How Powerful Is Solar Energy?
Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal energy, solar architecture, molten salt power plants and artificial photosynthesis (https://www.electronicsandyou.com/solar-energy-journal-uses-types-benefits.html). It is an important source of renewable energy and its technologies are broadly characterized as either passive solar or active solar depending on how they capture and distribute solar energy or convert it into solar power. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light-dispersing properties, and designing spaces that naturally circulate air.
Renewable energy sources like solar are becoming increasingly important as the world looks to transition away from fossil fuels and reduce greenhouse gas emissions that contribute to climate change. Solar energy offers a sustainable and clean alternative that can supplement or replace conventional energy sources. Some of the key questions around solar power include how cost-competitive it is with coal and natural gas, how much it could realistically contribute to overall energy demand, how best to store and distribute solar electricity, and what supportive policies and incentives are needed to drive further adoption.
Solar Energy’s Share of Global Energy Production
Solar energy currently accounts for around 4-5% of global electricity generation. According to the International Energy Agency (IEA), global solar PV capacity reached over 1,000 GW in 2022, supplying around 4.5% of global electricity demand [1]. In 2021, solar PV accounted for 3.6% of global electricity generation [2].
Solar power capacity has been growing rapidly over the past decade. According to the IEA, solar PV investments increased by over 20% in 2022 to surpass $320 billion, marking another record year of growth [3]. Total renewable energy capacity is projected to reach 4,500 GW in 2023, equal to the current total global power capacity from all sources [1]. Most of this growth is expected to come from solar PV additions.
Solar Energy Potential
Solar energy has enormous potential when considering the amount of solar irradiance that reaches the Earth’s surface. According to one study, the potential solar power available in areas with at least 1,700 kWh/m2/year (a common threshold for economic viability of solar projects) amounts to about 80 PWh/year globally, over 20,000 times the current global energy consumption (Kim, 2021).
Solar irradiance maps provide more precise detail on the solar energy potential in different geographic regions. Analysis of data from 1996 to 2019 showed that the highest annual solar irradiance levels in South Korea were in the central and southern regions, with totals exceeding 1,400 kWh/m2/year in optimal locations. Northern regions had lower potential closer to 1,200 kWh/m2/year (ResearchGate, n.d.).
Cost Competitiveness
Solar energy has become increasingly cost competitive with traditional energy sources like coal, natural gas, and nuclear power. According to a 2023 study in Science Direct, the global average Levelized Cost of Energy (LCOE) for solar photovoltaics declined about 89% between 2010 and 2020, reaching $0.039/kWh (1). The Department of Energy found the average utility-scale solar LCOE dropped from $359 per MWh in 2009 to $37 per MWh in 2021, an 90% reduction (2).
The LCOE estimates the lifetime costs of an energy generating system divided by its energy output over time. This allows an “apples to apples” comparison of different energy technologies. As solar costs have plummeted, solar is now cheaper than coal and gas across many parts of the US and the world.
According to the IEA, new utility-scale solar projects are cheaper than new coal plants in all major markets. In 2021, the global weighted-average LCOE of solar was $0.046/kWh, compared to gas combined cycle at $0.142/kWh and coal at $0.170/kWh (3). This cost advantage has enabled solar’s rapid growth and highlights its potential as a mainstream energy source.
While solar remains more expensive than some energy sources in some markets, costs are projected to keep falling in the future. Continued technological improvements, economies of scale, and supportive policies can further reduce solar’s costs and improve its competitiveness.
Sources:
(1) https://www.sciencedirect.com/science/article/pii/S2666389923000752
(2) https://www.energy.gov/eere/solar/solar-energy-cost-analysis
(3) https://www.iea.org/reports/renewable-power/solar-pv
Environmental Benefits
Solar energy has significant environmental benefits compared to fossil fuels. By generating electricity from the sun rather than burning fossil fuels, solar energy dramatically reduces air pollution and carbon emissions. According to one source, solar panels emit no pollution during their operation and are increasingly affordable and efficient (Source 1). Solar energy systems release no carbon dioxide or other greenhouse gases responsible for climate change. In contrast, the burning of coal, natural gas, and oil for electricity is a major contributor to air pollution. The Environmental Protection Agency estimates that replacing fossil fuel energy sources with solar power in the United States could reduce carbon dioxide emissions by over 80 million metric tons per year (Source 2). The development of solar energy can significantly limit the environmental impacts of energy production through reduced emissions and cleaner air.
Grid Integration
As more solar energy is added to the electrical grid, there are challenges that arise in integrating this intermittent renewable resource. Solar power output can fluctuate throughout the day and seasons due to changes in sunlight. This is very different from conventional power plants that provide consistent baseload power. The resulting net load variability from adding solar is commonly known as the “duck curve.”
The duck curve illustrates how the timing of peak net load changes across the day as more solar is added. Net load is lower in the middle of the day when solar production is high, then ramps up steeply in the evening as solar production decreases but demand remains high. This requires grid operators to ramp up other power plants quickly to meet evening demand. The steep ramping need is depicted in the shape of a duck’s curve (Department of Energy).
To address the duck curve, various solutions have been proposed. Grid operators can work to increase system flexibility, such as using faster ramping natural gas plants, energy storage, and smarter energy management systems. Geographic diversity of solar installations can also smooth variability. Additionally, time-of-use electricity pricing can incentivize consumers to shift more usage to the middle of the day (Ye). Overall, careful planning and new technologies can enable high penetration of solar energy on the grid.
Solar Energy Storage
One of the main challenges with solar power is that it only generates electricity when the sun is shining. Battery storage provides a solution to enable solar energy to be used 24/7 and provide power even when the sun isn’t shining The Benefits of Adding Solar Battery Storage to Your …. By pairing solar panels with battery storage, excess solar energy can be stored for use at night or on cloudy days.
Battery storage systems allow solar energy to be dispatchable and available on-demand, rather than just when it is produced. Homeowners are increasingly adding battery backup to their solar panel systems to enable full home backup power and maximize solar self-consumption Solar Battery Backup Storage Systems. Battery storage provides resilience and energy independence.
Lithium-ion batteries have become the dominant battery technology for home solar storage, providing affordable and long-lasting energy storage. Companies like Tesla offer solar battery solutions like the Powerwall to store solar energy. The costs of solar batteries have declined significantly, making battery storage more accessible to homeowners. Energy storage is key to enabling the world to transition fully to renewable energy.
Distributed Solar
Distributed solar energy refers to solar panels installed on rooftops or locally to provide electricity to homes, businesses or communities. Rooftop solar has seen tremendous growth in recent years due to several key benefits:
Cost savings – Rooftop solar allows homeowners and businesses to reduce their electricity bills by generating their own clean energy. The cost of solar panels has dropped dramatically, making rooftop systems more affordable.
Increased self-sufficiency – Local solar generation gives consumers and communities more energy independence and resilience. Rather than relying solely on the centralized grid, they can meet some of their own energy needs.
Cleaner energy – Rooftop solar offsets the need for fossil fuel-generated electricity. It helps reduce greenhouse gas emissions and local air pollution.
According to pv magazine, some key trends shaping rooftop solar include:
– Continued cost declines, especially with solar loans and financing options.
– Growth of community solar programs that allow participation by renters and those without suitable roofs.
– Emergence of solar + storage systems that provide backup power.
With the many benefits of local solar generation, distributed systems are projected to provide an increasing share of renewable energy in the future.
Solar Energy Policies
Governments around the world have implemented various policies and incentives to accelerate the adoption of solar energy. These include renewable portfolio standards, feed-in tariffs, tax credits, rebates, net metering, and renewable energy targets.
The renewable portfolio standard (RPS) mandates electricity suppliers to source a minimum share of their electricity from renewable sources. As of early 2020, RPS policies had been adopted in 30 U.S. states and territories. This has been a major driver for utility-scale solar deployment in the U.S. The feed-in tariff guarantees renewable electricity generators, including solar power producers, a fixed price over a long period of time for the electricity they feed into the grid. This policy has successfully enabled solar PV adoption in many European countries and elsewhere.
Investment tax credits, performance-based incentives, and rebates have helped offset the upfront costs of residential and commercial solar installations. Net metering policies allow solar panel owners to export excess electricity to the grid in exchange for credits. This enables self-consumption of solar power and makes adoption more feasible economically. Over 40 U.S. states have mandatory net metering rules.
Many governments have also set ambitious renewable energy or solar deployment targets. For example, the European Union aims for net-zero greenhouse gas emissions by 2050. India targets 175 gigawatts of renewable energy capacity by 2022. Such targets drive policy action towards incentivizing renewables.
Overall, these solar energy policies have accelerated cost declines and technology improvements through economies of scale. They have been pivotal in enabling the rapid growth of solar photovoltaics worldwide. Continued policy support will be essential for solar to maximize its potential as a mainstream energy source.
Future Outlook
Solar energy is poised for tremendous growth in the coming years and decades. According to projections from the Solar Energy Industries Association, solar will account for 20% of total electricity generation in the United States by 2030, up from just over 3% today (SEIA). Globally, solar power is projected to rise from around 3% of electricity generation today to over 25% by 2050 (IEA).
Several key innovations could accelerate the adoption of solar energy. Continued improvements in solar panel efficiency and energy storage technology will enable solar to become increasingly cost-competitive (NREL). The integration of solar with grid modernization and smart grid technologies will facilitate greater penetration of distributed solar generation (SEIA). Policies such as renewable portfolio standards, tax credits, and net metering will also drive growth. Overall, the future is bright for solar to become a major pillar of clean, renewable energy worldwide.
