This special interest group is for professionals to connect and discuss all types of carbon-free power alternatives, including nuclear, renewable, tidal and more.


The Fastest Way to Get There from Here

image credit: © Airubon |
Bill Conlon's picture
President Pintail Power LLC

Bill Conlon is the founder and President of Pintail Power LLC, based in Palo Alto, CA, which provides long-duration hybrid energy storage to bridge renewable and conventional generation. At...

  • Member since 2021
  • 1 items added with 1,349 views
  • Mar 23, 2021

This item is part of the Power Generation - March 2021 SPECIAL ISSUE, click here for more

Extreme weather events, from the polar vortex in ERCOT and MISO to wildfires in the west, and superstorms on the east coast, are compromising grid reliability and highlighting infrastructure interdependence. We experienced in stark terms how our modern life depends on reliable power for water and sanitation, communications and transportation, heating, cooling, and healthcare. Reliable power requires constant availability of primary energy resources in the form of water, wind, sunlight, or fuel. Extreme weather and climate change have compromised hydro resources, becalmed wind farms, caused fire ash to block the sun, and frozen fuel supplies. Reliability in the face of these extremes will require a broader, holistic, systems perspective that prioritizes consumers' need for service. 

Your access to Member Features is limited.

The energy transition is essential and urgent. Realistically, these extreme challenges will be with us for a century or more — throughout the transition to net-zero or net-negative emissions, and beyond.  Rather than focus on the limitations of generation technologies — wind, solar, natural gas — we can synergistically integrate these systems to build resiliency— leveraging each technology's strengths to bolster reliability and improve sustainability. 

Integrated resource planning to meet an objective (cost, sustainability and reliability) typically results in siloed procurement of renewable, conventional, and storage resources.  Faster progress on decarbonization can be achieved with integrated procurement of mutually complementary resources able to reduce cost by enhancing overall resource utilization and blending critical resources to enhance reliability and permit grid sectionalizing.

Unifying the renewable and conventional grids via hybrid energy storage provides just such a holistic glide path to meet climate objectives and maintain reliability at the lowest cost.  Large-scale hybrid energy storage – delivering tens to hundreds of gigawatt-hours – is feasible today with thermal energy storage using liquid salt or liquid air in above-ground tanks or with underground mechanical storage of compressed air. These hybrid approaches build on proven components already deployed at utility-scale in power plants around the world to leverage existing assets, personnel, and know-how.

With abundant long-duration storage, accelerated deployment of renewable resources can be greatly expanded without curtailment.  Stored energy can be time-shifted, reducing the fuel Heat Rate and emissions of thermal generation to provide low-carbon dispatchable power when wind or solar are unavailable.  Thermal storage also improves the operability and ramp rates of thermal units, expanding their economic and environmental operating range to buffer the variability of intermittent resources. 

The fuel efficiency of hybrid energy storage aids resiliency by reducing the burden on gas infrastructure, as well as reducing the cost burden associated with emerging use of expensive or scarce renewable fuels.  Both underground compressed air and liquid air hybrid systems can also provide on-site gas storage for fuel security.

Hybrid energy storage presents a unique opportunity to rapidly integrate our current and near-term energy resources to improve asset utilization, reduce emissions, and enhance resiliency. The fastest paths to meaningful carbon reduction are the ones we can execute immediately at reasonable cost.

Matt Chester's picture
Matt Chester on Mar 24, 2021

Large-scale hybrid energy storage – delivering tens to hundreds of gigawatt-hours – is feasible today with thermal energy storage using liquid salt or liquid air in above-ground tanks or with underground mechanical storage of compressed air.

You talk about how hybrid energy storage is feasible today-- is there anywhere it's in practice used today? Is this something we're taking from lab to field, or have pilot projects already demonstrated success? And if we're still just on the precipe, what's holding it back from implementation? 

William Conlon's picture
William Conlon on Mar 24, 2021

CAES Hybrids have been demonstrated and have been in use for decades.  My company specializes in hybrid systems using different forms of storage than compressed air, so siting is more flexible.  Hot thermal storage using molten salt is proven in CSP and is readily integrated into combined cycles.  Cryogenic liquid air  has similar storage conditions to LNG, and those storage tanks could hold many tens of GWh-AC.  After being pressurized and regasified the cryogenic combined cycle looks just like CAES.

All of these hybrids have much lower costs than alternatives at 6+ hour duration.  The benefits of long-duration storage, where hybrids shine, are just now being recognized, so I expect projects will start to be proposed and developed.

Jim Stack's picture
Jim Stack on Mar 26, 2021

Bill, thanks for this information and focus. Don't forget Hydro which is a great 24/7 clean resource. It can also be stored and released. As you show combining them all and we are set. 

Gary Hilberg's picture
Gary Hilberg on Apr 2, 2021

Bill - I hope that you succeed with the hybrid solution, as we are so far from excess renewable electricity model that so many  Hydrogen, CAES, Battery storage ...  solutions assume exist today.  Leveraging existing fossil assets provides a much lower capital & operating costs AND existing connection to the grid - all things you know.  The messaging has to be that we have 100's GW of renewable generation to install, we need to do it at the lowest possible cost - adding new unproven, at scale, technology for storage and raising that cost can slow the deployment timeline and lead to confidence reducing outages.  Using a very small amount of fossil fuels to meet short duration demands leveraging existing fossil assets is smart.  Recommend you lead with your $ / KWH capital to store/operate, timeline to construct, and your footprint - these assets will be needed for several decades as the transition continues.  They will provide grid reliability while better technology for storage is developed and deployed.  

Bill Conlon's picture
Thank Bill 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.
More posts from this member

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 »