Navigant Research Blog

To Spread, Energy Storage Needs Hybrid Solutions

— March 4, 2015

Imagine a single energy storage system capable of serving all potential needs, from a short burst of high power to keeping the lights on for many hours. Such a system could greatly improve the overall economics of energy storage by removing limitations on the amount of revenue a single system can generate.

This is the focus of several leading companies that are looking to develop hybrid energy storage solutions, combining multiple different technologies in a single system. Energy storage technologies all have their ideal applications; some, such as flywheels, ultracapacitors, and certain lithium-ion chemistries are best at delivering high power over shorter periods of time. Others, such as compressed air and flow batteries, are ideally suited for applications that require a lower level of power to be delivered over a longer period of time. Combining technologies into a single system with the flexibility to perform multiple tasks, could greatly improve not only the economic returns on investment, but also the overall lifetime of storage systems.

Life Extension

Many hybrid energy storage systems are currently available or have already been deployed. Power grid giant ABB has been actively developing its flywheel business and is looking to hybrid systems to fully realize the benefits that flywheels can provide. The company has installed a hybrid flywheel/battery system on remote Kodiak Island, in Alaska. In this installation, two 1 MW flywheels handle the grid’s frequency regulation and high power needs, while the batteries provide the energy density required to fill in the gaps of local wind power generation. As short duration/high power needs are more frequent, this hybrid system reduces the number of times the batteries must be discharged, greatly extending the overall life of the system.

Hybrid systems involving ultracapacitors are also finding promising applications. A leading company in this space is the Spanish firm Win Inertia, which has partnered with ultracapacitor manufacturer Maxwell Technologies to offer an integrated hybrid storage system. The ultracapacitors handle the frequent, intense power requirements, allowing the batteries to be discharged less often. This allows the optimal use of high energy density storage technologies, as well as a rapid response to short term issues. Win Inertia is primarily focusing on the software, controls, and system-integration challenges to make this technology as effective as possible.

Beyond Single Applications

Integration with existing electrical grids presents a major software challenge for energy storage system integrators. When multiple types of storage technologies are integrated into a single system, these challenges become even more complex. The overarching goal of energy storage system integration is to ensure the longevity of a system and its constant availability in the market, thus maximizing the return on investment for system owners.

If these challenges can be overcome, the potential for hybrid storage systems is enormous. Standard storage systems are often designed for only one application, for example frequency regulation, which limits the potential revenue they can generate. Hybrid systems with the ability to meet multiple grid needs and capture multiple revenue streams can be much more economical. While advanced hybrid storage systems are only beginning to emerge, they could one day lead the energy storage market.

 

Vanadium Batteries Await Breakthrough

— January 26, 2015

A remote hillside in the Nevada desert may hold the keys to developing the next generation of affordable energy storage systems.  One of the world’s largest deposits of vanadium, a hard, silvery gray mineral often mixed to create high-quality steel, is located underground on this site.  First discovered in the 1950s, the site is now being developed into a large-scale mining operation, known as the Gibellini Mine, by Vancouver, Canada-based American Vanadium.  The company, which partners with German flow battery manufacturer GILDEMEISTER, requires an affordable and secure supply of vanadium to develop its redox flow batteries.

With the majority of global vanadium supplies coming from China, a domestic source of the metal could be instrumental in reducing battery costs.  Despite the recent success of lithium ion (Li-ion) batteries, alternative technologies such as flow batteries address several shortcomings of Li-ion chemistries.

Stepping Up

There are several types of flow batteries with different characteristics currently competing for market share, including iron-chromium, zinc-bromine, and vanadium redox.  Well-suited to stationary applications, vanadium-based batteries offer several advantages over Li-ion systems.  Vanadium-based batteries can fully discharge with minimal degradation of key components, leading to a longer duration discharge and greater life expectancy.  Additionally, vanadium flow batteries are much safer than certain Li-ion chemistries, as they have no thermal runaway issues, which is a key consideration for systems located on densely populated distribution networks.

Significant improvements to flow batteries have been made in recent years as more companies enter the space and competition heats up.  One area in which flow batteries must improve is energy density; Li-ion and other batteries are much more energy-dense, giving them an edge in any project with limited space.  A recent milestone was achieved by UniEnergy Technologies with its vanadium-based flow battery, allowing a standard 500 kW, 4-hour system to be containerized and installed in a 1,000-square-foot pad.  The system has an expected operating life of 20 years and can be installed for around $750 per kWh.

As with most advanced batteries, makers of vanadium-based systems must reduce costs to fully capitalize on the diverse market opportunities available.  Fortunately, advances are being made in that area as well.  California-based Imergy, for example, claims that it will soon reduce costs enough to offer a vanadium-based flow battery for around $300 per kWh.  One reason for the low price is Imergy’s ability to use lower-grade vanadium, recycled from mining waste and other sources.  While vanadium flow batteries are currently somewhat more expensive than most Li-ion chemistries, they have the advantage of a longer life expectancy, allowing the upfront cost to be spread over several decades.

An Uncertain Future

Navigant Research’s report, Energy Storage for the Grid and Ancillary Services, found that flow batteries are likely to account for 2,357 MWh of capacity in 2020, about 7% of the total market for grid-scale systems.  However, these figures could increase dramatically with breakthroughs in system efficiency and cost.  A consistent, low-priced supply of key components, such as vanadium, could help rapidly reduce costs.  Additionally, greater diversity and competition among suppliers of key flow battery components can drive down manufacturing costs.  Given the very ambitious price reductions being forecast by manufacturers, many may be relying on market developments such as the Gibellini Mine to allow flow batteries to compete effectively with Li-ion.

 

How Green Is My Casino?

— December 21, 2014

On a recent trip to Las Vegas, I found myself wondering just how much energy is being consumed compared to other cities around the country.  It doesn’t take much research to grasp the enormous amount of energy needed to power all the neon, slot machines, sound systems, sportsbook TV screens, and massive air conditioners required to make the desert city an international tourist destination.  While recent efforts by resorts to “green” their operations have made an impact, they don’t address the root of the problem.  Sin City is unique in its geographic location – which provides both challenges and opportunities to operate a sustainable energy system.

Can’t Take the Heat

Las Vegas’ desert location would be very uncomfortable throughout the summer without modern air conditioning.  This presents significant challenges to resort designers who must overcome the desert sun to provide comfortable environments across millions of square feet.  At the scale of an individual hotel room, this challenge is easier to understand.  Large floor to ceiling windows are quite popular in the city but allow tremendous amounts of heat to enter the room.  Simply installing automatic blinds or smart glass windows could dramatically reduce this effect.

Although HVAC systems have been a target of recent conservation efforts, older hotels rely on outdated systems.  The New York, New York hotel I stayed in had only a very basic analog thermostat with simple controls and no ability to schedule.  Innovations to improve the efficiency of commercial HVAC system are discussed in Navigant Research’s report, Advanced HVAC Controls.  Perhaps the most effective addition to this hotel would be the installation of advanced occupancy sensors.  Visitors in Las Vegas often spend long periods of time outside of their hotel rooms.  In many cases, lights are left on and cooling systems set at full blast while a room is unoccupied for hours.  Occupancy sensors, integrated with a more intelligent building management system (BMS), could dramatically reduce the amount of energy used by each hotel room.  This could be an extremely beneficial investment for hotels that must absorb the cost of energy used by their guests.  Solutions to improve efficiency in hotels are explored in detail in Navigant Research’s recent report, Energy Management in the Hospitality Industry.

Untapped Resources

While the natural environment of southern Nevada poses challenges to conserve energy, it also provides vast untapped potential to generate it.  The Hoover Dam has enabled dramatic growth in Las Vegas over the years, although it currently provides barely 20% of the city’s peak energy needs.  As noted in a recent blog by my colleague Mackinnon Lawrence, recent droughts threaten the reliability of this resource, as well as the viability of fossil fuel plants requiring large amounts of water to keep cool.  A quick glance out my hotel room window revealed a massive casino roof – a perfect spot for a solar array totally unutilized.  Satellite images of the city show that this is very common and little to no solar power is installed on roofs of power-hungry mega-resorts.

For a city that receives intense sunshine nearly year-round, this is a huge opportunity to generate clean and affordable power.  And efforts are underway to take advantage of the clean energy resource available to the city.  This past summer, MGM Resorts announced a partnership with NRG Energy to install a massive rooftop solar array at the Mandalay Bay Resort.  The 20,000 panel, 6.2 MW installation is expected to generate nearly 20% of the Mandalay Bay’s power demand.  This project represents an important step in the right direction; hopefully, it will inspire others in the city to fully utilize the natural resources available to them.

 

Green Button Pushes Useful Usage Data

— December 3, 2014

The installation of advanced metering infrastructure is helping to transform the U.S. utility industry.  While over 43 million advanced meters have been installed, most electricity consumers have seen few benefits from the new device on their property.  Recently, the government has been making an effort to improve the accessibility of data from advanced meters.

The Green Button Initiative is an industry-led effort developed in response to the federal call-to-action to provide utility customers with easy and secure access to their electricity usage data in a user-friendly format.  A key focus of Green Button is standardizing electricity usage data; this will allow many stakeholders to use the data without the burden of converting proprietary formats.  Energy consumers, third-party software/application developers, public institutions, energy efficiency organizations, and utilities/energy service providers will all benefit from increased visibility of detailed electricity consumption data.

Developers of software and applications to help consumers understand and reduce their electricity consumption may have the most to gain.  Many advanced systems to manage energy use in buildings are already in operation; these will only be improved by easy access to more granular data from utilities.  Some solutions that can take advantage of this newly available data are discussed in Navigant Research’s report, Building Energy Management Systems

Tip of the Iceberg

Despite successful programs with many utilities, the Green Button Initiative has only scratched the surface of its full potential.  To date, at least 50 utilities have implemented the program, with a few dozen more committed.  Among the participating utilities, the amount of data available and the support provided to customers varies greatly.  In fact, some utilities are only providing monthly meter readings to their customers through Green Button.  This information has generally been available to customers online for years, and it does not provide enough new detail to enable many behavioral changes.

What’s more, many utilities are not actively promoting the availability of this data or helping their customers understand how to interpret the information.  Further collaboration between utilities and industry stakeholders is required, and a more developed app marketplace will be crucial to Green Button’s success.

Competitive Solutions

A major focus of the Green Button Initiative is to facilitate the development of third-party software programs and applications that use utility data to provide consumers with an easily understandable view of their consumption.  One interesting application is wotz, developed by a group of graduate students at the University of California, Irvine.  This application runs in a web browser and provides a simple to use, graphically pleasing interface to view and understand energy consumption over time.

Wotz relates household electricity use to more easily understood terms, such as a certain number of MacBook charges.  The program also includes challenges with guidance to reduce consumption over time and can be connected with Facebook to share results and benchmark against friends.

Another program utilizing Green Button-based data takes the idea of benchmarking and social media-based energy competitions even further.  Simple Energy, based in Boulder, Colorado, has a similar program with easy visualization and also features a community leaderboard that allows users to see how they stack up with their neighbors – as well as electricity consumers around the world.

 

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