Variable renewable energy sources like wind and solar need energy storage to help balance production and demand. Battery-based systems are fast emerging as an ideal solution, but with big differences between batteries; how can manufacturers provide performance assurance and how do project developers choose the right storage solution?
Please visit our website for more information on this topic.
Variable renewable energy sources like wind and solar need energy storage to help balance production and demand. Battery-based systems are fast emerging as an ideal solution, but with big differences between batteries; how do project developers choose the right one? Manufacturer warranties give an indication of lifetime and performance. However, given the scale of their investment, project stakeholders need more detailed, independently validated performance data to make an informed choice.
In DNV’s Energy Transition Outlook, we predict that annual energy storage usage could reach 50 terawatt-hours by . This global energy storage fleet will be used primarily for renewables integration and grid management, in a world where renewables will represent 80 percent of our electricity generation.
Large scale adoption of battery chemistries in the automotive sector mean battery energy storage provides a cost effective and readily available solution for managing variable renewables. As a result, manufacturers are developing a range of battery storage solutions to address this fast-growing market. But this presents a challenge for project developers and investors, who need to have confidence that the storage solution they choose will meet their specific needs.
In particular, they need to be sure their chosen system will perform reliably and have a predictable life expectancy. As the economic viability of entire projects is based on these factors, buyers want more reassurance than just the word of the manufacturer. They want independent validation of battery performance. And as performance can differ significantly for different battery configurations, detailed performance data is crucial to the decision-making process.
Why does battery performance vary so much?
Even though they are based on the same technology, similar lithium-ion batteries can still perform very differently. This is partly due to different manufacturing processes but is mostly because they each have their own unique formulation of chemistry additives. Also, to meet specific market demands, manufacturers engineer their batteries to have particular characteristics, perhaps focusing on high temperature resistance or a better cell charge rate (C-rate), for example. This is evidenced by the rich field of patents filed in Li-ion chemistries since the early ’s.
Each battery system also performs best in a particular state of charge (SOC) range or window. Keeping the battery within this window can extend its operating life. But, if the average SOC condition is not within this window, this could adversely affect the reliability of the battery. For instance, a battery that degrades at a faster rate at high SOC would not be a good choice for an infrequent peak-shaving function, where it would typically be sitting at high states of charge. A battery that performs well at high SOC may be a better fit for this particular application.
Batteries can also be designed for specific environments where there could be high or low ambient temperatures. As cell temperatures is critical to a battery’s lifetime, inadequate or too much cooling will shorten its life. In short, no two batteries are exactly alike, even if they are generically described as the same chemistry.
Performance data accelerates the decision-making process
Clearly, having access to detailed performance data on different batteries’ capabilities would be a significant asset to project developers and their lenders. Not only is this information invaluable in choosing the best-fit solution, it can also help mitigate the high financial risk by verifying manufacturers’ warranties and guarantees.
Built on test data compiled over several years, DNV’s Battery Performance Scorecard provides a level playing field to show stakeholders how batteries from different manufacturers compare across a range of key performance indicators including SOC conditions, C-rate (a measurement of power) and temperature. This enables project developers to compare the performance characteristics of different batteries and choose the best match for their specific system design.
Closing more deals
Deployments in the solar industry accelerated when a contractual mechanism was standardized (the power purchase agreement, or PPA) and the data to support warranties became widely distributed and accepted. The financial community expects the same of energy storage.
Link to SolarEast
DNV saw the gap in lifetime and degradation data for batteries, and developed the Battery Performance Scorecard to provide more confident independent engineering reports on energy storage projects, thereby enabling their financing. The Scorecard helps project developers choose the best solution for their systems and provides independent validation of the system performance and manufacturer warranties. This makes the decision-making process easier and quicker.
Battery manufacturers can also benefit from having their products in the Scorecard. It provides developers with assurance on the performance of their systems. It can even bring them new business by providing instant validation of their solutions against other manufacturers products. Since the Battery Performance Scorecard was published, independent engineering reviews can be performed faster, and DNV has received many requests from developers for more information about the storage systems covered in the Scorecard. In the end, more closed deals will lead to more growth in the renewables and energy storage markets.
With the declining cost of energy storage technology, solar batteries are an increasingly popular addition to solar installations. It's not just residential and commercial solar shoppers that benefit from installing energy storage. Utility-scale battery storage is also playing a significant role in the operation of the electric grid, providing cost savings, environmental benefits, and new flexibility.
Unlike residential energy storage systems, whose technical specifications are expressed in kilowatts, utility-scale battery storage is measured in megawatts (1 megawatt = 1,000 kilowatts). A typical residential solar battery will be rated to provide around 5 kilowatts of power. It can store between 10 and 15 kilowatt-hours of usable energy, as with the Tesla Powerwall 2 and LG Chem RESU 10H. A typical utility-scale battery storage system, on the other hand, is rated in megawatts and hours of duration, such as Tesla's Mira Loma Battery Storage Facility, which has a rated capacity of 20 megawatts and a 4-hour duration (meaning it can store 80 megawatt-hours of usable electricity).
Utility-scale storage, or large-scale or grid-scale storage, has historically been provided by resources such as pumped hydro. In a pumped hydro system, a facility will pump water uphill into a reservoir at times when the cost of electricity is inexpensive (in the middle of the night, for instance) and then run that water back downhill through a turbine when electricity costs are higher, and the grid needs extra energy. With declining battery energy storage costs and the increased introduction of renewable energy, batteries are beginning to play a different role at the grid-scale.
The size and functionality of utility-scale battery storage depend upon a couple of primary factors, including the location of the battery on the grid and the mechanism or chemistry used to store electricity. The most common grid-scale battery solutions today are rated to provide either 2, 4, or 6 hours of electricity at their rated capacity. However, it's not unrealistic to anticipate that longer-duration batteries will be available someday soon. Generally, grid-scale batteries are paired with a generating resource, such as a wind farm, or placed on the transmission and distribution system at substations to help balance local electric supply and demand.
Storage can act like a load (charging from the grid when electricity prices and demand are both low) or like a generator (pushing electricity back onto the grid when demand and prices are both high). Moreover, when power plants take minutes or even hours to turn on, battery storage can inject electricity onto the grid in milliseconds. This level of flexibility from a resource is unprecedented, and the possibilities for harnessing this capability are endless.
Utility-scale battery storage is beneficial when paired with renewable resources like solar or wind farms. While these renewables are fantastic resources for producing affordable clean energy, they can be unpredictable when weather patterns change. Utility-scale battery storage allows resource developers to smooth out the output from these resources, ensuring that renewable energy is injected into the grid when needed.
There are a few primary players in the battery energy storage industry at the utility-scale level. Perhaps the best-known provider is Tesla, whose 100 MW battery in South Australia made waves a few years ago. Beyond this deployment, Tesla has also contributed to the Aliso Canyon storage projects to help alleviate the need for the leaky natural gas facility. The company markets the Powerpack, its original utility-scale storage solution, and the Megapack, a new product designed for even larger-scale applications.
Another major player in the utility-scale battery storage space is AES Energy Storage. Like Tesla, AES also developed a storage project in a couple of months in response to the Aliso Canyon gas facility crisis. Recently, AES announced the groundbreaking of a new 400 MWh battery storage facility in Southern California Edison's service territory, which will be among the most extensive battery storage facilities ever brought online.
Beyond the benefits of installing battery energy storage at the grid scale, there are plenty of reasons to pair one or more batteries with a solar panel system on your property. Though there may only be one grid-scale solar + storage system, these types of installations are increasing in popularity for homeowners nationwide, with tens of thousands of systems installed in California alone over the last few years. If you're interested in participating in the solar + storage movement, register for a free account on EnergySage to receive custom solar or solar + storage quotes for your home.
For more information, please visit Large Scale Battery Storage Solutions | One-Stop Energy Storage Provider.