What Do You Call Solar Power?
Solar power, also known as solar energy, refers to the conversion of energy from sunlight into electricity or heat. It is one of the cleanest and most abundant renewable energy sources available today.
The term “solar power” broadly refers to two technologies: photovoltaics, which directly convert light into electricity, and concentrated solar power, which uses heat from the sun’s rays to drive traditional steam turbines to generate electricity (1).
Solar power has a history dating back to the 19th century, when the photovoltaic effect was first discovered. However, it has only become a mainstream energy source in the last few decades. The growth of solar power has accelerated rapidly in the 2000s and 2010s due to plummeting costs and supportive government policies (2).
Today, solar power provides just over 2% of global electricity demand, but is growing faster than any other renewable energy source. With abundant solar resources and continued cost reductions, solar has the potential to become one of the main pillars of a clean energy future.
(1) https://en.wikipedia.org/wiki/Growth_of_photovoltaics
(2) https://www.ief.org/news/the-remarkable-rise-of-solar-power
Types of Solar Power Systems
There are three main types of solar power systems that are commonly used today: photovoltaic, concentrated solar power, and passive solar.
Photovoltaic (PV) solar power systems https://www.gogreensolar.com/pages/solar-system-types directly convert sunlight into electricity using solar panels made up of solar cells. The solar cells are typically made of materials like crystalline silicon, thin-film, or perovskites that exhibit the photovoltaic effect. PV systems can be grid-tied, off-grid, or used for backup power.
Concentrated solar power (CSP) systems https://ilumsolar.com/the-3-types-of-residential-commercial-solar-power-systems/ use mirrors or lenses to concentrate sunlight and convert it into heat, which then drives a steam turbine to generate electricity. CSP requires direct sunlight and is suitable for large-scale utility power plants.
Passive solar uses building design features like large south-facing windows, thermal mass, and insulation to collect, store, and distribute solar energy for heating, cooling, and lighting homes and buildings without requiring any mechanical power.
Residential Solar Power
Rooftop solar panels are the most common way that homeowners go solar. Solar panels are typically installed on the roof, but they can also be mounted on the ground if there is sufficient space (Homeowner’s Guide to Going Solar). Homeowners with rooftop solar can take advantage of net metering programs, which allow any excess electricity generated to be fed back into the grid for credit from their utility provider (Planning a Home Solar Electric System).
There are financial incentives available to make residential solar more affordable. The federal solar tax credit provides a 26% tax credit for systems installed in 2022-2023, and 22% after 2023 (Solar Cheat Sheet: Your Guide to Getting Solar Panels). Many states and utilities also offer additional rebates and incentives. Going solar can offset electricity costs over time, and solar panels may increase a home’s value.
Commercial Solar Power
Businesses and organizations of all sizes are increasingly turning to solar power to reduce electricity costs and meet sustainability goals. Commercial solar power systems generate electricity for industrial buildings, schools, businesses, hospitals, apartment complexes, retail stores, and more (Solar Electric Supply). Some key types of commercial solar installations include:
Solar Farms – Large-scale ground or rooftop solar panel systems designed to feed electricity directly into the grid. Solar farms can range from 1 MW to over 500 MW and provide clean power to utility companies (Aurora Solar).
Off-Grid Solar – Commercial systems installed in remote areas without access to the electric grid. Off-grid solar combines solar panels with batteries to provide a standalone power source (Solar Alliance).
Community Solar – Allows customers to purchase solar electricity without installing panels on their own property. Customers subscribe to a portion of a shared solar farm and receive credits on their utility bills based on the energy produced (Solar Alliance).
Utility-Scale Solar Power
Utility-scale solar refers to large solar photovoltaic (PV) and solar thermal power plants that generate electricity to feed into the grid. These plants have capacities of 10 megawatts and greater, which compares to residential rooftop solar systems that usually range between 4-8 kilowatts. Utility-scale solar power plants can produce hundreds of megawatts up to 1 gigawatt or more, enough to power entire cities. According to the Solar Energy Industries Association (SEIA), as of 2020 there were over 2,500 utility-scale solar projects operating in the United States totaling 43.5 gigawatts of capacity, with another 100 gigawatts in the pipeline.
The main technologies used for utility-scale solar include photovoltaic solar panels arranged in large arrays, and concentrated solar power using fields of mirrors to concentrate sunlight and generate high temperatures to drive steam turbines. Major benefits of utility-scale solar power plants are producing renewable energy at massive scale to displace fossil fuel power generation, stabilizing the grid, and providing power during peak daytime hours when electricity demand and rates are highest. Large solar generation facilities with capacities in the 100s of megawatts are typically built on rural land spanning hundreds of acres. Construction costs have fallen dramatically over the years making utility solar competitive with fossil fuels. Given the plummeting costs and environmental benefits, utility-scale solar is expected to continue robust growth and play a major role in the renewable energy transition.
Solar Power Storage
One of the main challenges with solar power is its variable and intermittent nature. However solar power storage solutions help to address the issue of storing solar energy for later use when the sun isn’t shining.
Some of the key ways solar power can be stored include:
Batteries: Lithium-ion batteries like the Tesla Powerwall are becoming increasingly popular for residential solar power storage. Batteries allow excess solar power generated during the day to be stored and utilized at night or during cloudy weather. Tesla Powerwall and other integrated battery storage systems can provide backup power to homes when the grid goes down.
Pumped Hydro Storage: This involves pumping water uphill into a reservoir during times of excess solar power generation and then releasing it through hydroelectric turbines to generate power when needed. Pumped hydro allows large-scale energy storage from solar power plants.
Thermal Energy Storage: Excess solar heat can be stored in materials like molten salts and then used to generate electricity on demand via steam turbines. This allows solar thermal power plants to provide consistent power day and night.
Solar power storage technologies are rapidly evolving to allow greater grid integration and reliability of solar energy. Storage provides a critical solution to overcome solar’s intermittency challenges.
Solar Power Costs
The cost of installing solar panels has decreased significantly over the past decade. According to Sunrun, the average cost of a typical home solar installation now ranges from $16,200 to $21,400, a 62% decrease since 2010. The main components that make up this cost include hardware, labor, permits and other soft costs.
The hardware, including solar panels, inverters and racking, accounts for about 50-60% of the total installation cost. Labor makes up 10-25% of the cost. The remaining soft costs like permits, financing, customer acquisition and inspection fees make up the rest.
The levelized cost of energy (LCOE) from solar ranges from $0.048 to $0.078 per kWh for residential systems and $0.03 to $0.045 for utility-scale projects, according to the National Renewable Energy Laboratory. This makes solar competitive with conventional electricity prices in many markets.
Ongoing efforts to streamline permitting, reduce supply chain costs and improve installer efficiency are bringing down soft costs and further reducing the total price of solar for homeowners and businesses.
Solar Policy and Incentives
There are several key policies and incentives at both the federal and state level that support solar power development in the United States. These policies aim to make solar power more affordable and encourage more solar adoption. Some of the main solar incentives include:
Solar Tax Credits – There is a federal solar tax credit that allows homeowners and businesses to deduct 26% of the cost of installing a solar energy system from their federal taxes. Many states also offer additional solar tax credits and rebates.
Renewable Portfolio Standards – Many states have implemented standards that require utilities to source a certain percentage of their electricity from renewable sources like solar. This creates increased demand for solar power.
Net Metering – Most states have net metering policies that allow solar panel owners to send excess solar power they generate back to the grid. Owners then receive credits that reduce their electricity bills. This makes installing solar panels much more cost-effective.
Environmental Benefits
Solar power provides numerous environmental benefits compared to fossil fuel-based electricity generation. Most significantly, solar photovoltaic (PV) systems generate electricity without emitting greenhouse gases like carbon dioxide that contribute to climate change. According to the U.S. Energy Information Administration, solar PV and solar thermal systems generate zero direct emissions while operating. Replacing fossil fuel energy sources with solar can dramatically reduce overall carbon emissions from electricity generation.
The US Department of Energy reports that in 2019 alone, solar offset more than 80 million metric tons of carbon dioxide emissions from fossil fuels. Widespread solar adoption is crucial for transitioning to a sustainable energy system and mitigating human impacts on the climate. Solar energy systems require virtually no ongoing fuel inputs or extraction once installed, providing clean and renewable electricity for decades. With solar power, we can work towards energy independence while safeguarding the environment for current and future generations.
Future of Solar Power
The future looks bright for solar power. As technology continues to advance, solar panels are becoming increasingly more efficient at converting sunlight into electricity. New materials and manufacturing techniques are enabling solar cells that can absorb more of the sun’s energy.
Some emerging solar technologies that may play a bigger role in the future include perovskite solar cells, organic photovoltaics, concentrator photovoltaics, and solar nanomaterials. Researchers are also working on improving energy storage options that can enable solar power to provide electricity 24/7.
Solar power is projected to see tremendous growth worldwide in the coming decades. According to the International Energy Agency, solar PV capacity could reach over 4700 gigawatts globally by 2050, a 14-fold increase over 2020 levels. This is based on solar power continuing to fall in cost and countries around the world implementing policies to reduce carbon emissions and support renewable energy growth.
With innovations in technology, supportive policies, and increasing cost competitiveness, solar power is poised to be one of the key solutions to transition to clean energy and mitigate climate change. The future is looking bright as solar continues on its trajectory to becoming a mainstream energy source worldwide.
