Solar energy has been exploited in direct capacities, for various purposes, well before solar photovoltaic cell and module technology became the most prominent example of “solar energy technology.” Solar stills, solar cookers, sunlight concentrators, solar furnaces, solar fire starters, et cetera, have a long history of use and/or suggestion of use. For instance, there’s fairly good evidence (though disputed by some academics) that solar fire-starters have been in use in Central Asia for a fair many thousands of years.
While that may not be new knowledge to many of those reading this, it may still surprise some people just how widely solar energy technologies and potential applications were explored in the near-recent time period of the 1700s through early 1900s.
During that time period, there was a swell of interest in concentrating solar steam engines and cookers, amongst other things — often with the idea being that the extant coal-powered age was dependent upon the one-time burning of a resource that was ultimately limited (being the result of photosynthesis and geological processes occurring over timespans of tens and hundreds of millions of years).
With all of that in mind, I’m going to highlight a couple of interesting ideas explored and prototyped by figures during that timespan — particularly those put forward by the French solar-steam-engine developer Augustin Mouchot and the American solar-thermal-train developer Frank Shuman.
Augustin Mouchot (1825–1912) — Solar Steam Engines, Parabolic Trough Solar Collectors, & Solar Powered Ice Cream Makers
“Eventually industry will no longer find in Europe the resources to satisfy its prodigious expansion. … Coal will undoubtedly be used up. What will industry do then?”
That’s the question that Augustin Mouchot is quoted as having posed after demonstrating one of his designs back in 1880. Taking a look at modern Europe, the answer seems to be, with the benefit of contemporaneous hindsight: to offshore to poorer parts of the world that can still be wealth-pumped; to dig up every last bit of low-quality lignite (with the high quality reserves in Europe mostly now long gone); and to rely upon imports.
The prodigious expansion of the modern industrial world has of course long since ceased being centered in Europe, and has re-centered itself around China and nearby countries.
You’ll note, though, that basic and effective solar energy technologies are still mostly only used in niche applications, and that even more complicated (and arguably more cost-effective) technologies such as solar photovoltaic (PV) panels only represent a very limited proportion of total energy supply in Europe (and elsewhere as well, it should be noted), although its growth continues.
Was Mouchot thus wrong, as some shills for the coal industry might proclaim? No, the reality is that there are limited reserves of coal, oil, and natural gas — and far more importantly, there are very limited high-quality reserves. What that means is that as time has gone by, the economics of extraction have been approaching a brick wall — whereby the use of such resources will become more expensive as time goes by, and thus less use will occur. That being the case, if anything like modern industrial-style civilization is to exist a few hundred years from now (an open question), it would have to rely upon renewable energy technologies — including possibly solar energy technologies, such as those designed by Mouchot.
Amongst the designs created by Mouchot were solar cookers, parabolic trough solar collectors (definitely still of use for various purposes); various solar steam engine designs (with modified versions of some designs potentially being of value); and even a concentrated-solar-steam-engine-powered compressor used to make ice and/or ice cream.
To highlight his work on solar steam engines, Mouchot displayed a number of designs — including the aforementioned concentrating-solar design that powered a compressor to make ice cream — at the Universal Exhibition in Paris in 1878. Despite winning some accolades at this show, his support from the French government was soon cut due to improving economics for coal transport and import. Solar energy was deemed by the government of the time to be “uneconomical.”
It was at the just mentioned Universal Exhibition in Paris that Mouchot was quoted as stating: “One must not believe, despite the silence of modern writings, that the idea of using solar heat for mechanical operations is recent. On the contrary, one must recognize that this idea is very ancient and (through) its slow development across the centuries it has given birth to various curious devices.”
Frank Shuman (1862–1918) — Solar Steam Engines, Solar Thermal Train, Solar Thermal Power Stations, & Various Types Of Associated Safety Glass
“One thing I feel sure of … is that the human race must finally utilize direct sun power or revert to barbarism.” — Frank Shuman (1862–1918)
That statement comes to us from the American solar energy system developer Frank Shuman — perhaps best known for building the “world’s first” solar thermal power plant, back in 1912 in Egypt. In that system, parabolic troughs were used to concentrate light, create steam, and thus power a ~65 horsepower steam engine that was able to pump a reported 6,000 gallons of water a minute to agricultural fields from the Nile River.
Other designs of Shuman’s included a solar thermal train demonstrated in 1910; various types of solar engines including those utilizing self-designed low-pressure steam turbines; and various types of laminated and/or wired safety glass (and machines and processes to manufacture these safety glasses); amongst other things.
Also notable here is that Shuman founded a company known as the Sun Power Company back in 1908, with the intent being to commercially develop solar energy technologies. The plans never came to serious fruition, though, due to the increasing exploitation of fossil oil reserves in the years following his 1918 death.
Given that the cheapest reserves of oil have now largely been pumped to the point of low-flow rates, and that developers are increasingly dependent upon relatively high-cost extraction methods (hydraulic fracturing, aka fracking, and tar sands), difficult locations (offshore rigs), and geopolitically ambiguous regions (the Middle East and soon the Arctic), it seems likely that solar energy technology usage will increase in the decades ahead. So, Shuman appears to have simply been “early,” not wrong.