Out of this World

One of the most outré solutions being proposed to solve the world energy crisis is space-based solar power. Eric Payne examines why this technology might be about to enter a new commercialisation phase.

The world is facing an energy crisis. Energy consumption is expected to grow by 53 percent from 2008 to 2035 with the vast majority of that growth (85 percent) occurring in countries outside of the Organisation for Economic Co-operation and Development (OECD), where demand is being driven by strong long-term economic growth, according to the International Energy Outlook 2011 published by the US Energy Information Administration (EIA).

The problem is meeting these energy needs without pumping vast quantities of extra carbon dioxide and pollution into the atmosphere. Concerns about man-made climate change aside, sustainability and energy independence are key public policy issues shared by countries around the world – both in developed and emerging markets.

A wide range of highly innovative schemes has been proposed. These include massive Solar Thermal Energy (STE) projects, which harness useful solar energy in the desert for distribution over vast distances via high-voltage direct current (HVDC) power lines; and Carbon Capture and Storage (CCS) projects, which capture carbon dioxide from single point sources such as power plants, before it is emitted into the atmosphere, for sequestration in large geological structures, mostly under the sea. Both of these initiatives have attracted large-scale institutional, governmental and industrial support, despite not being proven in terms of technical viability.

Another idea is space-based solar power, which involves launching satellites into geostationary orbit around the equator where they can collect solar energy using photovoltaic cells and then beam that energy back to Earth via microwave or laser transmission. Given the depth of the energy crisis and the lack of a widely accepted long-term solution, this kind of idea is now considered reasonable and is even garnering investment. But how viable is it and what are the technical, financial and operational challenges associated with deploying such a system?

Efficiency gains

The space-based solar power satellite was first proposed by Dr Peter Glaser of Arthur D. Little in the late 1960s and has been the subject of almost continuous research & development and market analysis for the past 40 years. Interest in solar systems deployed in the vacuum of space has peaked in recent years, with scientists citing increased efficiency, almost continuous operation and the absence of adverse weather conditions that negatively affect ground-based systems on Earth.

The most significant commercial project to date is being undertaken by Pacific Gas and Electric Co. (PG & E), a San Fransciso-based utility, which has signed a contract to procure space-based solar power equipment from Solaren Corporation. There is something entirely appropriate about the fact that the home of Silicon Valley, Hollywood and the hippie movement of the 1960s should be the first place to embrace space-based solar power. But is it destined to be another West Coast folly – akin to Buckminster Fuller’s Geodesic Dome – that fails to find acceptance outside Orange County?

When a major company – PG & E is California’s largest utility company – signs an agreement of this kind, one has to take notice. “While emerging technologies like space solar face considerable hurdles under a traditional viability analysis, PG & E believes that potential, significant benefits to its customers from a successful space solar installation outweigh the challenges associated with a new and unproven technology,” the company said in a press statement in April 2009. The 200 MW space-based solar power project will use satellites in geosynchronous orbit to collect solar energy, which will then be transmitted to the ground for conversion into electricity.

The US National Space Agency points out: unlike oil, gas, ethanol and coal plants, space solar power does not emit greenhouse gases; unlike coal and nuclear plants, space solar does not compete for or depend upon increasingly scarce freshwater resources; unlike bio-ethanol or bio-diesel, space solar power does not compete for farm land; and unlike terrestrial solar and wind power plants, space solar power is available 24 hours a day, 7 days a week, in huge quantities. The biggest obstacles faced by space-based solar power are economic, as opposed to technical.

Economic feasibility

Study after study has asserted that space-based solar power is at least ‘technically feasible’. The latest report by the International Academy of Astronautics, The First Interna-tional Assessment of Space Solar Power: Opportunities, Issues and Potential Pathways Forward, published in August 2011 said: “As a result of its assessment, the IAA concurs with the findings of previous groups, including the US National Academy of Sciences: Solar Power Satellites are technically feasible. There are no fundamental technical barriers that would prevent the realisation of large-scale SPS platforms during the coming decades. However, as noted, questions remain as to the economic viability of SPS.”

The cost of launching anything into space is enormous. Although, the increasing number of communication services delivered via satellite (television broadcasts, internet, GPS) has spawned a commercial space industry, independent of government-funded bodies such as NASA and the European Space Agency. Yet another aspect of the endeavour that has an air of science fiction unreality about it is the fact that several of the most high-profile ‘space tourism’ companies are owned by high-tech and media billionaires. Richard Branson’s Virgin Galactic is aiming to launch its first commercial flight into low-earth orbit in 2013, while Blue Origin, founded by Jeff Bezos, who also owns Amazon.com, is in the process of building a new spacecraft for the purpose of space tourism. The point of these initiatives is that sufficient demand for commercial space flights will give the companies operating in this sector a significant incentive to develop cheaper launch vehicles.

The Indian Space Research Organisation and US National Space Society signed an agreement in November 2011 known as the Kalam-NSS Energy Initiative, wherein the pair agreed to collaborate on a multilateral space-based solar energy programme. The Government of India is particularly interested in the technology as a solution for bringing rural electrification to the vast swathes of the Indian population that still live on small family holdings or in remote towns and villages, where the brutal landscape and vast distances make it difficult to install a traditional electrical network connection.

The Canadian authorities have expressed similar enthusiasm for space-based solar power, believing that it might be a viable means of delivering much-needed energy to the Alberta tar sands, where Shell is developing a complex, automated system for extracting oil, and where the government has rejected nuclear power.

Space junk?

Energy and economic activity seem to enjoy a proportional relationship, with a cheap, secure and plentiful supply of energy being one of the principal determinants of economic growth. Given that increasing demand and the certainty that, at current rates of production, fossil fuels will one day run out, many experts agree that government and industry together should be trying to develop as many different kinds of energy as possible. To that end, government will have a vital role to play in any future that incorporates space-based solar power, given the enormous upfront investment required to develop and deploy the system in the first place. Although, the hope is that systems developed for the commercial space sector could also help to spur innovation in this sector.

What remains to be seen and what is very difficult to test without launching an operational system into space, is how it will operate once it is up there. How effective will communications be, what sort of impact will solar radiation have on the silicon alloys that make up the arrays, without the protection of the Earth’s atmosphere, and how long will a typical system last? Once a system is deployed in space, there is no viable way to correct for failure or to carry out maintenance and repair, without which the vessel would be lost. Given the amount of investment involved, operational longevity and time enough to pay back initial investments, before the craft becomes space junk, are vital.Solar energy is routinely used to provide power to existing spacecraft and geosynchronous satellites. Given the ‘technical feasibility’ and commercial incentives that now exist, advocates are hopeful that the technology might soon provide a viable energy source for vast numbers of people down on the planet as well.