Written by Olivier Loidi In August 2018, ennomotive launched a circular economy challenge to find ways to repurpose waste materials found in mine tailings. For 6 weeks, 74 engineers from 30 countries accepted the challenge and submitted different solutions. After a thorough evaluation, the solutions that best met the evaluation criteria were submitted by Cliff Edwards, from Canada, and Oliver Loidi, from France. ennomotive asked Olivier to write an article about a topic he likes and here are his views on the future of solar energy and the high concentrated photovoltaic. Solar energy is key for curbing global warming, I truly believe that. As a matter of fact, ten years ago I was actively working in this field and most particularly in the high concentration photovoltaic field (CPV). Back then it was seen as a true competitor for standard PV panels, but years of aggressive price-dumping have seriously undermined its development. The short-term approach of 'low capital cost/low lifespan' of standard PV appears to be much more tempting than the wiser 'moderate initial cost/long lifespan' path, even with more than double the efficiency. Now that standard solar panels begin to compete favorably with coal and gas and CPV companies still struggling to survive, it could be easy to conclude that the match is already over. However, research is still going strong to reduce the capital cost gap and, if the threshold is reached, could pave the way to a massive comeback for CPV. In this article, I will try to explain the pros and cons of the CPV technologies along with my personal views of what should be improved to make it successful.
What is High Concentration Photovoltaic?The principle of CPV is to focus sunlight onto an extremely high-efficiency solar cell that would be otherwise too expensive to use directly. These exceptional robust solar cells, usually made for space or military applications, can handle a concentration ratio of a thousand or more and still be nearly three times more efficient than a traditional PV cell made of silicon (Si-Pv). This approach has its own drawbacks: it needs to be directly oriented toward the sun and equipped with concentrating optics.
Types of optics
Advantages of CPV over normal solar panels
- Very stable performance under high temperature
- Very good durability
- Potential double usage of the land
- Easily recyclable
Why has CPV failed so far?
- Higher initial capital cost
- Higher maintenance need
- Clouds degrade performance
- Low land occupation density
- Technology is still young
Why CPV has the potential to succeed in the future
- CPV Cells are getting better, smaller, and cheaper
- SI-PV module price drop is stalling
- Remaining available locations are more demanding
What I think should be improved for CPV to be successfulAs I said in the beginning, CPV has a special place in my heart and I never stopped thinking about new designs or possible improvements. Here are my thoughts on which points need attention for future CPV success:
- Reducing module weight is critical
- Use of Fresnel lenses optic is a dead end
- Reflective optics should evolve from the classical “telescope design”
- Use of automated cleaning with very low water consumption