There's a reason Curiosity's fancy new Multi-Mission Radioisotope Thermoelectric Generator isn't going to be installed until just days before launch. It's radioactive, powered by a special form of plutonium dioxide that won't be rendered useless by the red planet's dust issues.
In this video, Ashwin Vasavada, the Deputy Project Scientist for NASA's Mars Science Laboratory, explains how issues with Spirit and Opportunity's dust covered solar panels led to the larger and heavier Curiosity rover being outfitted with an MMRTG power source, which harnesses heat from the natural decay of plutonium dioxide. The heat is then turned into 110 watts of continuous electrical power through a set of thermocouples, keeping the rover, and its 75kg of scientific instrumentation, warm and powered for up to two years. [NASA via Coudal]