Is solar really the cheapest energy source in history?

Development of Film solar cell

Recently, Popular mechanics released an article entitled: “It’s Official: Solar Is the Cheapest Electricity in History”.

This article proves two things.

1.       Clickbait is still a thing in 2020

2.       Even tech writers can’t see confirmation bias.

What the Article Says

The International Energy Agency recently published a report  that claims solar photovoltaic (PV) systems are the cheapest form of electrical generation for a utility to build. In a nutshell, they took the average cost to construct a solar farm and divided by the average output of a solar farm and voila! Dollar per kWh produced.

With this method, solar PV systems are anywhere from twenty to fifty percent cheaper to build (per kWh) than all other forms of electrical generation. This is factually correct.

Yet….

The Entire PM article is only 374 words. By the end of this sentence I will have already written 190 just paraphrasing the darn thing. To give PM some credit, they do point out a few things that the idiots on your Facebook feed and subreddit of choice are not mentioning. Despite bashing you over the head with a 32-point bold-font clickbait headline, PM still takes the time to mention that a lot of factors have made this particular comparison unfair. They graciously use an entire sentence to remind us that “risk reducing financial policies around the world” are the key factor to the success of solar PV in this metric.

What the Article Neglects to Mention

Everything is Cheaper when someone Else is buying It

Let’s start with “risk-reducing financial policies.” What PM really means when they say that is “enormous taxpayer-funded subsidies and incentives.” It is very easy to win a “cost per unit” contest when SOMEBODY ELSE IS PAYING THE “COST” PART. Most G20 countries have embraced robust programs accelerating the development of renewable energy projects (a good thing) and that has driven first-cost for solar PV projects down to an artificially low level.

For instance, the average cost of a fixed-tilt solar PV array on the utility scale (greater than 2 megawatts) in 2010 was $4.63 per installed watt. (U.S. Solar Photovoltaic System Cost Benchmark: Q1 2018, Ran Fu, David Feldman, Robert Morgolis, NREL) By 2018, that same system could be built for $1.06 per installed watt. How did the cost drop by 71% in just eight years?

Some of the reduction has to do with more efficient supply chains, better production technology, and economies of scale. That is what the article does not mind you believing. Otherwise they might have spent a few words on the introduction of SRECs, feed-in subsidies, and a 30% tax credit, guaranteed no-interest loans, and straight up cash grants that account for most of that drop. On top of these, enormous amounts of federal dollars across multiple countries were funneled into programs developing new solar PV technologies and companies. This tidal wave of free money created from whole cloth those better supply chains and production systems in the first place. Solar PV almost disappeared entirely before 2001 for no other reason than it had a terrible cost to kWh ratio for a long time. Because of its position as a clean renewable energy source that the average person could recognize, the whole industry has been propped up from the start. Across the board, the world has spent trillions on getting solar photovoltaic systems into the hands of consumers and utilities. Money that came from the constituent taxpayers, incidentally. Remember Solyndra?

To be fair, this is probably an overall positive thing. It represents progress that benefits humanity. However, when it comes time to evaluate how effective we have been in developing clean energy, this system gives solar PV an unfair advantage in any “cost per kWh produced” contest you care to host. The results are skewed away from objective reality and now those results paint an inaccurate picture of what we have actually accomplished.

Cheaper is Not Always Better

Which brings us to the other elephant in the room.

Photovoltaic systems are not as good as most people believe them to be. We’ll start with the complex bit and get it out of the way first. There exists something called the “Shockley-Queisser Limit” which is a horrible name for a horrible bit of material science. It basically says that no crystalline solar panel will ever be more than 30% efficient. Why? Fine. You asked for it.

An electron that gets excited by the sun enough to move into the conduction band needs even more energy to move from the p position to the n position of an adjacent atom. Once it does so, the atom it just left will have a positive charge. It will try to grab another electron from an adjacent atom and voila! Electrons go marching across the panel and we get electricity! The super-basic takeaway is that there needs to be enough extra energy from the sun to push the electron across the divide and hold it there until the original atom can grab another electron. That extra energy does not become electricity, it is a tax on the electricity that gets made.

Of course, sometimes the original atom just pulls its old electron back, and we get a net zero electricity production. This process is called ‘recombination,” and it is non-negotiable. It actually happens a lot more than ‘chain ionization’ which is what gives us that sweet sweet juice we love so much. The original atom is close, and the electron just hops right back to where it started because it is convenient.

Worse, every time that stubborn electron falls back into a lower energy state, it dumps a photon and the energy of that photon leaves the system forever.  This is called radiative recombination. Designers try to minimize this, but the very atomic structure of crystalline panels makes elimination chemically impossible. It is literally the photovoltaic process in reverse. If you want light to produce electricity, then you have to accept that sometimes the electricity will produce light (photons).

In practice, the typical solar panel converts about 20% of the light that hits it into electricity. Better ones go as high as 25%. For comparison, a tri-gen natural gas power station converts about 65% of its fuel to energy. A wind Turbine can hit 75% without too much trouble. That terrifying specter of 50’s sci-fi tropes, nuclear power, converts between 91-93% of the fuel source to energy.

This was one of the options on the stock image source we actually pay money for. The caption they provided was “Beautiful young engineer near solar panels outdoors”. If you stopped scrolling, *Bonk* straight to jail with you.

You had ONE Job!

A huge consideration in utility-scale power production is something called “base load.” As you have probably already figured out, “base load” is the average required power for an area regardless of external factors. Lot’s of things affect the power we use, but there is a kind of minimum level that levelizes very nicely over large populations. This is the power that needs to be available at all times. It runs the fridge all night long. It keeps the internet up and running. It makes sure that when you go to the bathroom at three AM the lights go on and the toilet flushes.

You do not need an engineering degree to know that solar panels only produce power when the sun hits them. Absent enormous storage systems, they are useless at night and mostly useless in bad weather. The systems in the report cited by Popular Mechanics do not include (massively expensive) storage capacity, and as such cannot meet base load requirements. Period. If the panels were FREE, they still could not do the most basic job of other generation technologies.

Base load is the real reason solar PV is never likely to become a primary source of power for the world. We become more and more energy hungry every day. Base load grows every year, and we could not build enough solar farms and storage batteries to meet it without several more trillion dollars in investment.

Public Opinion Should not matter… But it Does.

This was another… “option”. The caption was “Frau fährt in Ihrem Elektroauto übers land und lädt diese mittels Solarpanels”. Was zum Teufel.

Solar PV has been getting a lot of good press and a lot of financial help. However, that alone is not entirely responsible for what we will loosely call its “success.”

On a dollar-per-kWh to produce, absent construction costs, nuclear power and hydroelectric are the unrivaled kings of reliable base-load energy production. Utility scale Solar PV requires about 7 acres of land per megawatt of production. The largest solar farm in the world is the Tengger Desert facility in China. It makes 1,547 mW and sprawls over an enormous 43 square kilometers of land. It cannot meet base load, it produces no power at night, and it is still only about 22% efficient.

An average nuclear power plant is 1,000 mW at 91% efficiency, and it takes up a couple of acres. The American side plants of Niagara Falls produce a combined 2,700 megawatts and you can’t even see most of those.

Both types produce electricity at a fraction the cost of fossil fuels with none of the pollution. Both can handle enormous base loads reliably. However, the siting, licensing, construction, and installation of these much-more-favorable types of generation are logistical and administrative nightmares.

Building a nuclear power plant in the US is simply a losing proposition for reasons that have nothing to do with the merits of nuclear power. The sheer quantity of red tape and NIMBY backlash for a nuclear plant drive the construction costs of what is already a pricey bit of tech well into the stratosphere. Nuclear power is a complex, counterintuitive technology. Despite a long history of safe, efficient, inexpensive power production, the bad press of the cold war era still haunts the industry. For instance, the US navy operates hundreds of nuclear power plants accident-free and has since the seventies. The US has never had a nuclear power plant fatality. Ever. Virtually every nuclear-power-related fatality in history occurred either at Chernobyl or inside a Russian submarine. The vast majority of radiation exposure death and injury is from radiotherapy and radiology material handling accidents outside of the US. If you mention any of this to your environmentalist friends, you’re going to catch a  few hurled expletives.

The track record of nuclear power is extremely good, and the only reason we are not building a hundred reactors right now is because people who saw “Chernobyl” on HBO are afraid of them. If nuclear power enjoyed the same financial and PR push solar PV is getting, fossil fuel use would be long on its way to the dustbin of history.

Hydroelectric is limited by siting. You need a good spot for it to work, and most of the good spots have people on them who don’t want to get flooded out of their homes. Costa Rica powers it’s entire country off hydroelectric power during the rainy season, but they have a lot less people than the US.

Hard Truth Time

We did not need Popular Mechanics, or anyone else, to tell us that a generation system heavily subsidized by tax money that uses a free fuel source was going to look pretty inexpensive on paper. What you should take away from the article is not that solar PV is going to be our savior and only the evil mega-corporations of “Big Oil” are stopping that from happening. What you should take from the article is that any technology with the right amount of good press and a few trillion in investment can be made better.

The rise of solar PV is a great example of how to accomplish this. It has terrific optics in that the fuel is free and the energy production produces literally zero by-products. Everyone can understand the advantage of those factors. Everyone can feel the fuel source on their face when they go outside, anyone can walk up and touch a solar panel without fear. The technology is intuitive, approachable, and benign. It is the Jonas Brothers of renewable energy. It looks good, it does not scare the parents, and with enough autotune it even sounds halfway decent.

But there is one teensy-tiny problem with our wholesome boy-band of clean energy. Solar PV is probably the least-effective path toward clean energy independence for any nation. Just like the Jonas Brothers, solar PV just not hardcore enough for the world’s needs. The investors in solar PV solved that problem the way corporations always do: They convinced the world there was no problem by firehosing a ropey stream of pure liquid cash at politicians incapable of understanding the technology in play. Those politicians then proceeded to vomit taxpayer money back into the PV industry until sheer fiscal horsepower alone slightly improved what had always been a marginal technology at best. Much of that money was lost or wasted, too. Solyndra alone cost the US taxpayers a half a billion dollars.

But it worked. The state of solar PV is well ahead of where it was ten years ago. Furthermore, solar PV will be a big part of our energy future, and it will absolutely fill a vital role. It will provide peak-hour trim and low-cost extra grid capacity. When the storage technology gets cheap enough, we will see it on every home in the US. The rise of solar PV is without a doubt a good thing. In this the Popular Mechanics article has every right to crow.

What the reader and energy consumer should be concerned with is how much further along our environmental and energy goals might be if that money and energy had gone into a more effective technology. In this case, virtually any other clean energy source would have produced better results. From a purely objective and logical point of view, it is hard to understand why there has been no massive increase in nuclear and hydro plants over the last thirty years. But then again, these decisions and policies are rarely made on the basis of objective logic.

Keep that in mind the next time you see a headline like the one Popular Mechanics chose for their sub-400 word article on an issue critical to the continued survival of humanity.

(Author’s note: This piece is more than 2200 words and I’ve barely scratched the surface of Solar PV’s role in our energy future. It took me 5.5 times as many words to begin to deconstruct that bit of fluff as Popular Mechanics spent to put it in your face. Remember kids, propaganda is easy. Comprehension is hard.)