THE ROLE OF ELECTRICITY STORAGE IN THE ENERGY TRANSITION
Electricity storage is thus set to become one of the key facilitating technologies of the energy transition. In the Remap (Renewable Energy map_IRENA) analysis, electricity storage power capacity reaches more than 1 000 GW by 2030, when total installed solar and wind capacity will be 5 000 GW. This storage power capacity is split into 600 GW from EVs, 325 GW from pumped hydro and 175 GW from stationary battery storage. Total storage capacity grows to nearly 3 000 GW by 2050, with EVs in operation accounting for a majority of this total.
CURRENT ELECTRICITY STORAGE DEPLOYMENT IN THE ENERGY SECTOR
It also has been historically expensive and difficult to store for long periods; hence, the necessity to balance electricity generation and demand in real-time. Pumped hydro storage is the major exception to the difficulty and expense of storing electricity, and it represents the largest source of today’s electricity storage at around 169 GW of power, accounting for 96% of the approximate 176 GW of total energy storage of all types estimated to have been operational in mid-2017 (US DOE, 2017)
Thermal energy, electro-chemical and electro-mechanical storage technologies contribute a total of 6.8 GW of energy storage globally.
Electro-chemical storage is one of the most rapidly growing market segments, although operational installed battery storage power capacity is still only around 1.9 GW. Although there is a number of emerging BES technologies with great potential for further development, Li-ion batteries account for the largest share (59%) of operational installed capacity at mid-2017.
Nevertheless, since most ESSs generally provide more than one service. Hence, they can be remunerated for, while simultaneously contributing to, a range of services.
Despite their much lower levels of deployment, the main services provided by electro-chemical are more diverse than those of PHS plants (Figure 7). This is particularly true for BES systems (i.e. electrochemical in the “DOE Global Energy Storage Database”), where the capacity of the top five main-use cases amounts to 80% — still less than the share of electricity time shifting for PHS.
ELECTRICITY STORAGE SYSTEM CHARACTERISTICS AND APPLICATIONS
Energy storage technologies have different intrinsic properties that determine their technical suitability for certain applications or provide certain services to electricity systems. For example, depending on their discharge times — at a rated power ranging from seconds to hours and with system power ratings from the kW level up to the GW order – these technologies are more suited to specific applications within electricity systems.
Electricity storage systems in the electricity sector are used in three main segments:
• Grid services
• Behind-the-meter applications
• Off-grid applications
ELECTRICITY STORAGE SYSTEM COSTS AND PERFORMANCE TO 2030
The contribution of cell costs to the total BES system cost will vary, depending on the BES system size. A lower contribution of cell cost components as system size increases can be expected, since for larger systems, the power electronics and periphery costs become more relevant (Müller et al., 2017). For example, aggregated cost breakdown estimates for Li-ion BES systems in various market segments place cell costs at 35% for large systems, compared to 46% for residential systems (Figure 28).
Global manufacturing for Li-ion cells has ramped up considerably and plans to further expand capacities continue. The annual manufacturing capacity for Li-ion batteries today, for all chemistry types, may be 100 GWh or more and may possibly exceed 250 GWh by 2020 (Enerkeep, 2016).
GLOBAL ELECTRICITY STORAGE MARKET OUTLOOK TO 2030
Total electricity storage capacity in energy terms may grow from an estimated 4.67 TWh in 2017 to between 6.62 TWh and 7.82 TWh in the REmap Reference case in 2030, which is 42-68% higher than in 2017.
