Electricity Generation and Delivery

The average age of large power transformers (LPTs) currently operating in the U.S is 40 years, with 70% older than 25 years. Insulation failure contributes to more than 60% of LPT failures, costing the U.S. over $18 billion annually. To improve transformer life, GE Research will develop a long-term stable nanofluid dielectric to double the service life of current LPTs to at least 80 years. GE’s TiO2-based nanofluid will replace the conventional transformer insulating fluid and is expected to improve thermal conductivity by >25% and enhance dielectric strength by at least 50%.

To make the power density of electric aircraft closer to conventional aircraft, an electric power system (EPS) with high power delivery and low system mass is necessary. As an essential component of aircraft EPS, cables are necessary to transmit power from one node to another. Virginia Tech will develop a high-power density, cost-effective ±5 kV cable for twin-aisle all-electric aircraft.

Fault protection must be provided for future turboelectric aircraft’s medium-voltage direct current power systems, but not necessarily from conventional circuit breakers. Illinois Institute of Technology will develop a 10 kV/150A superconducting momentary circuit interrupter (SMCI) to provide fault protection with ultralow power loss (<1 W), ultrafast response (<10 μs or ten millionth of a second), and high-power density. The architecture comprises an SMCI with a fast mechanical disconnect switch.

GE Research will develop a safe, lightweight, and altitude-capable megawatt power cable system with electromagnetic interference shielding capability for large aircraft. The proposed 10 MW cable system is expected to achieve ten times greater power density than conventional technology without degradation by partial discharge and is fire safe and oil resistant.

There are two key engineering challenges in the development of 10 kV, 10 MW electric power distribution cables for double-aisle passenger aircraft. One is providing sufficient electrical insulation at high voltages and the second is transferring heat away from the conductors.

Fusion power plants will need efficient, high-power electrical drivers for plasma heating, compression, and control. Wide-bandgap (WBG) semiconductor devices and innovative amplifiers may speed up the development of high-power fusion systems and reduce their eventual levelized cost of electricity. Princeton Fusion Systems will develop integrated, power-dense, reliable, and scalable power amplifier boards for plasma heating and control applications using WBG silicon carbide devices and employ advanced cooling. Individual boards will be capable of delivering more than 10 kW of power.

Robust, affordable, and durable plasma-facing components (PFCs) are key to commercial fusion energy. PFCs must maintain the capability to handle the extreme heat, high-density plasma, high-energy neutrons, and fuel cycling in safe and economical operation. So far, a solution does not exist. Solid PFCs with a tungsten (W) armor, helium (He) cooling, and reduced-activation steel structure may satisfy the demanding requirements.

Prototype burning-plasma magnetic-fusion devices must operate at long pulse lengths to support power generation, making them susceptible to catastrophic disruption from plasma instabilities. Electron cyclotron heating and current drive powered by megawatt-level gyrotrons (vacuum electron devices that generate high-power, high-frequency radiation) are the most effective ways to heat and stabilize such plasmas. Megawatt-class gyrotrons are large, expensive to build and operate, inefficient, and have limited frequency and device lifetime.

Reduced-activation ferritic-martensitic (RAFM) steels are critical structural materials for fusion-energy subsystems such as integrated first-wall and blanket technology. Current RAFM steels cannot operate above ~550° C (1020° F). Castable nanostructured alloys (CNAs), recently developed at laboratory scale, can potentially achieve significantly higher temperatures, offering a pathway to more efficient operation, however. ORNL will establish a new class of RAFM steels based on carbide-strengthened CNAs to demonstrate industry-scale CNA production viability.

With significant improvement in high-temperature superconductors (HTS), several fusion projects are adopting HTS for high-field magnets. As compact fusion devices have less space for radiation shielding, HTS degradation is a potential design-limiting issue. There are currently no high-performance, compact shielding materials to enable the HTS technology in compact fusion devices. Stony Brook University seeks to improve the effectiveness and longevity of shield materials for HTS magnets.