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AbstractThe decarbonization of the economy, for which the contribution of power systems is significant, is a growing trend in Europe and in the world. In order to achieve the Paris Agreement's ambitious environmental goals, a substantial increase in the contribution of renewable sources to the energy generation mix is required. This trend brings about relevant challenges as the integration of this type of sources increases, namely in terms of the distribution system operation. In this paper, the challenges foreseen for future power systems are identified and the most effective approaches to deal with them are reviewed. The strategies include the development of Smart Grid technologies (meters, sensors, and actuators) coupled with computational intelligence that act as new sources of data, as well as the connection of distributed energy resources to distribution grids, encompassing the deployment of distributed generation and storage systems and the dissemination of electric vehicles. The impact of these changes in the distribution system as a whole is evaluated from a technical and environmental perspective. In addition, a review of management and control architectures designed for distribution systems is conducted.This article is categorized under: Energy Infrastructure > Systems and Infrastructure Energy Infrastructure > Economics and Policy

This paper describes an intelligent Vehicle to Grid (iV2G) Charging Platform for plug-in hybrid and electric vehicles that can be used at user's home, and which includes a mobile control system. The car drivers can control remotely the charging or discharging process through a mobile communication device. This mobile communication device can also gather information about charging places, their availability and the best road paths to reach them, as well as energy market prices, informing the best periods to charge the car regarding the energy costs.

Abstract One of the main obstacles for the use of thermoelectric generators (TEGs) in vehicles is the highly variable thermal loads typical of driving cycles. Under these conditions it will be virtually impossible for a conventional heat exchanger to avoid both thermal dilution under low thermal loads and TEG overheating under high thermal loads. The authors have been exploring an original heat exchanger concept able to address the aforementioned problems. It uses a variable conductance thermosiphon-based phase-change buffer between the heat source and the TEGs so that a nearly constant, optimized temperature is obtained regardless of operating conditions. To the best of the authors’ knowledge, the thermal control feature of the system is unique among existing TEG concepts. The novelty of the present work is the actual computation of operating pressure and temperature and the corresponding vaporization and condensation rates inside the thermosiphon system during driving cycles along with the assessment of the influence of the volumes and pre-charge pressure on electrical output. The global energy and emission savings were also computed for a typical yearly driving profile. It was observed that indeed the concept has unparalleled potential for improving the efficiency of vehicles using TEGs, with around 6% fuel and CO2 emissions savings using the system. This seems a breakthrough for such light duty applications since the efficiency of conventional (passive) systems is strongly deprecated by thermal dilution under low thermal loads and the need to by-pass high thermal load events to avoid overheating. On the contrary, the present concept allows the control of the hot face temperature of the TEGs even under highly variable thermal load (i.e. driving cycle) environments.

In a society with a high growth rate and increased standards of comfort arises the need to minimise the currently high-energy consumption by taking advantage of renewable energy sources. The mortars with incorporation of phase-change materials (PCM) have the ability to regulate the temperature inside buildings, contributing to the thermal comfort and reduction in the use of heating and cooling equipment, using only the energy supplied by the sun. However, the incorporation of phase-change materials in mortars modifies its characteristics. The main purpose of this study was the production and characterisation in the fresh and hardened state of mortars with incorporation of different contents of PCM in mortars based in different binders. The binders studied were aerial lime, hydraulic lime, gypsum and cement. For each type of binder, different mortars were developed with different content of PCM. The proportion of PCM studied was 0, 20, 40 and 60% of the mass of the sand. It was possible to observe that the...

This paper presents a efficient stand-alone battery photovoltaic (PV) lighting system which can provide functional illumination based on power light-emitting diodes (PLEDs). PLED with specific features of small size, long life and high-brightness light will be choices of future light sources. The PLEDs are feed using a lead acid battery that is charged with a PV panel. This paper presents an interface board with a ATMEL ATTINY861V microcontroller, a single-ended primary inductance converter (SEPIC) and input and output voltage and current measurements. The microcontroller runs the perturbation and observation (P&O) maximum power point tracker (MPPT) algorithm used in battery charging process. This algorithm makes the system more efficient. In order to control the PLEDs current, an equal interface board is used running now the proportional integral (PI) current PLED control algorithm adjusting the wanted level of light in the PLEDs array. The two identical interfaces boards based in the economic microprocessor achieved very good results in battery charging and discharge supervision improving the efficiency a life-time of the lead acid batteries (first board) and presents good current control results in the PLEDs array (second equal board) providing a constant PLEDs light even in voltage battery variations or discharges. The stand alone lighting system monitors the surround area and if it feels any movement it changes the level of light of PLEDs from signal light to illumination light. After a pre-defined time it comes back to signal light, saving energy.

Abstract This research has the goal of determining, comparing and substantiating the actual outcome of using sustainable practices, from a financial and environmental comfort point of view. The selected context was of interest due to the challenge of quality sustainable construction at controlled costs, meant for inhabitants of the Portuguese cooperative housing, due to its economical implications and especially its social ones. Two case studies of cooperative housing developments built in Portugal are presented, the first with characteristics of traditional construction and the second including sustainable building features. With these examples, it is intended to demonstrate that it is possible to build below cost limits imposed by law in order to substantially reduce energy consumption costs for heating and cooling as well as for domestic water heating. So, calculations of energy savings in indoor heating and cooling, as well as for domestic water heating are presented in this article for two specific situations: first, for a standard comfort use of housing, as opposed to a situation of real consumption of housing developments as obtained by monitoring carried out for one year in the same dwellings studied for standard comfort. The causes that lead to a substantial decrease in energy consumption in the building of sustainable construction are also described, as a starting point to the improvement of future cooperative housing. Finally are presented, for each of the two situations, calculations of the payback period of investment, according to the specific incremental cost in sustainable construction and the benefits in reducing consumptions. The results show an effective contribution to the improvement of the environment and environmental comfort, due to sustainable construction.

Animal-based proteins are the most consumed worldwide given their well-balanced nutritional composition. However, the growing demand for animal proteins will not be sustainable due to their low conversion efficiency and high environmental footprint. Specific consumers' dietary restrictions and modern trends emphasize the importance of finding alternative sustainable non-animal sources to meet future food (and, in particular, protein) global needs. Algal biomass is considered a relevant alternative, presenting advantages over terrestrial biomass such as higher growth rate, low water consumption, no competition for arable land, carbon-neutral emissions, and production of numerous bioactive compounds. This review provides an overview of recent research advances on algae as source of proteins, including production strategies from relevant protein-producing species. Particular emphasis will be given to algae protein current applications and forthcoming challenges of their use. Nutritional and functional aspects of algae biomass or its protein-enriched fractions will be overviewed.

Abstract Biomass based power plants are one of the few renewable energy sources (RES) units that may be used as base load technologies, contributing also to the reduction of external energy dependency and of the greenhouse gas (GHG) emissions. The availability, heterogeneity and cost of the resource are however important barriers to the effective development and spread of these technologies. This paper aims to make a contribution to the evaluation of biomass power plants based on dedicated energy crops. The particular case of Portugal is analyzed and the strategic, environmental and economic interest of the project is evaluated under the present RES support schemes. The results suggest that the value of the assumed Feed-in Tariff (FIT) may not be enough to attract private investors’ interest for these projects. The need for the creation of a specific FIT for this kind of biomass is highlighted and may be justified both by the perceived project risk and by the expected strategic and environmental value of these investments.