What is photovoltaic emergy?

Answer 1

Photovoltaics are direct energy conversion devices that convert electromagnetic waves (usually as thermal radiation from a high temperature source, like the sun) to electricity.

Emergy is defined as the energy required to supply the materials and manufacture a device that is somehow used to generate, harvest, or convert energy. For instance, as hydroelectric dam requires energy to bring the materials to the site, construct the dam, and install the various components.

In the case of photovoltaics, emergy is the energy required to collect and refine the materials (such as silicon and other semiconductors), to manufacture and assemble the units, and to distribute the devices. In the past, emergy estimates for photovoltaics have shown that the emergy of such devices is higher than the total output of the devices over the entire product life. This is still a topic of research and concern in photovoltaic research. It is also part of the reason that photovoltaics are difficult to make economically viable (particularly when compared to convectional electric generation systems).

Answer 2

Photovoltaic emergy is a measure of the solar energy that is used in photovoltaic (PV) systems to generate electricity. It is a way of quantifying the sunlight energy that is converted into electricity by PV systems. The term "emergy" is a concept developed to account for all the energy and resources that contribute to a system's operation, including both direct and indirect inputs.