#1 cleantech news, reviews, & analysis site in the world. Subscribe today. The future is now.

Clean Power

Published on June 26th, 2015 | by Anand Upadhyay


Largest Solar Plant On Planet Earth — Solar Star — Comes Online

June 26th, 2015 by  

I know, I know. All our heart goes out to distributed solar, but utility-scale solar installations in the United States are very much alive and kicking. In fact, of the 6 GW of new solar capacity added in the US during 2014, 63% of it came from utility-scale plants.

This included two mammoth projects — Topaz Solar and Desert Sunlight — 550 MW each, both developed by First Solar. However, both of these plants could not, as the phrase goes, “bask in the sunshine” even for a year (actually not even seven months).

The Solar Star solar power plant, with a total capacity of 579 MW, went fully online on June 19, 2015, as per the California Independent System Operator (CAISO). For now, it is the largest solar power plant in the world, with a lead of 29 MW over its closest competitors.

solar star implementation date

BHE Solar, a subsidiary of Berkshire Hathaway Energy (known as MidAmerican Energy Holdings Company until 2014, one of the investment arms of Warren Buffet) owns the projects. SunPower Corporation, which is the engineering, procurement, and construction contractor for Solar Star, will also cater to its operations and maintenance.

Our regular readers would be aware that BHE also owns the Topaz Solar plant.

The electricity produced by Solar Star is being purchased by the utility Southern California Edison under a long-term power purchase agreement (PPA). The specifics of the agreement haven’t been publicly disclosed.

Quite interestingly, at the moment, the world’s three largest solar plants — Solar Star, Desert Sunlight, and the Topaz project — are all located in California, USA.

solar star project layout

Solar Star Project Layout

Solar Star, which was formerly called Antelope Valley Solar Projects, is actually two projects — Solar Star 1 and Solar Star 2 — co-located in Kern and Los Angeles Counties in California, USA. Installed across 3,230 acres, the projects employ 1.7 million SunPower monocrystalline silicon PV panels.

The construction for the project started in January 2013, and was scheduled for completion towards the end of 2015, so it’s quite a feat that they could manage to wrap up 6 months ahead of schedule!

The Solar Star Projects will deliver enough electricity to power the equivalent of approximately 255,000 homes. The projects have also created approximately 650 construction jobs over a 3-year construction period. In addition to this, up to 40 operations and maintenance jobs, including 15 full-time site positions, will be created during the life of the project.

In terms of emissions, more than 570,000 tons of carbon dioxide will be avoided annually — the equivalent of removing over 2 million cars from the road over 20 years (source).

solar star google maps

Solar Star Satellite View

The plant is built on what SunPower calls “Oasis Power Plant” technology. Essentially, to cash in on the large-scale plant (and thus, the opportunity), a modular design is used for rapid deployment. Per the company, this helps save money, time, and land resources as well.

Each 1 MW “power block” integrates SunPower Trackers with SunPower solar panels, pre-manufactured system cabling, an inverter, and a power plant operating system. The power block kits are shipped pre-assembled to the job site for rapid field installation.

Since cleaning such a large facility would otherwise consume a lot of water, and time, SunPower has automated the process. This, the company claims, will consume 90% less water and is 4 times faster than manual cleaning methods (more information here).

The projects also employ SunPower C1 Trackers (single-axis), which are said to boost annual energy yield by 25% as against fixed-tilt systems. The tracker uses a single motor to control many rows.

According to data released by the Solar Energy Industries Association and GTM Research over the 2014 performance of the US solar market, the utility PV segment is becoming more competitive. The report points out that more than 4 GW of centralized PV capacity had been procured by utilities based on solar’s competitiveness with natural-gas alternatives.

2015 is expected to be another good year for utility-scale solar in the US. However, there are concerns that the aggregate net energy metering (NEM) capacity limit in California could be reached by the last quarter of 2015 or early 2016. As a result, installers are pushing to expedite sales through the first half of 2015.

Once the cap is reached, the next version of NEM is scheduled to take effect — although, decisions regarding NEM rule revisions could be announced by the CPUC as late as December 2015.

So, which would be the next plant to clinch the title? There are a few probables in the runup – herehere, and here), but your guess is as good as mine.

Want to know what 579 MW of solar awesomeness looks like? Open up Google maps on this link and see it for yourself!

Photo Credits: Solar Star Project Layout via SunPower, Solar Star Satellite View via Google Maps

Tags: , , , , , , , , , , , , , ,

About the Author

is an Associate Fellow with The Energy and Resources Institute (TERI, New Delhi) - an independent, not-for-profit research institute focused on energy, environment, and sustainable development. Anand follows the Indian solar market at @indiasolarpost. He also writes at SolarMarket.IN. Views and opinion if any, are his own.

  • Jesús Rafael Rojano Gonzaléz

    Somebody knows how much does it cost?

  • Larry

    Bravo Berkshire Hathaway!

  • plainview2

    If Southern California Edison is entering a long term PPA before the true avoided costs of fossil fuel production is fully quantified and installed solar continues to fall in price; are the people going to recognise a 50-60% reduction in their monthly power bills or is this just another monopoly grab at the consumers wallet for the benefit of Berkshire Hathaway?
    How can utilities make long term commitments when the price of production should fall in the future?

    • Matt

      If it falls too far, then they will do like FL power did. They acquired a coal plant and shout it down to get out from under a long term PPA from the plant.

    • Bob_Wallace

      You’re conflating issues. Renewables are almost certainly going to lower the cost of electricity in the future. How we create fair prices for consumer and utility companies is a different issue.

  • Robert Pollock

    Without more information I shouldn’t post this, but I’m pretty sure Mr. Buffet’s Energy company is in partnership with some big Petro people, specifically the Saudi’s, who seem to have many ‘highest’ level connections in America’s emerging ‘national’ energy sector. Personally I don’t care whose money makes this stuff happen, it’s the very best we’ve got at this time.
    I like owning my own systems however…..and biggest isn’t always ‘bestest’, especially when it comes to the little people.

    • Matt

      The big plus of DG verses central is plug parity (DG) verse grid parity(central). But even grid parity should be compare new to new. What is the PPA for new NG plant, new coal plant? We know the latest Nuc, it is in the UK and cost is not single digit per kwh. We need to get at least the health externals added into gas/coal and then this whole conversation goes away. Well at least for on shore wind and PV; no one has a long term working wave yet so don’t have real cost numbers for it.

  • TmH

    We should not be thinking “central” or “distributed” only.

    Use any and all.

    There can be not limit to the number of ways we accept to get clean energy.

    Even with every house and car on green energy there is still room for a future NUCLEAR FUSION plant to generate capacities that only it can do.

    Lets not limit ourselves at all.

    • Bob_Wallace

      Sure. Bring affordable nuclear fusion to the table and we can give it a good consideration.

      Thing is, right now affordable nuclear fusion is as available as affordable unicorn farts.

      • just_jim

        We have an existing nuclear fusion plant 93 million miles away that we are tapping for electricity right now. So don’t dis nuclear fusion.

      • Matt

        Bob as soon as I finish work my anti-gravity device, I’ll get to work on my fission/fusion machine. It splits the atoms then puts them back together again, it small about the size of a sub-zero dual until. My back to the TP guess is 0.001 kwh.

  • newnodm

    Can someone explain the open space? Why are the array sections spread out somewhat?

    • Bob_Wallace

      Some of the reason looks like it could be topography. Looks to be some rough patches within the greater site.

      I wonder if they will eventually fill in more….

      • I have actually emailed Sun Power to ask about this, will keep you guys posted

        • Bob_Wallace

          After seeing a picture of the site I’m withdrawing my topography guess. Now I’m guessing that this farm will grow and fill in the open spaces.

          Big advantage for wind and solar farms, they don’t have to wait until they are totally finished before they can fire up an income stream.

          • jeffhre

            I believe there was quite a bit of open space set aside in the final agreement IIRC. I don’t know how much flexibility BHE and SP had in choosing final panel locations. If there was some flexibility, then they could choose the easiest to erect locations. Maybe some time I’ll do a drive by – maybe not though. They all look about the same to me 🙂

  • SecularAnimist

    The article states: “The electricity produced by Solar Star is being purchased by the utility
    Southern California Edison under a long-term power purchase agreement
    (PPA). The specifics of the agreement haven’t been publicly disclosed.”

    Why have the specifics of the PPA not been publicly disclosed? It would certainly be interesting to know the going cost of electricity from a brand new, state of the art, utility-scale PV facility.

    • Bob_Wallace

      No information on that one but I read recently that solar PPAs are now being written for as little as $0.04/kWh. That makes the production cost under $0.055/kWh.

      (2.3 cents for first ten years production / 20 year PPA = 1.15/kWh subsidy.)

      • dcard88

        Not by So Cal Edison. Probably around .10, but I doubt if its under .08.

        • Check the bar chart in this article – http://cleantechnica.com/2014/11/29/dubai-shatters-solar-tariff-records-worldwide-lowest-ever/

          It’s been some time…

          • dcard88

            I already did, where do you think I got the 7.1 lowest KNOWN in the USA so far. Presumably there have been PPA’s lower this year, but the average is well over 7.1 so far. I have little interest in cost in other parts of the world where labor is dirt cheap.
            Its been sometime since you were selling 1 mW inverters and 20 mW switchgear to contractors (myself)? $800 combiner boxes? Since you have priced a system for your home? Been some time what?

          • Relax. I only meant that its been some time since that chart was published! Wonder what got you so excited.

            I am sorry though, that I did not read your previous comment.

            Also cheap labor in developing countries does not help much as financing costs are still VERY high. And yes, I have priced systems for 5 MW installations if you really need to know.

          • dcard88

            Don’t tell me to relax. You don’t have a clue what my emotional state is. Maybe you should focus on what you do know.
            You are the one who questioned the time. That’s the whole point of the discussion. When do we achieve parity? I say not yet. You can disagree or not.

          • Well. I agree with you on this. Pricewise grid parity is still tucked away somewhere in the (near) future.

            But I also think that parity should not be judged solely on the basis of price, dispatchability of solar power should also be a criteria.

            But I am optimistic that things will fall in place.

          • dcard88

            Agreed. Optimism is the best attitude. I hope the numbers are closer to your opinion.

          • Bob_Wallace

            There seems to be a problem with the last four bars in that graph. Or with two of them.

            The PTC is 2.3c/kwh for the first 10 years of production. That means on a 20 year contract the spread between subsidized and unsubsidized cost would be 1.15 cents. 0.9 cents on a 25 year PPA. The graph spread looks like it’s the entire 2.3 cents.

          • (I only have a working knowledge of solar finance in US.)

            Is it not that Investment Tax Credit (ITC) is valid for all solar projects that get commissioned before the deadline of December 2016? (Links – http://energy.gov/savings/business-energy-investment-tax-credit-itc and http://www.seia.org/policy/finance-tax/solar-investment-tax-credit)

            So that’s a 30% saving on the real LCOE right?

          • Bob_Wallace

            Solar in the US has a choice between a 30% Investment Tax Credit or a 2.3 cent/kWh for ten years Production Credit. One would think the economic benefit would pencil out roughly the same.

            If a company has other income they’d like to shelter then they can opt for the ITC and reduce their taxes by 30% of the value of the project. Some companies are going to do that because getting your money up front has value.

            Other companies are going to opt for the PTC and pay less taxes on profits over the first decade.

            I would imagine most wind farms are structured as free-standing corporations, don’t know if tax credits (in the case of the ITC) are transferrable to another party/corporation. Back 30 years ago some wind farms were structured to permit passback to investors (I looked into investing in one of the Altamont Pass wind farm projects).

            The 30% ITC would effectively lower the capital cost 30%. It wouldn’t mean a full 30% drop in LCOE, operating expenses would stay the same. And if the tax savings weren’t used to pay down the loan the financing cost would remain the same.

            What I don’t know is if the ITC is or is not an accelerated appreciation program. If it is then the taxes on farm profits would be higher as depreciation write off would be lower.

            Your first link is for PTC programs for commercial installations, not utility scale/wind farms. You second link is returning an error message.

          • Sorry about the links, the parenthesis in the second link was causing the problems. Here it is – http://www.seia.org/policy/finance-tax/solar-investment-tax-credit

            As for the first one, this report from NREL seems to be a better replacement – http://www.nrel.gov/docs/fy12osti/48685.pdf

            The executive summary of the NREL report makes a mention of accelerated depreciation schedules.

        • Bob_Wallace

          Don’t know what SoCal Ed is paying but here’s how things are running in the US.

        • Matt

          Ok dcard88, back at you. Please show copies of real contract they you have access to to should these 0.10 cost. You can’t keep repeating that only contract are valid for the debate and then not provide even one link to back up you claims. You don’t even provide a link to a claim of cost that high, just your doubt.

          • dcard88

            It appears you disagree with my educated guesses. OK

          • Bob_Wallace

            You toss out your “educated guesses” with no supporting evidence. And then you toss away information presented by others because you “don’t trust” information coming from well known and highly regarded sources.

            This does not look good….

          • dcard88

            If you want to consider me overly skeptical, thats fine. I don’t like evidence that could easily be colored. I hope you are correct about prices averaging below 5 per watt subsidized, but I don’t see it yet.
            And of course I could care less how it “looks”. I am right more than wrong, often when alone in my opinion, and thats good enough for me.

  • Jason hm

    All that metal and shade? combine that with some rock mulching and you could create a strong air well/ atmospheric moister condenser effect. Time we start thinking of land devoted to Solar energy as a system with possible multiple synergistic uses. Done right you could improve the local ecology by capturing retaining more water and create secondary revenue streams. You might be able to provide enough water by this to support orchards or vineyards interspersed among the panel arrays.

    Anyone know if this is being studied?

    • Kyle Field

      I’m not aware of anything happening in this space but it makes sense. I’m sure we’ll get there as more and more plants come online at this scale – 3300 acres!?! crazy!

    • Larmion

      Vines and orchards would be tricky, for various reasons:

      a) Solar farms are built on marginal land. As a result, yields will inevitably be marginal as well.
      b) The farming operation would have to be done entirely manually, as heavy machinery would struggle to get access.
      c) The solar farm would dampen winds. Expect increased proliferation of pathogenic fungi.
      d) Good luck finding a horticultural crop that thrives in partial shade and that doesn’t grow tall.

      In short, it wouldn’t make financial or agronomical sense. You could do it (just like you could also make stuff grow on the moon if you were so inclined), but it would be a waste of precious resources.

      Solar farms do support extensive grasslands, so a small herd of goat/sheep is an option. But serious food production? Not an option.

      Fortunately though, we have plenty of farmland and a huge global food surplus (something not mentioned often enough imo).

      • Bob_Wallace

        The general area might not be good for crops but there are things like lettuce that might do well under partial shade. And cultivating/harvesting machines do not have to be tall. Especially if they are fully automated.
        But I don’t think we are so starved for croplands that we need to concern ourselves that much about the area under solar panels.

        • Larmion

          Lettuce is extremely water and nutrient-hungry, prone to bolting in high temperatures, competes very poorly with pests and weeds and requires careful post-harvest storage due to its high water content. Solar farms are dry, hot, inacessible to machinery needed to deliver crop protection agents and far removed from processing facilities.

          Lettuce is an incredibly hard crop to grow in a good field, let alone in a solar farm. There’s a reason why most lettuce is now grown in greenhouses or polytunnels.

          Perhaps the best way to use solar farms is to simply leave them fallow. They could act as small nature reserves within agricultural areas, offering a haven to native flora and fauna.

          That’d fit in nicely with Borlaugh’s hypothesis, which is that maximizing output from the best fields while leaving the rest to nature is better for biodiversity than farming a greater amount of land in a more ‘eco-friendly’ but less productive way.

      • dcard88

        Not sure why you guys are suggesting growing in partial shade. The closest any plant that needs attention would get to a solar panel is many yards away. No shade anywhere. At a minimum we are talking a few yards to an 8 foot fence with big red warning signs to stay out. Probably closer to 10 yards.

        • Bob_Wallace

          There are anti-solar farm individuals who have bemoaned the ‘sterile’ ground beneath solar panels. That’s created a not-very-serious discussion about double use for solar farm lands.

          In desert areas we aren’t likely to grow crops underneath the panels. We’ll likely use robots for panel cleaning and they use very little water. (I think many people have very little idea how large US desert lands are and what a tiny percentage might get used for solar.)

          In high rainfall areas it might make sense to graze sheep or rabbits underneath the panels in order to avoid the cost of mowing. Might be simpler to use robotic lawn mowers.

          • dcard88

            The only sheep that will ever come close to a solar farm would have to have an EE degree, a permit from some authority, and a key to the gate.

          • Larmion

            Where is that college for sheep? It must turn out graduates at an astonishing rate, given so many sheep already happily much in and around solar farms.

            So much so, in fact, that the NFU (the British farmer’s trade body) already released a guide for farmer’s on the issue: http://www.bre.co.uk/filelibrary/nsc/Documents%20Library/NSC%20Publications/NSC_-Guid_Agricultural-good-practice-for-SFs_0914.pdf

            Many agricultural research organisations, both private and government-owned, are still researching the optimal grass mixture for solar farms, so expect further progress in productivity beyond what’s mentioned here.

            Solar farms will never be prime farmland, but they’re just fine for light grazing. In countries with low labor costs, hardy herbs and ornamentals can also be a viable second use, as Anand’s link shows.

          • dcard88

            How many solar farms have you been to personally? I am focused on the USA. Feel free to send me a picture of an animal grazing within 10 yards of a solar farm panel in the USA. I like finding out stuff, especially if I’m wrong.

          • Bob_Wallace

            “SAN ANTONIO — The landscapers at this 45-acre solar farm northeast of downtown do not complain that they are only paid in shrubbery. After about three months on the job, the bleating crew has kept the grounds in sheep-shape.

            Since April, the site’s operator, OCI Solar Power, has used about 90 Barbados-cross sheep as a low-cost, low-effort solution to controlling the overgrowth that would otherwise impede the company’s technicians.”


            U B Wrong.

          • dcard88

            Thanks for letting me know.

          • Bob_Wallace

            I’m guessing their degrees are probably framed up in the shed….

          • jeffhre

            Good to see the higher education system diversifying.

          • jeffhre

            PV system inspectors?

          • (only to quantify your water savings claim for the benefit of future readers)

            Robotic cleaning uses “only ½ cup of water per panel Vs. 5 cups of water per panel using manual cleaning methods.”


    • Marion Meads

      I have mentioned several times in the past that all you need is a little expense and you can capture a lot of water from those impervious solar panels. They would make excellent rain catching system. If you have a 100 acre farm for example, and you receive just 20″ of rainfaill in a year, but you would need 40″ of rainfall to grow one crop, it is better to convert 50 acres of your land into solar PV and capture the rainfall from that land and use it on the other 50 acre of your farm land. It doesn’t cost that much additional hardware to do it.

    • Steven F

      antelope valley is a desert valley. Humidity levels are often less than 25%, no rain for most of the year, and daily summer temperatures are above 90F. Any condensation under the pannels will quickly evaporate in the hot dry air. Farming is only posible via irigation.

    • jeffhre

      Micro climates under PV? It’s a good idea to look at macro effects for possible long term influences – but the Mojave Desert is about 33,000,000 acres. And it is one of the smallest North American deserts!

  • sjc_1

    SunPower C1 Trackers (single-axis), which are said to boost annual energy yield by 25% as against fixed-tilt systems.


  • Martin

    Having solar in a sunny place should be made mandatory or at least be fully supported with policy/incentives to save ‘our butts’ from our own stupidity as a race.
    Just like wind for windy places, lots of those around the planet as well.

    • Kyle Field

      We are close to the point where it will be mandated on all new buildings. Just need to reach cost parity…then there’s no reason not to. At $1/watt installed, it’s an absolute no-brainer (though that’s still no guarantee) which industry folks are saying will happen in 2017.

      • Robert Pollock

        California now mandates that all new residential construction built after 2020, be ‘Net Zero’. That pretty much means solar on every roof it fits on, but you could make a tent ‘ Net Zero’ if you generate enough of your own power.
        But when, is California going to start pushing passive design? Almost none, of the roofs that all these panels will end up on, were designed in the first place for solar installations. Almost none, of the residences that conform to current stick frame building codes contain anywhere near the thermal mass inside the conditioned space, that would optimize the buildings mechanical systems. More concrete please, but not, on the outside of the insulation, as we do with all that stucco. I live in the desert. All I need to build a nice, passively cooled house is some water, cement and steel. I’ll save the wood for cabinetry.

        • Matt

          If new homes in CA are Net Zero after 2020; will will be seeing a lot of passive design, it is the cheapest way to Net Zero. What the day for office Net Zero, be several Class A building in the US done Net Zero for cheaper than “normal” cost Class A.

          • margaret_davis3
      • dcard88

        Don’t know what “industry folks” you are talking to, but we need to get to $2 per watt before anyone predicts $1 per watt. At the current rate, we should be at about $2.50 or even $2.20 per watt by 2017.

        • Kyle Field
        • Bob_Wallace

          Here’s where we are and how fast we’ve gotten to where we are.

          There are now reports of solar PPAs being signed for 4 cents/kwh. That means that there are some utility scale solar farms that are likely well under $2/watt, closing on $1/watt. The plotted lines are averages.

          • dcard88

            The best I could find was from last year at 7.1 per watt, but we may get to that average this year. A lot is happening in the west where the price is still higher.
            I don’t believe we’ll get to $1.50 before 2020, but I was wrong once before. 🙂
            7 cents per watt cost is all we need in CA, since many of us pay more than .$30 per watt for power and the cheapest in the state is .19 . The cheapest new coal or gas here would be over 8 cents I would guess

          • Bob_Wallace

            “7.1 per watt”

            Are you talking residential, commercial or utility scale solar?

            Are you talking dollar per watt installed or cents per kWh?

            Clearly there is a lot of 5 cents/kWh utility scale PPAs are being signed. That’s a subsidized price. Credible sources have said PPAs for 4 cents/kWh have been signed.

            Clearly residential is being installed for less than $7/watt.

            ” A lot is happening in the west where the price is still higher.”

            The West, Texas to the Pacific Coast, is where the lowest utility scale prices are found.

          • dcard88

            the 7.1 is the only unsubsidized price I can find. Do you know of a confirmed price under that in the USA? How do you know there are PPA’s in the USA under the 7.1 cents from Texas last year? I would assume that to be true, but I haven’t seen any numbers confirmed. I would have no problem betting there has been no PPA signed by SC Edison, PG& E, or SDGE (25 million customers) for less than 10 cents un-subsidized. Probably around 8 with the subsidies.

          • Bob_Wallace

            OK, apparently you mean 7.1 cents per kWh for solar PPAs.

            How do I know? First there’s the graph I already gave you that shows large numbers of PPAs clustered around 5 cents in 2014 and 2015. I’ll link it again….

            Now Texas, specifically –

            “It was announced in March that Austin Energy would likely be buying electricity from a SunEdison solar power plant for less than 5¢/kWh under a 25-year power purchase agreement (PPA).”


          • dcard88

            The Austin Energy thing sounds real, but I assume thats with the subsidies.
            I don’t trust the other graph. I want to hear about a signed contract under 5, which the Texas thing may be. I am very skeptical that the cost went from 12 cents to 5 cents in only 5 years.

          • Bob_Wallace

            You suspect GTM just made up that data?

            You’re going to have trouble getting to see signed contracts as these are usually not released to the public. GTM, I would imagine, can access some of these contracts under a NDA and via “insider” contacts.

            Ask Eric how they obtained their numbers.

            A 5 cent PPA discounted by a 2.3 cents/kwh for the first 10 years would mean, roughly a 6.2 cents/kWh unsubsidized price. That’s 6.2 cents for LCOE + other costs (land, owner profits) not included in LCOE calculation.

          • Bob_Wallace

            How about Lawrence Berkeley National Labs, do you trust them? Page 26.


          • Matt

            If you have to see the contract, then it is very easy to see I don’t believe there are any PV for less that 0.10 kwh or NUCs above 0.01 kwh. Since I can’t see any of contract, all this announced data you talk about Bob is just gossip. #humor

        • Greg Hudson

          Move to Australia. We have been under AU$1/watt (installed) for a while….

Back to Top ↑