Scenarios of energy efficiency and CO2 emissions reduction potential in the buildings sector in China to year 2050

As China’s rapid urbanization continues and urban dwellers become more affluent, energy use in buildings is expected to grow. To understand how this growth can be slowed, we explore four scenarios for Chinese buildings, ranging from a high-energy-demand scenario with no new energy policies to lowest energy demand under a techno-economic-potential scenario that assumes full deployment of cost-effective efficient and renewable technologies by 2050. We show that, in the high energy demand scenario, building energy demand has an average annual growth rate of about 2.8%, with slower growth rates in the other three scenarios. In all scenarios, CO2 emissions grow slower than energy, with building CO2 peaking around 2045 in the high energy demand scenario, and as early as 2030 in the techno-economic-potential scenario. We show that although various technological solutions, systems and practices can be very effective in minimizing building energy use, rigorous policies are needed to overcome multiple implementation barriers

Balls-in-boxes duality for coalescing random walks and coalescing Brownian motions

We present a duality relation between two systems of coalescing random walks and an analogous duality relation between two systems of coalescing Brownian motions. Our results extends previous work in the literature and we apply it to the study of a system of coalescing Brownian motions with Poisson immigration.Comment: 13 page

Energy and CO2 implications of decarbonization strategies for China beyond efficiency: Modeling 2050 maximum renewable resources and accelerated electrification impacts

Energy efficiency has played an important role in helping China achieve its domestic and international energy and climate change mitigation targets, but more significant near-term actions to decarbonize are needed to help China and the world meet the Paris Agreement goals. Accelerating electrification and maximizing supply-side and demand-side renewable adoption are two recent strategies being considered in China, but few bottom-up modeling studies have evaluated the potential near-term impacts of these strategies across multiple sectors. To fill this research gap, we use a bottom-up national end-use model that integrates energy supply and demand systems and conduct scenario analysis to evaluate even lower CO2 emissions strategies and subsequent pathways for China to go beyond cost-effective efficiency and fuel switching. We find that maximizing non-conventional electric and renewable technologies can help China peak its national CO2 emissions as early as 2025, with significant additional CO2 emission reductions on the order of 7 Gt CO2 annually by 2050. Beyond potential CO2 reductions from power sector decarbonization, significant potential lies in fossil fuel displaced by renewable heat in industry. These results suggest accelerating the utilization of non-conventional electric and renewable technologies present additional CO2 reduction opportunities for China, but new policies and strategies are needed to change technology choices in the demand sectors. Managing the pace of electrification in tandem with the pace of decarbonization of the power sector will also be crucial to achieving CO2 reductions from the power sector in a scenario of increased electrification

Bank ownership and efficiency in China: what lies ahead in the world’s largest nation?

China is reforming its banking system, partially privatizing and permitting minority foreign ownership of three of the dominant ‘big four’ state-owned banks. This paper seeks to help predict the effects of this change by analysing the efficiency of virtually all Chinese banks in the years 1994–2003. Our findings suggest the big four banks are by far the least efficient and foreign banks the most efficient while minority foreign ownership is associated with significantly improved efficiency. We present corroborating robustness checks and offer several credible mechanisms through which minority foreign owners can increase Chinese bank efficiency. These findings suggest that minority foreign ownership of the big four is likely to significantly improve performance.foreign banks; efficiency; foreign ownership

Understanding and Improving the Wang-Landau Algorithm

We present a mathematical analysis of the Wang-Landau algorithm, prove its convergence, identify sources of errors and strategies for optimization. In particular, we found the histogram increases uniformly with small fluctuation after a stage of initial accumulation, and the statistical error is found to scale as $\sqrt{\ln f}$ with the modification factor $f$. This has implications for strategies for obtaining fast convergence.Comment: 4 pages, 2 figures, to appear in Phys. Rev.

Some Hamiltonian Models of Friction

Mathematical results on some models describing the motion of a tracer particle through a Bose-Einstein condensate are described. In the limit of a very dense, very weakly interacting Bose gas and for a very large particle mass, the dynamics of the coupled system is determined by classical non-linear Hamiltonian equations of motion. The particle's motion exhibits deceleration corresponding to friction (with memory) caused by the emission of Cerenkov radiation of gapless modes into the gas. Precise results are stated and outlines of proofs are presented. Some technical details are deferred to forthcoming papers.Comment: 19 Pages, 1 figur

Creep motion of a domain wall in the two-dimensional random-field Ising model with a driving field

With Monte Carlo simulations, we study the creep motion of a domain wall in the two-dimensional random-field Ising model with a driving field. We observe the nonlinear fieldvelocity relation, and determine the creep exponent {\mu}. To further investigate the universality class of the creep motion, we also measure the roughness exponent {\zeta} and energy barrier exponent {\psi} from the zero-field relaxation process. We find that all the exponents depend on the strength of disorder.Comment: 5 pages, 4 figure