ارزیابی اقتصادی و زیست محیطی تولید الکتریسیته مخلوط در آینده در کشور ژاپن - ارزیابی با استفاده از مدل کلان اقتصاد سنجی E3MG

In this paper we consider future options for Japanese energy and climate policy. We assess the economic and environmental impacts of changing the share of electricity generated by nuclear power and varying the mid-term GHG targets. The quantitative approach we use is based on the global macro-econometric E3MG model. Our analysis reveals that the cost of denuclearisation to Japanese GDP is close to zero, and for employment the impact is slightly positive. Our results also show a double-dividend effect if (revenue-neutral) carbon taxes are levied in order to meet the GHG reduction targets, and this double-dividend effect is largest in the scenarios without nuclear power. However, our analysis suggests that a very high carbon tax rate would have to be imposed in order to achieve a 25% reduction in GHG emissions in 2020 (compared to 1990 levels) while simultaneously phasing out nuclear power.

This paper uses the global macro-econometric model E3MG to analyse the economic and environmental impacts of the three options for the share of nuclear power in electricity generation in 2030 proposed in the report Options for Energy and the Environment (hereafter referred to as Options) published in June 2012. We consider the impacts of the three options in the context of three possible mid-term targets for reducing greenhouse-gas (GHG) emissions (0%, −15% and −25% by 2020 compared to the 1990 level); and we also analyse the contribution of Environmental Tax Reform (ETR) to achieving these targets. The main aim of the analysis is to determine the costs for the Japanese economy arising from denuclearisation, ETR or a combination of both. The Fukushima–Daiichi Nuclear Power Accident (the Fukushima Accident) of March 2011 made Japanese citizens aware of the dangers of nuclear power plants (NPPs). The Democratic Party of Japan (DPJ), which was then in government, had to respond to the public demand for denuclearisation, and so it reviewed the Basic Energy Plan. The Options report published in June 2012 proposed three options for the share of NPP in power generation in 2030 (0%, 15%, and 20%–25%). All three options were lower than the 45% share of NPP in 2030 1 that was envisaged in the most recent (June 2010) version of the Basic Energy Plan. After public discussion based on the Options report the Innovative Energy and Environment Policy, which declares “to implement all conceivable policy resources to enable zero NPP in the 2030s”, was published in September 2012. Nevertheless, nuclear policy was not seen as a priority in the Lower House Election in December 2012 and the Upper House Election in July 2013; and this election resulted in victory for the Liberal Democratic Party (LDP), which had previously promoted Japanese nuclear power. There is still much discussion about the direction of future energy policy and nuclear power in Japan. When it comes to assessing the effects of denuclearisation on the Japanese economy, there are two opposing views. The first is that reducing the share of NPP in the energy mix will lead to higher costs and be harmful to the economy, while the second emphasises the potential beneficial effects of the promotion of renewable energies and energy conservation. Four institutes have carried out model-based analyses of the three options for reducing the NPP share and have found that a lower NPP share leads to a slightly worse economic performance and a small increase in electricity prices. These results are discussed in Section 3. At the same time it is recognised that policy measures will be required to reduce GHG emissions. On this subject, the existing research shows that ETR, a policy that recycles the revenue from additional carbon/energy taxation by reducing other taxes in a revenue-neutral way, could have favourable impacts on economic indicators such as employment (see Section 4). However, as energy use in Japan is already quite efficient, the scope for emission reductions outside the power sector may be quite limited (Akimoto et al., 2010). This paper analyses the possible effects of denuclearisation and ETR on Japan's economy and GHG emissions levels, and the interaction between the two policies. We apply the global macro-econometric model E3MG (Energy–Environment–Economy Model at the Global level), which is quite different to the CGE models that were used for the previous analysis (see Section 5). We use the scenario assumptions of Options as reference data so that our results can be compared with previous analyses. Section 2 discusses the policy context in which this study has been carried out. Section 3 describes the three options in further detail, including the findings from previous analyses. In Section 4 we discuss ETR and the concept of the double dividend, and we introduce the E3MG model in Section 5. 6 and 7 describe the scenarios that we assessed and present the results from the modelling exercise. Section 8 presents our conclusions. The appendices contain further information about the assumptions that were used in forming the scenarios and about the E3MG model.

This paper assesses three scenarios for the share of nuclear power in electricity generation in Japan. The scenarios reflect the three ‘Options’ that were reported by Japan's Energy and Environment Council in 2012. The share of nuclear power in electricity generation is set at 0%, 15% and 25%10 in 2030 in the three scenarios. As in the Options report, when the share of nuclear power falls, it is assumed to be replaced with a combination of natural gas and renewables plants, with only very small increases in coal and oil-fired plants. The result is higher electricity prices, as generators must recoup the costs of increased natural gas consumption and the construction of renewables plants. The Options report contained estimates of the impacts of the three scenarios prepared by four Japanese research institutes using Computable General Equilibrium (CGE) macroeconomic models. These estimates showed that the scenario with zero nuclear power had the least favourable outcomes for GDP growth in Japan, but the differences between the scenarios were quite small (in most cases around 1%). However, the CGE models rely on economic assumptions about price adjustment that prevent them from assessing the effects of demand-side stimulus. Given the current economic situation in Japan, our view is that the assessment should include the possibility that spare capacity is available and consequently that higher demand could lead to increased rates of economic activity. The macro-econometric model that we apply in the analysis, E3MG, allows for this possibility. In the scenarios that were modelled we find that higher electricity prices and higher gas imports have a depressing effect on GDP, but there are benefits to GDP from higher levels of investment. Although we still find a very small reduction in GDP (0.04%) when nuclear power is removed from the mix, if the share of nuclear is reduced from 25% to 15% the net impact is zero. Furthermore, as the construction of new renewable plants is a labour-intensive exercise, reducing nuclear power could lead to a small increase in employment (0.08%). In our analysis we have tested a range of emissions reduction targets for 2020 under the different shares of nuclear power, using a revenue-neutral Environmental Tax Reform (ETR) on all non-power sectors to meet the targets. The model results show that a double-dividend from ETR is possible, with reductions in GHG emissions accompanied by increases in GDP ranging from 0.2% to 0.8% and some increases in employment. Again these model results reflect the fact that there is spare capacity in the Japanese economy and that diverting spending from fossil fuel imports to domestic production could lead to higher output. However, the model results also show that the carbon tax rate needed to achieve the targets can rise quite substantially if the share of nuclear power is reduced. For example, the previous mid-term GHG reduction target (−25% from the 1990 level) would require a tax of more than 56,000 yen/t-CO2 (around 435 euro/t-CO2) if the nuclear share is zero. In political terms, this seems an unattainably high rate, especially when compared with the current Japanese carbon tax rate (about 300 yen/t-CO2). In summary, the results from the analysis find that denuclearisation does not necessarily have a cost to the Japanese economy. Setting and meeting more stringent GHG reduction targets could yield a small benefit, if well implemented. Our results also find an important interaction between the two policies that will need to be considered carefully by policy makers.