Navigant Research Blog

Utilities Explore Different Approaches to Residential Energy Storage

— August 31, 2015

Residential energy storage systems are anticipated to see exponential growth over the coming decade. The capacity of annual installations worldwide is expected to grow from 562 MWh in 2015 to 38,525 MWh in 2024, according to Navigant Research’s report, Community, Residential, and Commercial Energy Storage. While numerous storage system developers are lining up to begin selling residential batteries, utilities around the world are struggling to determine how to integrate these new distributed energy resources into their networks.

Utilities can receive numerous benefits from residential storage, including deferring investments in distribution grid upgrades and stabilizing circuits with high penetrations of solar PV. Additionally, the use of residential storage in an aggregated virtual power plant configuration helps utilities manage their financial risk by calling on distributed batteries to supply loads at times of peak demand, thus avoiding purchasing costly wholesale energy. Despite these benefits, many utilities are unsure how residential storage can be integrated into their networks. While much uncertainty remains, two major utilities have recently announced pilot projects employing very different business models.

Different Approaches

In August, Australian utility Ergon Energy announced a program with leading vendors SunPower and Sunverge to deploy residential storage systems tied to solar PV (initially in 33 Queensland homes). Through this program, Ergon will own the battery systems located behind the meter in customer homes. The utility claims these 5 kW/12 kWh lithium ion systems paired with a 4.9 kW PV array will supply around 75% of a home’s electricity needs. Participating customers will pay an $89 monthly fee, and Ergon claims they will save at least $200 per year by purchasing much less grid-supplied electricity. This utility-owned approach to residential storage represents one path, while a very different model is being tested across the Pacific.

California utility San Diego Gas & Electric (SDG&E) recently launched a pilot program to encourage homeowners to install residential storage themselves. In contrast to Ergon’s program, SDG&E would like its customers, or third-party vendors, to own the distributed systems. The utility will offer a tiered system of cash incentives and reduced rates that could, when combined with the state’s other incentives, render the storage free to customers. SDG&E envisions a rate that reflects forecasted system and circuit conditions on a day-ahead basis, and through hourly price signals, will incent both charging and discharging activity. Grid operators will then rely on energy stored in these batteries during peak demand, reducing the need to upgrade their equipment, and avoid utilizing more costly conventional generation sources. This approach can greatly improve the overall efficiency of the grid and help address the duck curve issues that arise from the ramping down of distributed solar PV systems during peak demand. A key feature of this model is that outside of peak demand periods, customers can utilize the battery however they want to maximize their consumption of solar energy, reduce demand charges, and ensure they have power during grid outages.

Potential Paths

The economics of both pilot programs will be determined over the next several years and will likely influence other utilities around the world. SDG&E has also proposed a separate pilot project that will deploy utility-owned batteries under its direct control, and it will compare that project’s performance against the tariff-based systems in terms of cost and effectiveness. Key questions for both utilities revolve around opening the residential storage market to additional participants and ensuring optimal benefits for both customers and grid operators. Despite the uncertainty, these pilot programs demonstrate potential paths forward for what is expected to be a massive global industry.

 

A Better Battery through Better Materials

— August 6, 2015

Through the past decade, primary and secondary battery technology has boomed across all different kinds of applications. Incrementally improving chemistries compounded with decreasing costs have paved the way for a golden age in energy storage across multiple sectors, and developing technologies that create safer, more efficient means of procuring storage will be imperative to successfully integrating renewables on a global scale.

Business owners, manufacturers, and electrochemical scientists are searching for new battery chemistries that can be engineered to serve a multitude of purposes. Lithium ion (Li-ion) batteries are widely regarded as one of the best chemistries, and Navigant Research forecasts exponential growth in terms of energy capacity and cell shipments in the next decade. Current Li-ion batteries with cobalt boast approximately 4 times the energy of lead-acid, with specific energy densities anywhere between 80 and 220 Wh/kg and cycle life of 1,000 to 5,000. Though they perform better than traditional storage devices, they typically have electrodes that are subject to rapid degradation at elevated temperatures and electrolytes that have low flash points, which can lead to a significant loss in capacity. Li-ion technology performance is dependent on the rate of intercalated lithium between electrodes, but due to growing demands for lighter and more powerful devices, a need for new materials has emerged as the gateway for a better battery.

New Developments

Researchers in South Korea have developed a solid-state Li-ion technology that utilizes a porous solid electrolyte rather than a traditional liquid. It is said to greatly improve performance and reduce risks due to overheating. The solid nature and material structure enables ions to travel more freely between electrodes, helps regulate cell temperature, and negates the need for separators typically found in batteries. Ion transference rates of the solid electrolyte were recorded to be between 0.7 and 0.8 compared to 0.2 and 0.5 of traditional electrolytes, which could translate to a substantial increase in rate of discharge and energy density. This battery then could be used in applications such as load leveling, frequency regulation, and voltage support for utility-scale energy storage systems. The cells also underwent elevated temperature testing (ranging from 25°C-100°C) over a period of 4 days, resulting in little change in ion conductivity and no instances of thermal runaway.

What makes this innovation valuable is its ability to be integrated with existing lithium technologies as well as next-generation advanced batteries. As lithium sulfur and metal-air increase in manufacturing feasibility and decrease in cost over the years, implementing solid-state electrolytes could position new batteries to provide long-term energy and storage solutions to the residential, commercial, utility and transportation sectors. The transportation sector also could benefit from solid-state battery technology. Currently, companies like Volkswagen and General Motors are interested in and actively investing in solid-state batteries, potentially for their next wave of electric vehicles. Both companies have acquired stakes in different U.S. startup battery companies that specialize in these types of batteries in order to achieve longer driving distances from a single charge. Despite the hurdles, developing functional, cheaper materials for advanced batteries seems to be a priority across the board. Doing so successfully could have transcendental effects on renewable energy.

 

Regulatory Focus on Air Transit of Li-Ion Batteries Increases

— July 2, 2015

Lithium ion (Li-ion) batteries have been highly touted for their long lifespan, high discharge rate, and ability to perform effectively in a number of different energy storage applications, which has led to their widespread adoption across the consumer electronics, automotive electrification, and utility grid energy storage sectors. The key factors driving the design and application of Li-ion battery technologies include power capacity, energy capacity, cost, lifespan, and safety. On the cost side, Navigant Research sees the maturation of the automotive and energy storage manufacturing and supply chains creating market forces that are expected to drive costs to new lows. However, the safe transport and use of Li-ion batteries is paramount and must be factored into each step of the manufacture, sale, transport, and use phase of the battery.

Since Li-ion cells are shipped partially charged to maximize their lifespan and reduce the chance of oxidation over time, they are classified as dangerous goods for transport, according to the United Nations (UN) Model Regulation for the Transport of Dangerous Goods.  Further, it has been well-documented that heat generation coupled with metal contamination and poor battery management systems can increase the risk of thermal runaway and fires during the use phase of a Li-ion battery. Whereas design, manufacturing, and quality control improvements have been implemented to reduce these risks during battery use, new scrutiny is being placed on the air transport of partially charged Li-ion cells and battery packs due to combustion risk from extreme temperatures. These developments are creating a challenge for Li-ion battery manufacturers that are considering export strategies due to the increasingly complex set of regulatory challenges facing airline carriers.

For example:

Assessing and Addressing the Risks

To address safety risks during transport and use, scientists at NTT Facilities, Inc. have tested adding a chemical flame retardant called phosphazene to lithium batteries to increase their safety in different applications. Their study has shown that fully charged 200 Ah packs, like those commonly used in portable electronics, did not explode, ignite, or undergo thermal runaway when undergoing significant laboratory testing protocols. Further, larger battery packs were also tested and operated for 400 days in a state of floating charge with positive results and minimal impact to battery capacity.

Though this advancement is still in the early stage of development, the prospect of integrating a material that is commercially available with a high voltage resistance and low cost to further improve safety while balancing costs merits a watchful eye. Whereas battery manufacturers are loath to add materials, those battery manufacturers and energy storage systems integrators looking to ship (or procure) Li-ion batteries from long-distance manufacturing sites will want to track these developments.

 

High-Accuracy Mapping: An Opportunity for the Post Office?

— June 23, 2015

Telescopers_webSynergy is one of the most overused and abused words in business. Whenever this word is uttered, it’s time to break out a big hunk of salt. However, at the recent TU-Automotive Detroit conference in Detroit, an actual synergistic opportunity popped up in the course of discussion. The U.S. Postal Service (USPS)—and by extension, other postal services globally—could play an important role in the future of automated driving. According to Navigant Research’s Autonomous Vehicles report, nearly 95 million vehicles with some autonomous capability will be on the world’s roads by 2035.

High-Resolution and High-Accuracy Mapping

One of the most common topics to arise during the 2-day gathering of people involved in automated driving and connectivity was the need for high-resolution and high-accuracy mapping data. Alain De Taeye, management board member at TomTom, gave a keynote presentation on the requirements for highly automated driving systems. While sensors including a global positioning system (GPS) that can detect the immediate surroundings are clearly a critical component, they are insufficient for robust automated control. Maps can help extend visibility well beyond the line of sight of either the driver or sensor system.

More importantly, the combination of high-definition 3D maps and sensors enables greater capability than either on its own. For example, GPS sensors are notoriously unreliable in the urban canyons where automated vehicles offer some of their most important potential benefits. As satellite signals bounce around off tall buildings set closely together, a GPS-only system often places the user far from their actual location. On the other hand, cameras and LIDAR sensors can contribute to a fused real-time map of the surroundings that can be correlated with stored maps for validation and provide more accurate and precise location information.

De Taeye discussed the sources of data used by TomTom and other map providers, including HERE and Google. By blending data from satellite imagery, government data, real-time crowdsourced information, and fleets of vehicles that traverse the actual roads, maps are constantly updated. De Taeye emphasized the need for continuous updates on road information to ensure accuracy as well as precision, which is where the USPS could come to the rescue. Even companies as large as Google have practical limits on how frequently they can drive down each road.

Capturing Data with Future USPS Vehicles

Ryan Simpson, an electrical engineer with the USPS, attended the conference to learn about some of the new technologies that could potentially be put to use in future service vehicles. With more than 150,000 daily delivery vehicles and another 100,000 vehicles of various form factors, the USPS has the largest commercial vehicle fleet in the world. Those 150,000 delivery vehicles traverse a huge proportion of the roads in the United States 6 days a week, 52 weeks a year. The USPS is currently in the process of defining a next-generation delivery vehicle to replace its rapidly aging fleet. If the new vehicles were equipped with some cameras and sensors, they could capture data with much higher frequency than any of the existing mapping companies. Real world data about everything, including road construction, bridge problems, and even potholes, could be updated daily.

Given the persistent financial difficulties of the USPS, providing fresh and reliable navigational data to mapping companies could provide a significant revenue stream that helps support a very important service to the U.S. population. At the same time, such data would also help to enable automated driving systems. This would be genuine synergy.

 

Blog Articles

Most Recent

By Date

Tags

Clean Transportation, Electric Vehicles, Policy & Regulation, Renewable Energy, Smart Energy Practice, Smart Energy Program, Smart Grid Practice, Smart Transportation Practice, Smart Transportation Program, Utility Innovations

By Author


{"userID":"","pageName":"Advanced Batteries","path":"\/tag\/advanced-batteries","date":"9\/3\/2015"}