A power plant configured for converting thermal energy to electricity includes a source of thermal energy provided by a temperature difference between a primary fluid having a first temperature and a secondary fluid having a second temperature that is different from the first temperature. The plant also includes a collector configured for enhancing the temperature difference between the primary and secondary fluids, and a heat engine configured for converting at least some thermal energy to mechanical energy. The heat engine includes a pseudoplastically pre-strained shape-memory alloy disposed in heat exchange relationship with each of the primary and secondary fluids. Further, the plant includes a generator driven by the heat engine and configured for converting mechanical energy to electricity. A method of utilizing a naturally-occurring temperature difference between air and/or water to change a crystallographic phase of the shape-memory alloy to convert the temperature difference into mechanical energy is disclosed.