Impose a carbon tax only on certain sector or tech

[Reliefzxc1]

Could GCAM impose a carbon tax only on a certain sector or tech (like energy sector, coal (IGCC))?

If GCAM could do that, how to create or modify a policy file in GCAM.

thanks for your help！

[pkyle]

The way to do this is to create a new named CO2 tag, assigned to all relevant technologies and model time periods. For example, here's a policy that would constrain CO2 emissions from two coal power plant technologies in China to 200 MtC/yr in 2025. Note that this would only apply to the plants built in the 2025 time period, so to have the intended effect you'll probably need to assign CO2_elec to all model time periods starting in 2015:

<scenario>
    <world>
        <region name="China">
            <supplysector name="electricity">
                <subsector name="coal">
                    <stub-technology name="coal (conv pul)">
                        <period year="2025">
                            <CO2 name="CO2_elec"/>
                        </period>
                    </stub-technology>
                    <stub-technology name="coal (IGCC)">
                        <period year="2025">
                            <CO2 name="CO2_elec"/>
                        </period>
                    </stub-technology>
                </subsector>
            </supplysector>
        </region>
    </world>
</scenario>

Then in a policy-portfolio-standard, you can constrain CO2_elec just as if it were CO2:

<scenario>
    <world>
        <region name="China">
            <ghgpolicy name="CO2_elec">
                <market>China</market>
                <constraint year="2025">200</constraint>
            </ghgpolicy>
        </region>
    </world>
</scenario>

As a final note, the default queries for CO2 do not distinguish between the different named objects. Unless you modify the queries' XPATH to disambiguate CO2 types, each of these technologies will have its CO2 emissions double counted. This is not an issue in the model, but rather in the post-processing. I think if you just replace /CO2/ in the existing queries with /*[@type='CO2']/ or /*[@type='GHG']/ then that should disambiguate the CO2 types.

[Reliefzxc1]

执行此作的方法是创建一个新的命名 CO2 标签，分配给所有相关技术和模型时间段。例如，以下政策将在 2025 年将中国两种燃煤电厂技术的 CO2 排放量限制为 200 MtC/yr。请注意，这仅适用于在 2025 年时间段内建造的工厂，因此要获得预期效果，您可能需要将 2015 年开始的所有模型时间段分配给：CO2_elec

<scenario>
    <world>
        <region name="China">
            <supplysector name="electricity">
                <subsector name="coal">
                    <stub-technology name="coal (conv pul)">
                        <period year="2025">
                            <CO2 name="CO2_elec"/>
                        </period>
                    </stub-technology>
                    <stub-technology name="coal (IGCC)">
                        <period year="2025">
                            <CO2 name="CO2_elec"/>
                        </period>
                    </stub-technology>
                </subsector>
            </supplysector>
        </region>
    </world>
</scenario>

然后，在策略组合标准中，您可以像 CO2 一样进行约束：CO2_elec

<scenario>
    <world>
        <region name="China">
            <ghgpolicy name="CO2_elec">
                <market>China</market>
                <constraint year="2025">200</constraint>
            </ghgpolicy>
        </region>
    </world>
</scenario>

最后要注意的是，CO2 的默认查询不区分不同的命名对象。除非您修改查询的 XPATH 以消除 CO2 类型的歧义，否则这些技术中的每一种都将重复计算其 CO2 排放量。这不是模型中的问题，而是后处理中的问题。我认为，如果您只是在现有查询中替换为 or，那么应该可以消除 CO2 类型的歧义。/CO2/``/*[@type='CO2']/``/*[@type='GHG']/

Wow, i will have a try! Thanks!