Will a space-based fusion reactor power the entire Earth?

Yes, I'm talking about our sun.  To date it's the only viable net-positive fusion reactor that we have access to.  Although renewable energy is moving forward on many fronts like wind, hydro and marine energy, it's solar energy– and specifically the photovoltaic panel variety – that is showing the most progress and potential for becoming the dominant source of energy on Earth.  

Here are a few reasons why solar panels may eventually dominate fossil fuel and other renewable resources:

IBM Mainframe
IBM 360 Mainframe computer (Picture courtesy of Plyojump)

  • Modularity -  In the 1960s the vision of a computer future centered around massive mainframes.  No one considered that people would want a powerful computer in the home.  This is a trend that happens often in history - as technology is refined and made cheaper - it becomes more personal.  Sewing machines are no longer just for textile factories and tailors - ice is no longer just made in large commercial refrigerators and delivered to homes - and likewise electricity is poised to become a personal, or at least household technology.  This isn't to say that solar plants don't have a future; these "energy mainframes"  do have the advantage of the conomy of scale - but may be disadvantaged by the cost of delivering power to homes - transmission lines, transformers, and a staff to manage the whole network are all costs that a homeowner doesn't carry for their installation.  Utility-scale solar can also be  a problem in Cleanleap countries where the poles and lines might not be there already.  Solar panel systems have great capability to be modular and distributed because most people have a roof over their head that can serve as a solar collector - for those living in apartments, that roof may be a community rooftop solar garden, but it's still modular when compared to a centralised grid. 

    "What about wind turbines?" - you might ask.  On a small scale, wind turbines may not be as efficient as rooftop solar. They require smooth breezes and are affected by turbulance. Trees, a busy road or just being near rooftops decreases the efficiency of small turbines.  They still work great on a large scale as Scotland and Germany have learned.

Map courtesy of SolarInsolation.org

  • Solar insolation map - just look at this map that shows the areas of Earth that recieve the highest levels of solar radiation.  In most cases these are the areas of the world that need a cheap, decentralised form of energy the most.  In Africa and Asia a growing  middle class is using more energy per household, stressing traditional energy grids and forcing homes and businesses to find alternatives to the local power company.  Additionally these warm areas of the world need an increasing amount of energy-intensive refrigeration for perishables like food and medicines. (See Angela McClowry's post: 'Tank of Cold' is a Cleanleap to cool food and a cooler future).  In a "pure solar" future, countries in high insolation zones may become magnets for high-tech industries that rely on large quantities of electricity to manufacture products for the rest of the world.  Countries in this zone are also less likely to have a resiliant grid system already in place.  In the same way that mobile phones leapfrogged fixed line phones in these regions, there's a good chance they'll make a cleanleap for distributed solar power. 



  • Swanson's Law - this is an observation by Richard Swanson, the founder of SunPower.  It says that every time the global amount of solar panels shipped doubles, the price per watt drops 20%.  It's been true for the last 20 years and means that panels get 50% cheaper every 10 years.  PV panels started at $76.67 per watt in 1977 and fell to $0.36 per watt in 2014. This is good news for rooftop solar owners who may want to swap out their panels for more efficient ones after several years - and if the law holds true, it may mean that panels will be showing up in places that you would not expect - roof shingles, bike paths, street lights,  windows, and car roofs are just a few of the places where low-priced, ubiquitous  solar panels may enter our lives.  

When you're at the bottom of an exponential graph, it's hard to predict your rate of ascent.  No one predicted in the 1960s that a small company called Intel would drive a technological revolution that has radically changed the lifestyles of billions of people.  Likewise, we are just at the beginning of the curve for solar energy.  Technologist and futurist Ray Kurzwell notes that installed solar energy capacity doubles every two years and this trend has held for the last 20 years.  He summarised his optimistic outlook like this:

"After we double eight more times and we’re meeting all of the world’s energy needs through solar, we’ll be using 1 part in 10,000 of the sunlight that falls on the earth."

Viable fusion reactors seem to be 10 years away, eternally - here's hoping that Ray is right and that big fusion reactor in the sky meets his expectations - just 16 years from today.  

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