Solar Power

NASA Goddard Space Flight Center, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons

We don’t think about the Sun as much as we ought to.  It is just there, rising and setting predictably every day, shining so bright that our eyes cannot perceive anything more than a blazing white circle, with less apparent complexity and interesting features than the Moon.

In the words of They Might Be Giants, “The Sun is a mass of incandescent gas, a gigantic nuclear furnace.”  Of course, a distant observer might make a similar generalization about our home: “The Earth is a block of mostly-solid rock, a mid-sized spherical planet...”

Our eyes and cameras are not particularly suited for sun-gazing.  Turn down the brightness, however, and marvelous complexities become apparent.  The entire million-mile-diameter sphere rotates every 27 days.  Great arcs of plasma rise, fall, and explode off into space.  Deep convection creates intricate patterns and knots of magnetism, confining vast energy in “sunspots” that is released in sudden flares, inundating Earth in high-energy particles that create the Aurora Borealis and – at the highest intensities – threaten our electric grids.  For reasons nobody really understands, these sunspots wax and wane and their magnetic polarity flips on an approximately eleven-year cycle: one that never repeats exactly and that defies all of our attempts at prediction. 

Charles Eisenstein recently penned an essay titled “The Sun is Alive,” in which he suggests that our Sun exhibits sufficient patterning and complexity and self-regulating homeostasis that it is reasonable to assume it is conscious, aware, alive – albeit it in a form so different from our bodies and minds that we are unable to recognize it.  Perhaps the eleven-year cycle is the Sun’s heartbeat, which would give it about a billion “beats” over its lifespan – coincidentally in line with the expected heart-life of most Earthly animals.

The Sun is so hot that we imagine it as a “furnace”, an inferno, a million atomic bombs exploding every second.  But the reality is surprising: on a per-volume basis, the Sun’s “metabolic rate” – 277 watts per cubic meter - is only one-quarter of a human body’s resting heat production.  The Sun is a tremendous source of energy not because it is in a state of continuous detonation, but because it is unfathomably large.  A fusion reactor that replicated the core of our Sun would be merely warm, like a compost pile, and not at all useful.  Our Sun’s low rate of “nuclear metabolism” grants it a lifespan of some ten billion years, despite never taking on additional hydrogen fuel during that time.  Throughout that time, complex homeostatic processes cycle new fuel into the core, maintaining a nearly steady energy output that has sustained the conditions for biological life on Earth for three billion years and promises to continue for billions more.

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The Sun bathes our planet in a nearly constant stream of energetic radiation: one thousand three hundred and sixty-one watts per square meter before our atmosphere starts absorbing it.  The majority of it falls in the range of wavelengths we call “visible light” – simply because it is what our eyes evolved to perceive.  Other eyes – of bees and butterflies and salmon and bullfrogs – can see ultraviolet or infrared rays from the Sun that are completely invisible to us.  Although some is reflected by clouds and snow, most of this incoming energy is absorbed and ultimately re-radiated to space as infrared heat: the difference in energies serving to power winds, weather patterns, the entire hydrologic cycle, and of course the biosphere.

It is often said that the Earth receives more energy from the Sun in one hour than human civilization uses in a year.  This is typically accompanied by optimistic hand-waving about how we will soon have cheap and abundant renewable energy if only we invest in the right corporations and vote for the right politicians.  While technically true, this statement ignores a great many inconvenient details about embodied energy, transmission, conversion, storage, and availability of materials.

Our “green energy” economy, as it currently exists, is not so different from our fossil-energy economy.  Materials for panels and batteries and generators are mined in giant pits, at significant ecological cost and using a great deal of fossil fuels.  These materials are shipped around the world to polluting factories, from which the finished components are again carried by bunker-oil-burning ocean freighters and diesel-downing eighteen-wheelers.  Once installed, turbine blades gradually weaken and panel output declines, until they are decommissioned and landfilled, forcing the mines to keep digging deeper for the next generation.

Perhaps we could envision a world in which self-replicating, self-assembling, and fully biodegradable solar panels convert sunlight into electrical potential and thence into food, fiber, structure, and a diverse array of useful organic chemicals, a world in which those solar panels expand to cover nearly every available surface, in which they absorb carbon dioxide from the atmosphere and convert it into stable carbon. 

Perhaps we would then realize that we already live in such a world. 

We call them leaves.

The trouble with leaves, of course, is that they are not *industrial*.  They serve their own ends and support food webs and ecosystems and ultimately the biosphere.  Leaves cannot generate gigawatts of electricity to power data centers and air conditioners.  They cannot generate millions of gallons of gasoline and jet fuel or pipelines full of compressed methane.  By the time we force leaves to these ends – through biomass-burning power plants and ethanol and biodiesel and biogas – we expend so much energy and lose so much in conversion that it is hardly worth it and offers no real hope of substituting for our dwindling and climate-altering supply of ancient fossilized bio-converted sunlight. 

It is an important and deeply relevant question whether we could build an industrial green energy economy that closes its own loops: that builds and recycles solar panels using their own output power, that builds and maintains wind turbines using wind power, that converts renewable electricity to hydrogen and liquid fuels when needed.  The energy world has its own version of the Progress mythology - an essentially religious belief that such a future is our destiny - that distorts nearly all attempts to ponder this question objectively.  In my own PhD-level investigation into bioenergy, I discovered that there is a wide gulf between the hype, the press releases, the “prevailing wisdom” and the reality in which major hurdles, resource limitations, and energy inputs are conveniently ignored as “opportunities for future research”. 

I can’t say for certain what our civilization will look like a century or two from now when our fossil energy reserves have been exhausted, nuclear power has been curtailed by too many disasters and waste leaks, and fusion remains always at least 25 years away.  I am neither a techno-optimist nor a doomer.  I think it is fair to say that we will no longer be jetting off to Europe for vacations, commuting an hour to work every day, and using a whole country’s worth of electricity to “mine” virtual currency.  I think it is also fair to say that hydropower will drive industry along our major rivers, that windmills will pump water, that solar panels will power some devices, that biodigesters will turn waste into fertilizer and fuel. 

I also hope that, somewhere ahead in the tumultuous transition, an ecological spirituality might begin to take root.  I hope that we might begin to regard energy as a gift rather than as an entitlement or a commodity, that we might more often give thanks to the Sun, to the forests, to the rivers, to the winds, to the great interplay of forces between our living star and our living planet that we can humbly tap into to build our homes, to create comfortable living spaces, to grow our food, to supply clean water and return our wastes to the endless cycles, to carry us along on the currents and flows, to power our art and creativity and explorations of what it means to be embodied in human form.