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SoPhAr: Solar Phased-Arrays to boost the range of electric, hydrogen and SAF airliners in a solar world

Christian Claudel

TL;DR

Decarbonizing international aviation remains challenging due to economics and scalability of SAF/e-fuels, hydrogen, and battery options. The paper proposes a ground-based energy-beaming concept using solar farms that host microwave emitters to form large phased arrays, delivering propulsion power to aircraft for turbo-electric or fuel-cell propulsion without onboard energy storage. It provides a concept design of 1 km-aperture solar farms with RF/solar tiles, beamforming capabilities, and quantitative safety/economic analyses, including surface exposure below 100 W/m^2, costs around 100 $/m^2 for RF layers, solar costs near 24 $/MWh, potential 36 $/MWh at scale, and end-to-end efficiencies up to 54%. With projected solar capacity growth to around 1600 GW by 2050, this beam-powered approach could substantially reduce aviation fuel burn and extend aircraft range while avoiding major aircraft redesigns.

Abstract

In late 2022, ICAO member states adopted a long-term global aspirational goal (LTAG) to achieve net zero carbon emissions from international aviation by 2050. To date however, no economically scalable solution to the aviation decarbonization problem has been proposed. Despite considerable research on potential alternative fuels including e-fuels, Sustainable Aviation Fuel (SAF), Hydrogen or Ammonia, and extensive research on purely electric propulsion, low-carbon propulsion methods are unable to replace fossil-fuels with identical or better economics. A possible alternative to current propulsion technologies is to directly beam the required propulsive power to aircraft. Several techniques have been considered to date, in particular laser energy beaming and microwave energy beaming. This paper proposes a possible concept where future airliners are mostly powered with ground-generated power. With expected improvements and scaling in solar panel manufacturing, the proposed concept would be economically competitive even with current jet fuel prices, while considerably reducing CO2 emissions.

SoPhAr: Solar Phased-Arrays to boost the range of electric, hydrogen and SAF airliners in a solar world

TL;DR

Decarbonizing international aviation remains challenging due to economics and scalability of SAF/e-fuels, hydrogen, and battery options. The paper proposes a ground-based energy-beaming concept using solar farms that host microwave emitters to form large phased arrays, delivering propulsion power to aircraft for turbo-electric or fuel-cell propulsion without onboard energy storage. It provides a concept design of 1 km-aperture solar farms with RF/solar tiles, beamforming capabilities, and quantitative safety/economic analyses, including surface exposure below 100 W/m^2, costs around 100 /MWh, potential 36 $/MWh at scale, and end-to-end efficiencies up to 54%. With projected solar capacity growth to around 1600 GW by 2050, this beam-powered approach could substantially reduce aviation fuel burn and extend aircraft range while avoiding major aircraft redesigns.

Abstract

In late 2022, ICAO member states adopted a long-term global aspirational goal (LTAG) to achieve net zero carbon emissions from international aviation by 2050. To date however, no economically scalable solution to the aviation decarbonization problem has been proposed. Despite considerable research on potential alternative fuels including e-fuels, Sustainable Aviation Fuel (SAF), Hydrogen or Ammonia, and extensive research on purely electric propulsion, low-carbon propulsion methods are unable to replace fossil-fuels with identical or better economics. A possible alternative to current propulsion technologies is to directly beam the required propulsive power to aircraft. Several techniques have been considered to date, in particular laser energy beaming and microwave energy beaming. This paper proposes a possible concept where future airliners are mostly powered with ground-generated power. With expected improvements and scaling in solar panel manufacturing, the proposed concept would be economically competitive even with current jet fuel prices, while considerably reducing CO2 emissions.
Paper Structure (11 sections, 5 figures)

This paper contains 11 sections, 5 figures.

Table of Contents

  1. Introduction
  2. Aviation in the context of the energy transition
  3. Energy beamimg: solar farms as phased arrays
  4. Phased arrays
  5. Physical considerations
  6. Safety and economics
  7. Safety
  8. Economics
  9. Power reception
  10. Conclusion
  11. Acknowledgements

Figures (5)

  • Figure 1: Locations of solar farms with capacity exceeding 20MW as of November 2023 (Source: USGS)
  • Figure 2: Ground mounted 100 MW solar farm (Credit: Erthos)
  • Figure 3: Simulation of wave propagation from a phased array, focusing at a particular (controllable) point in space (source: Mathworks)
  • Figure 4: Illustration of energy beaming from an array of PV-RF tiles using beamforming. Energy is beamed to a turbo electric airliner.
  • Figure 5: Potential receiver locations for an Airbus A320 (orange areas).