The TUPPERWAVE PTO concept for Oscillating Water Column (OWC) generates a unidirectional air flow which can be converted into electricity via a conventional high efficiency unidirectional turbine. In order to assess the relevance of the Tupperwave PTO, the Tupperwave device is compared with a conventional OWC using the same spar structure and equipped with a state-of-the-art self-rectifying turbine. Wave-to-wire numerical models were developed for the two devices. The thermodynamics of the models take into account the energy conservation law, turbine heat losses and heat exchanges through the devices walls. Simulations show that the temperature rise of the enclosed air in the Tupperwave device does not represent a risk to the device working principle. The devices electrical power performances over a year were assessed and compared in terms of energy production and power quality in the wave climate of the EMEC wave-energy site. The Tupperwave device produces more electrical power than the conventional OWC and with a greater power quality.