The low cost solar cell is an effort to make solar power price competive with traditional (fossil fuels and nuclear power) energy sources.

The polysilicon shortage^[1]has changed the economics, making technologies such as thin films, which use little or no silicon, more attractive.^[2] The cost per watt will be the determining factor for success.^[3] The solar industry can potentially reduce costs 40 percent over the next five years as the silicon shortage ends, according to Graham Stevens, an associate director at Navigant Consulting.^[4][5]

Grid parity, the point at which photovoltaic electricity is equal to or cheaper than grid power can be reached using low cost solar cells. It is achieved first in areas with abundant sun and high costs for electricity such as in California and Japan.^[6] Grid parity has been reached in Hawaii and other islands that otherwise use diesel fuel to produce electricity. George W. Bush has set 2015 as the date for grid parity in the USA.^[7][8] General Electric's Chief Engineer predicts grid parity without subsidies in sunny parts of the United States by around 2015. Other companies predict an earlier date.^[9]

A number of analysts have predicted that polysilicon prices will drop as companies build additional polysilicon capacity more quickly than the industry’s projected demand.^[10] The development of the Renewable Energy Corporation´s world-scale Singapore site will enable REC’s ability to deliver polysilicon solar products that can compete with traditional energy sources in the sunny areas of the world without government incentives.^[11]

On the other hand, the cost of producing upgraded metallurgical-grade silicon, also known as UMG Si, can potentially be one-sixth that of making polysilicon.^[12]

Thin-film solar is another technology with the potential to reduce costs. First Solar, for example, reached costs of $1.10 per watt in the fourth quarter.^[13]

Dye-sensitized solar cell is considered nowadays the low cost solar cell.

This cell is promising because it is made of low-cost materials and does not need elaborate apparatus to manufacture, so it can be made in a DIY fashion and allows more players to produce it than any other type of solar cell. In bulk it should be significantly less expensive than older solid-state cell designs. It can be engineered into flexible sheets. Although its conversion efficiency is less than the best thin film cells, its price/performance ratio should be high enough to allow them to compete with fossil fuel electrical generation.

Organic solar cells is a relatively novel technology, promising substantial price reduction (over thin-film silicon) and better energy payback time. These cells can be processed from solution, enabling the possibility for a simple roll-to-roll printing process, leading to a cheap, large scale (square kilometers per month) production.

• Intersolar North America
• Investment in renewable energy
• Solar Hot Carbon

• Photovoltaic technologies beyond conventional silicon (IDTechEx).
• Charting a Path to Low-Cost Solar.