At present SPV electricity is costlier than grid electricity (which is substantially subsidized). To make SPV electricity cost competitive with grid electricity the module cost should be ~US$ 0.5/pW). There is a need for a low cost method of converting sunlight into electrical energy.
The ultimate way to reaching the cost goal is to improve the mass production technology and by using low cost production technology. The following technology options are available now for large-scale use of SPV: (1) single crystal silicon; (2) multicrystalline silicon and (3) thin film technologies.
Only thin film solar cell (TSF) technologies have the potential of reaching the cost goal of $1-1.5/pW. This is due to the following factors: (1) low cost of materials; (2) low energy payback period and (3) capability of fabrication of large area module in a single step. Amongst the TFS technologies a-Si has the following special advantages viz: (1) no problem with availability of materials for very large scale production; (2) proven production technology suitable for large area modules (1 sq.mt.) (3) no environmental hazard with the process and the product (4) low material requirement (0.5 micron compared to 200 μm for single crystal silicon).