Our sun is the source of all life on Earth, and solar energy is useful to us in many different ways. The sun creates two main types of energy – light and heat – that we can harness for many activities ranging from photosynthesis in plants to creating electricity with photovoltaic (PV) cells to heating water and food. So, what are some uses of solar energy? Let’s explore seven common uses and benefits of sunlight in our daily lives.

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1. Solar Electricity

This is one of the solar energy applications that has gained a lot of momentum in recent years. As solar panel costs decline and more people become aware of the financial and environmental benefits of solar energy, solar electricity is becoming increasingly accessible. While still a very small percentage of the electricity generated in the U.S. (1.9% in 2017), solar electricity is growing rapidly (almost tripling over a three year period and up +40% versus 2016) according to the U.S. Energy Information Administration.

A distributed solar PV system is typically installed on the rooftops of homes or businesses. These solar power systems generate electricity to offset the property owner’s usage and send any excess production to the electric grid.

A solar battery can connect to your solar power system to enable you to use solar after the sun goes down, power an EV overnight, or provide backup power during emergencies. Some homeowners may choose to go completely off the grid with a solar power and battery system or a solar power and generator system.

In some cases, solar PV may be installed on an adjacent structure such as a barn or mounted to the ground, and then connected to the meter using underground cabling.

Other uses for solar energy include utility scale solar PV farms that can generate enough electricity to power entire cities. An even more efficient solar technology is concentrated solar power (CSP). A CSP solar farm uses mirrors to reflect and concentrate the sun’s energy towards a tower or other receiver, generating heat that can power a turbine to create electricity. That thermal energy may be stored before powering a generator, which makes it a more flexible source of electricity than solar PV. The world’s largest CSP solar farm is the 390 megawatt (MW) Ivanpah project in California’s Mojave Desert, although an even larger 580 MW CSP plant under construction in Morocco may soon claim that title.

2. Solar Water Heating

Uses for solar energy extend to water heating systems. Most solar water heating solutions create hot water that is consumed inside the home. Solar water heaters use a rooftop cell to absorb the sun’s heat and transfer it to the water tank. Solar water heaters usually have a five to ten year payback according to the U.S. Department of Energy (DOE).

Another application of solar energy, especially in the southern and southwestern U.S., is heating swimming pools. Water is circulated to a collector where it is heated by sunlight and then pumped back into the pool. With costs between $3,000 and $4,000 and a payback of 1.5 to 7 years, the U.S. DOE says that “solar pool heating is the most cost-effective use of solar energy in many climates.”

3. Solar Heating

Typical uses of solar space heating systems include powering radiant floors or pairing with a Forced Hot Air (FHA) system to heat a home. Passive solar home design can also heat homes and businesses in the winter by taking into consideration the placement of windows and the selection of materials used in the building.

4. Solar Ventilation

Solar ventilation solutions such as solar attic fans can reduce the burden of your HVAC by helping to cool your home during the summer. This may be a good option if you are not able to install a solar PV system that offsets your home’s entire electricity use. One innovative product is the Solatube solar attic fan.

Commercial and industrial applications of solar process heat include solar ventilation technologies that can preheat a building’s air in cold climates, reducing energy costs.

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5. Solar Lighting

Solar lights have become ubiquitous and can be found everywhere from home landscaping and security lights to road signs and street lights. These solar lighting technologies for your home are inexpensive and readily available from basic to high-end designs everywhere from your local hardware store to online shopping websites such as Amazon.com.

One innovative use of indoor solar lighting, featured on Mashable, is the Solatube skylight that adds natural light while reducing energy usage.

6. Portable Solar

In our connected world, phones and tablets are always with us and, let’s face it, often running low on battery. Portable solar PV chargers can keep our personal electric devices charged on the go. The technology already exists to integrate solar cells into our phones and has been in watches since the 1970s (see the Citizen Eco-Drive). Researchers in Japan have even developed lightweight, water-resistant solar cells that could someday be sewed into clothing to power our devices.

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7. Solar Transportation

Solar-powered vehicles may be the future, with existing applications including buses, trains, airplanes, and race cars built by students in Australia and the U.S. A fully solar-powered car is even slated for commercial release in 2019. This use of solar energy is not yet widely available, unless you own an electric car or EV and charge it with solar panels (generally via a solar-connected battery).

A Solar-Powered Future

Renewable energy is already becoming a more familiar part of our lives, and innovation will continue to drive new applications of solar energy technologies that will improve our daily lives and help power a cleaner world. How many more uses of solar energy will there be in the future? We are excited to find out

Solar panels use the sun’s rays to generate electricity that can power our lives. Learn more about the history of solar cell technology, how solar panels convert sunlight to electricity, and how a solar energy system powers a home or a business.

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A BRIEF HISTORY OF SOLAR ELECTRIC POWER TECHNOLOGY

The sun’s energy is critical to all life on earth, and humans have always found ways to harness solar energy. Solar photovoltaic (PV) technology as we know it today has been around since Bell Labs created the first silicon cell in 1953. By the end of the decade, solar cell efficiency had improved from 4% to 14% (source: DOE).

The solar energy industry expanded throughout the following decades. Solar technology improved thanks to research & development investment. Federal and state governments established regulatory frameworks for solar interconnections. These policies included policies such as tax credits, rebates, and renewable energy standards.

By 1999, cumulative installed solar capacity had reached 1,000 megawatts (MW). In 2000, while astronauts were installing solar panels on the International Space Station, Sandia Laboratories invented the modern inverter that improved system safety during power outages. In the almost two decades since then, solar panel costs have fallen dramatically due to innovations in solar panel design and improvements in racking systems that have made installations easier and faster.

As solar panel prices fall, the amount of solar installed globally has grown dramatically, from just over one MW in 2000 to more than four gigawatts (GW) in 2017 (source: Wikipedia).

The future of innovation in solar technology is likely to focus on new materials beyond or in addition to silicon. For example, recent breakthroughs with perovskites may lead to higher efficiency panels and the ability to coat various surfaces with solar as easily as painting or spraying.

Given that the amount of sunlight that reaches the earth every hour is enough to power the entire globe’s electricity use for a year, we know that the potential for solar power is unlimited.

WHAT IS A SOLAR PANEL?

A solar panel is a collection of solar PV cells that absorb sunlight and convert that light into electricity. For most installations, multiple solar panels are connected to create a solar array. The components of a solar panel include the solar cells, glass casing, backsheet, metal frame, and cabling to transmit electricity.

Solar cells are made from silicon and are built with a positive layer and a negative layer to create an electric field, similar to a battery. Here are a few fun facts about silicon:

  • Silicon (Si on the periodic table) is a metalloid chemical element, which means it has properties of both metals and nonmetals.
  • Silicon is a semiconductor, with conductivity between that of an insulator and most metals, which makes it useful for most electronic circuits
  • More than one-quarter of the earth’s crust is comprised of silicon (by mass).
  • Silicon is the second most abundant element after oxygen.

Most solar panels are made from either monocrystalline or polycrystalline silicon:

Monocrystalline silicon

  • Wafers are cut from a block of a single crystal of silicon, and cells form a distinctive shape – small black squares with notched corners.
  • Monocrystalline solar panels have a more uniform appearance
  • These panels perform better in high temperatures and shaded conditions, making them higher efficiency.

Polycrystalline (or multicrystalline) silicon

  • Silicon fragments are melted together to form a large cell that typically has a multifaceted blue appearance.
  • Polycrystalline solar panels are less efficient but are less expensive.
  • There is less waste in the manufacturing process of polycrystalline cells.

The solar cells are covered by a glass casing, generally made from anti-reflective glass to increase sunlight absorption and improve solar panel efficiency, and they are protected by a backsheet.

HOW SOLAR PANELS WORK

The sun releases tiny packets of energy called photons, which travel to earth. When photons hit a solar cell, they knock electrons loose from their atoms. If conductors are attached to the positive and negative sides of a cell, it forms an electrical circuit. When electrons flow through the circuit, they generate electricity.

Solar panels create direct current (DC) electricity, a circuit in which electrons flow in a single direction (similar to a battery powering a lightbulb).

The electricity we use from the grid today, including our lights, appliances, and devices (anything that gets plugged into a wall outlet) use alternating current (AC) electricity. With AC electricity, the electric charge can flow different directions.

Thomas Edison developed DC electricity, which was the standard in the United States until the 1880s. Nikola Tesla believed that AC was a better solution because it could easily be converted to different voltages, making it easier to transport over long distances. The tide began to turn when Tesla’s technology was chosen for the Chicago World’s Fair in 1893, and AC electricity became the standard for the electric power grid in the United States (source: DOE).

Thus, an inverter is required to convert the electricity generated by solar panels from DC to AC current. The AC current is then routed to the electrical panel, where it can be used directly by a home or business, connected to an onsite battery, and/or connected to the electric grid.

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TYPES OF INVERTERS

Another key part of a solar electric power system is the inverter technology. There are three main types of inverters:

  • String inverter: The DC electricity from all of the panels on the array is routed through a single inverter that is then connected to your electrical panel. String inverters are the least expensive inverter solution, but they can make it more difficult to assess performance issues with individual panels.
  • Microinverter: Micro-inverters are attached on the back of each individual panel. These tend to be more expensive but enable panel-level monitoring.
  • Hybrid: This offers a middle-ground solution that combine a centralized inverter with power optimizers on each panel. Power optimizers are a DC-to-DC converter technology that improves performance by tuning each panel’s output to match the inverter. This technology is intended to offer some of the system performance benefits of microinverters but at a lower cost.

Inverters provide additional features beyond converting the electric current for our use. Inverters also offer ground fault protection and provide intelligence regarding energy production and maximum power point tracking.

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SunPower Equinox Microinverter

HOW SOLAR PANEL SYSTEMS WORK

Here is an example of how a solar power system works.

  • Sunlight shines on solar panels installed at your home or business.
  • Your solar panels convert the sun’s energy to electricity.
  • Electricity flows through conduit to an inverter.
  • The inverter converts the electricity from DC to AC current.
  • That electricity then flows to your electricity meter and is used to power your home or returned to the electric grid.

When the sun is not shining, your home continues to be powered from the electric grid. If your solar panel system generates more electricity than you are using at any given moment, that electricity will flow out of your home back into the grid. Many utilities have net metering policies that credit you for the excess solar power you generate.

TYPES OF SOLAR PANELS

Today, there are manufacturers who are making solar panels using many different solar technologies and types of solar cells. Silicon (Si) is the most common material in solar cells, which are a key component of solar panels. There are different types of solar panels made from silicon, each of which have different advantages and disadvantages. There are many uses of solar energy as well as some emerging solar cell technologies that use additional techniques or materials.

SILICON TYPES OF SOLAR PANELS SUMMARY

Silicon Cell Type Efficiency Key Advantages Key Disadvantages
Monocrystalline 15%-24% Most efficient, durable, proven, aesthetically pleasing Highest cost
Polycrystalline 12%-16% Lower cost, improving efficiencies Lower efficiency, poorer aesthetics
Thin film 7%-13% Low cost, easy to make, best aesthetics Low efficiency, less proven

In order to discover which is the best type of solar panel to fit your needs, let’s compare the various solar panel technologies:

Monocrystalline solar panels

  • Average efficiency range: 15%-24%
  • How it’s made: Wafers are cut from a block of a single crystal of highly pure silicon.
  • Appearance: Monocrystalline solar cells have a uniform appearance, and the cells form a distinctive shape – small black squares with notched corners. Solar panels made with these solar cells typically have either a white or black backsheet.
  • Features: These panels conduct electricity more efficiently and perform better in high temperatures and shaded conditions, enabling them to generate more solar power than other panels of the same size. That makes them ideal for smaller rooftops. Because this type of technology is the most established, it also has a proven track record of durability. However, these are the most expensive panels and generate more waste in the manufacturing process.

Polycrystalline (or multicrystalline) solar panels

  • Average efficiency range: 12%-16%
  • How it’s made: Fragments from multiple silicon crystals are heated, melted, and pressed together to form a large solar cell.
  • Appearance: These solar cells have a multifaceted, non-uniform, gem-like surface and are typically blue in color.
  • Features: Polycrystalline solar panels are composed of polycrystalline solar sells. They are less efficient but are less expensive. There is less silicon waste in the manufacturing process. These are the most prevalent solar panels globally, primarily due to a production boom in China over the last few years.

Thin film solar panels

  • Average efficiency range: 7%-13%
  • How it’s made: A thin layer of photovoltaic material or combination of materials such as non-crystalline amorphous silicon (a-Si), Cadmium Telluride (CdTe), or copper indium gallium selenide (CIGS) is deposited onto a surface like glass, plastic, or metal.
  • Appearance: Thin film silicon panels are generally larger and have a uniform, solid black appearance.
  • Features: This is a commercially available but newer technology that makes sense where space is not an issue. Thin film solar panels are low cost, easy to produce, flexible, portable, and lightweight. They are expected to be less durable and to have a shorter lifespan
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OTHER SOLAR CELL TECHNOLOGIES

Multi-junction solar cells are based on the same principles as silicon-based cells, except that they are designed with multiple layers of different semiconductors that can capture more of the light spectrum.

Heterojunction with Intrinsic Thin-layer (HIT)

HIT solar cells, which were invented by Panasonic, uses thin intrinsic amorphous silicon layers on the top and bottom surfaces of a crystalline silicon wafer.

Perovskites

Solar cells made from Perovskites, a family of crystals is named for the Russian geologist Lev Perovski, are less stable than silicon but have the potential to achieve similar solar energy efficiency as monocrystalline cells at a lower cost. Although not yet commercially available, this promising technology could soon be applied as a film over existing silicon-based cells to boost the efficiency of standard solar panels. Oxford PV is piloting production of this technology in Germany, and a good overview of perovskites is available from the Financial Times.

A well-designed solar system can meet the majority of the electricity needs for a homeowner, but there are times when power needs to be pulled from the grid. While many energy providers give the option of net metering to cover the cost of electricity used from the local power company, it’s not available to all solar homeowners. Having a backup supply of electricity can provide power during outages like PG&E’s Public Power Safety Shutoffs and can also provide more electricity cost savings.

Let’s face it, emergencies happen. California wildfires, rolling blackouts and power outages happen. Many people don’t realize it, but homes powered by PV solar are usually tied to the grid, and they’re shut down along with everyone else during an outage to keep utility workers from getting hurt. Backup power is needed to keep the lights on and your refrigerator running, and the two main ways to achieve that are with a generator or a solar battery for a solar system.*

While generators have been a common backup for grid outages for decades, solar batteries are now a more viable option for homeowners to consider. Here are the factors to consider:

 

Size

The “whole-house” generators needed to power a home over time are bigger than their portable cousins – roughly the size of a typical HVAC unit. But that can vary depending on the size of your house and its electrical needs.

SunPower’s solution, the SunVault™ Storage system, comes in two sleek, aesthetically pleasing boxes – the SunVault battery and the Hub+™. Typically located in a utility room or garage, the larger box is slightly smaller than a refrigerator and stores excess energy not used throughout the day. The smaller box features intelligent software that gives homeowners the option to control when and how their stored solar energy is used.

Advantage: Solar battery

 

Noise

Whole-house generators usually make less of a racket than portable ones, but they can still be loud. For the quietest ones, imagine a motorcycle engine running nonstop. Solar batteries are silent.

Advantage: Solar battery

 

Fuel

Generators run on natural gas, gasoline or liquid propane, all fossil fuels that pollute the air. Solar batteries run on stored-up solar power and reduce your carbon footprint.

Advantage: Solar battery

 

Cost

A generator can cost anywhere from $2,000 to $30,000, though most are at the low end of that range. Once a generator is installed, the owner still has to pay for regular maintenance and fuel. Solar batteries have little or no maintenance costs and the fuel is solar energy from the sun. There’s an unlimited amount of sunlight, so the battery can keep recharging – and powering your home. On top of that, the U.S. government offers incentives for buying a solar battery storage system, and so do some state and local governments. Usually, there are no tax incentives for buying generators.

Advantage: Solar battery

 

SunPower Equinox® home solar system with SunVault™ Storage can save homeowners money in other ways as well. It’s the only home solar and storage system designed by one company. That means it can be managed easily and its intelligent software maximizes the use of solar power each day to help save dollars on peak-time energy charges. During a blackout, it can be programmed to power select appliances – like a refrigerator full of food – depending on the size of the battery.

The Equinox system with SunVault Storage is also covered by a single warranty: The SunPower Complete Confidence Warranty.Learn more about how much solar plus storage can save you.

When we experience natural disasters or pandemics or other significant disruptions to our lives, it’s normal to take a step back and evaluate what’s important. It is also a time when many people are looking for opportunities to become more self-sufficient and to take steps to protect the things that are most important to us. In addition to food, shelter, and protecting the health of our family, another important aspect of our lives that we may have previously taken for granted is the electricity powering our home. The current pandemic has awakened many people to the benefits that solar panels and a backup power supply can provide to help make your home more self-sustaining.

 

Why Go Solar Today

If you have been thinking about going solar, there are five compelling reasons to make the decision today.

1. Self-Sufficiency and Reliability

Going solar alleviates some of your reliance on grid electricity, and generating your own energy frees you from depending entirely on energy companies. A home solar panel array combined with high capacity battery backup provides you with a dependable on-site energy source and the ability to store excess energy to use during emergencies, which makes your household more self-sufficient instead of relying entirely on energy from the grid.

2. No Money Down

With the continued availability of our great financing options, you can go solar with no money down. This means you can leave your money in the securities markets until they recover while investing in solar right now. This is an economic benefit of solar energy that is especially relevant during these tumultuous times.

3. Offsetting Higher Usage

According to a 2020 study by the financial institution Fundera, the number of regular telecommuting employees has grown by 115% since 2005. As more and more people shift to working from home during the stay-in-place orders from cities and counties across Texas, electricity usage and utility bills will inevitably increase for many households. Adding solar panels to your home can help offset increased energy costs, letting you save money while you work remotely.

4. Rising Solar Prices and Potentially Limited Supply

Many components of solar panel systems are made in countries whose manufacturing industries have been disrupted for several months due to the COVID-19 virus. These global supply chain disruptions are likely to cause increases in the price of solar panels, inverters, and related equipment due to limited availability. Going solar now protects you from higher prices or panel shortages in the future.

5. Eco-Friendly Energy

Aside from the economic benefits of solar energy, there are other reasons to go solar. Solar panels are an environmentally friendly way to generate energy. You can harness the energy of the sun to power your home or business without contributing to local air pollution. Solar panels have a usable life of 40+ years and can be recycled once they reach the end of their life.