Are Solar Energy and Solar Power the Same Thing?

If you’re considering the advantages of adding a solar system to your home, it’s important to fully understand the language used when comparing and how the system works. Solar energy and solar power are not the same, and this distinction is important when weighing your options. 

Having a firm grasp on what each system can do, how it provides the electricity needed to power your home, and how it will affect your current electric bill will ensure you have the knowledge to make the best decision for you and your family. 

To further explain, in this blog we’ll review:

• Energy vs. power
• Converting solar energy into usable electricity
• Storing excess energy with solar batteries
• The impact on your electric bill

Energy vs. Power

Because the difference is pretty nuanced, the terms ​“energy” and ​“power” are used interchangeably by most people, including solar professionals at times. However, there is a key distinction.

Solar power refers specifically to the technology used to convert the sun’s rays to electricity. Solar energy is a broader term that includes this technology along with other types of energy transfer, such as solar thermal water heaters.

To put it simply, any change created by the sun’s rays is the result of solar energy. Solar power is limited to the deliberate conversion of that energy into the electricity used to run electrical devices and appliances.

Converting Solar Energy into Usable Electricity

For residential purposes, solar panels are made up of photovoltaic (PV) cells that absorb sunlight. These cells include a semiconductor layer that generates an electric current through the photovoltaic effect when exposed to energy from the sun. Two outer conductive layers attract this electricity to be used to power your home or to be directed into solar batteries for storage until needed.

The electricity that is generated from the solar panels and sent to your batteries or home is a direct current, or DC, flowing in one direction from its source. From there, the electricity goes through an inverter to convert it to an alternating current, or AC, that is able to flow in both directions. AC is the type of current used to provide electricity to your home’s appliances and devices.

When DC is converted into AC, there is some power loss experienced depending on the conversion efficiency. A solar quote that includes DC expectations does not give the full picture without an AC measurement to back it up. Ideally, under standard test conditions (STC), you’d want a conversion efficiency of around 80% to get the most out of your system.

To learn more, check out our blog, How Much Electricity Does a Solar Panel Produce?

Storing Excess Energy with Solar Batteries

If your system includes solar batteries, any electricity generated from your solar panels will first go to power the home. Excess electricity generated will be directed to the batteries to store for later use. Batteries require DC to charge but many modern solar batteries are considered AC. So how does this work?

AC batteries include a built-in inverter that changes the AC power into DC power to create the charge. This means the battery can pull excess power from the home, making it usable with every solar system available. When the home needs to draw electricity back from the battery, the inverter simply changes the outgoing current back to AC. Although convenient, AC batteries require a higher investment for the built-in inverter technology.

A DC battery is connected directly to the solar panels with a specialized inverter that prevents the conversion to AC. When electricity is drawn from the battery for the home, an external inverter changes the DC to AC as needed, minimizing any energy loss that comes with repeated inversions. DC batteries are often cheaper, since they don’t have built-in inverter technology, and can be considered more efficient with fewer degrading inversions. The Tesla Powerwall 3, a DC-coupled battery with continuous output, is designed for modular, scalable installation. This requires less inversions of energy and is therefore more efficient.

The Impact on Your Electric Bill

One of the major selling points of going solar is the impact it can have on your electric bill. Many times, the savings generated from solar installation are enough to cover the cost of installation and maintenance over a certain period of time, creating a positive return on your investment. Depending on where you are located and the options available with your power company, there are two ways a solar system can pay for itself and save you money.

Some electric companies offer a net metering option that allows you to sell excess solar energy back into the grid to be used in your community. In exchange, you’ll receive a credit for the energy provided that lowers your monthly bill for any electricity drawn from the power company. This credit is in addition to the money you save by relying on solar to reduce your traditional power consumption.

If your power company doesn’t offer net metering, you may find additional savings if you’re subject to a time-of-use (TOU) rate plan. TOU plans charge higher rates for the electricity used in the late afternoons and early evenings when families are often home from work or school and consumption increases. This affects the rates offered for excess solar power generated in the middle of the day, reducing the value of your credit when solar power generation is high and electricity consumption is low. Electing to include solar batteries in your system will store this energy instead of sending it into the grid at these reduced rates. This ensures you have the energy stored to power your home during these high-use hours, preventing the need to draw from the grid when rates are at their highest, maximizing your savings.