26 October 2021
Wolfspeed and Biophysical Economics Institute demonstrate SiC’s superiority for energy efficiency
Wolfspeed Inc of Durham, NC, USA and the Biophysical Economics Institute (BPEI), a non-profit multidisciplinary organization dedicated to bringing the natural sciences into economic analysis and decision making, have completed a study that demonstrates the superior performance of silicon carbide (SiC) versus traditional silicon semiconductor devices in electric cars. When SiC is used in the powertrain of an electric vehicle (EV), it delivers a 13:1 energy saving versus the incremental energy invested compared with traditional silicon chips. This significant energy conservation allows for longer range, lighter weight and faster charging – all of which foster lower long-term energy usage and enhanced environmental sustainability.
Led by BPEI partner Hedgerow Analysis LLC, the study uses BPEI’s proprietary ‘Energy Saved on Energy Invested’ (ESOI) metric, which allows for an apples-to-apples comparison of energy efficiency across applications and industries, taking into account the long lifespan of many advanced technologies. This analysis quantifies the energy saved over an equipment’s life cycle versus the incremental energy used in its production – with SiC as an illustrative use case. As a concept based in the natural sciences, ESOI offers corporations, industry organizations and non-profit groups an objective standard, based on measurable energy and material flows, for evaluating the energy efficiency of any technology.
“These methods represent a reliable, rigorous metric to quantify environmental, social and governance benefits,” says Dr Charlie Hall, BPEI board member & co-chair, advisory board. “ESOI-anchored decision making allows us to maximize the potential of our precious natural resources, paving the way for a more effective energy transition.”
Key findings of the study include:
- Replacing silicon insulated-gate bipolar transistors (IGBTs) with silicon carbide metal-oxide-semiconductor field-effect transistors (MOSFETs) produces substantial energy savings for electric vehicles.
- The lifetime energy savings from employing SiC MOSFETs are many times the incremental energy required to produce these devices.
- The ESOI for 400V vehicles is about 7:1 versus a typical EV sedan (400V SiC MOSFET versus 400V silicon IGBT).
- The ESOI of an 800V SiC implementation in an EV sedan is 13:1 (800V SiC MOSFET versus 400V silicon IGBT) – an 85% increase versus the 400V SiC MOSFET, due to reduced chip surface area and corresponding energy invested.
- The ESOI gain is greater for fleet vehicles, such as taxis and delivery vans, with higher duty cycles.
- This analysis underscores the potential for large fuel savings based on intelligent location of manufacturing hubs. Wolfspeed’s operations in upstate New York, which offers ample clean energy via hydroelectric power, has the potential to substantially increase the ESOI of this technology.
“We believe the next generation in power semiconductor technology will be driven by silicon carbide,” says Wolfspeed’s chief technology officer John Palmour. “These study results reinforce the superiority of silicon carbide and the direct impact a more energy-efficient technology has on the reduction of carbon emissions, which has a positive impact on the environment,” he adds. “As the world shifts to a more sustainable future, it will need efficient materials to power it.”