Energy Demand Assessment for Long Term Operation of Vehicles

In the next years Distributed Poly-generation Systems are expected to play an increasingly important role in the electricity infrastructure and market. The successful spread of small-scale generation either connected to the distribution network or on the customer side of the meter depends on diverse issues, such as the possibilities of technical implementation, resource availability, environmental aspects, and regulation and market conditions. The aim of this study is to develop an economical and parametric analysis of a Distributed Generation System based on gas turbines able to satisfy the energy demand of a typical Hotel complex. Here we show the economic performance of six cases combining different designs and regimes of operation. The software Turbomatch, the gas turbine performance code of Cranfield University, was used to simulate the off-design performance of the engines in different ambient and load conditions. A clear distinction between cases running at full load and following the load could be observed in the results. Full load regime can give a shorter return on the investment than following the load. Despite of CHP systems currently are not economically attractive, in the future this scenario may change due to the environmental regulations and unavailability of low price fuel for large centralised power stations. CHP has a significant potential but requires favourable legislative and fair energy market conditions to successfully increase its share in the power generation market.

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SMP Production in an Anaerobic Submerged Membrane Bioreactor (AnMBR) at Different Organic Loading Rates

Membranes ◽

10.3390/membranes10110317 ◽

2020 ◽

Vol 10 (11) ◽

pp. 317

Author(s):

Sandra C. Medina ◽

Nataly Zamora-Vacca ◽

Hector J. Luna ◽

Nicolas Ratkovich ◽

Manuel Rodríguez Susa

Keyword(s):

Membrane Fouling ◽

Energy Demand ◽

Membrane Surface ◽

Oxygen Demand ◽

Domestic Wastewater ◽

Term Operation ◽

Submerged Membrane Bioreactor ◽

Anaerobic Membrane Bioreactors ◽

Microbial Products

Anaerobic membrane bioreactors (AnMBRs) have demonstrated an excellent capability to treat domestic wastewater. However, biofouling reduces membrane permeability, increasing operational costs and overall energy demand. Soluble microbial products (SMPs) that build up on the membrane surface play a significant role in the biofouling. In this study, the production of SMPs in a 32 L submerged AnMBR operated at three different organic loads (3.0, 4.1 and 1.2 kg chemical oxygen demand (COD)/m3d for phases 1, 2 and 3, respectively) during long-term operation of the reactor (144, 83 and 94 days) were evaluated. The samples were taken from both the permeate and the sludge at three different heights (0.14, 0.44 and 0.75 m). Higher production of SMPs was obtained in phase 2, which was proportional to the membrane fouling. There were no statistically significant differences (p > 0.05) in the SMPs extracted from sludge at different heights among the three phases. In the permeate of phases 1, 2 and 3, the membrane allowed the removal of 56%, 70% and 64% of the SMP concentration in the sludge. SMPs were characterized by molecular weight (MW). A bimodal behavior was obtained, where fractions prevailed with an MW < 1 kDa, associated with SMPs as utilization-associated products (UAPs) caused fouling by the pore-blocking mechanism. The chemical analysis found that, in the SMPs, the unknown COD predominated over the known COD, such as carbohydrates and proteins. These results suggest that further studies in SMP characterization should focus on the unknown COD fraction to understand the membrane fouling in AnMBR systems better.

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Hydrogen vs. Battery in the Long-term Operation. A Comparative Between Energy Management Strategies for Hybrid Renewable Microgrids

Electronics ◽

10.3390/electronics9040698 ◽

2020 ◽

Vol 9 (4) ◽

pp. 698 ◽

Cited By ~ 5

Author(s):

Andrea Monforti Ferrario ◽

Francisco Vivas ◽

Francisca Segura Manzano ◽

José Andújar ◽

Enrico Bocci ◽

...

Keyword(s):

Renewable Energy ◽

Energy Management ◽

Energy Demand ◽

Renewable Energy Sources ◽

Management Strategies ◽

High Mass ◽

Management Systems ◽

Cumulative Energy ◽

Term Operation

The growth of the world’s energy demand over recent decades in relation to energy intensity and demography is clear. At the same time, the use of renewable energy sources is pursued to address decarbonization targets, but the stochasticity of renewable energy systems produces an increasing need for management systems to supply such energy volume while guaranteeing, at the same time, the security and reliability of the microgrids. Locally distributed energy storage systems (ESS) may provide the capacity to temporarily decouple production and demand. In this sense, the most implemented ESS in local energy districts are small–medium-scale electrochemical batteries. However, hydrogen systems are viable for storing larger energy quantities thanks to its intrinsic high mass-energy density. To match generation, demand and storage, energy management systems (EMSs) become crucial. This paper compares two strategies for an energy management system based on hydrogen-priority vs. battery-priority for the operation of a hybrid renewable microgrid. The overall performance of the two mentioned strategies is compared in the long-term operation via a set of evaluation parameters defined by the unmet load, storage efficiency, operating hours and cumulative energy. The results show that the hydrogen-priority strategy allows the microgrid to be led towards island operation because it saves a higher amount of energy, while the battery-priority strategy reduces the energy efficiency in the storage round trip. The main contribution of this work lies in the demonstration that conventional EMS for microgrids’ operation based on battery-priority strategy should turn into hydrogen-priority to keep the reliability and independence of the microgrid in the long-term operation.

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