Renewable energy is energy from sources that are naturally replenishing but flow-limited; renewable resources are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. renewable energy consumption will continue to increase through 2050.The major types of renewable energy sources are Until the mid-1800s, wood was the source of nearly all of the nation's energy needs for heating, cooking, and lighting.
The (WEO2016) makes the points that VRE have five technical properties that make them distinct from more traditional forms of power generation.
First, their maximum output fluctuates according to the real-time availability of wind and sunlight.
It includes capital, financing, operation and maintenance, fuel (if any), and decommissioning.
Another relevant metric is energy return on energy invested (EROI).
An EROI of about 7 is considered break-even economically for developed countries.
The US average EROI across all generating technologies is about 40.Today we are well advanced in meeting that challenge, while also testing the practical limits of doing so from wind and solar (variable renewable energy, VRE).The relatively dilute nature of wind and solar mean that harnessing them is very materials-intensive – many times that from energy-dense sources.Wind turbines have developed greatly in recent decades, solar photovoltaic technology is much more efficient, and there are improved prospects of harnessing the energy in tides and waves.Solar thermal technologies in particular (with some heat storage) have great potential in sunny climates.Technology to utilise the forces of nature for doing work to supply human needs is as old as the first sailing ship.But attention swung away from renewable sources as the industrial revolution progressed on the basis of the concentrated energy locked up in fossil fuels.There is a new focus on system costs related to achieving reliable supply to meet demand.In the following text, the levelised cost of electricity (LCOE) is used to indicate the average cost per unit of electricity generated at the actual plant, allowing for the recovery of all costs over the lifetime of the plant.Second, such fluctuations can be predicted accurately only a few hours to days in advance.Third, they are non-synchronous and use devices known as power converters in order to connect to the grid (this can be relevant in terms of how to ensure the stability of power systems).