Virtus Solis Space Based Solar and Power Beaming White Paper 2023

Introduction

The path to clean energy is not clear. Nuclear fission is proven and supplies firm power, but regulation and waste disposal limit deployment. Fusion is advancing but is not yet practical. Options like hydro and geothermal offer clean and firm power but are limited in location and total capacity. Scalable options like wind and solar require large amounts of land and only supply power intermittently. The power output varies by the day and by the season. Adapting this intermittent power generation to the grid requires massive amounts of energy storage and expanded transmission networks. While the costs for wind and solar power generation continue to drop, the systemic costs in the grid alone are expected to triple[1]. The benefits of a clean energy transition are limited by these costs and the pace needed to upgrade the grid.

However, clean energy can be generated without the limitations of terrestrial renewables. More than 100 years ago, Konstantin Tsiolkovsky made the first proposal for space based solar power. Since then, dozens of detailed designs have appeared. All these designs consist of a satellite in orbit and a receiver on the ground. The satellite converts uninterrupted sunlight into radio frequency (RF) power that is wirelessly sent to the receiver. The receiver converts the RF energy into electricity and delivers power to the electric grid. This approach can supply clean, firm, renewable energy.

Figure 1 - Space Based Solar Power (SBSP) System

The concept of Space-Based Solar Power (SBSP) was scientifically validated during the 1960s through wireless power transfer demonstrations. With appropriately sized antennas, it is possible to transmit power with almost 100% efficiency. Although the technology needed for its implementation has been accessible since the 1970s, practical viability was hindered until recently. This was primarily due to the high cost of launching materials into space and the low efficiency of solar cells.

Unlike ground-based solar power plants, which are constrained by factors such as weather conditions, seasonal changes, nighttime, and atmospheric interference, solar power satellites have the potential to generate significantly more energy. In fact, for equivalent area on the ground, SBSP energy production is six times better than the best terrestrial solar plants and can generate 100 times more energy than solar plants located at higher latitudes. This remarkable advantage stems from the higher intensity and the continuous exposure to sunlight that satellites enjoy in space. Additionally, SBSP can deliver power without wires to where demand is located. Since wireless power transmission is used to move power from orbit to a receiver, satellites can easily dispatch power between multiple locations with no added transmission or distribution lines. The result is that SBSP can deliver power anywhere at lower cost than any other source without the need for massive transmission build out or long-term storage.

Figure 2 - Comparative Costs of Different Power Sources

Implementation

Virtus Solis is developing the world’s first commercial Space Based Solar Power (SBSP) system to address the world’s need for economical, carbon-free energy. Our architecture relies on the continuing trend of decreasing launch costs. It is based on simple arrays of individual satellite tiles placed in Molniya orbits (Figure 3). Two such satellite arrays can supply power 90% of the time at a given site; three can supply 100% redundantly. A constellation of 16 satellite arrays can provide 24/7 redundant power anywhere on Earth.

The simplicity of the Virtus Solis architecture results in higher reliability, lower mass, and lower launch costs compared to competitive approaches. Our approach is innovative and highly scalable. Unlike other proposed SBSP systems, our architecture supports arrays capable of scaling from 100 megawatts (MW) to 20 gigawatts (GW). With the use of phased-array antennas (PAAs), multiple ground stations can simultaneously receive power. More arrays can be added to the constellation as needed to meet demand and increase redundancy. The system capacity can scale up by gigawatts annually.

Each satellite tile (Figure 4) is a hexagon 1.65 meters across. Each tile is monolithic with no moving parts. One face has solar cells that collect power. The other face features the antennas of a PAA which beams energy to the ground. Between the two sides are power electronics and thermal management elements. Features allowing interconnection to other tiles appear on each side of the hexagon (Figure 5). Each tile incorporates computing and communications resources to support peer-to-peer management and an algorithm that configures the satellite transmitters into a massive PAA that can target any ground station positioning.

Power will be transferred from orbit to ground stations using 10GHz RF electromagnetic wave via PAAs. Virtus Solis developed accurate RF simulation capabilities that allow modeling billions of individual antennas. We have built wireless power transfer demo systems of increasing complexity; in March of this year, we controlled 6,400 transmit antennas via software with beam steering and transferred 68W across 100 meters (Figure 6).

Summary

The world needs a clean, inexpensive, and reliable source of baseload energy as soon as possible to address many concerns. Fossil fuels continue to supply roughly 80% of today’s roughly $8 trillion total energy supply. This major source of pollution increases atmospheric carbon, increasing greenhouse capture and acidifying oceans. Fossil fuels are finite and must eventually be replaced. Fluctuation in prices hit those least able to pay. Fossil fuel replacements have significant limitations. Nuclear power is clean and reliable but too expensive to build – the last US reactors took seventeen years to build and cost over $35 billion (Plant Vogtle Units 3&4). Terrestrial solar is intermittent – it is unavailable at night and when cloudy and is at its lowest output during winter when energy demands are highest. (In Germany, solar power runs at a capacity factor below 3% during winter.) Finally, the living standard for much of the developing world is well below the Western standard and affordable energy is the key to improvement.

SBSP can deliver the firm, clean, renewable energy needed to make a significant impact on the world’s energy supply. It is achievable today. The Virtus Solis solution builds on 50 years of prior developments in launch, solar, and robotics. It can reduce the cost of electricity while eliminating the need for massive investments in storage and infrastructure.

[1] BloombergNEF (2023, March 8). A Power Grid Long Enough to Reach the Sun Is Key to the Climate Fight. Www.Bnef.com. Retrieved August 19, 2023, from https://about.bnef.com/blog/a-power-grid-long-enough-to-reach-the-sun-is-key-to-the-climate-fight