Polycrystalline silicon, or multicrystalline silicon, also called polysilicon, poly-Si, or mc-Si, is a high-purity, polycrystalline form of silicon, used as a raw material by the solar photovoltaic and electronics industry. Polysilicon is produced from metallurgical grade silicon by a chemical purification process,…

PTT Public Company Limited (Thai: บริษัท ปตท. จำกัด (มหาชน)) is a Thai state-owned SET-listed petroleum and natural gas company.

Pacific Gas and Electric Company (PG&E) is an American investor-owned utility (IOU). The company is headquartered at Kaiser Center, in Oakland, California.

Eskom Hld SOC Ltd or Eskom is a South African state-owned electricity public utility. Eskom was established in 1923 as the Electricity Supply Commission (ESCOM) (Afrikaans: Elektrisiteitsvoorsieningskommissie (EVKOM)).

An energy transition (or energy system transformation) is a major structural change to energy supply and consumption in an energy system. Currently, a transition to sustainable energy is underway to limit climate change.

NRG Energy, Inc. is an American energy company, headquartered in Houston, Texas.

Tesla Energy Operations, Inc. is the sustainable energy division of Tesla, Inc.

In energy economics and ecological energetics, energy return on investment (EROI), also sometimes called energy returned on energy invested (ERoEI), is the ratio of the amount of usable energy (the exergy) delivered from a particular energy resource to the amount of exergy used to obtain that energy…

Geothermal energy is thermal energy extracted from the Earth's crust. It combines energy from the planet's formation and from radioactive decay.

Open energy-system models are energy-system models that are open source. These models can also be known as open energy models or open-source energy-system models or some combination thereof.