An out-of-the-box perspective at solar power

SunPower® Signature™ Black Solar Panels. Credit:

I read a short interview to Richard Swanson, who founded SunPower 30 years ago and he is still at the helm. Over these thirty years technology progress has been relentless resulting in more efficient and less costly panels to convert sun light into electrical energy.

Less than 15 years ago, around the turn of the century, it was felt that to become competitive with respect to the fuel fossils, the cost per W should be in the range of 1$ and that seemed to be wishful thinking, at least with silicon based technology.

In 2014 we are below the 1$ per W and we are still using silicon based solar panels. And yet, like a moving rainbow, it is still difficult to say that solar energy can compete with fossil fuel energy. Now the thresholds has been moved to 0.5$ per W and that seems to be a thresholds that can be met at the end of this decade.

The problems are several, the most basic one being the unavailability of sun light for many hours a day and its scarce effectiveness in adverse meteo conditions. 

This is nothing new, but (relatively) new are the ideas to address the discontinuous availability of Sun light. Storing energy once it is produced to make it available at a later stage is crucial if we are to depend on Sun power and gradually fade out fossil fuel sources. 
Storing electrical energy is not cheap, batteries cost a lot of money (per Wh of capacity) and you need a lot of them. Furthermore, the life time of a battery is relatively short and replacing it means more cost and more pollution.  Other alternatives are based on converting electricity in heath (using sodium-sulphur / thermal batteries) and then using the heat to generate electricity again when needed (the system works but is not something you would like to have in your basement and there is a significant waste of power in the back and forth transformation).

Another aspect that is becoming relevant and got me intrigued, as photovoltaic panel cost decreases, is the installation cost.

Half of the cost for the photovoltaic if you decide to have it on your roof is taken by the installation. And I was surprised to learn that there are now a few applications using satellite data to assist installer placing the panels in the best possible place on the roof! I would have never imagined that the investment in sending satellites orbiting the Earth would provide benefits to people working on roof shingles.

Here I find yet another interesting confirmation of the fact that once the cost gets below a certain thresholds ICT has to kick in to lead to further optimisation. And this is an area where we are putting lot of effort at EIT ICT Labs, the Smart Energy Systems, looking at how to apply ICT to get that tiny, but essential improvement to energy efficient that, as we have seen, can tip the balance between one technology to another.

Author - Roberto Saracco

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