Here is the David Criswell interview by Sander Olson. Dr. Criswell is an advocate of building solar power stations on the moon to generate solar power that can be beamed to the earth. Dr. Criswell believes that a series of solar power stations on the moon could be made from materials found in lunar regolith, and that these stations could continuously send electricity to earth. Such stations would only need to take up .2% of the lunar surface in order to meet the current energy needs of earth.
Question: How much continuous power does a sustainably prosperous Earth require?
Answer: Today Earth’s 6.7 billion people are provided an average of 225 2250 watts of thermal power per person. They need at least 6,000 to 7,000 watts of thermal power per person to enable the level of power consumption and prosperity achieved by the 1 billion people in the developed nations. The developed nations are slowly converting to consuming electric power. Electric power is approximately 3 times more economically productive than thermal power. Future power systems need to provide at least 2,000 watts of electric power per person to achieve the same or greater economic output as in the developed nations. This implies 20,000,000,000,000 watts of electric power for 10 billion people. In scientific notation the power is 20•10^12 watts-electric or 20 terawatts-electric.
Most commercial power is produced today by using fossil carbon and hydrocarbons fuels to consume the oxygen of Earth’s atmosphere. The fuels and oxygen are consumed and carbon dioxide, ashes, and acids that are released lead to greenhouse heating of the biosphere and the degradation of our air, land, fresh water, and oceans. We must have a non-carbon fuel source of electricity that eliminates the use of molecules of fuels and air to generate electricity within the biosphere. The Lunar Solar Power System does this by directly and dependably collecting solar energy in space and outputting pure electric energy on Earth.
Question: What aspect of the moon makes it so advantageous for power generation?
Answer: The sunward hemisphere of the Moon dependably receives 13,000 terawatts of solar power. Capturing only a few percent of that dependable solar power and delivering it consistently as low-intensity microwaves to Earth will enable sustainable global prosperity.
All of the main resources for power generation – reliable solar power, lunar real estate, and appropriate materials – are readily available on the moon. I have examined the concept of using modified phased-array radars to transmit electrical power, and found the concept viable. It is well demonstrated that microwave power can be converted back into electric power at 90% efficiency. My research shows that generating power from the moon is at least 50 times more cost efficient than competing approaches such as large solar arrays on Earth or solar power satellites deployed to orbit about the Earth either from the Earth or from the Moon.
Question: How much of the moon would need to be covered in solar cells to deliver 20 terawatts-electric (20 TWe) to Earth and how does that vary with the efficiency of the solar cells?
Answer: Lunar Solar Power bases that employ 1980s technology and 10% efficient solar cells that occupy on 10% of the area of a power base would occupy approximately 25% of the lunar surface. The energy can be reliably provided for less than 1 cent per kilowatt-hour. LSP System bases scaled to 2020s technology, with contiguous solar arrays (35% efficient), and solar mirrors in orbit about the Moon could occupy as little as 0.2% of the lunar surface.
Question: So 20 TWe could be delivered 24/7, with no energy storage requirements?
Answer: Yes, for 24/7 operation the LSP System uses power beam relay satellites around earth. These relay satellites will transfer multiple beams down to earth.
Question: Would even the very first lunar power station be constructed out of lunar soil?
Answer: All construction and operating systems will be demonstrated on Earth prior to the first deployment to the Moon. The first LSP base components would be made from the lunar soils. LSP construction is primarily a glass-making process. For instance, fiberglass coated with metal would provide the microwave reflectors. Glass housing would be made for microwave transmitters. These would be coated with iron or aluminum, which is found in regolith. The ultrathin sheets of silicon solar cells would be created using solar power. Soon after the production of electric power on the Moon approximately 90% of mass of the machines of production on the Moon could be made out of lunar regolith.
Question: How thoroughly has this concept been tested?
Answer: Adequate solar cell technology has been available for decades. The power transmission concept does not require new technological. It simply requires scale-up of existing technologies and proven concepts, such as radar. We’ve been sending radar beams to space for decades with ballistic missile defense radars and to the moon with planetary radars such as the one near Arecibo, Puerto Rico. The Arecibo beam passes through the lower ionosphere at 10% of the power level recommended for beaming commercial power to Earth.
Question: Is there any danger that all of the energy sent to earth would increase earth temperatures?
Answer: This LSP System is designed and operated to be thermally neutral. The rectennas that would receive the electricity can be 80% or more transparent to sunlight. The area below them could be painted white to reflect, averaged over a year, an equal flow of sunlight back into space. Each rectenna can be thermally neutral and not contribute excess thermal power to the biosphere.
Question: Have any studies been done specifically comparing the costs of lunar power generation with alternate power sources, such as solar or nuclear?
Answer: I’ve been doing studies since 1980 comparing the costs of power generation of lunar power with competing energy generation methods. Once the system is in place, lunar power generation is clearly more cost-effective than any other approach. It can be ramped up exponentially to provide electricity without having to move molecules within the biosphere. For more details see chapter 9 of Watts, R. G. (editor) (2002) “Innovative Energy Strategies for CO2 Stabilization” Cambridge University Press
Question: Some have argued that employing solar cells on only 2% of the Sahara desert could meet all of the earth’s electricity needs.
Answer: Two percent of the Sahara desert is approximately 0.2 million square kilometers. To provide worldwide 20 terawatts of terrestrial solar power would require global power lines between solar arrays located in all the major deserts, massive power storage facilities, and likely over 2 million square kilometers of solar arrays. Even this enormous system will experience power reductions due to weather and events like dust and smoke from volcanoes and regional fires. Realistic studies employing renewable technologies like wind and solar to provide 20 terawatts of electric power require similar enormous areas and will be extremely expensive. In comparison, the LSP System rectennas can output 20 TWe from 0.1 million square kilometers of land. The LSP electric power will not require the massive global power lines or power storage facilities.
Question: The costs of establishing such a solar-power infrastructure on Earth would be tiny compared to the costs of establishing a lunar infrastructure.
Answer: Renewable systems on Earth are expensive compared to coal and natural gas even though they provide only a fraction of the total commercial energy consumed in a given large region. As they are scaled up beyond 20% of local power production to be the dominant source of commercial power the cost of delivering dependable electric energy rapidly increases. That is why the installation of new wind or solar facilities stops when government subsidies are eliminated.
The world now spends over 300 billion dollars a year on oil exploration and development to maintain the global production of 85 million barrels of oil per day. The global oil industry would have to produce 1,000 million barrels of oil per day to generate 20 TWe. That will never happen. About 2 years of the global oil production cost would cover the cost of implementing the LSP System and bringing it to economic breakeven. Thereafter the LSP System would grow exponentially to provide the 20 TWe, or much more if needed. Its growth would be paid from selling the electric power on Earth. Operating costs will decrease as more electric energy is delivered to Earth. There aren’t weather or clouds on the moon, so the equipment will last longer and operate more safely and reliably than similar facilities on Earth. Moreover, no energy storage facilities would be needed on the moon, since all of the electricity would be immediately sent to earth.
Your readers can email me for a recent overview paper, Enabling Sustainable & Rapidly Growing Global Wealth by Implementing the Lunar Solar Power System, that was presented in Beijing, China late May at the IAF Global Lunar Utilization Conference. [ [email protected] ]
Question: What is your background and how long have you been studying the concept of deriving power from the moon?
Answer: I obtained my PhD in space physics and astronomy from Rice University back in the 1960s. I worked for TRW in the 1968-1970 during the peak of the Apollo program and during the 1970s I worked at the Lunar Science Institute near the Johnson Space Center. I administrated the review of the first 3,500 proposals submitted to NASA for studies of the Moon and conducted research on lunar dust motion driven by electric fields and several other topics. In the mid 1970s I became intrigued by the concept of developing materials industries on the Moon and space-based commercial solar power. I also began collaborating with Gerard O’Neill at Princeton University and a NASA grant to study the conversion of the common lunar materials into industrial feedstocks.
Dr. Robert Waldron (deceased) and I developed the LSP System concept toward the end of the joint NASA-Department of Energy studies on space solar power satellites deployed from Earth. We asked ourselves a simple question. Why build satellites in space? The Moon exists. It is much larger than any satellite that humans could build and we knew that it had the right materials and environment to build solar collectors. I have been studying and promoting the Lunar Solar Power System concept ever since.