Photovoltaic (PV) systems are systems that convert sunlight into electricity using photovoltaic cells. These cells are made of materials, such as silicon, which absorb photons of sunlight and release electrons, creating an electrical current. PV systems can be installed on rooftops, as well as on the ground, and can be used to power homes, businesses, and even entire communities.

Renewable energy refers to energy that is derived from sources that are replenished naturally and rapidly, such as sunlight, wind, and water. Unlike non-renewable sources of energy, such as fossil fuels, renewable energy does not contribute to climate change and is sustainable over the long term.

Solar power plants are large-scale installations that use PV systems to generate electricity on a massive scale. These plants are typically located in areas with high levels of sunlight and are capable of supplying electricity to entire cities or regions.

Energy efficiency refers to the practice of using less energy to accomplish the same tasks. This can be achieved through a variety of measures, including the use of energy-efficient appliances, the implementation of energy-saving technologies, and the adoption of more sustainable behaviors. By reducing energy consumption, we can reduce our carbon footprint, save money on energy bills, and help mitigate the impacts of climate change.