Solar power is simply usable energy generated from the sun in the form of either electric or thermal energy. Solar energy is captured in a variety of ways, with the most common being a solar photovoltaic system, or PV system, that converts the sun’s rays into usable electricity. Aside from using photovoltaics to generate electricity, solar thermal energy, or concentrating solar power (CSP), is commonly used to heat indoor spaces or fluids. Residential and commercial property owners can install solar hot water systems and design their buildings with passive solar heating in mind to fully take advantage of the sun’s energy with solar technology.
Interested in benefiting from solar power? Solar panels are installed at three main scales: residential, commercial, and utility. Homeowners can take advantage of residential-scale solar, typically in the form of rooftop solar or in ground-mounted solar installed in open land. Generally, residential solar systems are between 5 and 20 kilowatts (kW), depending on the size of the home.
Commercial solar energy projects are typically installed at a greater scale than residential solar. While individual installations can vary greatly in size and cost, commercial-scale solar arrays serve a consistent purpose: to provide on-site solar power to businesses and nonprofits. Finally, utility-scale solar projects are typically large-scale solar power plants that are several megawatts (MW) in size — utility-scale solar installations provide solar energy to a large number of utility customers.
For some solar shoppers who may not be able to install solar on their property due to cost or other factors, community solar is a viable solar option that more directly connects utility-scale solar energy projects to residential consumers. As such, community solar farms are typically built in central locations as opposed to on any single property. Subscribers (homeowners, renters, businesses, or non-profits) can join a community solar project to receive many of the benefits of solar power without installing solar panels on their property.
How do solar panels work?
A solar panel (also known as a solar module) consists of a layer of silicon cells, a metal frame, a glass casing unit, and wiring to transfer electric current from the silicon. Silicon (atomic #14 on the periodic table) is a nonmetal with conductive properties that allow it to absorb and convert sunlight into usable electricity. When light hits a silicon cell, the light causes electrons in the silicon to be set in motion, initiating a flow of electric current. This is known as the “photovoltaic effect,” and it describes the general functionality of solar panel technology.
The science of generating electricity with solar panels boils down to this photovoltaic effect. It was first discovered in 1839 by Edmond Becquerel and can be thought of as a property of specific materials (known as semiconductors) that allows them to create an electric current when they are exposed to sunlight.
The photovoltaic process works through the following broad steps:
- The silicon photovoltaic solar cell absorbs solar radiation
- When the sun’s rays interact with the silicon cell, electrons begin to move, creating a flow of electric current
- Wires capture and feed this direct current (DC) electricity to a solar inverter to be converted to alternating current (AC) electricity
A brief history of solar power
In 1954, Bell Labs developed the first silicon photovoltaic cell. Although solar energy had previously been captured and converted into usable energy through various methods, only after 1954 did solar power begin to become a viable source of electricity to power devices over extended periods of time. The first solar cells converted solar radiation to electricity at an efficiency of 4 percent — for reference, many widely available solar panels today can convert sunlight to solar power at above 20 percent efficiency, a number constantly on the rise. Although solar energy adoption was slow at first, a number of state and federal incentives and policies contributed to driving down the cost of solar far enough to become more widely adopted.
Concurrent with an increase in solar efficiency, the cost of solar panels has fallen substantially. In the last decade alone, the cost of a solar panel installation fell over 70 percent, and many industry experts predict that will continue to fall in the years to come.
Additionally, depending upon where you live, several rebates or incentives for solar power may contribute towards lowering the cost of solar energy even further. Nationwide, the federal Investment Tax Credit (ITC) is one of the primary incentives available to anyone interested in solar energy, as it allows you to deduct 30 percent of the cost of installing a solar array system from your federal taxes. This incentive won’t last forever: in 2033, the federal ITC steps down to 26% and it will go away completely for residential solar installations in 2035. Many states and utilities offer further incentives (such as net metering) in addition to the federal ITC, dropping the cost of solar power even further.
Interested in seeing what solar will cost you? Try our solar calculator for a quick estimate.
Solar power – unlimited source of energy
Solar power is the key to a clean energy future and plays a crucial role in the decarbonization of our societies. Every day, the sun gives off far more energy than we need to power everything on Earth. Fortum has excellent experience producing solar power and co-owns several solar plants in India. Also, in the Nordics, the conditions for solar power are promising. That is why we are developing solar plants also in our home market.
Solar panels produce electricity by transforming the continuous flow of energy from the sun to electricity.
CO₂-free
No harmful emissions are released into the air when electricity is produced by solar panels.
Low operating costs
The photovoltaic process that transforms sunlight into electricity doesn’t require any fuel and has no variable costs.
Limitless solar energy
The sun provides more than enough energy to meet the whole world’s energy needs, and unlike fossil fuels, it won’t run out anytime soon. As a renewable energy source, the only limitation of solar power is our ability to turn it into electricity efficiently and cost-effectively.
No greenhouse gas emissions are released into the atmosphere when using solar panels to create electricity. And because the sun provides more energy than we’ll ever need, electricity from solar power is an essential energy source in the move to clean energy production.
No fuel to burn
After installing solar panels, operational costs are pretty low compared to other forms of power generation. Fuel isn’t required, which means that solar power can create large amounts of electricity without the uncertainty and expense of securing a fuel supply.
Solar power and the environment
As a renewable CO2-free power source, the environmental impact of solar power is significantly smaller than other power generation methods. The impact is mainly related to the production and supply of the special materials and metals that are required to produce solar panels. The location and the water used to clean the solar panels also affect the environment. We are working hard to find alternative ways to clean our solar panels.
FAQ – Solar power
A power generation method that converts energy from the sun into electricity. It uses solar panels that are often arranged on a building or concentrated in solar farms to facilitate a reaction that converts the sun’s light radiation into electricity.
Photovoltaic cells in a solar panel turn sunlight into direct current electricity (DC). Then, an inverter converts the DC electricity into alternating current electricity (AC), and once this process has taken place, the electricity is used, fed into the grid or stored in a battery.
In the Nordic region, we have really good conditions for solar power. In the summer, the sun shines here a majority of the hours of the day. The slightly cooler climate in the Nordics is also very beneficial for solar energy, as warmer temperatures reduce the efficiency of the solar cells.
Several large-scale solar power parks are currently being developed in the Nordic region. In 2022, Sweden entered the top 10 in terms of the largest markets for solar energy within the EU, while Denmark has eighth place on the same list. According to calculations from Solar Power Europe, electricity production from solar power will reach one gigawatt in Finland by 2025.
The main advantage is that it is a renewable, clean source of electricity. Solar power is also scalable. This means that it can be deployed on an industrial scale, or it can be used to power a single household. When it’s used on a small scale, extra electricity can be stored in a battery or fed back into the electricity grid. Overall, the sun gives off far more energy than we’ll ever need. The only limitation is our ability to convert it to electricity in a cost-effective way.
Disadvantages of Solar Energy
The disadvantages of solar energy are becoming fewer as the industry advances and grows, creating economies of scale. Technological advances are helping solar go mainstream. Here are how the disadvantages of solar energy and the pros and cons stack up.
The high initial costs of installing panels
The most commonly cited solar energy disadvantage, cost, is declining as the industry expands. The initial cost to buy and install the equipment is not cheap. Still, if cost is an issue, leasing options may reduce the amount of your initial outlay. If you do choose to buy, you will need to live in your home for a number of years before the system pays for itself. It’s a long-term investment better suited to property owners than renters.
Solar energy storage is expensive
Of the disadvantages of solar energy, the temporary decline in energy production during bad weather has been a major issue. Days with low solar energy, however, are having less of an effect due to advances in battery technology. Old technology for storing solar energy, like lead acid batteries are being replaced by alternatives. Lithium ion batteries offer greater power at a lower cost. Nickel-based batteries have an extremely long life. New technologies, like flow batteries, promise scale and durable power storage.
Solar doesn’t work for every roof type
Not every room will work well with solar panels. Orientation matters. If your roof doesn’t face the sun, you won’t be able to capture enough solar energy. Roofs that angle into the sun tend to work better than flat roofs.
Roofing materials like asphalt shingles, metal and tiles make installing solar panels easier. If your room is made with other materials, installation may be more expensive. Part of what makes energy-efficient roofs is their ability to support solar panels.
Solar panels in the winter | How does climate affect solar power?
Solar panels are dependent on sunlight
It’s obvious that solar panels need sunlight to generate electricity. They won’t produce electricity at night when you need it for light and they can be inefficient during storms and gloomy days. Your solar energy system needs batteries if you plan to fully depend on solar energy to power your home.
Batteries are one of the more expensive components of your system. Unlike solar panels, they do wear out and need careful maintenance to lengthen their lives. Comparing wind power vs. solar power, wind will keep generating electricity at night and during storms, as long as there is enough wind. Many people use both in residential systems.
Renewable Energy | Everything You Ever Need to Know | Fergal McEntee | 5 August 2023
Constellation Energy and Solar Energy
When weighing the pros and cons of solar energy for your home, there are additional options worth considering. Community solar projects are a great way to get the advantages of solar energy without buying and maintaining a system yourself.
If your home and roof won’t support solar panels or if you don’t have enough money to invest in one, community solar might be your answer. With this option, you agree to participating in a program that allows you receive credits for every kWh generated by the solar facility. You get a credit on your electricity bill proportional to your percentage of ownership in the project’s energy.
What are flexible solar panels and how do they work?
Flexible solar panels and conventional solar panels are both made of material that absorb light and produce electricity.
Can solar panels save you money?
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The clear distinction between those two types of solar panels is thickness. In thin-film solar panels, the layers of photovoltaic materials are much thinner and, therefore, sometimes flexible.
Matthew Reese, a researcher at the National Renewable Energy Laboratory in Colorado explained thin film panels don’t have to be flexible, but materials tend to become flexible the thinner they get.
Any technology can be made flexible. Part of the question is how flexible, Reese said. You can also make them foldable.
A number of technologies harnessing different materials have been used over the decades to develop thin film or flexible solar modules, including amorphous silicon, copper indium gallium selenide, cadmium telluride and gallium arsenide. Newer, emerging technologies that could have flexible applications in the future include perovskite, organic and quantum dot photovoltaics.
There are also products on the market that use very thin monocrystalline silicon modules similar to rigid rooftop panels but with some limited amount of flexibility.
What are the benefits of flexible solar panels?
The clear advantage of flexible solar panels is the ability to install them on a wider variety of surfaces and locations.
Something we say around NREL is ‘PV everywhere’.- if you could have a flexible, roll-out PV technology; you can imagine lots of places to put this stuff, another NREL researcher, Lance Wheeler, said.
You could imagine flexible photovoltaics covering a car or any part of a building, including Windows. Some solar tiles make use of thin films for rooftops.
Thinner panels are also inherently lighter, which opens up applications like putting them on drones and airplanes and hanging them from hikers’ backpacks. Certain thin-film technologies also operate better under high-heat conditions, making them preferable for use in space and certain desert locales.
Thin-film technology struggles to compete with rigid PV on both efficiency and price, but has the potential to surpass those widespread rooftop panels on both counts at some point in the future.
What are the downsides of flexible solar panels?
Today, flexible panels compete against a massive solar industry that mostly pumps out rigid silicon-based rooftop panels at ever cheaper costs. Some flexible solar panels can already beat those glass panels in terms of efficiency by a wide margin, but at a significant cost.
For homeowners, the industry’s FOCUS remains on those big glass rectangles.
There’s lots of other flavors of PV, and a lot of them aren’t very widespread when it comes to residential, Wheeler said.
The less expensive of the thin film technologies tend to be less efficient than a conventional rooftop panel, while still costing more than a rigid silicon-based module. There can also be concerns over durability with flexible panels, and some materials used in their production, like cadmium, are extremely toxic.
Thin-film solar panel efficiency varies depending on the type of material but can be expected to be between 7% and 18%. Conventional panel efficiencies can reach 25%, but commercially available panels typically range from 18% to 22%
Because of their lower efficiencies, current thin-film systems require more roof space than conventional panels, meaning they won’t be suitable for a large number of homes.
Pros and cons of flexible solar panels
Thin-film solar panels are still limited in availability, but as solar technologies continue to advance, these panels could take off in popularity.
If you have a larger home or business with adequate roof space, thin-film panels may be the most efficient and effective way to achieve your solar goals and save money on energy costs. They may also be an adequate energy solution for portable use on things like RVs, buses or boat rooftops.
Flexible solar panels may also be worth considering in instances when regular, rigid panels on a rooftop or ground rack won’t be possible to install for some reason, like a curved facade or vehicle roof.
In such a case, using a flexible module is not only likely to be more aesthetically pleasing, but it will allow your panel to have multiple lines of sight to the sun, likely producing more power over the course of the day and year.
In the future, flexible panels atop an electric vehicle could be a way to extend your car’s range.
Finally, if you live in a desert area where heat and sunlight can be extreme, it could be worth exploring whether thin-film technology might actually operate more efficiently for you.