With the introduction of renewable sources, energy grids have evolved to be able to adapt to changes in production and demand almost instantly. In addition, traditional centralized production is now complemented with edge production where consumers  become providers of energy to the grid. For the fluctuations to be managed with precision, data need to be collected from meters, meteorology stations, solar panels, etc. then processed by computers to  finally dispatch orders all along the grid and even to the consumers.
Fast and reliable communication technologies are required to maintain  this connectivity.
Today LTE poses as the best radio technology for  communication in smart grid thanks to its ultra-low latency and the fact that it already has a network which is ubiquitous, reliable and secure.