Solar Energy: A Complete History from 19th Century Experiments to Today‘s Gigawatt-Scale Plants

Hello friend! Welcome to our journey through the fascinating history of solar photovoltaic (PV) technology. We‘ll explore how an obscure 19th century discovery grew into a dominant renewable energy source today through never-ending human innovation.

By the end, I hope you gain an appreciation for solar‘s winding road over nearly 200 years and the immense potential still untapped. So let‘s dive in!


We‘ll start at the very beginning by reviewing what solar energy actually is and how we utilize it. Then we‘ll walk through solar PV advancements decade-by-decade highlighting key milestones in research, commercialization and real world adoption.

You‘ll see how global politics, economic trends and environmental priorities continually influenced solar‘s uneven path from niche technology to renewable energy heavyweight.

We‘ll glimpse the future too, where experts predict solar meeting 20-25% of global electricity demand within this decade.

So whether you‘re new to energy technology or an experienced industry geek, I‘ll ensure by the end you understand:

  • The science empowering solar PV innovation over two centuries
  • Pivotal breakthrough innovations behind each era of solar adoption
  • How solar has already redefined energy economics today
  • Why solar PV will keep exponentially getting bigger, cheaper and more efficient

Let‘s get started!

What Exactly Is Solar Energy?

Quite simply, solar energy is radiant electromagnetic energy from the Sun converted into electricity or heat using various technologies. Those technologies harnessing or concentrating sunlight go all the way back to antiquity with tools like magnifying glasses and curved mirrors to ignite fires.

But our focus is on solar photovoltaics (PV) – generating usable electric current directly from sunlight exposure on suitably prepared materials and devices like solar panels.

So how do we perform this solar alchemy of turning light into electricity? Read on.

Photovoltaic (PV) Effect

Photovoltaics get their name from the Greek roots "photos" meaning light, and "voltaics" referring to electricity. The photovoltaic effect behind solar energy was first scientifically demonstrated in 1839 by French physicist Edmond Becquerel.

He built a primitive solar cell using metal electrodes submerged in electrolyte fluid and produced a tiny electric current simply by exposing it to sunlight. This defining discovery revealed light can generate electricity without moving parts or heat-based steam generators.

But just how does this magical phenomenon work exactly? Let‘s break it down.

How Solar Panels Convert Photons to Electrons

The key is the interactions between photons (light particles) and electrons within semiconductor materials like silicon used in solar cells.

Incoming photons impact and energize electrons, knocking them loose to flow freely as electric current. We call this a photo induced charge separation, generating a positive-negative polarity across the solar cell similar to a battery.

Diodes and wiring routes the separated negative/positive charges into a closed circuit, delivering useful electricity we can harness for work.

And it all starts with photovoltaic materials getting bombarded by trillions upon trillions of photons streaming in from the sun daily!

Of course we‘ve come a very long way since Becquerel‘s crude cell to today‘s solar panels classmates 15-20% efficient at converting photons into productive current.

Major strides came through semiconductor research and increasingly layered solar cell architectures to optimize gathering those precious loose electrons before they dissipate.

Now you‘ve got the gist of solar PV magic! Next we‘ll walk through the evolutionary tale of refining this 19th century scientific discovery into a mainstream renewable powerhouse.

The Long Road for Solar PV from Obscurity to Ubiquity

Solar energy‘s rise from quirky lab experiments to globe spanning 100+ gigawatt plants has taken over 180 years…and counting! Let‘s explore some signature waypoints that got us here.

Note solar heating/cooling tech also made great strides, but our focus is electrical generation innovations.

1870s – 1900: Exploring Solar After Discovery of PV Effect

Becquerel‘s initial discovery in 1839 of electrons flowing freely from sunlight exposure failed to spur much investment or interest initially. The produced current was miniscule and hopelessly inefficient for any commercial applications.

But over the next decades, more researchers conducted solar experiments to validate principles and improve outputs using different materials like selenium and copper oxide.

A breakthrough came in 1883 when American inventor Charles Fritts constructed the very first genuine working solar cells for electricity generation. He coated selenium semiconductor material with an extremely thin gold layer to form a basic solar cell array.

It was only around 1% efficient, but Fritts‘s demonstration was pivotal, proving the feasibility of the PV effect to accomplish real work. He used his rooftop solar array to run a small motor.

Unfortunately, that low efficiency still meant an extremely limited range of uses. And Western society was increasingly fueled by abundant cheap coal for steam engines during the mid-late 1800s. So solar research stagnated for a few more decades.

1950s Space Race Era Catalyzes Solar Cell Research

Everything changed in the 1950s and 60s however, as the Cold War space race between the United States and the Soviet Union kicked into high gear. This drove massive investment into satellites, spacecraft and missions pushing deeper into our solar system.

Chemical batteries severely limited mission durations and functionality as you scaled further out into space. Solar power offered a lightweight, durable and indefinitely renewable alternative perfectly suited for extraterrestrial applications.

The nascent NASA prioritized solar research, launching the satellite Vanguard 1 in 1958 – one of the very first solar-powered spacecraft.

And the space race delivered! Funding flooded into semiconductor materials and solar efficiency R&D, yielding huge performance gains in just a few years. Silicon solar cell efficiency doubled from 6% in early 1950s to 14% by 1960.

We‘ll continue solar‘s fascinating tale later. But first, let‘s recap the different generations of solar cell technology improvements behind these leaps.

Solar Cell Generations: Driving Higher Efficiencies

Generations of solar cells denote evolutionary improvements delivering progressively higher solar electric conversion efficiency and lower costs. Let‘s dive into the key advances enabling 20%+ commercial cell efficiency today.

First Gen – Single-crystalline silicon wafers doped to form simple PN junction diodes. 6-8% efficiency range initially.

Second Gen – Added anti-reflective silicon nitride coating layer to boost light absorption and improved manufacturing processes. Jumped efficiency range to 14-17% range.

Third Gen – PERC cells (passivated emitter rear contact) reduced electrical losses significantly through rear-side contacts and silicon dioxide layer passivation. Up to 21% efficiency.

Fourth Gen – Back contact solar cells have contacts only on rear for unimpeded top-side light exposure. Efficiency levels nearing 26% demonstrated.

Fifth Gen – Tandem/multi-junction cells with layered semiconductors tuned to wider solar spectra absorption profiles reaching 30%+ conversion efficiency. Mostly used in concentrated PV plants and satellites today.

And the 6th generation is already underway using advanced nanomaterials like perovskites to push efficiencies closer to commercial silicon theoretical limit of 33%!

Phew, that was quite a technology whirlwind tour! But it shows the immense innovation still rapidly occurring even 60 years after solar panels first powered spacecraft.

Now back to solar PV history!

1970s Oil Shocks Resurge Global Interest in Solar

The optimism around solar in the 1960s receded somewhat as the space race concluded. But the early 1970s delivered an enormous exogenous jolt to solar R&D in the form of back-to-back global oil crises.

In 1973, Arab members of OPEC imposed an oil embargo that quadrupled prices practically overnight. It exposed the energy vulnerability of industrialized nations like the US heavily dependent on imported Middle East oil.

Then 1979 saw crude prices double again amidst the Iranian revolution. These oil shocks created tremendous concern over energy security and acquiring affordable fuel for expanding economies.

In response, forward-looking countries like Japan, Germany and the United States initiated major alternative energy programs plowing money into solar and other renewables. Suddenly solar enjoyed support and enthusiasm akin to the space race.

It worked beautifully! New solar panel production capacity exploded higher over the next decade:

1975 – 500 kilowatts
1985 – 21 megawatts

And that set the stage for solar‘s next era of blistering worldwide growth.

1990s Onwards: Solar Scales Up and Wins on Cost

The solar industry spent the 1980‘s pursuing meaningful scale with new thin film cell technologies that used 99% less semiconductor materials. This brought production costs down substantially.

Germany emerged as an early leader promoting rooftop solar adoption through generous guaranteed subsidies. Their early support nurtured solar companies like SolarWorld into global PV players.

By the mid-late 1990s, average solar panel pricing had dropped nearly five-fold while conversion efficiency surged upwards from 15% to over 20% on the back of advances like PERC cell optimizations.

For the first time ever, solar electricity reached grid parity in many regions like California and Italy – meaning it directly cost competed with retail electricity from fossil fuels without subsidies.

And this kickstarted the exponential hockey stick growth trajectory that continues through today. Let‘s look at what catalysts keep driving stunning solar expansion.

Present Era: 2010 Onwards – Epic Scalability Changes Everything

Fast forward to today, and solar PV remains on a relentless path to ever cheaper costs per kilowatt-hour while also scaling to epic multi-hundred megawatt plants.

It represents the shortest path for emerging nations to bridge energy access gaps without expensive grid builds. And it‘s now the outright lowest cost form of electricity in most regions.

Let‘s cover some signature milestones cementing solar PV as the energy story of the 21st century:

700 Gigawatts Global solar Capacity today and rising exponentially every year

2 new solar panels installed per second across the planet

100 GW scale solar projects coming online in China‘s deserts

63% lower average solar panel pricing since 2009

29% efficiency for commercial PERC solar modules from 21% just six years ago

46% efficiency for ultra high concentrator solar cells proving more room ahead

And all those factors keep feeding on each other in a virtuous cycle. More panel deployment drives economies of scale reducing solar‘s LCOE (levelized cost of energy). Cheaper solar electricity accelerates global capacity additions.

The 2010s saw solar establish overwhelming economic advantages over alternatives to redefine energy access and affordability for hundreds of millions in emerging markets. The 2020‘s now appear poised to see solar dominate additions to electricity capacity in industrialized nations too.

Let‘s see solar‘s meteoric rise in action with some bellwether mega-projects you may have heard or read about before.

Real World Case Studies: Bellwether Solar Projects

Let‘s explore some tremendously ambitious solar projects pushing boundaries on sheer size and technology innovation. They provide templates for what‘s coming next.

Kamuthi Solar Power Project – Tamil Nadu, India

With intractable air pollution and hundreds of millions still electricity-deprived, India aims to rapidly solarize amidst soaring energy demand. An emblem of their aggressive renewable pivot is the Kamuthi solar plant.

Key Stats

  • Location – Kamuthi, Tamil Nadu
  • Capacity – 648 megawatts – Largest single location solar PV plant globally
  • 2.5+ million solar modules splayed over 10 square kilometers
  • Powers 150,000 homes at just US$679 million total project cost

As a reference, a comparable sized coal plant costs 3-4X more upfront needing vast mining and transport infrastructure before even producing a single watt.

India continues targeting 100 gigawatts of national solar capacity by 2022, anticipating surging electricity demand in coming years with no signs of slowing appetite today.

Topaz Solar Farm – San Luis Obispo County, California

Starting in 2014, solar developer First Solar built out an enormous 550 megawatt solar PV farm – among the first exceeding half a gigawatt capacity.

Sprawling over 25 square kilometers, Topaz features 9 million thin-film cadmium-telluride solar modules tilting to track the sun throughout the day. The US$2.5 billion project powers 160,000 Californian homes and saves over 377,000 metric tons of CO2 emissions annually.

At utility scales, solar‘s levelized cost proves far cheaper than coal and combined-cycle natural gas plants. So California retired its last coal plant in favor of solar accelerating its push towards 100% zero-carbon electricity by 2045.

Ivanpah Solar Electric Generating System

As the largest concentrated solar thermal power plant in the world, Ivanpah offers an alternative solar technology showpiece. Rather than photovoltaics, it uses a "power tower" design featuring vast fields of mirrors directing sunlight onto a central tower filled with water and steam turbines.

Vital Stats

  • Location – Mojave Desert near Nevada/California border
  • Capacity – 392 megawatts across three power tower units
  • 173,500+ mirrors each size of garage door focusing rays on towers
  • Avoid 400,000+ tons yearly CO2 emissions.

Concentrated solar allows power generation even when sun goes down through molten salt-based heat storage tanks. As coal retires, 24/7 carbon-free solar CST plants provide essential grid reliability.

Ivanpah supplies 140,000 California homes and serves as blueprint for more multi-hundred MW plants replicating the technology like Noor II and III in Morocco.

The Future is Bright for Cheap, Scalable Solar PV

As we‘ve explored together, the state of solar PV keeps advancing exponentially thanks to human drive and ingenuity. Efficiencies continue rising while costs keep falling to surpass even optimistic expert predictions.

Consider that the US Department of Energy roadmapped $1 per watt module costs in the mid-2030s after heavy investments into next gen solar R&D. Yet the industry marched ahead faster, hitting under 50 cent per watt module costs in 2021, using existing mass production technology!

So where is solar headed next? Consensus expects solar generating 20-25% of total global electricity by 2030 given increasing hubris around scaling plants to multi-gigawatt capacities.

Assuming momentum in technology improvements, cost declines and climate change concern continues, behold some exciting milestones ahead:

By 2040 – Solar providing one-third electricity globally. Entire deserts covered end-to-end with solar panels delivering terawatt-hours to major population centers via high voltage DC transmission lines. Millions of residential rooftops may feed surplus generation back to grid.

By 2050 – Most grid supply peaks met by solar regionally. Solar CST (concentrated solar thermal) with molten salt storage delivers reliable 24/7 carbon-free power even lacking PV backup.

By 2060 – Intercontinental transmission supergrids tapping abundant solar resources from world‘s sunniest regions like Sahara desert. Dedicated continent-spanning HVDC power highways become backbone of clean energy era.

Beyond 2060 – Space based solar power finally technically and economically viable using lunar materials mined to construct vast space arrays beaming endless terawatts of energy via microwaves to planetwide receivers. Science fiction no more!

And throughout human civilization shifts to run on renewable sun juice from sand crystals, we‘ll keep chasing the tantalizing theoretical limits of solar conversion efficiency.

Who knows, we may crack past 50% thanks to wild world of quantum dot and molecular solars still largely untapped. The outlook remains thrillingly uncertain.

Closing Thoughts My Friend

And with that, we‘ve covered solar‘s complete history from quirky beginnings to global energy titan!

I hope you feel reenergized learning about everything pioneering researchers, entrepreneurs and solar adopters went through over nearly two centuries to make PV tech affordable and accessible at global scales.

It took equal parts scientific prowess, commercial risk-taking and government policy foresight to escape early obscurity and mature into the highest potential renewable energy source on Earth.

Yet we‘ve really only scratched the surface of solar‘s awesome potential. As cells touch theoretical efficiency limits through nanomaterials, and projects expand to nation-sized capacities, our energy economics get redefined.

The 21st century certainly belongs to solar. And with your newfound insight into solar‘s winding backstory, I hope you feel invested like me in this industry still writing its history each passing year.

Let the sun shine on!

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