Guided by the national “dual-carbon” policy, the energy storage industry has become a key pillar of energy transition. As practitioners in the energy storage industry, we need to master the following basic professional knowledge. I have compiled 50 core terms in the field of energy storage.
I. Core Infrastructure Category
01 Energy Storage:
The process of storing energy in a medium or device and releasing it on demand. Through charge and discharge control, it achieves spatiotemporal matching of energy production capacity and consumption, and is a core technology for improving energy flexibility. Classification: Generation-side/Power-side Energy Storage (supporting new energy power plants), Grid-side Energy Storage (regulation of key grid nodes), User-side Energy Storage (end-user self-use and emergency); Grid Connection Attributes: Pre-meter Energy Storage (independent metering, tradable, including power source/grid side), Post-meter Energy Storage (user side, low connectivity).
02 New Energy Storage:
Energy storage projects (excluding pumped storage) that focus on outputting electricity and providing services to external parties. They are characterized by short construction cycles, flexible site selection, and strong regulation capabilities, and are suitable for new energy consumption. Mainstream Technology Routes: Compressed air, flow batteries, sodium-ion batteries, molten salt, gravity, and flywheel energy storage.
03. Long-term energy storage:
Energy storage systems capable of charge-discharge cycles of 4 hours or more (including several days or months). Technologies include pumped hydro storage, compressed air storage, solar thermal storage, hydrogen storage, and flow batteries.
04. Electrochemical energy storage:
Energy storage technology using batteries as the energy storage medium. It achieves the storage and release of electrical energy through electrochemical reactions and is the mainstream technology direction for new energy storage (including lithium batteries, sodium batteries, and flow batteries).
05. Mechanical energy storage:
Technology that stores energy through mechanical motion. Core types include pumped hydro storage, compressed air storage, flywheel storage, and gravity storage. It features long lifespan and strong environmental friendliness.
06. Electromagnetic energy storage:
Technology that stores energy using electromagnetic fields or electromagnetic induction principles. Mainly including superconducting energy storage and supercapacitor energy storage. It has advantages such as fast response speed and high power density.
07 Thermal energy storage:
Thermal energy storage is a technology that stores energy in the form of thermal energy. The mainstream type is molten salt energy storage (used in conjunction with solar thermal power plants). Energy is stored by heating the energy storage medium, and when heat is released, it is converted into electrical energy or directly supplied as energy.
II. Equipment and Systems
08 PCS (Power Conversion System)
The core power conversion equipment of the energy storage system, realizing bidirectional conversion between DC (battery side) and AC (grid/load side), while also undertaking charge/discharge control and grid-connected regulation functions.
09 EMS (Energy Management System)
The “brain” of the energy storage system, collecting and analyzing electrical parameter data to formulate charging and discharging strategies, achieving coordinated operation of energy storage with the grid, load, and new energy sources, ensuring system efficiency and safety.
10 BMS (Battery Management System)
The “monitoring center” of the battery pack, responsible for monitoring battery voltage, current, temperature, and other parameters, realizing overcharge/over-discharge protection, equalization management, and ensuring battery safety and lifespan.
11 Battery Cell
The smallest functional unit of a battery, the core carrier of electrical energy storage and conversion. Based on chemical system, it can be divided into lithium-ion cells, sodium-ion cells, flow battery single cells, etc.
12 Battery Module
A unit composed of several cells connected in series and parallel, equipped with heat dissipation and fixing structures, and is a component of the battery pack.
13. Battery Pack:
A complete energy storage battery pack consisting of battery modules, BMS, cooling system, and casing, which can be directly connected to an energy storage system.
14. Microgrid:
A small-scale autonomous power system with bidirectional power supply. It can operate independently or be interconnected with the main grid. Energy storage is its core component, balancing supply and demand and improving energy efficiency.
15. Energy Storage Power Station:
A centralized energy storage facility consisting of energy storage batteries, PCS, EMS, transformers, and other equipment. It can provide large-scale energy storage and grid regulation services (including independent energy storage power stations and new energy energy storage power stations).
III. Application Scenarios
16. Distribution Area Energy Storage:
A grid-side sub-type, fixed energy storage deployed in distribution areas (transformer-supplied areas) to solve problems at the end of the distribution network such as low voltage and heavy overload, and also has emergency power supply capabilities.
17. Mobile Energy Storage:
Like a mobile power bank, it can be flexibly moved, plug-and-play, and quickly deployed, especially suitable for temporary power supply needs such as power supply for Class I and II loads, unplanned power outages, and uninterrupted power supply operations.
18. Residential Energy Storage:
Energy storage systems suitable for residential users, usually paired with photovoltaic systems. It stores surplus photovoltaic power during the day and releases it for power supply at night, with selective grid connection.
19. Industrial and Commercial Energy Storage:
Energy storage systems for users in industrial parks, commercial complexes, etc. Core functions include peak-valley arbitrage, demand-based electricity management, and emergency backup, which can reduce electricity costs.
20. Off-Grid Energy Storage:
Energy storage systems not connected to the main grid, usually paired with distributed photovoltaic/wind power, to provide power to areas without grid coverage (such as remote rural areas and islands). 21. Grid-connected Energy Storage: Energy storage systems interconnected with the main power grid, enabling bidirectional energy flow. They can both receive charging from the grid and discharge to it, participating in grid regulation.
22. Integrated Photovoltaic-Storage-Charging System:
A comprehensive energy solution integrating photovoltaic power generation, energy storage systems, and charging facilities. It enables closed-loop operation of “photovoltaic-storage-charging” and is suitable for charging stations, industrial parks, and other similar scenarios.
23. Shared Energy Storage:
Multiple new energy projects or users share a single energy storage system. Capacity leasing and revenue sharing models reduce the investment costs of a single entity and improve energy storage utilization.
24. Emergency Energy Storage:
Energy storage equipment specifically designed for scenarios such as sudden power outages and disaster relief. Its core characteristics are rapid deployment and high reliability, primarily in the form of mobile energy storage.
25. Distribution Network Energy Storage:
Energy storage systems deployed at the distribution network level, including substation energy storage and distributed energy storage. Their core functions are alleviating distribution network overload, improving power quality, and ensuring power supply reliability.
26 Distributed Energy Storage
Small-scale energy storage systems that are distributed and deployed on the user side or at the end of the distribution network, characterized by proximity to the load and flexible adaptation.
IV. Technical Parameters and Safety Related
27. Cycle Life:
The lifespan of a battery after charging and discharging cycles, indicated by the number of charge-discharge cycles or the depth of cycle time. A higher cycle life results in lower replacement costs.
28. Rate Performance:
The battery’s charge/discharge capacity per unit time, usually measured in “C” (1C means 1 hour to fully charge or discharge the rated capacity). A higher rate performance means faster charging and discharging speeds.
29. DOD (Depth of Discharge):
The ratio (percentage) of the battery’s actual discharged capacity to its rated capacity. A higher depth of discharge means more energy is released per charge, but may shorten cycle life.
30. SOC (State of Charge):
The ratio (percentage) of the battery’s current remaining charge to its rated capacity. This is a core monitoring parameter of the BMS used to determine the battery’s charge/discharge status.
31. SOH (State of Health):
The ratio (percentage) of the battery’s current performance to that of a new battery. It reflects the degree of battery aging and is affected by factors such as the number of cycles and the usage environment.
32. Energy Density:
The electrical energy that a battery can store per unit mass or unit volume. The unit is usually Wh/kg or Wh/L. Higher density results in a smaller and lighter energy storage device.
33. Power Density:
The power output per unit mass or unit volume of battery. The unit is usually W/kg or W/L. Higher density indicates a stronger instantaneous power output.
34. Self-Discharge Rate:
The rate at which a battery naturally loses charge (usually expressed as a percentage per day/month) when at rest. A lower self-discharge rate indicates a stronger energy storage and retention capacity.
35. Thermal Runaway:
When a battery experiences internal short circuits, high-current self-heating, or other factors that cause its temperature to exceed limits, triggering a chain reaction of chemical reactions, rapid heat and gas release and diffusion, potentially leading to explosion or spontaneous combustion.
36. VOC (Open Circuit Voltage):
The terminal voltage of a battery under no-load conditions. It is an important reference parameter for determining the battery’s SOC and SOH.
37. Operating Voltage:
The terminal voltage of a battery during charging and discharging operations, which is divided into nominal voltage (typical operating voltage), charging termination voltage, and discharging termination voltage.
V. Market Knowledge Category
38. Independent Energy Storage:
Pre-meter energy storage with independent market entity status, capable of independent bidding, dispatching, and settlement, with core services for grid regulation and energy market transactions.
39. Peak-Valley Price Difference:
The price difference between peak hours (high electricity prices) and valley hours (low electricity prices) is the core source of revenue for energy storage peak-valley arbitrage; the larger the price difference, the shorter the payback period.
40. Dynamic Capacity Expansion:
Storing and discharging energy through energy storage systems during transformer overload periods reduces equipment load, replacing traditional capacity expansion and retrofitting, while also generating peak-valley arbitrage revenue.
41. Demand Response:
A market mechanism where energy storage systems adjust their charging and discharging behavior according to grid dispatch instructions, discharging during peak grid load and charging during valley load to obtain response subsidies.
42. Virtual Power Plant (VPP):
A platform that aggregates distributed energy storage, new energy power plants, and other resources through information technology to form a virtual power source, participating in grid dispatch and electricity market transactions.
43. Capacity Fee:
The fee paid by grid companies to operators to guarantee the available capacity of energy storage power stations. This is a significant source of revenue for independent energy storage power stations.
44. Green Certificates:
Environmental certificates proving the generation of renewable energy. The generation of renewable energy projects配套 with energy storage can be used to apply for green certificates, which can be traded to generate additional revenue.
45. Transmission and Distribution Fees:
Transmission and distribution fees that electricity users or energy storage projects must pay when connecting to the grid. This directly affects the grid connection costs and revenue of energy storage projects.
