Why This Solar Technology Is Already Dead

When critics of solar energy talk about the downsides of the clean energy, one of the criticisms that always pops up is the intermittent nature of solar power. The sun only shines for 12 hours a day on average around the world, and the most energy intensive time is far shorter than that.

So, it's easy to see why a technology like concentrated solar thermal power could be appealing to industry observers. Designs like power towers or parabolic trough designs concentrate the sun's energy on a point that then heats oil or another liquid, creates steam, and then turns a turbine to generate electricity. The energy can even be stored in molten salt to provide power into the evening hours.

But there's a big reason concentrated solar thermal technology won't be more than a small player in the market, and it's not the birds these plants are reportedly scorching mid-air.

Ivanpah Solar Electric Generating System's power tower collects solar rays from over 300,000 mirrors. Photo credit: Craig Dietrich via Wikimedia

The driver of solar energy long term
For solar energy to be competitive with fossil fuels it has to compete economically. That means that a kW-hr of electricity from a solar plant has to be cheaper than a kW-hr of electricity from a coal, nuclear, or natural gas plant.

It's on this basis that concentrated solar thermal energy was at or near the industry lead in 2008 when these plants were popular and power purchase agreements were around 21 cents per kW-hr, according to the DOE. But today they're not economically competitive; former leaders like Solar Millennium are going bankrupt, and projects like BrightSource Energy Hidden Hills and Palen projects are cancelled or delayed.

For a cost example, the Ivanpah Solar Electric Generating System that was recently completed began construction at a similar time to First Solar's (NASDAQ: FSLR  ) Topaz Solar Farm and, as you can see below, cost 29% more per watt.  


Topaz Solar Farm



Thin-film solar panels

Concentrated solar thermal-power tower 


550 MW 

392 MW

Construction Cost

$2.4 billion

$2.2 billion

Cost per Watt



Source: Ivanpah and First Solar.

The table above is even showing a favorable comparison for solar thermal energy because these projects were both approved years ago. Since then, the solar industry has seen panel costs fall over 50%, and according to GTM Research the cost to install a utility scale system is down 61%. We're even starting to see power purchase agreements fall below 7 cents per kW-hr, with PV technology winning those bids.  

Source: GTM Research.

There aren't many concentrator projects that have begun construction or even moved forward in the planning phase in the last two years, so it's difficult to give an apple-to-apples cost comparison today. But I would bet that the cost of mirrors, turbines, and molten salt for energy storage hasn't fallen at the same rate as thin-film or silicon based solar systems. That's the core problem for concentrated solar thermal technology.

Small solar installations on residential rooftops are a big part of the industry's future. Source: SolarCity.

Fighting industry trends
Cost isn't the only uphill battle for concentrated solar thermal. To build a solar thermal power plant you need to think big. These are plants you build on hundreds or thousands of acres in the desert, not something you can put up in your backyard.

That's fighting the solar industry's trend of moving closer to the demand source with smaller projects, even for utility scale projects. Systems between 10 MW and 50 MW are now a sweet spot because they can be built relatively close to demand sources with standardized designs and are easier to get through the permitting process.

So, not only is concentrated solar thermal energy higher cost than traditional PV solar, it's becoming hard to justify plants that are on the scale of 500 MW, no matter the solar technology.

Intermittent solar won't kill the grid
If you still think there's immense value in the less intermittent design of concentrated solar thermal plants, there's one region that shows that intermittent energy sources won't cause the grid to collapse.

Germany is the closest thing we have to a solar focused electric grid, so it's like a proving ground for the industry. The country is a leader in both PV solar and wind, which are both intermittent. In the first half of 2014, the country got 28.5% of its energy from renewable sources and as much as 75% of peak demand is now being filled by renewables.

The surprising thing is that with all of that renewable energy, Germany also has one of the most reliable grids in the world. The average German customer had 15.9 minutes of lost power according to recent data compared to 244 minutes in the U.S. So, having intermittent energy sources like solar won't kill the grid.

Concentrated solar thermal energy is already on its last leg
The fact of the matter is that PV plants built with standard solar panels are now so cheap that they make concentrated solar thermal plants uneconomical. That's why they've had a hard time getting off the ground in the U.S. and other places around the world over the last few years. Most plants that are being completed were planned and approved between 2008 and 2010 when the technology was competitive with other solar sources. But the solar industry changes rapidly and today PV is the future of solar, not concentrated solar thermal energy.

Uncle Sam is letting you in on the energy boom
You already know record oil and natural gas production is changing the lives of millions of Americans. But what you probably haven't heard is that the IRS is encouraging investors to support our growing energy renaissance, offering you a tax loophole to invest in some of America's greatest energy companies. Take advantage of this profitable opportunity by grabbing your brand-new special report, "The IRS Is Daring You to Make This Investment Now!," and you'll learn about the simple strategy to take advantage of a little-known IRS rule. Don't miss out on advice that could help you cut taxes for decades to come. Click here to learn more.

Read/Post Comments (5) | Recommend This Article (9)

Comments from our Foolish Readers

Help us keep this a respectfully Foolish area! This is a place for our readers to discuss, debate, and learn more about the Foolish investing topic you read about above. Help us keep it clean and safe. If you believe a comment is abusive or otherwise violates our Fool's Rules, please report it via the Report this Comment Report this Comment icon found on every comment.

  • Report this Comment On August 27, 2014, at 2:28 AM, terestactus wrote:

    One misleading aspect of this argument is that CSP only main competitor is PV. It's not - it's mostly Gas actually. And where gas is expensive and sunlight is relatively plentiful (ie India or Portugal) CSP makes economic sense. The author makes a simple assessment of what the energy market is like from the outside - CSP is being used to meet very different demands than what PV can provide.

    Second misleading item in this article is that it is implied that CSP only works on the large-scale. Completely wrong. There are plenty of cost-effective projects that work on the 10 to 50 MW scale. Link here -

    Third point - CSP is not just thermal. There are combined systems that collect of 60% of solar energy into a heat/electricity mix. On a per MW/acre basis this is incredible, especially combined with storage systems. One example is Sunfish Solar -

    Final point - Bird deaths at Ivanpah are regrettable, but much lower than existing coal plants and of course, the same problem occurs with wind turbines. Perhaps on a large scale. In that context, is any energy production method totally safe for birds?

  • Report this Comment On August 27, 2014, at 2:16 PM, TMFFlushDraw wrote:


    You make a good point about CSP not being just thermal and that's the reason I was very careful to say "concentrated solar thermal" and not CSP in the article. There are CSP technologies that will survive long-term. Maybe I could have made the distinction more clear.

    On your second point I disagree and and the Wikipedia list shows my point that almost all of the solar thermal projects were permitted in 2008-2009 timeframe when solar thermal was cost competitive with PV. Also, the costs seem pretty consistent at around $6 per watt for solar thermal. But I'd be happy to look at cost structures of these projects and compare to current PV plants (currently at <$2/watt) if you want to let me know what data you're looking at for these smaller projects.

    Travis Hoium

  • Report this Comment On August 27, 2014, at 5:36 PM, SkepikI wrote:

    And if you compare these with gas turbines at about $0.3 to $0.8/watt they both look very expensive....

  • Report this Comment On August 28, 2014, at 8:17 AM, SteveK9 wrote:

    The comments about Germany are the usual exaggeration.

    Germany got 4.5% of its electricity from Solar last year, after spending enough money to have built a nuclear fleet that would have completely eliminated coal burning (which supplied 46% including half of that from lignite burning ... about as 'dirty' as it gets).

  • Report this Comment On September 02, 2014, at 3:14 AM, coolice wrote:

    This article covers PV as a hero and CSP as a Villain. But there are more than this.

    I agree that the CSP is not as cost competitive as PV. But it is only a current scenario. PV price comes down only in the last 4-5 years. The earlier CSP has focused mainly on the Parabolic Trough technology. But now a days there are many other technologies which makes CSP future bright. Currently, they are not cost competitive and technologically workable in large scale but they are the future.

Add your comment.

Sponsored Links

Leaked: Apple's Next Smart Device
(Warning, it may shock you)
The secret is out... experts are predicting 458 million of these types of devices will be sold per year. 1 hyper-growth company stands to rake in maximum profit - and it's NOT Apple. Show me Apple's new smart gizmo!

DocumentId: 3082609, ~/Articles/ArticleHandler.aspx, 8/30/2015 2:12:07 AM

Report This Comment

Use this area to report a comment that you believe is in violation of the community guidelines. Our team will review the entry and take any appropriate action.

Sending report...

Travis Hoium

Travis Hoium has been writing for since July 2010 and covers the solar industry, renewable energy, and gaming stocks among other things.

Today's Market

updated 1 day ago Sponsored by:
DOW 16,643.01 -11.76 -0.07%
S&P 500 1,988.87 1.21 0.06%
NASD 4,828.33 15.62 0.32%

Create My Watchlist

Go to My Watchlist

You don't seem to be following any stocks yet!

Better investing starts with a watchlist. Now you can create a personalized watchlist and get immediate access to the personalized information you need to make successful investing decisions.

Data delayed up to 5 minutes

Related Tickers

8/28/2015 3:59 PM
FSLR $47.80 Down -0.04 -0.08%
First Solar CAPS Rating: ***
SCTY $48.00 Up +1.77 +3.83%
SolarCity CAPS Rating: ****