Nowadays especially with the libraries the hardware requirements are quite moderate again, but they depend not so much on "openLCA" but on the databases you plan to use, as openLCA can handle many different databases with even 30,000 connected processes in one system. 32 GB RAM are good if you have big systems, a modern processor is also good, but if you do not have a laptop that is older than 8 or so years, and if you have a 64 bit system, then you should be good.