Are Solar+Storage Closing Gas Plants? Is that really what’s most important?

Over the last year or two, we’ve heard much about solar + storage – specifically battery storage, replacing [natural] “gas plants” and “peakers” and sometimes infrastructure investments, namely transmission.  The hoops and hollers often reach feverous levels if new investment in natural gas “peakers” were avoided.  But I have still yet to find evidence of single cycle combustion turbines – actual “peakers” proposed to be … actually avoided.

I am not going to rehash my corrections about two of the more notable stories that happened in California (three “peakers” and transmission for some big batteries in PG&E – Pacific Gas & Electric territory).

[Edit: 4/14/19 – I guess I must, so here it is. ~Hans]

At stake are 2 ultra-low CF (nearly zero – not even low single digits) single cycle gas turbine units (barely considerable a “power plant” and as “distributed generation” as we get at grid scale) and an older CCGT (Metcalf Emergy Cemter) at the hub of NorCal’s 500kV transmission system (at the critical intersection between high load centers and several inefficient larger plants – Moss Landing, that are closing due California’s “Once Through” Ruling.  This is the basis of Diablo Canyon NPP needing to close in 2025 also).

And depending on what the alignment of the solar system is on any one day or the current state of smart grid-edge rate redesign efforts are, whether they will be actually closed is anyone’s guess. [edit 4/19 – FERC denied closure of all 3]

All 3 plants & units are IPP – Independent Power Producer, owned.  And all 3 have nearby BTF/M – Behind the Fence/Meter NG CHP – Combined Heat & Power units (agricultural processing facilities) within earshot.  Which, when we look at the bigger picture of managing grid resources more intelligently through the ISO/RTO/Balancing Authorities, we will see ERCOT is incorporating large scale BTM/F NG CHP plants as part of their arsenal of enablers for higher RE integrations.

This last part was detailed in a presentation for ESIG – Energy Systems Integration Group by ERCOT’s Lead Planning Engineer, Julia Matevosyan, and how they are addressing legitimate “Inertia” concerns pro-actively with advanced systems management technology enablers.  Something that is desparately needed throughout the US, as I wrote about recently here, and several years ago here.

Or in Arizona with TEP – Tucson Electric Power adding (some solar+storage  to address local NOx concerns from some very low Capacity Factory (CF) single cycle turbines – full speed ahead with distant coal plants), that started this most recent buzz gaining steam during 2018.

Nor should I focus on already dated exciting solar+storage news from Oregon, where it was added to an existing wind farm on the very sunny, eastern side of the Columbia Gorge.  Solar exploding in Oregon’s high desert has long been anticipated to correct the area’s existing wind imbalance, largely waiting for Solar PV’s price to hit a magic point.  Massive Columbia Basin Hydro and transmission capacity to California needed solar or storage to even wind out, while a pumped storage proposal has languished for over a decade.  Not surprisingly [to me anyways], it was an Energy Company of the Future – Nextera Energy Resources which developed this project.

[Edit already required while writing this article – that’s how fast news is breaking … Add Idaho to the list of “groundbreaking” announcements – very much interconnected to Columbia Basin Hydro generation and storage, the BPA – Bonneville Power Authority transmission system and existing wind.]

Nor will I reference back to earlier claims about “peakers” shuttering around New York City, but not within New York itself, as those are stories about natural gas combined cycle plants replacing old “dual fuel” steam turbine plants in New Jersey, Connecticut, Rhode Island and Massachusetts.  Natural Gas fleet re-construction completed in 2018 as noted by the Energy Information Agency’s unwelcome” announcement recently, that once again “natural gas” power plants were a substantial portion of the year’s new capacity addition.  This should not have been a surprise to anyone, as “Houston, we have a problem” as I detail here with renewable energy deployment in the eastern United States.

But unfortunately, this buzz continues as I recently wrote about here, forcing our attentions away from important regulatory and distribution system operator (DSO) level improvements, not only software enabled, but also physical hardware-based, that are desperately needed for a 21st Century Grid with high renewable energy penetration and already here… Distributed Energy Resources (DER).

So to get right to it, here are the latest solar+storage buzzes hitting the US energy transition space with some really big batteries.  No disrespect to Christian Roseland at PV Magazine USA as I respect his efforts, but he [as several other authors/RE media resources running off FPL’s press releases alone] has served up two softballs back-to-back to MLB “sluggers” in Florida and Texas. These are going out of the park once we unpack the backstories.

Has Spring Training begun yet?!


First up, Florida…

“The FPL Manatee Energy Storage Center is scheduled to come online in 2021, and will replace two natural gas-fired units at a nearby power plant. FPL notes that it will use this battery to meet costly evening power demand, meaning that it will be a solar+storage “peaker”, replacing the flexibility that the gas plants offered.”

and not to be outdone, ArsTechnia running with this story too, even claiming a new power plant will be built – even though Manatee Energy Center has been its name for some years.

What Florida Power & Light (FPL), otherwise know as Nextera Energy Resources when the understory is not about vertical monopoly IOUs – Investor Owned Utility, is replacing is two “dual fuel” natural gas/heavy fuel oil steam boiling turbines, not “peakers“.

Manatee Energy Center, south of Tampa consists of multiple operating units, which is common in the US. 20th Century “power plants” or “generation stations” are now routinely named “energy centers” in the 21st Century. Nothing has fundamentally changed; centralized generation “plants” diversified with different Prime Mover technologies and Prime Mover operating units.

Wind+Solar+Storage is no different.

“D!ck Swinging Contests” and Power Plants 101

How US Energy Information Agency (EIA) track and power plant owners report key metrics is at a bit of an impasse in the industry. EIA likes basing all metrics upon a “spinning mass“; i.e., a turbine as the fundamental operating unit, whereas increasingly wind, solar, fuel cells and batteries are reported through a common inverter or transformer at its connection to the transmission system.

Boys will be boys, and make no mistake about it… this impasse is very much a “firehose” swinging competition!  It unfortunately opens up a lot of room for tall tales, fish stories, debates over “inertia” and boasting from both sides, which only stalls the energy transition, not power it forwards.

And here, Manatee Energy Center is no different, with different types of gas plants, in different capacities and quantities, plus solar PV already incorporated in 2017.

Screenshot 2019-03-30 21.42.19

Manatee Energy Center – “Gas Plants” & Solar PV

So what is being replaced or closed with solar+storage?

Two steam turbine units with a combined capacity of 1,726 Megawatts (MW) commissioned in 1976 and 1977. They are on the right side of the “power plant” above, which is connected to the cooling water lakes/lagoons which all steam plants require if they do not have cooling towers. Just above and not in the picture are 2 large heavy fuel oil tanks.

To Flex or Not to Flex…

Under no circumstances, unless we are talking about coal or nuclear, do any power generation experts consider natural gas steam turbines “flexible“.  They ramp slowly like a coal plant, taking a long time to boil water, build enough steam pressure to turn massive turbines and synchronize with the grid.  Under very few circumstances do plant owners want to ramp them up or ramp them down, resulting in unprofitable fuel costs and emissions without the production of any usable energy.

Natural Gas steam plants are seasonally flexible, but I struggle to classify days or weeks-long seasonal operations as “peaking” under general implied references from some authors or commenters.  Would be the same as calling a coal plant, when not in scheduled maintenance, a “peaker” for doing what it is supposed to do, generate electricity 8760 (industry speak for 24/7/365).

Conversion Efficiency & Specific Carbon

Are natural gas fueled steam [electric generation] plants efficient?

Not really.  Although, they do emit less carbon dioxide than coal plants.

Given their age, EIA actually assesses this Prime Mover class a higher Heat Rate than generally “more modern” coal plants, 10382 over 10045 respectively.   The higher the Heat Rate, the lower the efficiency.

Lower CO2 emissions per unit of electricity produced is baked into the specific carbon content of the fuels themselves, not the small efficiency difference between steam turbines and their different fuels.  However, we often hear this claim in simplistic discussions of “natural gas” being better than coal, with the implied meaning that “gas plants” are less carbon intensive than “coal plants“.  Fuel specific carbon content is indifferent to Prime Mover technologies employed. Natural gas contains about 60% of the specific carbon content compared to lignite, sub-bituminous, bituminous or anthracite; collectively “coal“, per unit of energy – the MMBTU, Million British Thermal Units.

Power Gen Carbon Emissions Reduction – The Bridge “Decade”

A few months ago, the NY Times released an article, much to my dismay with some squiggly colorful waves representing our energy transition since 2000 based on “fuel” for every state. I’m sure you recall it, but it drove a huge stake in my ribs as I had spent a couple hundred hours attempting to correct the EIA Prime Mover – Fuel impasse from the same data that was used to the generate the colorful squiggles.  Facebook never fails to stick pins in my eyes, this article is “promoted” every other time I log into my newsfeed.

Yes, the state by state history waves are nice, but they do not account for efficiency improvements that are largely an American technology story, given most countries have not converted steam to combined cycle plants. And this actually matters from a climate change and climate change mitigation/abatement perspective.


This is what state energy mixes would look like if Prime Mover technology and Fuel type were accounted for accurately.  Texas in 2017 (not just ERCOT “Texas”).  It’s not so simple, but there are at least 8 different “gas plants” here and how, when and how much they are used matters from a carbon and energy perspective.

America’s power generation carbon emissions reduction during the “transition” or “bridge” period between roughly 2000 to 2014 did not come simply from increasing natural gas consumption in existing steam turbines and running coal plants out of the market.  It came from the other Prime Mover class generation unit at Manatee Energy Center – the “combined cycle” natural gas plant or CCGT – Combined Cycle Gas Turbine[s] – which not unsurprisingly, is not closing from this solar+storage project.

These are flexible operationally and highly efficient.  Most in the US achieve around 60% energy in [natural gas] to energy out [electricity] efficiency, roughly double that of steam turbines regardless if the fuel is coal, oil, natural gas or nuclear.  And they ramp fast, meaning they don’t need to be “idling” burning fuel and spewing any number of emissions into the environment.  Operational Expense (OpEx) is pretty low too, many of these are remotely operated without full-time onsite staff needed.  Oh, and water consumption… that too is much lower than steam turbines.

This is what is at Manatee Energy Center, not being replaced by solar + storage, a CCGT.

Manatee CCGT is no sluggish “sea cow”…

Specifically, it is a hybrid combined cycle plant consisting of four natural gas combustion turbines (CT or GT), each paired with a HRSG – Heat Recovery Steam Generator, and one steam turbine.  Electric power is produced at each combustion turbine connected to an individual electric generator and also at the steam turbine paired with an electric generator fed by the steam from one, two, three or four HRSGs depending on how many combustion turbines are operating.

If you dozed off, we just advanced to Power Plant 102, so I will repeat what we just covered.

The only fossil fuel fed into the CCGT was into the combustion turbine[s] – which is little different than what makes our airplanes fly, not the steam turbine.  The steam was produced in the HRSG by capturing the normally expelled heat from the combustion turbine’s exhaust.  Without the HRSG, we have a single cycle combustion/gas turbine, a true “peaker” and a horrible efficiency or Heat Rate of 11214 according to EIA.  With HRSG and steam turbine, Heat Rate drops into the 7000s and energy conversion efficiency rises into the 60% or greater range.

Not surprisingly with EIA’s 20th Century accounting/reporting method entrenched in “spinning mass” thinking – some plant operators report natural gas or fuel oil as being consumed by the HRSG/ST itself, while others get it “right” as the only fossil fuel consumed is by the combustion turbine, not the heat recovery part of the CCGT.  Ah… old ways of thinking die hard, and old dogs don’t learn new tricks.

Combined at Manatee Energy Center there are 752.8 MW of combustion turbines which feed steam into a single steam turbine (ST) with a capacity of 471.8 MW.

Optimally, all 4 CTs plus the ST are running at the same time, but blocks of electric power of 752.8 / 4 = 188.2 MW plus one-fourth the ST output (118 MW) or 306 MW are possible, without significantly sacrificing the high efficiency rating of a combined cycle plant. This also means, no fuel is being consumed by the other 3 combustion turbines is there is only a need for one-fourth the CCGT’s total capacity of 1,224.6 MW.

Manatee Energy Center’s hybrid CC plant, a “four in one”, is relatively rare for the US, where 3-in-1 or 2-in-1 are far more common, I tend to really like it, from the flexibility and efficiency perspective.

Screenshot 2019-03-11 10.06.24.png

Two “2 in 1” hybrid CCGT in Arizona, not far from massive solar PV deployments and Palo Verde Nuclear Power Plant.

I could discuss 1 to 1 combined cycle “gas plants“, but lets just suffice it to say the combustion turbine and steam turbine “after” the HRSG are connected by a common mechanism to rotate the single electric generator.  As such, they are less responsive, take longer to ramp, and would fit more of a “baseload” generator definition… whatever “baseload” really is anyways. 😉

FPL built this hybrid combine cycle plant in 2005.  It’s not going anywhere, getting stranded nor being shuttered anytime soon, and especially not with this giant battery going in at the site.  One might say, the battery compliments the CC plant just as it mitigates limitations from solar PV.

In fact, whether the battery is charged by the solar plant or from the CCGT as it is ramping down and un-synchronozing from the grid, the battery will minimize partial ramps of the CCGT, resulting in not only significant carbon dioxide emissions, but more importantly, NOx – Nitric Oxides and CO – Carbon Monoxide emissions from the combustion turbines as they ramp and not running at full capacity.

These are all good things in our collective challenge to reduce our carbon emissions. I feel like I am a “naysayers“, for having to “bust this myth” at Manatee of solar+storage shuttering “gas plants” or “peakers“, but this myth is busted!

We’re still transitioning, not fast enough for my liking either, but some of us need to hold your leapfrogging jets!


Everything’s bigger, err… better in Texas, especially our energy transition strategy

Strap on your massive belt buckle, pull on your cowboy boots, put on our 10-gallon cowboy hat, grab your dancing partner and enjoy this song by Rick Tervino as… “Everything’s Better in Texas“, especially our energy transition!  Yee-haw!

Here’s our breaking solar+storage news,

Everything is bigger in Texas

Juno Solar and Juno Storage projects, 495 MW of solar and 495 MW of batteries …. already have interconnection agreements, and together are easily the largest solar+storage project seen by pv magazine. However the project is not expected until May 2021, and in the next two years it is likely that even larger batteries will be announced.

This is indeed impressive, as I often find myself talking in Gigawatt (GW) and Gigawatt-hour (GWh) scales, especially as we discuss that other “peak” in California, evening peak increasingly outgrowing 8 GW and 25-40 GWh every day requiring natural gas “peakers” with limited pumped hydro and battery storage.  Half a gig instantaneous capacity from any prime mover technology is a big deal.

But Juno Solar and Juno Storage is not just plugging into the existing grid way out in West Texas, where distributions systems have been strengthened to support explosive load growth in the nation’s most productive oil patch, the Permian.  It’s going even further out into the West Texas scrub brush into Far West Texas, where transmission expansion has not completed.  So far west a wind farm was so old, it was cheaper to decommission after damage from an ice storm and it is unlikely to be rebuilt until transmission arrives.

Not to worry, new transmission and substations are already under construction – the last if you will of Texas’ CREZ – Competitive Renewable Energy Zone infrastructure projects to be developed to facilitate the expansion of wind [and solar] in the Longhorn State.

Screenshot 2019-03-31 10.07.16.png

Red lines are single or dual circuit 345kV transmission.  Most (left of the black line) did not exist a decade ago. New trans/subs in circle is under construction by Oncor, American Electric Power and Xcel (in SE NM).

I’ve been writing about this for some time, at least 5 years anyways.  Solar PV is going to explode in Texas, but not on its own accord, standalone or solving any problems by itself.

Same is true with batteries, or their combination, as Texas is where pairing renewable generator with batteries began at NoTrees Wind Farm.  The 36 MW storage project, after its rightful groundbreaking deployment by Duke Energy, much more quietly went through a battery changeout about 2 years later.  Not knocking it, only highlighting we are very much still within the early years of very large batteries, and we don’t have the histories from actual use cases to make any hard claims as to actually longevity we will witness, nor certainties on costs over the long run.

Starting to note a theme here, like horns in Texas?

Solar. Like Storage.  Like Wind.  Like Transmission. Is a part of a lonnnngggggg strategy.

One which many might think was built specifically for solar+storage.  It was, but it wasn’t.  It was built based on a comprehensive, long term plan to enable all carbon reduction technologies to participate in the end goal – reducing the carbon intensity within our electric grids cost effectively.

Natural gas is definitely at play and a new natural gas reciprocating engine bank was recently completed by Golden Spread Electric Cooperative to maximize efficiency, flexibility and dispatchability.  I suspect, this plant will have far greater operational longevity compared to a similarly sized battery – as it is the closest technology “match” there is to a grid-scale battery for providing grid services.

But this history and future is really about wind and transmission, massive new load growth in the oil patch and not enough flexible or fossil generation out in West or Panhandle Texas.  A lot of it is about ERCOT, but it is not exclusive to North America’s second smallest “Grid“.


Wait, what?!  Who just killed Rick Tervino on our Texas Roadhouse jukebox?!

Small” and “Texas” should never be in the same sentence, but isn’t that better than saying “third largest grid“?  Enough already, by line miles, generation resources, peak capacity, peak load, etc., it goes something like this; Eastern Interconnect, Western Interconnect, Texas (ERCOT) and then non-synchronous Quebec.

Sorry Texas, am I forgiven if I say this?  Texas is the undisputed leader in new transmission and wind farm deployments in… North America.  And soon, it will be a solar “success story” also.  TBH, electric markets and light “don’t tread on me” regulatory and policy intervention in Texas is… going to blow away more heavy-handed and mandate-drive renewable energy deployments in places like New York, North Carolina and wait for it… California!

Make no mistakes about it, the “Golden Platter” transmission, wind and natural gas have worked hard to forge and polish for solar and/or storage in Texas (and the Great Plains) is actually going to crush any other efforts around the world (minus China) to enable our energy transition, once solar arrives.

Which brings us back to the announcement about solar+storage in Texas being some revolution in our energy transition efforts.

I’ll let Tom Bodett cover this,


“I’m Tom Bodett for Motel 6, and we’ll leave the light on for ‘ya.

And that’s exactly what has happened in Texas with transmission, wind, utilities, EPCs – Engineering Procurement & Construction companies, large construction contractors and small, regulators, electric cooperatives, natural gas and both ERCOT and Southwest Power Pool… they have built a Motel 6 waiting for solar and storage to finish each their own journey through scaling, cost reductions and technology maturation.

One might ask,

What’s took you so long?

But I think most would say,

Ready to get to work? There’s no lack of things to be done here!

Screenshot 2019-03-31 18.16.48.png

If you’re not certain what those things are?  This is a detailed breakdown from 2017 for the entire US.  Speaking strictly from a carbon abatement issue (measured in million metric tonnes) we should be focusing the the “grays”, then the “reds” and once those are done, then we can focus on the “greens”.  Spoiler alert, if we’re hoping are Canadian friends are going to decarbonize through electrification also – that’s another 75-85 Terrawatt-hours per year they supply us with currently.  Honestly, thank you Canada!



[If you’d like to comment or discuss further, please do so on LinkedIn… here or connect with me on Twitter.  Better yet, as this article is the product of four years long years of “bootstrapping” my way through the otherwise boring energy sectors, please consider sharing it with your networks, social media accounts, etc. ~Hans]


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