減碳政策在台灣：補貼或課稅？

CARBON MITIGATION POLICY IN TAIWAN: SUBSIDIES OR TAXES?

再生能源固定收購電價制度（feed-in tariffs，FIT）是對再生能源價格之補貼，這是國際上常見的、也是我國主要的減碳經濟工具，然而，多數經濟學家認為對溫室氣體排放引起的氣候變遷，最有效的補救措施是碳稅及能源稅，但是，我國政府卻長年不採行碳稅或能源稅，僅採用FIT，主要原因是行政與立法部門都擔心碳稅或能源稅對經濟成長與所得分配的負面衝擊，降低其政治接受度。本研究目的為在可設定的最大潛在費率下，比較碳稅與FIT兩種減碳經濟工具何者的減量成效較能做到深度減碳政策目標。本研究首先根據全球減碳目標設定台灣的深度減碳目標，再比較碳稅與FIT兩種減碳經濟工具的減碳效果，及其對電力結構、經濟成長與所得分配的影響。我們設計多種綠色稅制改革方案，在政府總稅收不因課徵碳稅而增加的原則下，設計四種碳稅稅收循環方案，包含：（1）調降營業稅率、個人綜合所得稅率、雇主負擔之社會安全捐；（2）增加社會安全給付與社會福利給付；（3）定額移轉（以每人等額的方式發還全民現金）；（4）定額移轉與調降營業稅率併行。我們應用E3ME總體經濟計量模型（energy-environment-economy global macroeconomic model）進行政策模擬分析。結果發現：（1）碳稅的節能與減碳效果較FIT大很多，以2030年為例，相較基準情境，實施碳稅的總發電量減少約30%，FIT僅減少約2%；碳稅的減碳幅度約46%，FIT則約3.6%；（2）碳稅與FIT都可增加再生能源發電量，碳稅情境再生能源發電量約250億度，FIT情境只有約166億度；且碳稅情境的再生能源占比大於FIT情境的占比，分別為15%與7%；（3）FIT對經濟成長與所得分配有小幅度但負面的影響，而碳稅若搭配各種稅收循環策略都可以促進經濟成長與提高所得分配公平。最後，根據研究成果我們提出深度減碳政策建議。

The renewable energy feed-in tariff (FIT) is considered a price subsidy for electricity from renewable sources. This policy tool is commonly seen globally and has been one of the major climate change mitigation measures in Taiwan over the past two decades. The main reason why government agencies in Taiwan always prefer FIT to carbon or energy taxes can be attributed to their fear over those possible adverse effects that taxation may have on economic growth and income distribution, and, consequently, low public acceptability. Nevertheless, the majority of economists still regard carbon and energy taxes as the most effective economic incentives to mitigating climate change resulting from greenhouse gas emissions. This paper aims to compare the effectiveness of carbon tax and FIT in meeting the policy target of deep-decarbonization with their respective highest possible rates. By doing this, we first determine the carbon emission targets for Taiwan based on the global targets and then compare the effects of the two policy tools on emission reduction, energy structure of electricity, economic growth, and income distribution. For carbon tax simulations, we further incorporate in the simulations four potential green-tax reform measures that will recycle the entire carbon tax revenue: 1) lower VAT, and enterprise and household income tax rates, as well as the social security payment accrued to employers; 2) increase in social security and welfare payments to low-income households; 3) uniform transfers; and 4) combined uniform transfers and VAT reduction. We apply the E3ME model to conduct the analysis. Three significant results emerge. First, the carbon tax is far more effective than FIT in terms of carbon emissions reduction. In 2030, the carbon tax will reduce electricity generated by 30% relative to the baseline, while FIT can reduce only 2%. Similarly, the carbon tax can curtail 46% of carbon emissions, while FIT can mitigate only 3.6%. Secondly, both carbon tax and FIT will increase the electricity from renewable sources. In 2030, that amounts to 25 billion kWh for the carbon tax, and only 16.6 billion kWh for FIT, which corresponds to 15% and 7% of total generated electricity, respectively. Thirdly, FIT will have a negligible yet negative effect on economic growth and income distribution. However, carbon tax, when coupled with tax revenue recycling strategies, do have positive growth and distributional effects on the economy. Based on these results, this paper offers policy suggestions for deep decarbonization in Taiwan