Solar Electric

Solar power is an immensely potent, low pollutant renewable source of energy that may readily be transformed into electricity. Indeed, considering the sheer quantities of energy that are contained by sunlight alone it is one of the most powerful sources of energy there is on the planet, never mind that it is not as easily harnessed as other kinds of fuel. The solar electricity industry is still only in its infancy, and as a consequence it only amounts to a very meagre share of the global energy supply. This small part is in turn split up between photovoltaics and concentrated solar power, which are two different ways of converting sunlight into electricity.

Photovoltaics convert sunlight to electricity directly in solar cells. The basics of this process is that photons in the sunlight hit the solar panel of the solar cell and are absorbed by semi-conducting material, usually silicon. Negatively charged electrons in the solar cell are consequentially knocked loose from their atoms, allowing them to roam free through the material as an electrical current. This electrical current may consequentially be fed into the power grid using inverters or into a standalone system.

Concentrated solar power instead uses lenses or mirrors and tracking systems to focus a large area of sunlight into a single beam thereof. This beam, which has a high energy density, is then used as a heat source for a conventional power plant. Concentrated solar power is almost exclusively used in commercial power plants, whereas photovoltaics are as likely to be found in commercial power sources as it is in those reserved for private use.

For all their potency, both photovoltaics and concentrated solar power are compromised by the highly intermittent quality of solar power. It, like wind power, cannot be dispatched and must be used up or stored immediately upon being produced. Moreover it is affected by the cycle of night and day as there naturally is no sunlight to be had during the night. These issues could be handled by the same power grid demand management measures as wind power; that is to say by pump-stored hydroelectricity that is accumulated during times of high production and released in times of high demand. However solar power may also be stored in molten salts, which is a low-cost item with high heat capacity as well as energy that is compatible with conventional power systems. Rechargeable batteries are another alternative to energy storage, as they could be plugged in when needed and then be stored separate from the network. Either of these ways would be suited to maintaining energy production levels overnight, or for all that matters over a day or two without sunlight.

An alternative and currently just theoretic proposal is the disputed idea of generation of solar power in space. The reason for this would be that a satellite or space craft would not be subject to the weather and time of day limitations that plague solar power generators on earth. However the launching of a satellite for generating electricity from the sun would hardly be cost-effective considering the amounts of solar power that already make it to the surface of the earth. In a sole year this amounts to more than twice the amount of all the energy that all the coal, oil, methane gas and uranium in the world could ever produce. It thus stands to reason that the money that would be needed for developing a means of converting sunlight to electricity in space would be better spent on new and improved ways of collecting and converting the energy that already arrives on earth on its own.