What's Holding Up Utility Scale Concentrated Photovoltaics (CPV)?

What's the CPV hold up?

While CPV technology harnesses the power of the sun directly onto compact, electricity producing photovoltaic materials, thereby reducing the need for expensive silicon, land and water use requirements of their concentrated solar thermal rivals (even taking solar thermal dry cool technologies into account), the CPV industry is still fraught with new industry growing pains.

To date, only a few scattered, small scale CPV demonstration projects are on the books, and thus far, small scale production has translated into higher production costs.

Absent a successful large scale operational track record, investments for large scale material production are still considered high risk, mostly because of questions regarding the reliability of the the triple junction solar cells. The largest planned CPV project, to date, the 150 megawatt Midura project in Australia, recently hit the financial risk road block. The company ended up in receivership, followed by asset liquidation.

The use of triple junction cells for CPV also introduces an efficiency conundrum. While the current triple junction cells can reach a record 40% efficiency level, they are only one portion of the CPV efficiency equation.

The efficiency of the surrounding concentrators, often called optical efficiencies, (currently at the 85% - 90% mark) reduces the benchmark efficiency level.

System inefficiencies from electricity generation to electricity use, via the electricity transmission system, further reduce system efficiency levels to the 25% range.

Taken together, CPV hardware costs plus CPV efficiency levels translate into a product with double the costs of concentrated solar thermal projects.

The most recent National Renewable Energy Laboratory (NREL) publication, Opportunities and Challenges for Development of a Mature Concentrating Photovoltaic Power Industry presents some high-concentration CPV industry goal metrics for 2015:

• $/W installed cost=<$2
• System reliability=20 years
• Commercial system efficiency=29% to 36%

Despite its current drawbacks, projected future technology improvements along with the situational advantages offered by CPV, make it a utility scale solar technology of the future.

The NREL report expands the definition of CPV to include medium concentration systems (typically 10X to 20X concentration) and low concentration systems (2X to 3X enhanced PV modules).

With a bit of human ingenuity, these lower concentration technologies could translate into the creation of simple enhancing covers that double or triple today's roof top installations, thereby giving a big boost to both utility scale and distributed CPV.

© 2010 Patricia A. Michaels.