Tapping into the Sun's power and beaming it down to an energy-hungry planet is an idea that has been around for decades. Now, amid stark predictions that even the most renewable energy resources will be insufficient to sustain the Earth's population later this century, serious attention is beginning to be paid to how such grandiose schemes can be turned into reality.

Ambitious plans for one such internationally developed Space Solar Power (SSP) system to provide energy on a global scale by the middle of the century has been unveiled by a space pioneer, humanitarian and former president of India, Abdul Kalam. A long-time champion of space-based solar power, Kalam says first steps will include the establishment of a “world space knowledge platform” under which specialists from the U.S., India and other spacefaring nations will join forces to develop a “societal” SSP mission.

“This World Space Knowledge Platform, which is to be an International Virtual Laboratory, will take the form of a coalition of leading academic institutions in space and energy science and technology, [with] one or two in each of the partner nations. Guided and coordinated by the World Space Knowledge Platform's International Advisory Committee, they would be directed toward bringing out an International Feasibility Study for SSP,” says Kalam.

The study will be conducted by teams from a minimum of 10 nations interacting with an international “virtual laboratory” which should be funded “as a cooperative venture” costing $4 billion over five years, says Kalam. Unveiling the plan at the U.S. National Space Society's International Space Development conference where he received the Werner von Braun memorial award, Kalam says the target is to brief the feasibility study to upcoming summit meetings of the G8 and G20 nations.

The process will begin with the creation of a 20-page research document for “marketing” the benefit of the SSP concept to the spacefaring nations.

The initiative has been welcomed by other groups, such as the U.S.-based non-profit Space Solar Power Institute (SSPI). The group's executive director, Darel Preble, says: “Our government certainly should look more seriously at the proper pathway for America's energy policy toward Space Solar Power. There has been too little deep consideration about how to take advantage of SSP, our greatest clean baseload (24/7) energy source.”

However, while welcoming the spirit of the initiative, the institute criticizes the fiscal side of the plan. “It lacked money, but more importantly it lacked the necessary business perspective,” says Preble. “To create a viable SSP business is very different than sending a satellite to the Moon for science. It is instead like sending a satellite to orbit for a real-world business venture, such as a communications satellite. This is the only perspective that can create a functioning business.”

Preble cites the formation in Japan of a public-private SSP development project as a better way to proceed along the lines of the Comsat Corp. created by the U.S. Congress in 1962 to help kick-start the satcom market. “We also should now charter another public/private corporation—to develop a power satellite industry to transfer our energy dependency away from fossil fuels directly to the Sun itself. This will happen, the only question is who will develop it first.”

However Kalam, who outlined a five-point action plan for the first phase, proposes that the participating academic institutions from each partner nation will be “sufficiently funded by world governments and industries. In their turn, academic institutions would fund and coordinate subscale technology demos of SSP and reusable launch vehicles on the ground, in the air and in space.”

Each of the nations involved in the feasibility study will focus on “clearly defined missions.” The virtual lab will help steer the development of an integrated design, which will include the best use of reusable launch vehicles for low-cost access to space, and the optimized design for transmitting SSP to the Earth's surface.

Focus areas will include comparisons on various single- and two-stage-to-orbit reusable launch concepts under study in China, India, Japan, Russia, U.K., U.S. and some other European nations. Others will concentrate on answering energy-transfer-related technology questions over advanced photovoltaic systems and microwave transmission concepts.

“There are choices for Space Solar Power wireless transmission including microwave, millimeter wave (W band), Laser Wave or “Nano Energy packs,” and Visible sunlight deflection through the space-mirror approach. In three years, the Virtual Laboratory for Space Solar Power can bring an optimum, workable and possible solution, particularly for transportation of Space Solar Power to terrestrial stations,” Kalam adds.

Recognizing that technology is only part of the battle, the plan also includes a parallel track devoted to developing policy and political guidance, which will be needed if the SSP concept is to stand a chance of becoming a reality. An advisory committee, working with the virtual lab, will help craft the beginnings of a policy document.

The overall notion of space solar power, Kalam says, is “scalable, safe and global, provides continuous power and needs no fundamental breakthroughs in technology.” He adds that the scale of the SSP project will have spin-off benefits, triggering the “industrialization” of space and building a robust infrastructure for access to low and geostationary Earth orbit that will benefit other projects such as asteroid and Lunar mining, as well as exploration.

Kalam floated his concept six months after China proposed a joint agreement with India over collaboration on an SSP project. Last November, officials from the Indian Space Research Organization confirmed that, following the approach from the China Academy of Space Technology, they would explore the potential of a joint venture with India and the country's Defense Research and Development Organization.

Although the idea of SSP has been studied for more than 20 years in some countries, Kalam says the insatiable energy demands of the world's growing population, added to the increasing cost of fossil-fuel exploitation, mean that the time is ripe for action. The world's population, which passed the 6 billion mark in 2007, is forecast to grow to 8 billion by 2025—56% of which will be in Asia. By 2075, the population is expected to reach 11 billion. “Clearly our planet has to be livable before it can be prosperous, and it must be both livable and prosperous before it can be peaceful,” says Kalam, who adds: “There can be no greater mission for space collaboration. I believe that is the driving force that builds a livable planet.”

While population growth in Asia and elsewhere is expected to outstrip that of the U.S., the energy requirements of the nation will still climb by 75% if the population doubles beyond today's tally to an estimated 625 million by 2100, says Mike Snead, president of the Spacefaring Institute.

Speaking via video at the conference, Snead says that—measured in energy terms of BOEs (barrel of oil equivalent)—the U.S. consumed around 1 trillion BOEs in 2010 versus 18 billion in 1850. Although energy use per capita has fallen from a peak of 62 BOEs in 1979, the rate of use has dropped only 6% since 1980 and a decline to around only 50 BOEs per capita is predicted through the end of the century. On this basis, Snead says the U.S. will need 2.25 trillion BOEs cumulatively by the end of the century. “That's twice all that has been used over the past 150 years. How much longer should we expect this use of non-sustainable energy sources to be rationale and efficient?”

Around 1.4 trillion BOEs of fossil fuels is projected to be affordably recovered over the rest of the century. This means the U.S. “will still fall substantially short of reaching 2100 with an adequate energy margin.” Although a sizable hydrocarbon energy industry will remain by this time, Snead says, “clearly the era of fossil fuel is ending in U.S.” To meet the shortfall, he says 6,600 1-gigawatt nuclear powerplants would be required, each costing around $10 billion. “The U.S. must pragmatically look at other sources to replace fossil fuels.”

Ground solar energy and wind turbines are both subject to daily and seasonal cycles, and are limited in growth, Snead adds. To meet the energy shortfall there would need to be wind turbines covering more than 1 million sq. mi. of the U.S., or more than 500,000 sq. mi. of solar panels on the ground.

In contrast, Snead estimates an array of space-based solar-power satellites positioned in GEO would require about 1.7 sq. mi. of solar-collector area to deliver 1 gigawatt. To meet the projected energy shortfall in 2100, he says, more than 11,220 sq. mi. of collectors will be needed in orbit, and a further 53,000 sq. mi. of solar-panel collectors on the ground.