Oda seems to be orienting himself to the real world again, because "free energy" is also suppressed here. By free energy is meant another type of energy that has different names, such as zero-point energy or vacuum energy. In 2012, MIT proved that a light-emitting diode gave off more energy than it was fed into ("Thermoelectrically Pumped Light-Emitting Diodes Operating above Unity Efficiency"). The Casimir effect, which causes a force to act on two parallel, conductive plates in a vacuum that presses them together, was experimentally proven as early as 1958.
The only question is whether it is possible to construct a machine that uses this energy. In fact, numerous researchers have claimed so. A well-known example was Eugene Mallove, who became persona non grata when he announced that cold fusion research would be suppressed.