A new system developed at MIT can harness temperature fluctuations to produce electricity. The new “thermal resonator” system could, for example, enable continuous, years-long operation of remote sensing systems without requiring other power sources or batteries, the researchers say. The device does not need direct sunlight. It generates energy from ambient temperature changes, even in shade. A test produced 1.3 mW of power from a 10°C (18°F) temperature change.