There could be a revolution in the role of energy storage as energy systems are decarbonized. Novel energy storage technologies are expected to make an important contribution in the future, particularly in the event of heat and transport electrification or if intermittent renewables and nuclear come to dominate electricity generation. Numerous energy storage technologies have been proposed to store excess electricity, with electrical energy conversion to mechanical, thermal, gravitational, electrochemical, and chemical energy for storage, and many of these technologies are classified in this chapter. Energy storage technologies are complicated and poorly understood relative to most low-carbon technologies. A series of metrics have been proposed to compare storage technologies, but understanding how to integrate energy storage into low-carbon energy systems remains a difficult challenge for several reasons. The value of storage to an energy system depends on the electricity generation portfolio, particularly the relative amounts of inflexible and flexible generation. Existing energy system, dispatch, and network models are either not broad enough to examine all energy storage and alternative options, or have insufficient temporal resolution to realistically portray the need for and performance of storage technologies. Innovation is required to reduce technology costs. There is a dearth of knowledge on public attitudes toward energy storage technologies. Finally, even if the long-term value of energy storage could be demonstrated, existing electricity markets are designed for incumbent systems and market regulation would need to be adapted to reflect the technological, economic, and social value of energy storage to an energy system. Further R&D and a better understanding of the integration of energy storage technologies are vital to provide information to underpin future market design and regulation to realize the value of energy storage.
Table 1.1
List of Energy Storage Technologies that are Examined in this Book, by Category
Mechanical/thermomechanical/gravitational: • Pumped hydro
• Ground-breaking energy storage (GBES)
• Advance rail energy storage (ARES)
• Compressed air energy storage (CAES)
• Pumped hydro with compressed air
• Flywheels
• Liquid air energy storage (LAES)
• Heat-pumped temperature difference
Thermal: • Sensible thermal energy storage
• Latent heat storage
• Solar ponds
|
Electrochemical: • Rechargeable batteries (e.g., lead–acid, lithium–ion, sodium–sulfur)
• Flow batteries
• Supercapacitors
Chemical: • Reversible endothermic chemical reactions
• Power-to-gas
• Large-scale hydrogen storage
• Traditional energy storage (natural gas, oil, and coal)
|
Table 1.2
Key Characteristics Used to Compare Energy Storage Technologies in Studies by the IEA [13], Barton and Infield [21], and Luo et al. [22]
IEA | B&I | Luo | |
Storage duration | × | × | × |
Typical size | × | × | |
Charge duration | × | ||
Discharge duration | × | × | × |
Cycles | × | × | |
Response time | × | × | |
Roundtrip efficiency | × | × | |
Discharge efficiency | × | ||
Daily self-discharge | × | ||
Energy and power density | × | ||
Specific energy and power | × | ||
Maturity | × | ||
Energy and power capital costs | × | × | |
Operating and maintenance costs | × |