Dr Gregor Czisch is a pioneer for the idea of using long-distance supergrids to allow power from widespread sources to be traded across long distances, for example delivering renewable energy harvested in Africa to the EU. Unlike Desertec’s solar-based supergrid plan, his 2011 supergrid plan focused mainly on using wind, which he saw as the best source to use. That idea has yet to be taken up and Desertec’s CSP/PV plan is also now defunct, but with solar PV costs now having fallen, Czisch has looked at PV again to see if it was now an option. However, he has still found it wanting. And he still looks to wind, including power imported from North Africa, as a better bet. In a recent interview Czisch argues that, as PV moved down its learning curve, we have seen PV expanding, driven by cost reductions, but this may not continue for much longer. Moreover, it was‘not unexpected that the cost reduction per doubling of the installed power fell from 16% to just slightly more than 10%. This is well in the frame of cost reductions of technologies in a mature production state and could indicate that for PV the time is over in which it was a new technology with high techno-economic learning rates’. He argues that ‘ultimately, the cost of individual components is not the single criterion. The system as a whole must always be considered in case of the electricity supply. As long as a technology is not able to be used at all times and in a sufficient amount to produce the power required, its availability over time plays a significant role. This is well illustrated in my scenarios where I was looking for the most cost-effective way to provide an electricity supply for Europe and its neighbours utilizing renewable energies only. This was achieved by means of mathematical optimization, not least to achieve results having the greatest possible objectivity. PV was not going to be very viable for supergrid use, and using it locally, in the EU, had limited value, given its lower intensity level and higher variability. That was case even with energy storage: while hydro pumped storage could help, he was dismissive of most storage options, including P2G hydrogen, especially for longer term balancing. They were too expensive, inefficient and limited compared with long distance supergrid trading of surpluses. And he insists that wind is better for that than solar CSP or PV, as he claims the Desertec group eventually found.
Environmental Research Web 17th June 2017 read more »