This group brings together the best thinkers on energy and climate. Join us for smart, insightful posts and conversations about where the energy industry is and where it is going.


Cost Of PV Cells Has Dropped 99% Since 1977, Bringing Solar Energy To Grid Parity


The price of solar photovoltaic cells has dropped 99% in the past quarter century. So in an increasing number of markets around the country, solar is at or very close to grid parity.

Consider Colorado. The Denver Business Journal reported last month the results of months-long competitive bidding process:

Xcel Energy Inc. is proposing to triple the amount of utility-scale solar power on its grid in Colorado, and add another 450 megawatts of wind power….

If approved, the plan would cut Xcel’s carbon dioxide emissions by more than one-third compared to 2005 levels.

David Eves, the CEO of Xcel’s Colorado subsidiary in the state told the Journal solar power is now cost-competitive with natural gas-fired generation:

“This is the first time that we’ve seen, purely on a price basis, that the solar projects made the cut — without considering carbon costs or the need to comply with a renewable energy standard — strictly on an economic basis.”

If solar power is seeing this kind of growth strictly on a cost basis, imagine how fast it would be growing if carbon dioxide had a price reflecting its actual harm to the environment and human health.

The Journal reports that Xcel’s proposed plan includes:

    • 170 megawatts of big, utility-scale solar power plants to be built in Colorado — separate from Xcel’s proposal to add 42.5 megawatts of small-scale solar power the utility proposed in July.
    • 450 megawatts of new Colorado wind power, bringing the company’s total wind-based power supply in Colorado to 2,650 megawatts.
    • 317 megawatts of “low-cost” power from natural gas plants the utility will use when the wind stops and the sun goes down.

Much of the credit for the sharp drop in solar prices goes to state and federal governments here and around the world for decades of R&D support, PV purchases, subsidies, and renewable energy standards.

Those who say renewables are not ready for mass deployment, that we need decades more research or more breakthroughs before renewables are ready, are living in the past. The future is now.

The post Must-See Chart: Cost Of PV Cells Has Dropped An Amazing 99% Since 1977, Bringing Solar Power To Grid Parity appeared first on ThinkProgress.

Joseph Romm's picture

Thank Joseph for the Post!

Energy Central contributors share their experience and insights for the benefit of other Members (like you). Please show them your appreciation by leaving a comment, 'liking' this post, or following this Member.


Spell checking: Press the CTRL or COMMAND key then click on the underlined misspelled word.
Bob Meinetz's picture
Bob Meinetz on Oct 8, 2013

Joe, I don’t really understand what we’re supposed to be excited about when Colorado’s plans to incorporate solar include installing eight times as much natural gas generation, when capacity factor is included. Is the cost of these plants included in your “grid parity” calculation? What about incentives/rebates?

I’ve always respected your opinions in the past, in particular your writing on hydrogen transportation. But claiming grid parity for this tiny, highly-subsidized and incentivized source of energy backed up by fossil fuels is just absurd.

Though solar will always have a place in energy generation, when I hear a scientist using hyperbolic advocacy of “mass deployment”; that the “the future is now”; or implying anyone who doesn’t join in the party is a Luddite – it’s somewhat depressing. Countering denial with denial is just counter-productive.

Robert Bernal's picture
Robert Bernal on Oct 8, 2013

I used to project massive and global solar based on its past (and exceptional) growth rate. Now, I see fundamental material limitations as a major wall inbetween much further price reductions. Consider the following hypothetical scenario. In ten years, machine automation makes hundreds of thousands of square miles of solar panels for 50 cents per watt… AND the battery storage for like 50 cents a Wh. Will we even be able to afford such a massive erecting of framework? Yes and no. Yes, if we are “allowed” to mine such large amounts of metal, and no, if things go on as usual with environmentalists continuing to complain about large wind and solar…

A deployment of molten salt nuclear could easily power the production of total wind and solar as well as replace most fossil fuels use!

Josh Nilsen's picture
Josh Nilsen on Oct 8, 2013

It sounds like you just don’t like being told you’re wrong, which you are.  The facts disagree with everything you’ve written.

Bob Meinetz's picture
Bob Meinetz on Oct 9, 2013

Troy, in a word: nonsense. Perhaps the Church of Renewables finds it acceptable to lie and cajole in order to attract new recruits, but these numbers are false – and solar, at a little over one-tenth of one percent, indeed represents a tiny sliver of American electricity generation. Here are the actual figures from the U.S. Energy Information Administration:

Bob Meinetz's picture
Bob Meinetz on Oct 9, 2013

Troy, the 1% quoted on the graph is its composite part of 12% renewables. Its share of total electricity generation is .12%.

No doubt when the information is updated, solar advocates will trumpet how it’s share has doubled – to one-fourth of one percent.

I have no “weird emotional attachment” to fossil fuels, in fact I believe we need to stop using them as quickly as possible. Ironically, renewables have become pawns of the fossil fuel industry and are helping to make fossils viable for decades to come. This is largely because most renewables advocates are coasting on enthusiasm and have little technical understanding of energy issues.

There are several other distortions in your post which are probably outside the scope of this discussion. I’d urge you to look outside industry sources for data, in particularly to the U.S. Energy Information Administration, which probably has the most objective numbers on generation and adoption of renewables.

Robert Bernal's picture
Robert Bernal on Oct 9, 2013

I’m not against hundreds of thousands of sq miles of solar installations planet wide… as long as it could be cheaper than nuclear.

Speaking of which, “those in the nuclear camp” have figured out a way to deal with the wastes… it’s called a molten salt reactor (search LFTR). Over 99% of the (un) spent fuel from conventional LWR’s would have been burned in a LFTR, thus leaving what’s called fission products. They are highly radioative, but become radioactive free in about 300 years. Since there is sooooo much less of them (than LWR waste) it is far easier to contain and isolate. Should the little glass and metal storage container break in a thousand years… no problem!

Consider that the LFTR wastes from powering an average American’s entire life would occupy a volume less than a soda can, perhaps much less (because only a ping pong ball sized amount of thorium is needed to power that entire lifetime)! In comparison, how large is the average American’s CO2 footprint???

Eventually, automation could make (that very large expanse of) solar and batteries cheaper… but not anytime soon. LFTR, on the otherhand, has already been proven on a demontration level, decades ago. Only fear and “other interests” have successfully interfeared to make it appear as if it was not!

Bob Meinetz's picture
Bob Meinetz on Oct 9, 2013

Thanks for that cogent dose of reality, Robert. I’ll toss in a plug for the LFTR’s significant resistance to proliferation:

“Molten salt reactors (MSR) have many non-proliferation attributes. They can operate on the thorium-uranium fuel cycle which protects the fissile material by the daughter products of the inseparable U-232. MSRs can completely fission all plutonium and HEU, and as desired, ‘convert’ them to U-233. This also results in high, and efficient resource utilization, while diminishing the plutonium stock. On line processing, when applied, could free the waste from all fissile material. The fuel in the reactor stays protected by the intense radiation of the fission products. Fuel can also be protected in the reactor as well as outside the reactor by denaturing with natural uranium. A wide variety of MSRs are available, from ‘once through’ minimum processing reactors to ones with fuel processing which can breed fuel for converters. MSRs are extremely safe and simple reactors with good economic potential.”

Bob Meinetz's picture
Bob Meinetz on Oct 9, 2013

Troy, T. Boone Pickens is a natural gas magnate who has cynically manipulated unwitting environmentalists for years through various schemes like “The Pickens Plan” (my link), which originally sought to build hundreds of square miles of wind in Texas which would be wholly dependent on his natural gas for backup.

His latest pig-with-lipstick was described in Forbes two days ago.

I’ve been following the solar industry since Jimmy Carter put solar panels on the White House roof almost forty years ago, and heard this “doubling, tripling every year” mantra fairly consistently since then. Though the last few years have seen an historic rise in PV worldwide, it’s largely thanks to government assistance which is neglected in virtually every assessment of grid parity. As to whether the money is being well spent, I’ll let you be the judge:



Stephen Nielsen's picture
Stephen Nielsen on Oct 9, 2013

There is not one commercial scale LFTR on line anywhere in the world. They exist on paper.  Yes, the LFTR in Oak Ridge back in the day worked – but if memory serves, it had maintenance issues and major decommissioning problems that lasted all the way to 2009.  China is trying to built an experimental LFTR now (with our help).  If it works, great, but it will still only put out 7mW and scaling up to 1gW will not be trivial. LFTRs would be much preferable over current high pressure reactors. But, as always, the devil is in the details:

1.  Regulatory problems –  LFTR would be a completely new way of thinking about nuclear which means big learning curves for operators and an entirely new and or expensive and varied regulatory regime.

2. Build times – the build times on an AP1000 (Gen 3 but still boiling water) are big.  How long would it take to build a LFTR? We don’t even know, right?

3 Investment – The nuclear industry has a serious lack of private investors problem and LFTR needs enormous amounts of taxpayer funded research dollars… we’re not even talking about actual construction yet. 

4. Waste – Waste will still be a problem. Even with LFTRs, a geological repository will still be needed

5. Politics – In a democracy, as opposed to authoritarian alternatives, all nuclear will continue to have steep political hills to climb

Meanwhile,  nanotech energy solutions are advancing exponentially.  By the time even a single commercial scale LFTR is up and running, nano energy will be cheaper and easier – AND more reliable – these technologies are not based on machines, but on materials – no moving parts

Looking ahead even in the mid term, nano energy techs are the wiser and obvious investment choice and the financial world knows it.  Better for us to invest our tax dollars there

Paul O's picture
Paul O on Oct 9, 2013


You Neglected to mention that HydroElectricity (AKA Dams) make up 6.2 percent of that 14% you are mentioning.

This means that the rest, Wind/Solar/Whatever produce only &.8 percent of US power. Now that is what anyone would call a sliver, don’t you think?

Speaking of Hydro power or Dams, It is a HUGE IRONY that “environmentalists are now in love with Dams, seeing that lesss than 10 years ago, they were spearheading a movement to remove and destroy dams because they were bad for the environment and species.

Robert Bernal's picture
Robert Bernal on Oct 10, 2013

I don’t like to base the future of energy on the past… just on physics.

Regulatory people are only thinking about the norm (as they should be). We need different inspectors for different power plants.

Build times would be less than the LWR, because less material is needed, less engineered safety components and because they need to be built in a factory, anyways, to be cheap enough to compete with new coal with CO2 regulations.

It was cut just before the final proving statges… no wonder there wouldn’t be any investors. A re-development plan into commercial testing stage is needed (so that investors would know that LFTR is worthwhile). If we are to seriously address the global excess CO2 challenge, we should at least be up to this challenge!

A few geological waste depositories are far cheaper and easier than dealing with the effects of global excess CO2.

Despite democracies’ continuously infighting, division and polarization, they are still adept to necessary changes (we hope).

Nanotech still needs to be proven (let alone on the commercial scale I ask for LFTR). Energy collection via nanotech would then require vast amounts of land in order to gather solar and wind. It would also require vast amounts of energy to build the necessary amounts of solar and wind (and heat?) gathering devices to power a planetary civilization without fossil fuels and nuclear because physics demands energy input. Every part of a building may collect energy but it will still be trivial unless such is facing the proper sun angles, just as with “conventional” PV. Shadows will still be real and houses will only be good solar collectors if they are proprely designed to be, just as now.

Hopefully, the nanotech counterparts would be more efficient at its own production as well as in gathering and storage.

I do NOT argue against these renewables, as “real” nuclear proponents do, because, eventually it may be cheap enough to have “machines” do all the work for us. Problem is, that democracy thing, and all the money that people want off of every little kWh. Machines could make “everything free”, but greedy people won’t stand for that!

I really hope you are right about nanotech, because that would be awesome. I promote LFTR because I know it can be done (and because it would be better than conventional). It takes less land, requires no international powerline commitments (for countries and states with weak renewable energy resources, is safer than conventional nuclear, is less proliferation prone, can be used to make energy from “spent” fuel, can be made in a factory, requires about 200x less mining as conventional nuclear and most importantly, can quite literally solve the most challenging issue of our time… excesss CO2 without having to impose too much of a carbon tax.

Bob Meinetz's picture
Bob Meinetz on Oct 10, 2013

Stephen, regarding the points you make about LFTR development:

1 – 2) Speculative, could be cheaper/faster/easier than PWRs.

3) Dr. Stephen Boyd is one of a generation of brilliant young physicists who has recognized the potential of LFTRs and aggressively sought funding. His experiences are laid out in detail here, but in a nutshell: while research continues apace in Canada, Russia, China, the Czech Republic, Australia and India there is pushback in the form of licensing and lack of funding from Washington. Much of it is attributable to “Big Uranium”, a multi-billion dollar industry which a successful breeder design could marginalize.

4) Waste will not be a problem (and is not a problem now) except in public perception. Education will be key to addressing public concerns.

5) The only political hill nuclear has to climb is the one outlined in #3: lobbying from competing technologies.

Regarding your final comment, what exactly is “nano-energy” (nanomaterials don’t generate energy out of thin air, and thus aren’t an alternative to nuclear or other sources)?

Stephen Nielsen's picture
Stephen Nielsen on Oct 10, 2013

I agree. All nuclear waste is a potential resource.  And if money grew on trees, all resources might be retrievable.

Stephen Nielsen's picture
Stephen Nielsen on Oct 11, 2013


Stephen Nielsen's picture
Stephen Nielsen on Oct 10, 2013

A varied regulatory regime would be cheaper? That’s an interesting point of view.  The proposition that waste is not now and will never be a problem is interesting too.

If only money were not a part of solutions.


No, nano materials do not generate energy out of thin air.  They harvest the very abundant energy that travels through the thin air, or water. They already do this more cheaply than today’s energy generation methods

Stephen Nielsen's picture
Stephen Nielsen on Oct 10, 2013

I absolutely agree that LFTR (once proven economically viable) is far superior to today’s nuclear.

Nathan Wilson's picture
Nathan Wilson on Oct 10, 2013

It’s ironic that Romm is now praising solar PV.  He has long been an advocate of concentrated solar thermal (which is being squeezed out of the market by PV, along with other baseload technologies).  In this 2008 article on Salon, Romm says, 

The [necessary massive amount of carbon-free] electricity cannot be intermittent and hard to store, as is energy from wind power and solar photovoltaics. … Solar electric thermal, also known as concentrated solar power (CSP), meets all these criteria. 

The popular notion that the cost of batteries will follow the same curve as PV does not match reality.  PV has dropped as the production volume has increased, but batteries have been produced by the tens of millions per year for many decades.  Dispite all attempts, no technology has surpassed lead-acid for low initial cost, and only utility-scale high-temperature batteries (like sodium-sulfur) have come close. 

Solarbuzz gives a cost of $0.213/Wh for lead-acid batteries.  Using 50% depth of discharge (which is the maximum for acceptable cycle life), a 15 hour system would cost $6.38/Watt (storage only).  This provides 24 hour a day PV power, but only in the summer; expect a year around average of only 50% of nameplate, even with 3x over-sized panels in most locations.

In addition to offering much cheaper energy storage (CSP has almost the same cost per kWh, with or without storage, especially when new transmissions is included), CSP also encourages utility-scale installations in desert locations which have fewer clouding days.  PV encourages use in cloudy locations (which virtually guarantees batteries will never be adequate for smoothing their output), and encourages rooftoop installation, which impedes maintainance (discouraging long life), and impedes end-of-life recycling.  Advocates toute the $0.74/Watt cost of the PV cells, but this balloons to $4.81/Watt for residential installation, and $2.10/Watt for utility scale (according to the SEIA).

The new 280 MWatt Solana solar CSP plant just came on-line, with 6 hours of thermal energy storage.  Like the other CSP plants now under construction by Brightsource and Solar Reserve, it was started back when CSP was cheaper than PV, so it’s not clear that there will be any new CSP in the US (thus the risk that solar could become nothing more than a means to lock-in fossil backup).

Stephen Nielsen's picture
Stephen Nielsen on Oct 10, 2013

Yes, I have heard of the 2nd law of thermodynamics. So, I’m sure, have the scientists working on these ingenious and elegant solutions. No, I’m not talking about static electricity or flux capacitors or warp drives.

It is not in my power to place a wager on the future of the atmosphere, I only have the power to point out trends in research and in the marketplace. Energy harvesting nanomaterials are almost certainly the future. Enormous, expensive machines with quadruple safety redundancies are almost certainly not the future.  

Yes, there are many troubling questions about nanomaterials, genetics, robotics, etc.  Undaunted, we step into the future nonetheless. Your emotional outbursts are irrelevant

Paul O's picture
Paul O on Oct 11, 2013

Troy, in a word: nonsense. Perhaps the Church of Renewables finds it acceptable to lie and cajole in order to attract new recruits, but these numbers are false – and solar, at a little over one-tenth of one percent, indeed represents a tiny sliver of American electricity generation. Here are the actual figures from the U.S. Energy Information Administration:

Thank You, finally somebody understands my frustration with RE advocates.



October 9, 2013

Paul O says:


You Neglected to mention that HydroElectricity (AKA Dams) make up 6.2 percent of that 14% you are mentioning.

This means that the rest, Wind/Solar/Whatever produce only &.8 percent of US power. Now that is what anyone would call a sliver, don’t you think?

Speaking of Hydro power or Dams, It is a HUGE IRONY that “environmentalists are now in love with Dams, seeing that lesss than 10 years ago, they were spearheading a movement to remove and destroy dams because they were bad for the environment and species.

Share this comment:

Bob Meinetz's picture
Bob Meinetz on Oct 11, 2013

Troy, that’s not my graph. It was created by the U.S. Energy Information Administration, an offshoot of the Dept. of Energy, which puts a lot of effort into trying to honestly assess various energy technologies and markets.

Here’s another illustration which hopefully will help you understand how insignificant solar’s contribution to the energy picture is – despite inflated claims made by industry sources and a few academic mystics. I’ve had to shrink the graphic to fit here, but solar is the thin yellow line, and only represents solar’s share of nonhydro renewables, not all energy:

I’ve also included a link to the page from which it comes, which, with links, presents more pertinent info than either you or I have the patience to examine.

That said, if you want to attack the graph I’m really only interested if you can take issue with the underlying methodology from which it’s prepared, all there on the EIA website. If there truly is a weak spot here, you’re going to have to be prepared to show why using more facts and less unsupported opinion.

Bob Meinetz's picture
Bob Meinetz on Oct 11, 2013

Richard, there aren’t any hard and fast rules but usually reactors are taken down during periods of low demand (winter, non-holidays) when there are plenty of other resources from which the regional system operator can draw. The capacity factor, or percentage of their maximum capacity they actually deliver, has improved over the last thirty years and is now over 90%. This is by far the most reliable performance of any energy source; 3x better than wind and 6x better than solar. Other capacity factors:

  • Natural Gas Plant–11.4%
  • Oil–7.8%
  • Hydroelectric–39.8%
  • Other renewables (Wind/Solar/Biomass)–33.9%
  • Coal–63.8%
  • Nuclear–90.3%

During last summer’s heat wave all but 2 of America’s reactors were operating at 100%, but Dominion Energy ran into trouble they they shut down two plants for maintenance in September and the East was hit with a late heat wave. It resulted in outages lasting for several days.

Get Published - Build a Following

The Energy Central Power Industry Network is based on one core idea - power industry professionals helping each other and advancing the industry by sharing and learning from each other.

If you have an experience or insight to share or have learned something from a conference or seminar, your peers and colleagues on Energy Central want to hear about it. It's also easy to share a link to an article you've liked or an industry resource that you think would be helpful.

                 Learn more about posting on Energy Central »