3 Questions for 3 Energy Storage Experts


lithiumionbatteryAmid heated debates over clean power sources, how to build out the smart grid, and the future of advanced transportation, one thing’s clear: Energy storage technology will play a key role in all of these transformations. Energy storage — from batteries to ultracapacitors to pumped hydro to compressed air — will be crucial for the development of electric vehicles, will make sporadic clean power (solar and wind) more reliable, and enable the utilities to more smartly manage power grid loads.

Energy storage provides the key to these innovations and will be the cornerstone of the economy that will emerge around the next generation of energy. Here are three questions for three experts — Rick Luebbe, CEO, EnerG2; Jill Watz, senior adviser, Vulcan Capital; and Ahmad Pesaran, principal engineer, National Renewable Energy Laboratory — that have spent years digging into the technologies, the chemistries, the economics, and the future hurdles for the deployment of energy storage. The following are edited excerpts of their answers:

3EnergyStorage.RickLuebbeHeadShotRick Luebbe, CEO, EnerG2

Why is energy storage so essential to the new energy economy?

Energy storage is essential because the ef?ciency and sustainability of the new energy economy is in absolute jeopardy without it. So many of the generation and capture technologies that are emerging and evolving will depend on storage to make them effective and, in some cases, viable. In addition, energy ef?ciency is a key element of the energy gains that have become an expected part of our collective future. Energy storage helps to synchronize energy supply and demand, which is an essential ?rst step in achieving global-scale gains in energy ef?ciency.

What is the most important use or implementation of energy storage?

There is no innovation-oriented market with brighter prospects — or greater sweep or scope — than energy storage. It’s nearly impossible to pick a single use of energy storage that rises above the others; rather, it’s the universality of the need for better energy storage that de?nes its role in our economy. To date, the energy industry has labored under a model where large-scale energy storage — when it’s even possible — is dif?cult and costly and usually implemented in the form of vessels of fossil fuel or chemicals. That model is broken and is in the process of being ?xed — to everyone’s bene?t.

Which energy storage innovation do you most believe in?

So far, the bulk of the energy storage conversation has revolved around ongoing advancements in battery technologies. Batteries are well-understood and virtually ubiquitous. Nonetheless, ultracapacitors, a powerful alternative to batteries, are being increasingly embraced by the automotive industry for hybrid electric vehicles, by electronics and power-tool manufacturers for enhancing the life and usability of consumer goods, and by a variety of industrial customers to deliver applications and technologies that improve energy ef?ciency. Any application that performs better or lasts longer using rapid charge and discharge cycles will bene?t from ultracapacitor-based energy storage systems.

In one particularly interesting example, electric-rail operators in Europe are adopting ultracapacitors to capture the kinetic braking energy created by trains approaching a station. They’re then using that captured energy to power departure and initial acceleration of that or another train. The energy ef?ciency gains of this relatively simply application have been enormous. If we can ?nd ways to meld batteries and ultracapacitors in new and unprecedented combinations, I believe we’ll double our chances for sustainable success in a variety of key industries while, at the same time, boosting both our energy and economic futures. (EnerG2 is focused on introducing advanced nano-structured materials for next-generation energy storage breakthroughs.)

3EnergyStorage.JillWatzJill Watz, senior adviser, Vulcan Capital

Why is energy storage so essential to the new energy economy?

The new energy economy requires a large-scale penetration of low-carbon electricity and an electric transportation system that depends on a new electric grid system that is ?exible, dynamic, self-healing, highly reliable and distributed. Energy storage is essential to achieving all of this functionality. At the system level, large-scale storage enables greater penetration of intermittent renewables like solar and wind, and it helps improve system robustness. At the distribution level, storage enables improved power quality to protect increasingly sensitive loads from voltage sags and transients, and enables greater penetration of distributed energy to directly serve load without costly transmission. Lower cost, as well as reliable and robust onboard storage, is also critical to the expansion of electric vehicles, which will greatly increase the ef?ciency of our transportation sector.

What is the most important use or implementation of energy storage?

Just as there is no single technology solution to solve the climate change problem, energy storage technologies vary by type, scale, application and location. Large-scale physical storage, like pumped hydro or compressed air energy storage (CAES), are proven technologies with well-de?ned costs, but they are geographically limited. Evaluating traditional large-scale hydro for its potential for ?rming intermittent power in the Paci?c Northwest and other hydro regions is another important opportunity for bulk energy storage, and it could reduce the
average cost of power for large-scale renewable penetration in those regions.

Storage plays an important role in improving the ef?ciency of electricity markets by enabling a more active demand side as well as greater distributed resources. For too long, investments have been skewed disproportionately to the supply side, leaving the demand side relatively inactive and creating market distortions. For example, distributed energy storage in electric vehicles can be aggregated through smart controllers to provide ancillary services to the power system and help reduce electricity costs. Similarly, energy storage devices, coupled with consumer-distributed generation, will enable more local, clean energy production and reduce expensive new transmission infrastructure requirements.

Which energy storage innovation do you most believe in?

There are promising new technologies under development to meet storage capabilities at all levels. Advances in materials science provide new and novel processes and materials to improve energy density and speci?c energy storage devices. I think there is great promise in the application of nanostructures to create super ultracapacitors for large-scale energy storage in vehicles, and to enhance the electrode capacity in more conventional battery chemistries to reduce costs and improve cycle life.

3EnergyStorage.AhmadHeadshotAhmad Pesaran, principal engineer, National Renewable Energy Laboratory

Why is energy storage so essential to the new energy economy?

The new energy economy must consist of renewable energy and energy ef?ciency in all sectors of the energy consumption market, including buildings, transportation and industry. Energy storage is a major and vital component of the green technologies needed in this new economy. In the transportation sector, hybridization and electri?cation of vehicles increase energy ef?ciency and fuel economy, thus reducing oil consumption. Hybridization of vehicles with electric energy storage allows signi?cant fuel ef?ciency increases by using regenerative braking, permitting engine downsizing, engine load leveling, electrifying accessories, and reducing fuel use during stops. Energy storage devices such as batteries and ultracapacitors are the enabling components that make hybridization and electri?cation possible.

Just as important, the electricity needed for the building, transportation, and industrial sectors could be generated through renewable energy technologies such as wind systems and solar photovoltaics (PV). But to generate signi?cant electricity from wind and PV, we must address one of their major drawbacks: intermittency. The fact that these resources are not always available limits their penetration into electricity markets. Previous studies have indicated that traditional electric power systems are inherently limited in their ability to accept very large amounts of PV or wind energy because of their intermittency. Analyses by NREL and others have shown that energy storage provides the ultimate solution by allowing excess PV or wind generation to be stored and delivered at a later time. Integrating electric energy storage with PV and wind generation has the potential to blur the line between intermittent and baseload generation technologies.

What is the most important use or implementation of energy storage?

Energy storage must be used for the generation and use of green electricity across all parts of the economy: gasoline and fuel-cell hybrid electric vehicles, plug-in hybrid vehicles, all-electric vehicles, PV and wind electric power plants, conventional power plants, substations and buildings.

Electric energy storage must be implemented in solar PV and wind power plants so that excess electricity can be stored for later use and allow greater market penetration of renewable sources into the electricity grid. This type of energy storage can be implemented in a centralized system consisting of megawatt-size units or in many smaller energy storage systems distributed throughout the grid. Energy storage devices can also be used in the building and industrial sectors to store electric energy locally for immediate, same-day or later use. In addition, energy storage systems could be deployed near neighborhood substations or even in residential buildings, to store electricity for later use during peak demand times to prevent brown-outs.

Which energy storage innovation do you most believe in?

There are several options for energy storage: batteries, ultracapacitors, ?ywheels, compressed air, pumped hydro, ?ow batteries, and superconducting magnetic energy storage or SMES. Each has advantages and disadvantages for different applications in transportation and stationary/grid applications. There are also many chemistry choices for batteries, such as lead acid, sodium sulfur, and lithium. Initial capital cost and life dictate the choice of energy storage for stationary applications, so $/Wh/cycle is an important selection parameter. For transportation applications, in addition to cost and life, vehicle manufacturers pay close attention to mass, volume, and safety. Connecting the energy storage system in plug-in and electric vehicles to the electricity grid using bidirectional lines will enable their use as distributed energy storage systems for ancillary services, commonly referred to as the vehicle-to-grid or V2G concept.

For vehicle applications, I believe only lithium batteries will be competitive in the new energy economy because of the tremendous advantages they possess for full hybrid as well as plug-in and electric vehicles. Ultracapacitors can play a signi?cant role in mild and start-stop hybrid markets; there could even be considerable potential for using ultracapacitors in conjunction with batteries for plug-in and electric vehicles if there is a signi?cant decline in the cost of the power electronics needed to integrate the two systems.

The synergy between the energy storage devices used in vehicles and the ones used for renewable grid applications is strongest when batteries and ultracapacitors are used for both. This dual use of batteries and ultracapacitors in transportation and utility applications will increase the demand and volume for lithium batteries and ultracapacitors. As high-volume production facilities are built, costs will drop and increase the market penetration of these two energy storage technologies. Therefore, we look forward to a lot of innovation in lithium battery and ultracapacitor technologies.”

Images courtesy of Flickr Creative Commons, NREL, EnerG2, and Vulcan Capital. Thanks to EnerG2 for putting this package together.



Someone needs to explain to me how my electric car can serve as a power storage source for my house. If I charge my car at night using cheaper off peak electricity, then it’s available to get me to work the next day. But if the energy in the batteries is being used to get me to work, it’s not available to power my house or send back to the grid. If my electric car is just backup storage for the electric company, wouldn’t it be cheaper to just buy the batteries and forget the car?

Victor Babbitt

Charles is right in stating a note of caution about Vehicle-to-Grid concepts, but more needs to be said. The present Lithium Ion batteries are much to expensive to be economic for Grid use. A Lithium Ion battery has cycle life limitations, i.e.; a limited number of charge/discharge cycles. For now and for the foreseeable future, the value that the battery degrades with each cycle is much more than the value of the grid electricity it would store. Giving a vehicle owner $1 for stored electricity while degrading his battery by $10 is not a viable model. If it were, then we would much more economically store Lithium Ion batteries at substations and wind and solar plants.

However, economic grid storage is close at hand, in flow batteries, metal-air batteries, and in Sodium Ion batteries. Also, the use of ionic liquid electrolytes and the new MIT all-liquid battery show great promise for grid level energy storage in the next 2-5 years.


Nor does this discuss thermal energy storage for buildings or intermittent energy sources, a very real technology being used for reducing peak demand.

Charles R. Toca

I thought the comments were reasoned, wide ranging and inclusive of all storage options. I note the belief and reliance in vehicle energy storage and caution that, if large scale and usable vehicle energy storage occurs, it won’t be available for 10 to 15 years in usable quantity. See “Bottling Electricity” by the Electricity Advisory Committee: http://tinyurl.com/yarq8dn We need to focus on what is doable sooner rather than later. VRB redox flow batteries are multi-megawatt solutions available now. More information at http://www.Utility-Savings.com.


Interesting. Not one of them mentioned that the lowest hanging fruit for energy storage on the grid is demand side management.

  1. The EV battery is expected to act as a catalyst to accelerate development of sustainable power, specifically as a storage for wind power at nighttime and for solar panel system via recycling. In return, this situation has a chance to bring a solid win-win outcome — rendering EVs affordable.

  2. In many cases, power plants like a nuclear reactor maintain operation during night, and EVs could take full advantage of the surplus energy :

With the concept of “V2H” (vehicle to home), the vehicle can supply 100V electricity stored in its on-board lithium-ion batteries to electric appliances in a house.

It is possible to charge the batteries at night, when electricity is cheaper, and use it for home appliances during daytime, Mitsubishi Motors said.

And the company claims that the batteries can provide almost all the electricity used in a normal household throughout the day.

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