Taipower AFC procurement
Taipower's energy storage Automatic Frequency Control (AFC) service utilizes energy storage system’s nature of fast charge/discharge cycle to regulate power frequency, stabilize power supply, and bring greater economic benefits to power generation. Among winners in the Taipower procurement exercise for AFC , TCC Green Energy, Datung, TPE Energy, and SIC have all announced news of systems coming online earlier in April and May, whilst Hengs Technology is expected to connect projects to the grid by the end of first half of the year.
The procurement held last year was not only the first public procurement process for AFC, but also the only bilateral contract in Taiwan. The winners’ energy storage systems shall serve exclusively for the AFC service as additional support at any time and pass muster under Taipower requirements. If the requirements are met, Taipower must defray charges within the three-year term. The contract could be extended for another three years, totaling six years of maximum term. From this year onward, Taipower’s ancillary services will be carried out along with day-ahead competitive bidding mechanism. This is good news for companies that wish to join the services, albeit without contracts, and provides more system flexibility when not serving for Taipower services.
The 2020 Taipower ancillary service awarded capacities in descending order: SIC, 5 MW/10 MWh; TCC Green Energy, 5 MW/5 MWh; TPE Energy, 2 MW/3.2 MWh; Hengs, 2 MW/1.2 MWh; Datung, 1 MW/1 MWh.
May 13 and May 17 Hsinta Power Plant incidents
Malfunctions at Hsinta Power Plant caused two nationwide power outages in Taiwan on May 13 and May 17. Grid ancillary services used to be provided by traditional coal-fired and hydropower generators, which require warm-ups or are driven by inertial force, thus take longer times to response. When such incidents occur, energy storage AFC ancillary services that comprise fast response batteries can convert, charge, and discharge electricity within the shortest time. It also offers supports during emergencies or short-term peak periods, mitigating the severity of incidents.
Taking the ESS operating mode of one company for instance. The ESS took 0.1-0.2 second to respond, enabled full-power discharge to the grid within one second, and provided continual regulating services, stabilizing frequencies of the grid and prevent larger crisis resulted from grid breakdowns caused by the incidents. However, energy storage systems in the AFC services are not designed for long-duration storages. As a result, with no backup power, outages would still occur inevitably. That is why Taipower proposed regulation reserve, spinning reserve, and supplemental reserve, which all require different response times and durations and cooperate with one another when discharging. During an incident, energy storage AFC comes to rescue as it was designated to do, highlighting the vital importance of expanding energy storage in the ancillary services to consolidate system resilience and minimize the severity of coming incidents.
Large scale energy storage systems required
Taiwan targets at least 20 GW of PV installed capacity and 5.7 GW of offshore wind installed capacity by 2025, with renewable energies taking up 20% of power generation. Against this backdrop, Taipower planned to add 590 MW of ESS by 2025. Calculated solely with power ratio, the storage capacity only accounts for 2.3% of renewable energy mix and is obviously insufficient to sustain the stability of the grid. Presently, international utility-scale power plants have 10-20% of ESS integrated. Therefore, Taiwan still has a long way to go in energy storage infrastructure. With the impacts of power outages and energy transition policies, it is hoped that the government and Taipower will accelerate and expand the applications of energy storage; in the meantime, invigorate Taiwan’s energy storage industry chain.