1 Impacts on the Transmission Grid for Integrations of Renewable Energy in Taiwan Chyou-Jong Lin, Member, IEEE, Chia-Chi Chu, Member, IEEE Chung-Liang Chang, Senior Member, IEEE, Yuin-Hong Liu, and Yuh-Fa Chuang application. Also, in July, 2009, the government has issued the Abstract--Due to the increasing recognitions in renewable Renewable Energy Development Act with 23 articles and its energy worldwidely, the development of renewable energy has major contents are: (i) to give credits to the total amount of also become major alternative energy resources in Taiwan. This renewable energy in the range of 6,500MW to 10,000MW, (ii) paper presents impact studies on the transmission grid for to establish funds to subsidize renewable energy, (iii) to set up integrations of renewable energy in Taiwan. First, Taiwan’s purchase rates, (iv) to design procurement rates for different renewable energy policy will be briefly reviewed. Recent renewable resources, (v) to give incentives to highly potential developments about integrations of renewable energy in the transmission grid will be presented. Finally, discussions about self-faculties, and (vi) to assist renewable energy owners in impacts on the transmission grid and suggested approaches are acquiring land. concluded. In order to toward the smart grid objective for future Taipower system developments, Taiwan government has Index Terms--Integrations, Transmission Grid, Renewable recently approved Taipower’s seventh transmission and Energy, Wind Power, Solar PV, Low Voltage Ride-Through substation construction plan from 2010 through 2015. One (LVRT). objective of this seventh plan is to enhance system’s stability through seamless integrations of a large-scale of wind power I. INTRODUCTION and solar PV to the transmission grids. This paper will present aiwan is a subtropical island nation with high dependence impact studiess on the transmission grid for integrations of Tupon imported energy. About 97% of its energy is supplied renewable energy in Taiwan. by imported fuels. Environmental pollution and greenhouse The organization of the paper is as follows: energy policy gas emissions are becoming significant issues in Taiwan. In in Taiwan is described in Section II; power system and this regard, Taiwan has also been keeping pace with other renewable energy developments in Taiwan is presented in developed countries in developing renewable energy Section III; integrations of renewable energy in the developments aggressively [1-2]. transmission grid is discussed in Section IV; impacts on the The development of the renewable energy can be traced transmission grid is presented in Section V. Finally, back to 1980s. The Energy Commission of Taiwan sponsored conclusions are made in Section VI. Industrial Technology Research Institute (ITRI) to conduct operations tests for 4kW, 40kW, and 150kWwind turbine II. ENERGY POLICY IN TAIWAN generators. In 2000, the Energy Commission subsidized some A. Government Energy Policy companies to install wind generation facilities at various sites. Later, the draft law for renewable energy development has Due to global climate change and energy shortage, the been reviewed by the Legislature since 2002. In 2003, as a crisis of environmental protection and energy development state-owned enterprise, Taiwan Power Company (Taipower) has significantly worsened in recent years. In response, issued practices of renewable energy procurement, which Taiwan government issued the Sustainable Energy Policy proposed the connection of renewable energy faculties to the Guidelines on June 5, 2008 and approved the Energy Taipower system. More recently, a national conference on Conservation and Carbon Dioxide Reduction Action Plan energy in 2005 concluded that the installed capacity for based on the Guidelines on September 4, 2008. The policy renewable energy should reach respectively about 10% and goals of the guidelines are as follows: (i) promoting energy 12% of the total installed capacities in 2010 and 2020. usage and production efficiency, (ii) increasing energy usage Since 2007, the Bureau of Energy of Taiwan announced for value-added products, (iii) pursuing low carbon and low that 300MW of offshore wind power capacity is available for pollution energy supply and consumptions, and (iv) reducing dependence on petrochemical energy and imported energy. In addition, the strategies of the guidelines are: (i) improving This work was supported in part by the National Science Council under energy structure and promoting generation efficiency; (ii) Grant NSC 98-3114-E-007-001-CC2 and NSC 99-2628-E-007-100-. reducing carbon emissions for industries and developing green Chyou-Jong Lin, Chung-Liang Chang, Yuin-Hong Liu, and Yuh-Fa Chuang are with Taiwan Power Company, Taipei, TAIWAN (e-mail: industries; (iii) establishing rapid transit systems and [email protected]) providing good traffic environment; developing conservation Chia-Chi Chu is with the Department of Electrical Engineering, National cities; (iv) promoting carbon reduction actions and recycling Tsing Hua University, Hsinchu, TAIWAN (e-mail: [email protected]) practices by citizens. The strategy is to be carried out from 978-1-4577-1002-5/11/$26.00 ©2011 IEEE 2 2009 to 2012. Based on the guidelines, the National Energy contract with the owner of renewable energy facility and file Conference further developed the following four major to the central government. A utility shall an approved policies on April 15-16, 2009. electricity rate to the renewable energy facility when it is z Sustaining energy development and establishing energy under maintenance. An owner of renewable energy facility security for a low carbon society; shall construct and maintain its transmission and distribution z Developing energy technology and applying energy connection to the grid of a utility. If it is necessary, the utility conservation and carbon dioxide reduction technology; shall provide assistance to the owner of a renewable energy, z Promoting efficient energy management and setting up but the owner of shall pay the cost for the assistance. green power and a concentrated non-energy industry; and C. Renewable Energy Connection Practices z Designing energy price and an open energy market for reasonable cost-based rates Taipower has issued a set of revised practice guidelines for renewable generation to be connected to its power systems B. Government Renewable Energy Development Act since December 31, 2009. The key articles require a new wind The government issued Renewable Energy Development turbine generator to have a capability of Low Voltage Ride- Act on July 8, 2009. The major contents of the Act related to Through (LVRT) starting on January 1, 2011 as in other renewable energy are as follows. developed countries as shown in Fig 1 [3]. z Providing credits: to the total amount of renewable z Meet the Taipower Low Voltage Ride-Through (LVRT) energy in the range of 6,500MW to 10,000MW in 20 Standard. Specifically, 0.15 p.u. low voltage for 500 years, to set up the development goal of renewable milliseconds. energy and portfolios of different types of renewable z Define a boundary for the “voltage recovery” excursion energy every two years ; that occurs between the time a transmission fault is z Establishing funds: in addition to getting funds from cleared and the time the transmission voltage returns to utilities, the government shall have a budget to subsidize 90% (0.9 p.u.) of the nominal voltage, as required of new renewable energy if it is necessary. In addition, with generation plants to remain on–line. approval of the central government (i.e. Ministry of Furthermore, the percentage of a reverse power from a Economic Affairs), the funds can be added to the distribution system to a transmission system is allowed to electricity rates; reach 30% of the capacity of a transformer. z Connecting renewable energy to grids: so that utilities can keep the power systems in a stable situation; z Designing procurement rates for different renewable resources: the central government shall organize a committee to design workable formulas for procurements rates, which cannot be lower than the average rate of domestic fossil fuel generation; z Providing incentives for waste heat utilization and high- potential renewable power generation; giving priorities to renewable power generation in new or remodeled public projects or buildings. z Assisting renewable energy owners in acquiring land: the renewable energy facilities and their related transmission facilities will follow specific public utilities requirements Fig. 1. Low Voltage Ride-Through Standard in Taiwan of Urban Planning Act, Regional Planning Act, Forest Act and Fishing Port Act to acquire or use land. In addition, since the 8th Article of the Act is related to D. Feed-in Tariffs for Renewable Energy renewable energy facilities to be connected to the power grid, Based on the feed-in tariffs in Fig. 2, Taipower shall it plays an important role for the transmission and distribution procure electric power from renewable energy developers and system planning. Specifically, renewable energy facilities sign contracts with them from July 10, 2009 to December 31, shall be connected to the nearest utility grid and the utility 2010 under these tariffs for 20 years. shall procure the renewable energy from these facilities as In Taiwan, Ministry of Economic Affairs (MOEA) shall well as supply them with sufficient electricity during the invite related ministries, scholars and experts, and other period of their maintenances. A utility cannot reject these parties to form a feed-in tariffs committee to decide the tariffs requests if it does not have reasonable reasons unless it is and the calculation formulas which shall be reviewed annually approved by the central government. A facility shall pay all of because of technical enhancement, cost variation, target its connection costs. However, a utility may add additional achievement status and so on. Finally, the tariffs shall not be requirements for keeping the power system in a stable lower than the average cost of fossil-fired generation from situation due to the connection to a renewable facility.