Many technological advances of the 20th century were driven by readily available electrical energy. Today, many of our daily activities rely on having electrical energy at our fingertips. We need stable electricity supplies readily available to maintain business, food production and storage, health care and general standards of living; one essential characteristic of the current integrated electrical industry is that generation and consumption of electrical energy must be kept in real-time balance.
Generating the necessary amount of electricity at the time it’s needed is a complex endeavor that can be simplified and supplemented by storing generated power for later use.
Historically, the reserves required to provide real-time electrical energy have been maintained by flexible generation sources or pumped-storage hydroelectric plants that offered large-scale storage. However, the recent development of battery energy storage systems has opened new possibilities for storing electrical energy. Technological and efficiency advances enable additional ways for battery storage systems to be deployed from small- to large-scale applications.
Applications and costs
Battery energy storage has started to receive broad interest in the electricity industry, and is starting to find special applications that are economically viable for some large industrial and commercial applications. Although applications of battery storage in small, everyday devices like cell phones and laptops are extensive and established, battery storage systems in large commercial and industrial applications have a shorter history. However, battery storage for commercial and industrial purposes is expanding as it becomes a more economical option.
With some energy storage technologies, costs are declining significantly because of improved manufacturing efficiencies and technological developments, including increased capacities and lifespans. Effective applications and technological advances in other sectors are presenting new opportunities in energy storage and subsequent benefits to customers. For instance, batteries can play a critical role in shifting peak energy usage times and operating a smart grid. Instead of purchasing energy during peak periods, a commercial operation could purchase cheaper energy during off-peak hours and store it for use later, potentially during peak times. As another example, the increased adoption of electric vehicles (EV) possibly enables supplementary energy storage using the EV battery systems. Some EV charging stations could also use supplemental solar power in conjunction with battery storage.
Barriers to adoption
As customers and electrical distribution utilities look for improvements in economic efficiency and reliability of their systems, battery energy storage may have an expanded role to play. However, some current electrical utility policies and provincial regulations are a barrier to the commercial application of energy storage. Provincial energy ministries and regulators will need to review the impact of energy storage on the distribution systems in their provinces and develop policies that will allow storage, particularly where there is a net positive economic benefit.
Ontario, at time of writing, has an Industrial Conservation Initiative (ICI) program that has provided an opportunity to employ behind-the-meter battery energy storage systems for loads greater than a certain threshold (often about 1 MW). Under the current electricity price structure in Ontario, customers with loads over about 1 MW receive lower electricity costs if they reduce their demand during predefined high-usage time periods. This special Ontario program makes it economically viable to install large battery energy storage systems with capacities from about 1 MW to 10 MW (which provides about two hours of operation at peak discharge rate). The impacts and benefits of this aggressive program may be evaluated and revised in the future.
Battery use for commercial or industrial energy storage is likely to become an increasingly feasible and common practice, but there are some key considerations to keep in mind:
Identify advancements in technology and applications
Monitoring new technological advancements for different energy storage technologies and their economic feasibility is important to identify valuable opportunities and applications. For example, electric vehicle (EV) and charging installations with special control features may become feasible and even commonplace.
Monitor standards and policies
It is important to monitor policy developments, utility connection requirements, and regulations affecting the safe and effective incorporation of energy storage technologies. Several new standards have an impact on energy storage systems in Canada. The Canadian Standards Association (CSA) will soon issue the new standard for Distributed Energy Resources (DER). CSA is also participating in the International Electrotechnical Commission (IEC) initiative to develop unified technical requirements for energy storage systems. Underwriters Laboratories (UL) has standards for energy storage systems that have approval requirements in Ontario, which may be adopted in other provinces. The US National Fire Protection Association (NFPA) is developing the fire regulations and requirements for energy storage facilities — a critical element, given the potential high heat generation from failure of an energy storage facility.
Consider the client’s specific applications and needs
To help clients evaluate the costs and benefits of energy storage technologies, many aspects must be understood and assessed. In addition to monitoring technology, applications, and government directives, the local electrical utilities requirements, provincial regulations, and electrical energy cost structures must be evaluated for each client and may change over time and with location.
Incorporate renewable energy sources
It may be possible for a renewable energy source to provide the electric power for special applications, such as smart grid, electric vehicle, or remote power systems. For example, combination systems of solar photovoltaic sources and battery energy storage used for EV charging systems could increase the proportion of transportation power that comes from renewable energy sources. But, concepts like this will need to be evaluated as a complete system to compare actual effectiveness relative to perceived effectiveness. Alternatively, some jurisdictions may permit customers to sign contracts for renewable sourced power from their distribution utility.
Energy storage systems may be used for either utility-connected or behind-the-meter applications. These systems can use their inverters and control systems to help electrical customers improve reliability and assist in possible smart grid applications. The new CSA DER standard in Canada requires some systems to include provisions for optional ride-through to maintain reliable power through some short-term power disruptions . The inverter systems and their controls are developed to be capable of 1) utility connection with or without voltage controls and 2) grid forming for possible islanded or uninterruptible power supply (UPS) operation.
The permissible amount of energy storage capacity that can be connected at customer locations on distribution systems can be affected by technical issues and policy decisions of the distribution company. New standards are supporting options for the energy storage to control the voltage or power by keeping the feeder voltage, controlling the customer voltage, and controlling net load power factor in an acceptable range while the facility is charging and discharging. The local distribution company should be consulted to obtain their site-specific requirements.
As the energy storage increases on a distribution feeder, the need for communications between the storage facility, the supply station, and/or the distribution operator increases. The cost of traditional communication systems is often high, and may be a barrier to connecting the storage facilities that require protection-grade communications. The development, or application of more affordable communication technologies, or the adoption of facility features, such as islanding detection, reverse power control, or tripping, may assist in addressing local utility requirements. It is important to monitor the types of communication facilities and protection features that can satisfy the distribution companies’ requirements and keep the communication costs manageable.
Bright future for battery energy storage systems
Given the focus on developing new storage technologies and improving existing ones, more opportunities will open up for the application of energy storage systems in a variety of roles. The increasing adoption and integration of battery energy storage into current electric energy systems will not only yield increasing capability and reliability of energy, but also advance the sustainability and resiliency of energy systems in the future. While battery energy storage systems cannot solve all the challenges, and there are environmental impacts and risks in disposal, they can make a positive contribution to increasing the share of electricity from renewable sources and enabling some smart grid solutions.