As energy storage becomes more prominent in the energy industry, it is beneficial to gain a better understanding of the various entities involved. When a general consumer tries to make a purchase, it can be confusing with all the terminology. There are many different entities in the energy industry, and each serves a different purpose. The goal is to provide an explanation of what each role is and how they relate to each other.
The end user is typically the one making the purchase. At times, there may be a contractor or project manager making a purchase on the end user’s behalf. Generally speaking, this is the entity using the energy whose requirements need to be met.
Energy System Financer
Given the general expense of a new power system installation, there may be a need for a loan of some sort. Most people relate loans to banks; however, early on, there was reluctance to provide funding to technology that was not fully proven. Therefore, companies were created by energy storage advocates to provide financing to help energy storage system installations. This entity would provide a loan to pay off the purchase and installation and would have a fixed payback system with the consumer.
As the title implies, this is a company that does the physical work behind assembling the battery. This company works with suppliers of various materials, like the electrode material and the electrolytes. Typically, there are metal and plastic suppliers that help in making the casing. There are different sealant suppliers that may be contracted by this company for sealing components. There are generally chemistry specialists on staff that study the specific composition within the battery and testing technicians that analyze the battery’s performance under different conditions. The Battery Manufacturer is able to take all those components and create a final battery product. Depending on the technology, the output from the Battery Manufacturer is either referred to as a cell or as a battery pack, if cells cannot be individual.
This entity helps move batteries from manufacturing to a buyer. The buyer can be a company that will use the batteries in a bigger assembly or a consumer who will put the battery to direct use. A distributor typically is the entity purchasing the batteries from the manufacturer and making it available to the consumer, helping transport it to an end user. There are also suppliers of batteries with storefronts that make the batteries available for walks-in purchase.
Battery Management System Provider
Depending on the battery chemistry, there may be a need to better monitor and control the operating conditions. A battery management system (BMS) is a set of electronics and a corresponding control program that is specific to the battery or set of batteries. These sophisticated controls monitor what goes in and out of the battery and have specific alarms created for regulation. The BMS is used to interface the batteries with a larger control system that integrates all the power resources of a house or building (referred to as an energy management system or EMS). A BMS is a necessity for advanced chemistries like NiMH and Li Ion that are not designed to vent during normal operation. They cannot sustain float charging like a lead acid battery, which can handle a continuous charging input well after it has reached 100%. For more advanced chemistries, the ability to float charge can only be done below a chemical equilibrium voltage. Therefore, the BMS provides sophisticated controls to ensure that the charging algorithm does not go outside the battery’s optimal operating conditions. Given these specific needs, many battery manufacturers have created a BMS specific to their battery to avoid any misuse.
The inverter is a critical component within an energy storage installation. It transitions the direct current (DC) that comes from the battery to alternating current (AC) at a specific voltage and frequency for use in the specific region. The voltage and frequency vary by country or state so there is no standard inverter that can be placed in multiple regions. For instance, the single phase voltage of 230V and a 50 Hz frequency is normal in France, but 120V and 60 Hz is typical in the US. There are a few different types of inverters and the decision on type can depend on the intended use of the energy storage system. There are some that can allow the input from both a photovoltaic (PV) system and a battery system simultaneously, where others are built specific to the equipment. Either way, the manufacturer of the inverter typically has a direct relationship with the battery manufacturer and whatever entity is integrating and installing the components.
Energy Management System Provider
At a single location, there can be multiple power systems in place. An energy management system (EMS) is a central program that takes all the inputs and can control how they are utilized together. There are many EMS providers on the market with varying complexity. In general, the EMS system should be able to monitor the load needs of the home or building and apply power from any available installed system to meet the loads. For example, in a house with a PV system and an energy storage system, the EMS would have the PV system providing power during the day to mitigate peak load periods, with any excess used to charge energy storage. Then, once the sun is no longer available, the EMS can utilize the energy storage system to mitigate the home loads. The EMS programming has to be able to communicate with all the installed systems, so the EMS provider tends to have close relationships with manufacturers and distributors. Although these communication protocols are not all the same amongst different technologies, there is progress towards standardization which will help the industry as a whole.
There are companies who take the energy storage components from different manufacturers and aggregate them into a packaged solution to sell to consumers. In some cases, the system integrator actually manufactures one of the components and use that to create a bundled system. For example, a system integrator can design and produce an energy management system (EMS) either as a separate component or as part of a complete solution including batteries and an inverter to directly interface with the EMS.
This is the company who takes all the components and installs them in the home or building where the system is needed. Typically, this will include an electrician who is making sure everything is code compliant. The installer should be knowledgeable of the applicable codes and regulations for the installation location.
Authority Having Jurisdiction (AHJ)
In order to start a system installation, the party providing the installation will have to gain some sort of approval. The approving entity is referred to as the Authority Having Jurisdiction. This varies from region to region and country to country. There may be permitting and code inspection involved. It just depends on the system and how it is connected and planned to be utilized. For storage systems that may be used in net metering, where electricity is able to be fed back into the grid, there is a need to interconnect with the grid. This means that, at minimum, the utility will need to approve of the system interconnection.
After Sales Support
Once a system is purchased and installed, unexpected challenges can arise. Typically, the customer will have been provided a support contact phone number or email address from the entity through which they made the purchase. There should be someone to contact for general troubleshooting of an installation. The sales representative who sold the item should be able to provide preliminary information and connect the customer to the specific people that need to be active for the particular situation.
Operations & Maintenance Support
Some batteries have defined maintenance procedures and schedules. Typically, there is a manual provided to the consumer upon purchase that details out those needs. Some of these procedures can be carried out by the system owner, such as adding new water to a flooded lead acid battery. For more sophisticated support, the installer of the system should be able to help or at least put the consumer in touch with the appropriate parties.