renewable energy/ solar energy/ technology/“Solar Energy: The Untapped Potential”

Before I start ,I would like to give a brief picture of solar energy. Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. The Earth receives 174 petawatts (PW)(total electrical energy consumption is 15TW per year which is quite less than total solar energy) of incoming solar radiation (insolation) at the upper atmosphere. Now, you can imagine the true potential of solar energy. Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans and land masses. Only a minuscule fraction of the available solar energy is used.

Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

The two main ways of electrical power generation are:-

1) Either directly using photovoltaics (PV)- PV converts light into electric current using the photoelectric effect. The largest photovoltaic (PV) power plant in the world is the Sarnia Photovoltaic Power Plant (Canada, 97 MW), The photovoltaic methods are improving but concentrated solar power looks more promising.

 2)indirectly using concentrated solar power (CSP). CSP systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam

CSP is used to produce electricity (sometimes called solar thermoelectricity, usually generated through steam). Concentrated solar technology systems use mirrors or lenses with tracking systems to focus a large area of sunlight onto a small area. The concentrated light is then used as heat or as a heat source for a conventional power plant (solar thermoelectricity). The solar concentrators used in CSP systems can often also be used to provide industrial process heating or cooling, such as in solar air-conditioning.

CSP is being widely commercialized, with about 1.17 gigawatts (GW) of CSP plants online as of 2011. 582 megawatts of them are located in Spain, and the United States has 507 megawatts of capacity. As you can see that CSP is able produce more electricity than conventional photovoltaic method and is cheaper than photovoltaic method. It is getting popular and will be able to harness of solar energy.

Future of CSP

A study done by Greenpeace International, the European Solar Thermal Electricity Association, and the International Energy Agency's Solar PACES group investigated the potential and future of concentrated solar power. The study found that concentrated solar power could account for up to 25% of the world's energy needs by 2050. The increase in investment would be from 2 billion euros worldwide to 92.5 billion euros in that time period. Spain is the leader in concentrated solar power technology. Also, it exports its technology, further increasing the technology's stake in energy worldwide. Because the technology works best with areas of high insolation (solar radiation), experts predict the biggest growth in places like Africa, Mexico, and the southwest United States. The study examined three different outcomes for this technology: no increases in CSP technology, investment continuing as it has been in Spain and the US, and finally the true potential of CSP without any barriers on its growth. The findings of the third part are shown in the table below:

Time	Investment	Capacity
2015	21 billion euros a year	420 megawatts
2050	174 billion euros a year	1500 gigawatts

Finally, the study acknowledged how technology for CSP was improving and how this would result in a drastic price decrease by 2050. It predicted a drop from the current range of 0.23 to 0.15 euros per kilowatt-hour, down to 0.14 to 0.10 euros a kilowatt-hour.

This facts and figures used in this article have been taken from Wikipedia.