To me, Asimov can do no wrong. But, in this book, he did little right either. Asimov’s Three Laws of Robotics may be remembered forever, but there are no robots in this story; instead, there is the Electron Pump (which won’t be long remembered).
The book is in 3 parts.  The discovery of the Election Pump,  the alien beings who have the para-universe’s complementary Proton Pump and  the discovery (by lunar-based scientists) that makes the Election Pump sustainable long-term. But the links between these 3 parts is quite tenuous – they easily could have been three completely separate short stories. The alien para-universe aliens were most interesting as Asimov describes them as being triad family units – as opposed to our human dual family units (i.e., mother-father).
Still, there was little tension, little excitement and little mystery to go with the Sci-Fi concepts.