During the 2000s, United States housing prices experienced a sharp run up and subsequent collapse affecting over half of the U.S. states. In many regions, a real estate bubble was the impetus for the subprime mortgage crisis.

The Energiewende (German for 'energy turnaround') (pronounced [ʔenɐˈɡiːˌvɛndə] ) is the ongoing energy transition by Germany. The new system intends to rely heavily on renewable energy (particularly wind, photovoltaics, and hydroelectricity), energy efficiency, and energy demand management.

Energy engineering is a multidisciplinary field of engineering that focuses on optimizing energy systems, developing renewable energy technologies, and improving energy efficiency to meet the world's growing demand for energy in a sustainable manner. It encompasses areas such as energy harvesting and storage, energy…

Saudi Arabia has a high-income developing economy highly reliant on its petroleum sector. Oil and gas account for approximately 22.3% of Saudi GDP and 55% of government revenue, with substantial fluctuations depending on oil prices each year.

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…

Renewable energy in developing countries is an increasingly used alternative to fossil fuel energy, as these countries scale up their energy supplies and address energy poverty. Renewable energy technology was once seen as unaffordable for developing countries.

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