Electricity rate plan

TPC has been promoting load management for over 40 years, and it continues to take on the responsibility of stable power supply for the entire Taiwan. From the demand management perspective, it has used the price incentive to guide customers to change power consumption behaviors in order to reduce peak power consumption and to achieve power supply stability. The price-type demand response measures currently being promoted by TPC include: Inclining Block Rate (IBR), Seasonal Rate, Time-Of-Use (TOU) Rate, and Critical Peak Pricing (CPP).

Inclining Block Rate (IBR) refers to the pricing according to different blocks of power consumption block. Currently the pricing is determined via 6 blocks, and the price per kWh is ranging from NTD 1.68 to NTD 8.46. Under such rate structure, the electricity bill will be increased along with the increase of power consumption. IBR can prompt users (especially those who consume a lot of electricity) to reduce unnecessary power consumption, thus enhancing the energy use efficiency and helping TPC to achieve the obligation of energy saving and carbon emission reduction. Most residential houses and small commercial users are using IBR plan.

The Seasonal Rate is for reflecting the higher power supply cost in summer. TPC’s Seasonal Rate is determined by two seasons (Summer and Non-summer), and it is implemented in all rate plans (except for the package rate). Seasonal Rate will force some users (such as large factories or enterprises) to shift a part of power demand to non-summer months. Even if the shift is impossible, Seasonable Rate can also contribute to the reduction of power demand during peak hours in summer while encouraging the enhancement of energy efficiencies of power consuming appliances. In addition to the package rate users such as streetlights, currently Seasonable Rate is applied to all users.

Time-Of-Use Rate refers to different electricity rates for different times of use. Currently TPC has introduced a total of 16 Time-Of-Use Rates for various users, which can be divided into two major categories: one is the rate including peak periods and off-peak periods (three-periods TOU), and the other is the rate including the partial -peak periods (two-periods TOU). TOU Rate can make most users shift power consumption during peak hours. Even if users cannot shift the power consumption load, TOU Rate can still encourage users to reduce the energy consumption during peak periods and to enhance the energy use efficiency. For example, users will try to raise the set temperature of air conditioner during peak hours in summer. So far, TOU Rate is enforced on users of high voltage and above, while it is optional for low voltage users. Users of TOU Rate account for 70% of all users.

In recent years, renewable energy (especially Photovoltaic solar energy) has increased significantly, and electricity demand peak has shifted from daytime to evening. Therefore, TPC has adjusted TOU period in 2022 on a pilot and formally implemented in 2023. Take three-periods TOU for example (divided into peak, partial -peak, and off-peak periods), the new TOU shifts the peak period from 10 a.m.-12 p.m. and 1-5 p.m. to 4-10 p.m. to provide accurate price information and guide users shift the power consumption load from evening to daytime, make full use of carbon-free energy, and implement energy conservation and carbon reduction.

The deployment of AMI allows TPC to adopt more delicate and diversified design of electricity rate plan, thereby launching diversified TOU rates, including: “Simple TOU Rate” introduced in 2016 for residential and small business which has a total of 91,352 users selected it in 2022; “Three-periods TOU for low tension service” introduced on May 1, 2021 to provide more diversified electricity rate options for low tension users which has a total of 6,225 users selected it in 2022; ”Electric vehicle charging infrastructure rate” with the development of electric vehicles introduced on May 30, 2022 to guide car owners in charging management, and introduced “Time-of Use Rate (C)”for High Voltage & Extra High Voltage Service on November 1 2023 to fulfill the Industrial users and power system.

Looking to the future with the Big Data and real-time bilateral communication function provided by AMI, TPC will persist in developing more diversified and dynamic electricity rates as well as various energy saving measures. TPC hopes to make users adjust their power consumption behaviors in coordination with cost variation and system situation. If so, it could reduce the costly power generator scheduling and thus reducing TPC’s demand for peak capacity and overall power system cost.

Demand Response

Due to the ever raising living standard, the demand for electricity in Taiwan has been stringent. Paris Agreement sets out a global action plan to put the world on track to avoid dangerous climate change by limiting global warming. Additionally, Taipower’s projects for power development have been hampered by difficulties in land acquisition and by opposition from various environmental protection movements. Consequently, engaging customers in demand-side management can always help solve a part of power supply problems. And for the reason, Load Management is adopted universally in order to increase the reliability of power supply and the efficiency of power utilization and to reduce the cost of power supply.

In order to increase the reliability of power supply and efficiency of power utilization, Taipower has accommodated customers with load management by adopting Demand Response Programs since 1979, with the first program of TOU Rate. The following programs have been implemented at present:

• A.　Time of Use Rate

• B.　Seasonal Rate

• C.　Preferential rate for Ice Storage Central Air-Conditioning System

• D.　Demand Response & Load Management Program

  • a.　Scheduled Load Reduction Program
  • b.　Emergency Load Reduction Program
  • c.　Demand Bidding Program
  • d.　Intelligent Load Reduction Program
  • e.　Energy Storage Load Reduction Program ( only for REO consumers)

The load profile in recent years in Taiwan are illustrated as follows：

Owing to the continuing growth of domestic economy and the promotion of the living standard, the demand for electricity has become much more stringent than before. It had boomed system peak load from 34,821 MW in 2014 to 40,157 MW in 2023. In year 2023, however, the system peak load declined over the previous year due to several short-term circumstances, including lower average annual temperature and slow recovery of post-pandemic global economy.

In 2023, the peak and off-peak load were respectively 40,157MW and 26,824 MW. The proportion between peak and off-peak load was 1：0.6678.

In order to reduce the demand for power and the growth of peak load, Taipower has implemented demand response program to encourage customers to transfer the period of production process from peak load to off-peak load. In August, the month of the most capacity that the customers applied for in 2023, 3,146 customers chose to participate in this program and applied for 2,747MW contracted reduction load. During the night peak day (July 6, 2023), the peak of net load was clipped by 1,166 MW.

Note: Taipower has implemented a new time-of-use rate system starting from 2023. The system involves a reconfiguration of peak and off-peak hours. Since then, Taipower’s demand response system has shifted the execution time respectively to clip net load.

In the future, Demand Response will be promoted continually through combining pricing strategy with hardware improvement. Furthermore, to enlarge the participation rate of the customers, Demand Response will be enhanced through R&D, absorbing the experience from other power companies, and taking the customers’ opinions into consideration. Moreover, with the advent of advanced meter infrastructure (AMI), Taipower will diversify its Demand Response Programs to encourage voluntary load reduction according to price signals.