While solar electricity has become less expensive in recent years, its cost remains approximately three times too expensive relative to grid power today. What technology would it take to break through the baseline defined by grid electricity and ultimately make solar electricity profitable?

It is important to understand that the cost of electricity (cents/kWh) from solar cells is determined by the cost/performance of the electricity-generating product over its lifetime, that is, it is equally driven by three factors:

• The cost of the solar cells, measured in $/area, or how much it costs to cover an area of sunlight collection,
• The performance, measured in Watt/area, or the amount of power generated per area of coverage (or equivalently the efficiency: the percentage of energy generated relative to the amount of incoming sunlight energy), and
• The lifetime, measured in the number of years that the electricity-generating system can be used (with cents/kWh of electricity cost resulting by dividing the cost/performance of the system ($/Watt) by the active lifetime).

Achieving low cost of solar electricity requires making technology and process choices that optimize across all three of these dimensions. But the global optimum of this is generally not the maximum of any individual dimension. For instance, higher efficiency does not necessarily result in lower cost of electricity. The latter would only be the case if a performance improvement does not also generate additional cost (or lowers the lifetime) by a corresponding percentage. Note that additional cost may result for instance from an efficiency improvement not being as reproducible as high-yield low-cost production requires or from additional capital expenditures required.

Nanosolar has been singularly focused on identifying and inventing the ultimate approach to low-cost solar electricity based on the most advanced design and process technology innovations developed in concert with comprehensive quantitative cost/process models across a wide range of possible technologies.