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- Decarbonizing Hard-to-Abate Sectors with Renewable Hydrogen: A Real Case Application to the Ceramics IndustryPublication . Sousa, Jorge A. M.; Azevedo, Inês; Camus, Cristina Inês; Mendes, Luís; Viveiros, Carla; Barata, FilipeHydrogen produced from renewable energy sources is a valuable energy carrier for linking growing renewable electricity generation with the hard-to-abate sectors, such as cement, steel, glass, chemical, and ceramics industries. In this context, this paper presents a new model of hydrogen production based on solar photovoltaics and wind energy with application to a real-world ceramics factory. For this task, a novel multipurpose profit-maximizing model is implemented using GAMS. The developed model explores hydrogen production with multiple value streams that enable technical and economical informed decisions under specific scenarios. Our results show that it is profitable to sell the hydrogen produced to the gas grid rather than using it for self-consumption for low-gas-price scenarios. On the other hand, when the price of gas is significantly high, it is more profitable to use as much hydrogen as possible for self-consumption to supply the factory and reduce the internal use of natural gas. The role of electricity self-consumption has proven to be key for the project's profitability as, without this revenue stream, the project would not be profitable in any analysed scenario.
- Metaheuristic approach to the Holt-Winters optimal short term load forecastPublication . Eusébio, Eduardo; Camus, Cristina Inês; Curvelo, CarolinaElectricity short-term load forecast is very important for the operation of power systems. In this work a classical exponential smoothing model, the Holt-Winters with double seasonality was used to test for accurate predictions applied to the Portuguese demand time series. Some metaheuristic algorithms for the optimal selection of the smoothing parameters of the Holt-Winters forecast function were used and the results after testing in the time series showed little differences among methods, so the use of the simple local search algorithms is recommended as they are easier to implement.
- Technical and economic assessment of energy from Tidal CurrentsPublication . Páscoa, Isabel; Camus, Cristina Inês; Eusébio, EduardoThe present work aims to study the feasibility of deploying a farm of sea current turbines for electricity generation in Portugal. An approach to the tides, which are they, how they are formed, its prediction, is held. It is also conducted a study about the energy of sea currents and it is presented some technology about ocean currents too. A model of tidal height and velocity of the currents it is also developed. The energy produced by a hypothetical park, built in Sines (Portugal), is calculated and afterwards, an economical assessment is performed for two possible scenarios and a sensitivity analysis of NVP (Net Present Value) and LCOE (Levelized Cost of Energy) is figured. The conclusions about the feasibility of the projects are also presented. Despite being desired due to its predictability, this energy source is not yet economically viable as it is in an initial state of development. To push investment in this technology a feed-in tariff of, at least €200/MWh, should be considered.
- Renewable energy in Islands: an integrated proposal for electricity generation and transportsPublication . Marques, Patrícia; Silva, Énia; Camus, Cristina Inês; Eusébio, EduardoThe purpose of this article is to analyse and evaluate the economical, energetic and environmental impacts of the increasing penetration of renewable energies and electrical vehicles in isolated systems, such as Terceira Island in Azores and Madeira Island. Given the fact that the islands are extremely dependent on the importation of fossil fuels - not only for the production of energy, but also for the transportation’s sector – it’s intended to analyse how it is possible to reduce that dependency and determine the resultant reduction of pollutant gas emissions. Different settings have been analysed - with and without the penetration of EVs. The Terceira Island is an interesting case study, where EVs charging during off-peak hours could allow an increase in geothermal power, limited by the valley of power demand. The percentage of renewable energy in the electric power mix could reach the 74% in 2030 while at the same time, it is possible to reduce the emissions of pollutant gases in 45% and the purchase of fossil fuels in 44%. In Madeira, apart from wind, solar and small hydro power, there are not so many endogenous resources and the Island’s emission factor cannot be so reduced as in Terceira. Although, it is possible to reduce fossil fuels imports and emissions in 1.8% in 2030 when compared with a BAU scenario with a 14% of the LD fleet composed by EVs.
- Metaheuristhic approach to the Holt-Winters optimal short term load forecastPublication . Eusébio, Eduardo; Camus, Cristina Inês; Curvelo, CarolinaElectricity short-term load forecast is very important for the operation of power systems. In this work a classical exponential smoothing model, the Holt-Winters with double seasonality was used to test for accurate predictions applied to the Portuguese demand time series. Some metaheuristic algorithms for the optimal selection of the smoothing parameters of the Holt-Winters forecast function were used and the results after testing in the time series showed little differences among methods, so the use of the simple local search algorithms is recommended as they are easier to implement.
- The electric vehicles as a mean to reduce Co2 emissions and energy costs in isolated regions: the São Miguel (Azores) case studyPublication . Camus, Cristina Inês; Farias, TiagoMost of small islands around the world today, are dependent on imported fossil fuels for the majority of their energy needs especially for transport activities and electricity production. The use of locally renewable energy resources and the implementation of energy efficiency measures could make a significant contribution to their economic development by reducing fossil fuel imports. An electrification of vehicles has been suggested as a way to both reduce pollutant emissions and increase security of supply of the transportation sector by reducing the dependence on oil products imports and facilitate the accommodation of renewable electricity generation, such as wind and, in the case of volcanic islands like Sao Miguel (Azores) of the geothermal energy whose penetration has been limited by the valley electricity consumption level. In this research, three scenarios of EV penetration were studied and it was verified that, for a 15% LD fleet replacement by EVs with 90% of all energy needs occurring during the night, the accommodation of 10 MW of new geothermal capacity becomes viable. Under this scenario, reductions of 8% in electricity costs, 14% in energy, 23% in fossil fuels use and CO2 emissions for the transportation and electricity production sectors could be expected.
- Short-term Value for the Water Stored in Headsensitivity Power System ReservoirsPublication . Eusébio, Eduardo; Camus, Cristina Inês; Mendes, VictorAs it is well known, competitive electricity markets require new computing tools for generation companies to enhance the management of its resources. The economic value of the water stored in a power system reservoir is crucial information for enhancing the management of the reservoirs. This paper proposes a practical deterministic approach for computing the short-term economic value of the water stored in a power system reservoir, emphasizing the need to considerer water stored as a scarce resource with a short-term economic value. The paper addresses a problem concerning reservoirs with small storage capacities, i.e., the reservoirs considered as head-sensitivity. More precisely, the respective hydro plant is head-dependent and a pure linear approach is unable to capture such consideration. The paper presents a case study supported by the proposed practical deterministic approach and applied on a real multi-reservoir power system with three cascaded reservoirs, considering as input data forecasts for the electric energy price and for the natural inflow into the reservoirs over the schedule time horizon. The paper presents various water schedules due to different final stored water volume conditions on the reservoirs. Also, it presents the respective economic value of the water for the reservoirs at different stored water volume conditions.
- Ensino a distância com recurso a MOOC para a capacitação ambientalPublication . Miranda, Sandra; Almeida-Silva, M.; Sarreira, Pedro; Camus, Cristina Inês; Monteiro, Ana; David, Alexandra; Manteigas, Vítor; Abreu, RenatoO contínuo desenvolvimento das tecnologias de informação e comunicação (TIC) reorganizaram o modo como vivemos, comunicamos e aprendemos. Para as instituições de ensino superior, as TIC potenciaram o crescimento das modalidades do ensino a distância e a abertura de novos ambientes de aprendizagem, com recurso à educação digital. Como exemplo, os MOOC ganharam protagonismo a partir do movimento da educação aberta, do software livre e da disponibilização de conteúdos abertos e representam ainda uma inovação educativa, que combina e difunde os recursos tecnológicos. O Politécnico de Lisboa, naquela que foi uma iniciativa pioneira, conjunta e multidisciplinar, mobilizou quatro das suas unidades orgânicas (ESCS, ESELx, ESTeSL e ISEL), como o apoio do EaD@IPL – Grupo de Ensino a Distâncias do Politécnico de Lisboa, para a criação do MOOC “Sustentabilidade Ambiental: Mobilizar, Observar e Operacionalizar”, alojado na plataforma NAU – Ensino e Formação Online para Grandes Audiências”.
- Micro-generation Evaluation of the Zero Emissions Technologies in the Portuguese MarketPublication . Camus, Cristina Inês; Eusébio, EduardoMicro-generation is the small scale production of heat and/or electricity from a low carbon source and can be a powerful driver for carbon reduction, behavior change, security of supply and economic value. The energy conversion technologies can include photovoltaic panels, micro combined heat and power, micro wind, heat pumps, solar thermal systems, fuel cells and micro hydro schemes. In this paper, a small research of the availability of the conversion apparatus and the prices for the micro wind turbines and photovoltaic systems is made and a comparison between these two technologies is performed in terms of the availability of the resource and costs. An analysis of the new legal framework published in Portugal is done to realize if the incentives to individualspsila investment in sustainable and local energy production is worth for their point of view. An economic evaluation for these alternatives, accounting with the governmentpsilas incentives should lead, in most cases, into attractive return rates for the investment. Apart from the attractiveness of the investment there are though other aspects that should be taken into account and those are the benefits that these choices have to us all. The idea is that micro-generation will not only make a significant direct contribution to carbon reduction targets, it will also trigger a multiplier effect in behavior change by engaging hearts and minds, and providing more efficient use of energy by householders. The diversified profile of power generation by micro-generators, both in terms of location and timing, should reduce the impact of intermittency or plant failures with significant gains for security of supply.
- PV panel for self-consumption in public buildingsPublication . Monteiro, Ana Catarina; Camus, Cristina Inês; Eusébio, EduardoNowadays, it is imperative to use renewable energy as a source for electricity generation. Energy production by self-consumption and lower costs photovoltaic (PV) panels has created a market for an increase in distributed PV generation. A self-consumption unit may waste almost all-day production if it doesn't match consumption and if there are no batteries in the system. In this case, most part of the energy generated is sold to the public grid. To avoid this situation, these panels should be installed, not in habitation houses, but in people's workplace, that is, public buildings, where photovoltaic production coincides with the load diagram peak of the building, reducing the amount of energy sold to the public grid. In addition, electricity generation decentralization avoids energy losses during transportation and distribution and reduces the number of large electrical plants, significantly contributing to the success of Paris Conference targets that are intended to slow down climate change. In summary, the main objective of this work is to study and evaluate the economic and energy impacts of photovoltaic panels installed in public buildings. Specifically, profitability study of a facility, which is very positive with an IRR of 14, % and an 8-year pay-back.