Some people, jocularly or otherwise, suggest that potato batteries could be used to produce significant amounts of electrical power, if you had enough potatoes.
Making potato batteries can be a fun sciencey activity for kids but the output doesn’t represent a net useful energy production. The key to the reaction is not the potato (which really is just a convenient holder of electrolytes) but the reactions happening at the metal electrodes. We only have copper or zinc etc because of energy expended in winning the metals from low-enthalpy ores.