Solar Energy

Solar energy is virtually unlimited, with the sun producing an amazing 173,000 terawatts of energy every second, which is 10,000 times the amount of energy the entire world consumes (Energy.gov 2016). Because of this huge potential, solar energy technologies, especially photovoltaic (PV) panels and concentrated solar power (CSP) systems, have grown exponentially in recent years.

Global solar power capacity has increased tremendously in recent years. BloombergNEF reports that global capacity grew to 1.6 terawatts (TW) in 2024 with 444 gigawatts (GW) of new solar photovoltaics (PV) installations in 2023. As solar expansion worldwide is accelerating rapidly, new installations are expected to reach 574 GW in 2024. China’s solar PV capacity remains the world’s largest market, with about 190 to 220 GW expected to be added in 2024 (EnergyTrend, April 2024), the United States and India are in second and third place, respectively.

Photovoltaic Technology

At the heart of this solar revolution are photovoltaic (PV) cells, which directly convert sunlight into electricity via the photovoltaic effect. The power output of a PV system can be calculated using this formula:

P=E×A×η

Where:

𝑃 is the power output (in watts),
𝐸 is the solar irradiance (in watts per square meter),
𝐴 is the area of the PV panel (in square meters),
𝜂 is the efficiency of the PV panel.

Solar Thermal Technology

While PV is leading the market, solar thermal systems also play a key role by capturing and concentrating sunlight to generate high-temperature heat to produce electricity or supply heat. The efficiency of these solar thermal plants is given by:

𝜂thermal= Quseful/Qinput

Where:

𝜂thermal is the thermal efficiency,
Quseful is the useful energy output,
Qinput is the energy input from the sun.

Environmental Impact

Although solar energy significantly reduces greenhouse gas (GHG) emissions compared to fossil fuels, solar PV's carbon footprint is only about 50 grams of CO2 per kilowatt-hour (g CO2/kWh) - substantially lower than electricity from coal-fired plants at over 1,000 g CO2/kWh (Cool Effect, June 2021).

Solar PV rapidly increasing as costs decrease and installations multiply exponentially yearly. By harnessing the sun's abundant energy, we can power our world while protecting our planet's climate.