Satellites harnessing solar winds can meet world’s energy needs100bn times overSaturday, September 25, 2010 4:00:32 PM by ANI ( Leave a comment )
London, Sep 25 (ANI): Bid adieu to wind power or conventional solar power, for scientists have suggested that the world’s energy needs could be met 100 billion times over using a satellite to harness the solar wind and beam the energy to Earth - though focussing the beam could be tricky.
The concept for the so-called Dyson-Harrop satellite begins with a long metal wire loop pointed at the sun.
This wire is charged to generate a cylindrical magnetic field that snags the electrons that make up half the solar wind.
These electrons get funnelled into a metal spherical receiver to produce a current, which generates the wire’s magnetic field - making the system self-sustaining.
Any current not needed for the magnetic field powers an infrared laser trained on satellite dishes back on Earth, designed to collect the energy.
Air is transparent to infrared so Earth’s atmosphere won’t suck up energy from the beam before it reaches the ground.
Back on the satellite, the current has been drained of its electrical energy by the laser - the electrons fall onto a ring-shaped sail, where incoming sunlight can re-energise them enough to keep the satellite in orbit around the sun.
A relatively small Dyson-Harrop satellite using a 1-centimetre-wide copper wire 300 metres long, a receiver 2 metres wide and a sail 10 metres in diameter, sitting at roughly the same distance from the sun as the Earth, could generate 1.7 megawatts of power - enough for about 1000 family homes in the US.
A satellite with the same-sized receiver at the same distance from the sun but with a 1-kilometre-long wire and a sail 8400 kilometres wide could generate roughly 1 billion billion gigawatts (1027 watts) of power, “which is actually 100 billion times the power humanity currently requires”, said researcher Brooks Harrop, a physicist at Washington State University in Pullman who designed the satellite.
Since the satellites are made up mostly of copper, they would be relatively easy to construct.
“This satellite is actually something that we can build, using modern technology and delivery methods,” New Scientist quoted Harrop as saying.
Satellites laden with solar panels that can beam their energy down 24 hours a day have been discussed for decades.
California agreed last December to a deal involving the sale of space-based solar power.
Solar panels cost more per pound than the copper making up the Dyson-Harrop satellites, so according to Harrop, “the cost of a solar wind power satellite project should be lower than a comparative solar panel project”.
However, there is one major drawback-to draw significant amounts of power Dyson-Harrop satellites rely on the constant solar wind found high above the ecliptic - the plane defined by the Earth’s orbit around the sun.
Consequently, the satellite would lie tens of millions of kilometres from the Earth. Over those distances, even a sharp laser beam would spread to thousands of kilometres wide by the time it reached Earth.
The study has been published in the International Journal of Astrobiology. (ANI)
Dyson Sphere is an idea to encase the sun in a ball to collect the whole solar energy output. There are problems – one is if all the matter in the solar systems was used and made into a material at about steel’s density it would be about 8cm or a little over 3 inches thick at a radius of 1 AU – but that’s too close, it would soon melt. To get to a low enough temperature the sphere would have to get at least 1.6 AU out – then the material is insufficient to self-support at steel’s strength.
Then moving the sphere – to keep the sun orbiting in the galaxy centered would consume practically all the power output. The Dyson idea while ambitious remains impractical.
Brian Wang at NextBigFuture caught up to a pdf file and paper abstract that explores an idea based on the Dyson idea called the Dyson-Harrop satellite (DHS). The modeling of such a device pops some big energy gathering numbers. Brooks L. Harrop and Dirk Schulze-Makuch at Washington State University published this idea in the International Journal of Astrobiology.
A DHS could be built – a 1-kilometre-long wire and sail 8400 kilometers wide could generate roughly 1 billion billion gigawatts (10^27 watts) of power, which is 100 billion times the power humanity currently requires. Time to sit up and take notice of orbital solar power?
But all that power has a drawback as well. To beam power from a Dyson-Harrop satellite to Earth, one “would require stupendously huge optics, such as a virtually perfect lens between maybe 10 to 100 kilometers across.”
A DHS would be relatively cheap to construct, given that the system is composed almost entirely of copper and doesn’t require circuitry. As Wang points out in his narrative, “Later versions could use carbon nanotubes (when they are cheaper and made in higher quantity) for lighter wires that can handle more current.”
A DHS is actually a simplistic, self-sustaining system that draws power from the solar wind and uses a laser to fire energy to collectors (on space stations, bases, etc.) positioned anywhere in the Solar System. The DHS draws energy from the solar wind’s electrons, using the Sun’s high-energy photons only to eject the electrons once their useful electronic energy has been collected. That means the electrons out there are collected which can’t get through the atmosphere and the much lower energy photos are used to keep the collector clean. Physics can be marvelous sometimes.
Here’s how it works. Looking at the diagram above you’ll see the Sun (A) emits plasma half-composed of electrons, half of protons and positive ions (B). Electrons are diverted via the Lorentz force from a cylindrical magnetic field (C) from their radial trajectory towards the ‘Receiver’ (D), a metallic spherical shell. When the Receiver is “full”, excess electrons are diverted through the hole in the Sail. The large positive potential on the Sail drives an electron current through the ‘Pre-Wire’ (E), which is a long, folded wire designed to cancel out the magnetic fields of the current towards the Sun. Once it reaches the end of the Pre-Wire, it travels down the ‘Main Wire’ (F), creating the magnetic field (C), which makes the field-current a self-sustaining system. The current passes through a hole in the Receiver and then through the ‘Sail’ (G), passing through the ‘Inductor’ (H), and the ‘Resistor’ (I), which draws off all of the electrical power of the Satellite to the ‘Laser’ (J), which fires the electrical-turned-photonic energy off to a designated target. Drained of its electrical energy, the current continues to “fall” to the Sail (G). Here, electrons will stay until hit by appropriately-energetic photons from the Sun, at which point they will leap off (K) from the Sail towards the Sun, and then be repelled by the magnetic fields (C) and excess solar wind electrons (B) away from the Satellite, imparting kinetic energy to the Satellite away from the Sun.
A bit complicated – but way elegant and self-position supporting as well.
Because the magnetic field diverts positive particles away from the satellite and electrons toward the Receiver, the DHS remains virtually untouched by excess solar wind particles. And since the satellite ejects electrons when their current cycle is complete, even large satellites have a minimal impact on the Sun’s solar wind output. Plus the kinetic energy from the photoelectrical ejection of electrons from the Sail provides a strong stabilizing force; in fact, it may be possible to design a satellite that can remain in a stationary position.
Sounds great – the other hand holds some major problems that could well be solvable. The DHS isn’t very efficient so its big, then so is outer space. Being so simple and large, protection from that high-speed stuff out there is a major concern. Staying in position while seemingly designed in has to be engineered and work. Then the DHS doesn’t self-start – a pre charge to get it in a self-sustaining cycle needs to be provided. Finally the DHS is going to get hot – shedding the heat is going pose an engineering task of considerable significance.
These all seem to be solvable problems, but there is one more.
One DHS could fully power humanity’s needs if the power could be brought down. Various transmission ideas are working, but so far nothing really seizes attention as a great way to get the power down here.
When such a space energy collection system exists, the orbital photovoltaic projects will need a rethink. Meanwhile, so much power so cheap can be its own lure. Its not such a giant leap to imagine that life off planet is much more practical if the DHS is made fully workable and redundantly reliable. That makes ideas like life off planet would be the main while the life on the planet itself would be a privilege or a resort kind of thing.
The resources out there are stupendous and with cheap energy at hand the idea of getting to them is quite alluring. The DHS concept is certainly one to watch – the numbers are simply too good to ignore.
More at: http://www.lpi.usra.edu/meetings/abscicon2010/pdf/5469.pdf
September 01, 2010
Interview of David Criswell Who Advocates Solar Power on the Moon by Sander Olson
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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 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. [ firstname.lastname@example.org ]
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.
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U.S.-India Business Council Launches Solar Power Task Force
Posted on admin on September 6, 2010 // Leave Your Comment
U.S.-India Business Council (USIBC)The U.S.-India Business Council (USIBC) announced the launch of a major new initiative to promote U.S.-India trade and investment in the burgeoning solar power sector. Comprised of private-sector companies, the USIBC Solar Power Task Force will help to bridge the United States’ aspirations to export leading technologies, while furthering India’s goal of attaining energy security by reducing its dependence on imported coal and fossil fuels. The USIBC Solar Task Force is a subcommittee of USIBC’s Energy, Environment, Enterprise (EEE) Executive Committee, comprised of more than 100 members.
Bryan Ashley, chief marketing officer of Suniva, and Aparna Doshi, chief operating officer of Astonfield, will Co-Chair the Task Force.
“The aim of the USIBC Solar Task Force is to ensure robust cooperation – both financial and technological – between American and Indian firms participating in this vital sector, and to promote an enabling environment that will spur the application of efficient, clean solar-powered energy throughout India and the globe,” said USIBC President Ron Somers. The U.S. and India signed a memorandum of understanding in November of 2009 on Energy Security, Energy Efficiency, Clean Energy and Climate Change to intensify cooperation in energy efficiency and “green” power development. The USIBC Solar Task Force will support the two governments’ efforts to accelerate utility-scale solar deployment.
The Government of India announced the Jawaharlal Nehru National Solar Mission (JNNSM) on November 19, 2009, with more than 20,000 MW of new solar generation targeted by 2022. The breakthrough program is attempting to mitigate the impact of climate change, while promoting rural development and energy security. The Government of India seeks to become a solar power generating hub, as well as a leader in solar services and equipment. USIBC’s Solar Power Task Force will support policy formulation leading to the success of the JNNSM, providing clean energy to sustain India’s double digit growth.
In the eight months since JNNSM’s introduction, the Government of India has worked diligently to develop the supporting mechanisms to ensure execution against the program’s milestones, the first being 1100 MW of solar generation by March 2013. In order for this goal to be met, it is essential that the solar policy, associated regulatory mechanisms, and contracting relationships be commercially viable and embraced by the private sector and financial community.
The USIBC Solar Task Force will support the JNNSSM by:
i. Sharing regulatory and policy best practices with the Government of India and respective states that will enable India to develop into one of the largest solar power markets and facilitate the development of commercially viable solar power plants;
ii. Advising of the latest developments in terms of leading solar technologies and implementation practices;
iii. Addressing risks, removal of difficulties, and encouraging discussion between all stakeholders to promote efficient implementation of effective policies for the transparent and competitive growth of the Indian solar sector;
iv. Facilitating financing of solar power projects and solar equipment manufacturing in India.
Source: Business Wire
Tags: Alternative Energy, clean energy, Energy economics, india, Renewable energy commercialization, solar energy, solar equipment, solar power, Sustainable energy, U.S.-India Business Council, usibc, USIBC Solar Task Force
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