• Energy Research
• Restricted close
• other engineering and technologies close
• CN close
• BE close
• IN close

There is a significant interest in utilizing demand response (DR) programs to increase the flexibility of sustainable power systems. The DR operators (e.g., aggregator companies) need a robust means to assess the performance of a potential DR program that will be employed in the future. Such assessments should be based on data, some of which are hardly available. Knowledge about the DR providers (e.g., the behavior of proactive consumers) is key to the success of a DR program. In this paper, we devise a data-driven framework to assess the impact of uncertainties associated with future DR programs. The proposed framework comprises two modules: the DR simulation module, and the data analytics module. The DR module solves an optimization problem which simulates the operation of a hypothetical DR program. The data analytics module, firstly, selects subsets from historical load and price data. Secondly, it performs sensitivity analysis on the optimal solution to capture the impact of uncertainties. We consider two sources of uncertainty. First, we consider lack of information about DR providers due to the absence of a DR program in the current system. Second, we consider errors in load and price forecasts, whose impacts are investigated by formulating a sensitivity matrix from the perturbed KKT equations of the optimization problem solved by the DR module. The proposed framework provides insights regarding the potential of a prospective DR program. Such information can be useful for DR operators as a starting point to decide their position in the contractual agreement they will engage in with the (distribution) system operator and/or DR providers in the future.

Abstract With the increasing access of renewable energy resources and fast ubiquitous connection of everything, the traditional one-way power flow from centralized generation to end consumers will give way to bidirectional-way power flow with multidirectional energy network among central grids and distributed prosumers. To empower the prosumer-centric Energy Internet (EI) and enhance the integration of energy-aware services, digitalization and decentralization are the key enablers to achieve transactive EI. This article presents a systematic overview on how Internet of Things (IoT) drives the digitalization of transactive EI and how blockchain empowers the decentralization of transactive EI. A comprehensive discussion on the key infrastructures is provided for presenting how to implement digitalization and decentralization of transactive EI, including the last mile “Advanced metering infrastructure” (AMI), renewables integrator “smart inverter”, energy flow adjuster “energy router”, and coordinator “Microgrid”. Challenges and future trends are discussed from an extensive point of view, including energy physical space, data cyber space and human social space.

AbstractThis study analyses the relationship between foreign direct investment, economic growth, urbanization, energy use, and carbon emissions in Brazil, Russia, India, China, and South Africa (BRICS countries) between 1990 and 2014. According to the empirical results, both environmental Kuznets curve (EKC) and pollution haven hypotheses (PHH) are confirmed. Urbanization contributes to reducing carbon emissions, while energy use is one of the main driving forces of ascending carbon emissions. The main advance of this paper lies in the moderating effect of foreign direct investment and energy usage on carbon emission in the case of the BRICS. The empirical results confirm a dampening impact of foreign direct investment on energy use, generating a correction in carbon emission. Thus, structural transformations are highlighted with a positive influence on energy efficiency and sustainable growth. It is expected that policymakers must promote renewable sources and boost clean foreign industries in selected host countries.

China contributes 23 % of global carbon emissions, of which 26 % originate from the household sector. Due to vast variations in both climatic conditions and the affordability and accessibility of fuels, household carbon emissions (HCEs) differ significantly across China. This study compares HCEs (per person) from urban and rural regions in northern China with their counterparts in southern China. Annual macroeconomic data for the study period 2005 to 2012 were obtained from Chinese government sources, whereas the direct HCEs for different types of fossil fuels were obtained using the IPCC reference approach, and indirect HCEs were calculated by input-output analysis. Results suggest that HCEs from urban areas are higher than those from rural areas. Regardless of the regions, there is a similarity in per person HCEs in urban areas, but the rural areas of northern China had significantly higher HCEs than those from southern China. The reasons for the similarity between urban areas and differences between rural areas and the percentage share of direct and indirect HCEs from different sources are discussed. Similarly, the reasons and solutions to why decarbonising policies are working in urban areas but not in rural areas are discussed.

Abstract Grate-firing technology is one of the commonly used technologies for municipal solid waste incineration, which recovers energy and largely reduces the volume of the solid wastes for landfilling. In grate-fired incinerators, the solid wastes are packed in the fuel bed on the grate, where the major heterogeneous conversion takes place. A proper modeling of the fuel conversion process in the bed not only benefits an in-depth understanding of the in-bed incineration but also facilitates the freeboard simulation. In this paper, a comprehensive model is developed to simulate solid wastes incineration in a packed bed, which advances the state-of-the-art with corrected boundary conditions, homogeneous reactions, and calculation method for pyrolysis products. The model is first validated by a simplified analytical problem. Then, the model is validated in detail by a dedicated experimental study in literature, in which the pyrolysis and gas combustion front and the subsequent char oxidation front both propagate from the bed surface to the grate due to the abundant oxygen availability in the fuel bed. The model also outperforms a latest modeling study in literature for reproducing the same experimental study. Finally, a model-based parametric study is conducted to investigate the effects of solid waste particle sizes and solid waste incineration in high-altitude areas. This paper also clearly explains the methods to transfer the packed-bed model to travelling grates and to accommodate the different waste fractions in real municipal solid waste, in order to make the model applicable to travelling grate-firing of real municipal solid wastes.

This paper presents a new topology of higher order power filter for grid-tied voltage-source inverters, named the LLCL filter, which inserts a small inductor in the branch loop of the capacitor in the traditional LCL filter to compose a series resonant circuit at the switching frequency. Particularly, it can attenuate the switching-frequency current ripple components much better than an LCL filter, leading to a decrease in the total inductance and volume. Furthermore, by decreasing the inductance of a grid-side inductor, it raises the characteristic resonance frequency, which is beneficial to the inverter system control. The parameter design criteria of the proposed LLCL filter is also introduced. The comparative analysis and discussions regarding the traditional LCL filter and the proposed LLCL filter have been presented and evaluated through experiment on a 1.8-kW-single-phase grid-tied inverter prototype.

The environmental profile of two municipal solid waste incineration (MSWI) technologies with semi-dry flue gas cleaning, namely grated firing incinerators (GFI) and fluidised bed incinerators (FBI) that are commonly used in China were evaluated and compared by life-cycle assessment (LCA) using the EASEWASTE model. All emissions of key pollutants as well as energy, resource and material inputs and outputs associated with the two MSWI technologies were determined and the corresponding environmental impact potentials were modelled. Incineration of MSW with a lower heating value (LHV) around 4.5 MJ kg—1 demands that auxiliary fuel is used, and both GFI and FBI caused environmental loads by contributing with environmental impact potentials in most categories except for some saving in global warming (GW100) and hazardous waste (HW). Coal combustion in FBI is a main contributor to the environmental impact potentials and thus should always be limited to a minimum. Auxiliary fuels can be avoided when the LHV of MSW is higher than 5—6 MJ kg— 1. For all scenarios, GFI saves more global warming potentials than FBI due to its higher net power generation from combustion of MSW itself. Leachate from the bunker could be sprayed into the furnace for evaporation under high temperature, as an alternative to waste-water treatment, without major changes in the environmental profile of the incinerator. The presented evaluations may contribute to a more balanced environmental assessment of the two incineration technologies with respect to incineration of MSW with low heating values as often found in Asia and China.

After more than a decade of successful collaboration in participatory plant breeding (PPB) between farmers and maize breeders in southwest China, and release of new improved varieties and hybrids, it was realised that their conservation objectives could not also be secured unless farmers had incentives to maintain their traditional cultivars in production. This article explores their experience of expressing the public value of farmers' cultivars through organizing novel relationships among public and private actors, by means of PPB programmes and market-based arrangements. The researchers reached beyond common agri-food development practices and theories, to apply concepts used in public administrations studies, in order to consider public and private interest and value in relation to the direct, indirect and option value of the plant genetic resources (PGRs) represented by farmers' cultivars. In this paper, seven organizational options from selected countries are examined in relation to their roles in (i) creating indirect and options values; (ii) sustaining the legitimacy of and support for related practices; and (iii) developing operational capacity of the associated organizations and actors. The three main findings are (a) innovations in breeding and conservation developed through PPB are key factors in the management by smallholders of the indirect and option value of agro-biodiversity; (b) market-based arrangements and the creation of new sets of property rights in the products developed from farmer-bred cultivars legitimize and support PPB and PGRs conservation; and (c), the organization of the indirect and option value of farmer-bred cultivars calls for the integration of the joint efforts of producers, consumers, market actors and public sector agencies in networked governance, that can take a variety of forms. Lessons are drawn from and for China, where legal and regulatory practices in the seed sector are still under development and smallholders still maintain crop and varietal diversity by their agricultural practices.