths of data from within and outside the home to learn about your behavior, preferences and goals, then acts on your behalf to keep your home comfortable and bills trimmed. Just as batteries allow homeowners to maximize the potential of their solar panel investment, a HEMS goes farther by optimizing power allocation from a battery.
If you're looking to optimize your energy use at home, Panasonic is a great place to start. The company's future-focused solutions offer customers a complete whole-home renewable energy package. Talk with a Panasonic authorized installer today and get all your questions answered.