• Energy Research
• 2021-2025close
• CN close
• DK close

<p>Increasing renewable energy penetrations bring complex feasibility and stability problems. Data-driven methods are applied in extracting and embedding these feasibility and stability rules in power system operations and planning. This paper presents a method of alternate support vector machine decision trees for rule extraction problems. The method has significant improvements to the classical decision-tree-based algorithms in terms of efficiency, stability and versatility. Finally, we apply the method to several power and energy system scenarios to show its effectiveness.</p>

AbstractThe production of Z boson pairs in proton–proton ($${\mathrm{p}} {\mathrm{p}} $$ p p ) collisions, $${{\mathrm{p}} {\mathrm{p}} \rightarrow ({\mathrm{Z}}/\gamma ^*)({\mathrm{Z}}/\gamma ^*) \rightarrow 2\ell 2\ell '}$$ p p → ( Z / γ ∗ ) ( Z / γ ∗ ) → 2 ℓ 2 ℓ ′ , where $${\ell ,\ell ' = {\mathrm{e}}}$$ ℓ , ℓ ′ = e or $${{\upmu }}$$ μ , is studied at a center-of-mass energy of 13$$\,\text {TeV}$$ TeV with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137$$\,\text {fb}^{-1}$$ fb - 1 , collected during 2016–2018. The $${\mathrm{Z}} {\mathrm{Z}} $$ Z Z production cross section, $$\sigma _{\text {tot}} ({\mathrm{p}} {\mathrm{p}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} ) = 17.4 \pm 0.3 \,\text {(stat)} \pm 0.5 \,\text {(syst)} \pm 0.4 \,\text {(theo)} \pm 0.3 \,\text {(lumi)} \text { pb} $$ σ tot ( p p → Z Z ) = 17.4 ± 0.3 (stat) ± 0.5 (syst) ± 0.4 (theo) ± 0.3 (lumi) pb , measured for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region $${60< m_{\ell ^+\ell ^-} < 120\,\text {GeV}}$$ 60 < m ℓ + ℓ - < 120 GeV is consistent with standard model predictions. Differential cross sections are also measured and agree with theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous $${\mathrm{Z}} {\mathrm{Z}} {\mathrm{Z}} $$ Z Z Z and $${{\mathrm{Z}} {\mathrm{Z}} \gamma }$$ Z Z γ couplings.

Summary: Chinese cities need independent but synergetic dual-carbon abatement roadmaps to mitigate climate change and achieve carbon neutrality. Using source-level data, we develop a time-series, full-scale emission inventory for all Chinese cities from 2005 to 2020, exploring associated heterogeneous and homogeneous patterns. We find that 31% of cities have had a significant carbon emission peak, with the main driver being carbon intensity reductions through efficiency gains and structural improvements. Despite discrepant emission levels and socioeconomic determinants, a uniform trajectory in emission changes exists across cities via four emission phases: growth of 8%–9% annually (95% confidence interval) before peaking; plateau and decline by 9%–13% for 5–7 years; and plain with slower declines. We project that if cities follow their early-peaked counterparts’ mitigation pathways, China will reach a carbon peak in 2026 at 13 Gt and carbon neutrality during 2051–2058, revealing the feasibility of Chinese climate goals and the importance of long-reaching, city-targeted planning. Science for society: China established its dual-carbon goals to achieve a carbon peak before 2030 and carbon neutrality by 2060. It is important for cities to identify their distinctive patterns and define individual dual-carbon roadmaps to achieve carbon neutrality in China. In this study, we conduct a carbon inventory for all Chinese cities from 2005 to 2020 to quantitatively define the emission phases in the process of carbon peak. We find that 31% of cities have had a significant carbon emission peak, with the main driver being carbon intensity reductions. A uniform trajectory in emission changes exists across cities, despite significant differences in emission levels and socioeconomic determinants. We project that if cities follow their early-peaked counterparts’ mitigation pathways, China could achieve its climate change goals ahead of the policy deadlines.