The search for a new, safe and stable renewable energy source led to the idea of building a power station in space which transmits electricity to Earth. The concept of Solar Power Satellites (SPS) was invented by Glaser in 1968. SPS converts solar energy into microwaves and transmit it to a receiving
antenna on Earth for conversion to electric power. The key technology needed to enable the future feasibility of SPS is Microwave Power Transmission. SPS would be a massive structure with an area of about 56 sq. and would, weigh about 30,000 to 50,000 metric ton. Estimated cost is about $74 billion and would take about 30 years for its construction. In order to reduce the projected cost of a SPS suggestions are made to employ extra terrestrialresources for its construction. This reduces the transportation requirements of such a massive structure. However the realization of SPS concept holds great promises for solving energy crisis.
Table of Contents
1. INTRODUCTION
2. WHY SPS
3. SPS-A GENERAL IDEA
4. WIRELESS POWER TRANSMISSION
5. MICROWAVE POWER TRANSMISSION IN SPS
5.1 TRANSMITTER
5.1.1 Klystron
6. BEAM CONTROL
7. RECTENNA
8. RECENTLY DEVELOPED MPT SYSTEMS
9. CONSTRUCTION OF SPS FROM NON TERRESTRIAL MATERIALS: FEASIBILITY AND ECONOMICS
10. MICROWAVES-ENVIRONMENTAL ISSUES
11. ADVANTAGES AND DISADVANTAGES
12. CONCLUSION
Research Objectives and Core Topics
The primary objective of this work is to evaluate the feasibility of Solar Power Satellites (SPS) as a sustainable and stable energy solution, focusing specifically on Microwave Power Transmission (WPT) as the enabling technology for space-to-ground energy delivery to address the global energy crisis.
- Technical conceptualization of Solar Power Satellites in geosynchronous orbit.
- Principles and components of Microwave Power Transmission (WPT).
- Design requirements for transmitter and rectenna systems.
- Economic and feasibility analysis of constructing SPS using extra-terrestrial resources.
- Environmental and health considerations regarding microwave exposure.
Excerpt from the Book
SPS-A GENERAL IDEA
Solar Power Satellites would be located in the geosynchronous orbit.The difference between existing satellites and SPS is that an SPS would generate more power-much more power than it requires for its own operation. The solar energy collected by an SPS would be converted into electricity, then into microwaves. The microwaves would be beamed to the Earth’s surface, where they would be received and converted back into electricity by a large array of devices known as rectifying antenna or rectenna.(Rectification is the process by which alternating electrical current ,such as that induced by a microwave beam , is converted to direct current). This direct current can then be converted to 50 or 60 Hz alternating current [4]. Each SPS would have been massive; measuring 10.5 km long and 5.3 km wide or with an average area of 56 sq.km.The surface of each satellite would have been covered with 400 million solar cells. The transmitting antenna on the satellite would have been about 1 km in diameter and the receiving antenna on the Earth’s surface would have been about 10 km in diameter [5].The SPS would weigh more than 50,000 tons. The reason that the SPS must be so large has to do with the physics of power beaming. The smaller the transmitter array, the larger the angle of divergence of the transmitted beam. A highly divergent beam will spread out over a large area, and may be too weak to activate the rectenna.In order to obtain a sufficiently concentrated beam; a great deal of power must be collected and fed into a large transmitter array.
Summary of Chapters
INTRODUCTION: Provides an overview of the rising global demand for renewable energy and the historical development of the Solar Power Satellite concept.
WHY SPS: Discusses the limitations of ground-based renewable sources and the environmental benefits of collecting solar energy in space.
SPS-A GENERAL IDEA: Describes the physical structure and operational concept of SPS in geosynchronous orbit, including power generation and beam transmission principles.
WIRELESS POWER TRANSMISSION: Introduces the concept of transmitting electrical energy without physical wires using microwave beams.
MICROWAVE POWER TRANSMISSION IN SPS: Details the technical requirements for converting DC to RF power, including the function of transmitters and klystrons.
BEAM CONTROL: Explains the mechanism of retro-directive systems for ensuring accurate and safe beam pointing.
RECTENNA: Outlines the design and function of the rectifying antenna used to convert microwaves back into electricity at the ground site.
RECENTLY DEVELOPED MPT SYSTEMS: Reviews prototype models like SPORTS and SPRITZ that demonstrate the viability of power transmission in space.
CONSTRUCTION OF SPS FROM NON TERRESTRIAL MATERIALS: FEASIBILITY AND ECONOMICS: Analyzes the potential for cost reduction by utilizing materials found on the Moon or asteroids for space construction.
MICROWAVES-ENVIRONMENTAL ISSUES: Addresses potential public and environmental concerns regarding microwave exposure and large-scale infrastructure.
ADVANTAGES AND DISADVANTAGES: Compares the benefits of space-based solar power against the challenges of deployment and technological complexity.
CONCLUSION: Summarizes the future prospects of SPS technology and the necessity of further engineering developments to overcome current hurdles.
Keywords
Solar Power Satellites, SPS, Microwave Power Transmission, WPT, Rectenna, Geosynchronous orbit, Renewable energy, Power beaming, Retro-directive, Magnetron, Klystron, Space-based power, Wireless energy, Phased array, Energy crisis
Frequently Asked Questions
What is the core focus of this research paper?
The paper focuses on the feasibility of Solar Power Satellites (SPS) as a long-term solution for the global energy crisis, specifically emphasizing Microwave Power Transmission as the core technology.
What are the primary thematic areas covered?
The main themes include satellite system design, wireless energy transfer, microwave physics, construction economics using extra-terrestrial materials, and environmental safety assessments.
What is the ultimate research objective?
The objective is to validate the technical and economic potential of collecting solar energy in space and beaming it to Earth to provide a continuous, high-capacity power source.
Which scientific methods are discussed for power transmission?
The work discusses the conversion of solar energy into microwaves, the use of phased array antennas, retro-directive beam control, and the rectification process via rectennas to convert microwaves back to DC power.
What topics are explored in the main body?
The main body covers the conceptual design of SPS, the physics of klystrons and magnetrons, antenna array configurations, beam safety protocols, and the use of lunar materials for construction.
How are the key aspects of the paper summarized?
The work is characterized by its focus on "space-to-ground energy transfer," "microwave beams," "renewable energy sustainability," and "technological feasibility."
How does the author propose to reduce the immense costs of constructing SPS?
The author suggests employing extra-terrestrial resources (such as lunar oxygen, silicon, and aluminum) and utilizing mass drivers to transport materials to orbit, thereby avoiding the high costs of rocket-based transport from Earth.
What is the role of the retro-directive system in the SPS design?
The retro-directive system provides a critical safety and control mechanism that ensures the microwave beam is accurately pointed at the receiving rectenna, minimizing environmental impact and power dispersion.
Why is 2.45 GHz considered the optimal frequency for WPT?
This frequency is preferred because it lies within the ISM band, allows for low-cost power components, and experiences extremely low atmospheric attenuation.
- Citation du texte
- Amit Sachan (Auteur), Preeti Sachan (Auteur), 2013, Microwave Power Transmission as a Future Feasibilty of Solar Power Satellite, Munich, GRIN Verlag, https://www.grin.com/document/213239
