SPS are back, thank you BP! Proponents of the project (including B. Aldrin) profit from this opportunity to put their plans on the table: the best solution to all environmental problems and more. You can have a look here for an illustration of the european projects (I was part of some of them): ACT – Energy systems.
You can see on the publication page, the effort is not negligible (there are of course a lot of redundancies, so just read the last year, it is enough). All these studies address in details the construction, the operation, the costs, the economy based on solar power, the ground infrastructure and so on.. It is technically sounding, the only problem is that one major difficulty is left aside: the transfer of elements from ground to orbit. Why? Because all these studies are based on the assumption of a future affordable ground-to-orbit green transportation system. But this system DOES NOT exist. So why elaborating and selling such projects when the main component is missing? Why asking for money? The logic behind is to say: if we have a viable solution to energy problems thanks to the SPS, it will boost the development of cheap green rockets. No, it has never worked that way and it will never work. When, and only when, affordable means of transport will be available, it will be possible to present and develop such projects. By asking funding now, the limited amount of money and manpower is diverted to dead-end projects. They give very nice Powerpoint slides and sound very serious because of all economic figures they contain. So, please let’s focus on the real technological issue: the rocket.