Energy Engineering - Journal Articles

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A 100 year review of electricity policy in Ireland (1916–2015)
(Elsevier Ltd., 2017-02-21) Gaffney, Fiac; Deane, John Paul; Ó Gallachóir, Brian P.; Bord Gáis Energy
Over the past century, Ireland's electricity sector has undergone a significant transformation. This paper documents the nation's struggle to build an electricity system, to improve security of electricity supply through portfolio diversification and to promote indigenous energy sources. This was a challenge for an (electrically) isolated island with little natural resources. The paper also identifies the ineffective policy decisions that left Ireland exposed to the 1970s energy crises. The crises did, however, provide a clear impetus for focusing Irish energy policy going forward. The successful deployment and integration of large-scale wind power was due to strong national and supranational policy decisions. In 2015, Ireland had the third highest wind energy share of national electricity demand (22.8%) of all IEA Wind Member Countries. The paper also traces Ireland's transition through market reform, regional fragmentation, and looks onwards to the EU internal market for electricity. In essence, this paper provides a holistic view of the implications of various policy decisions on the electricity sector along with the stresses of external factors on the electricity market and should be useful for policy makers elsewhere faced with similar decisions.
Capturing the distributional impacts of long-term low-carbon transitions
(Elsevier B.V., 2019-01-31) Fell, Michael J.; Pye, Steve; Hamilton, Ian; Energy Technologies Institute; Research Councils UK; UK Research and Innovation
Major policy proposals often require a distributional impact assessment, focusing on differential financial and other impacts across population segments. Such assessments are rare, however, at the multi-decadal scale addressed in long-term (e.g. to 2050) low carbon transition modelling. There is therefore a risk of socially inequitable outcomes, which in turn presents a socio-political risk for decision-makers driving transitions. This paper uses a literature review and expert interviews to identify mechanisms by which low carbon transitions could differentially impact population sub-groups. As well as impacts of policy costs on bills, this includes factors such as ability to connect to heat networks or install onsite generation or storage. An approach to exploring distributional impacts across a range of long term scenarios from a United Kingdom energy model (ESME), is proposed. This sets out how bill changes and other costs associated with low carbon transition could impact different income quintiles in the UK.
Consumption-based approach to RES-E quantification: Insights from a Pan-European case study
(Elsevier Ltd., 2017-11-05) Gaffney, Fiac; Deane, John Paul; Collins, Seán; Ó Gallachóir, Brian P.; Science Foundation Ireland; Bord Gáis Energy
The nexus between renewable electricity (RES-E) generation and interconnection is likely to play a large part in future de-carbonised power systems. This paper examines whether RES-E shares should be measured based on consumption rather than production with a European case study presented for the year 2030. The case study demonstrates the volume and scale of RES-E transfers and shows how countries have differing RES-E shares when comparing those derived based on the traditional production-based approach to the alternative. The proposed consumption-based approach accounts for RES-E being imported and exported on an hourly basis across 30 European countries and highlights concerns regarding uncoordinated support mechanisms, price distortions and cost inequality. These concerns are caused by cross-border subsidisation of electricity and this work proposes that an agency be appointed to administer regional RES-E affairs. This agency would accurately quantify RES-E shares and remunerate producers from the country that consumed their electricity instead of where it has been produced â policy would be enhanced by enabling more equitable and optimal electricity decarbonisation.
The cost of electrifying private transport - evidence from an empirical consumer choice model of Ireland and Denmark
(Elsevier B.V., 2018-07-31) Mulholland, Eamonn; Tattini, Jacopo; Ramea, Kalai; Yang, Christopher; Ó Gallachóir, Brian P.; Environmental Protection Agency; Innovationsfonden; Science Foundation Ireland; Fulbright Association
There is a growing consensus that moving to a low carbon future within the transport sector will require a substantial shift away from fossil fuels toward more sustainable means of transport. A particular emphasis has been given to battery electric vehicles (BEV) and plug in hybrid electric vehicles (PHEV), with many nations investing in improving their charging infrastructure and incentivising electric vehicle purchasing through offering grant schemes and tax relief to consumers. Despite these incentives, the uptake of BEVs and PHEVs has been low, while some countries, such as Ireland and Denmark, are in the process of removing the tax relief currently in place. This initial retraction has already been met with a fall in sales of BEVs and PHEVs, which is expected to continue decreasing as these incentives are further reduced. This study develops a socio-economic consumer choice model of the private transport sector based off national empirical data for Ireland and Denmark to analyse the long-term effects of these subsidy retractions, and to further analyse the policy measures and associated cost of moving toward a low carbon private transport sector.
Efficient and equitable climate change policies
(MDPI AG, ) Kypreos, Socrates; Glynn, James; Panos, Evangelos; Giannakidis, George; Ó Gallachóir, Brian P.; International Atomic Energy Agency; Science Foundation Ireland
This report describes the Integrated Assessment Model TIAM-MACRO, which is a Ramsey-type macroeconomic growth model linked with a technology-rich engineering model of the energy-system and with a stylized sub-model of climate change. TIAM-MACRO contributes to coherent and consistent policy analyses at both the world and regional level and correlates demand for energy services to macro-economic developments across regions and time until the end of the 21st century. With the help of this model, two contrasting scenarios are defined related to the reference development (BASE) case and the 2 °C (2DS) case that follow long-term policies on climatic change mitigation in the spirit of the Paris agreement. Finally, we define ex-post market and non-market damages together with the damages related to Local Atmospheric Pollutants (LAP). The stringency of the 2DS case requires the complete restructuring of the energy and transport systems to be relying on carbon-free technologies and fuels together with technologies of negative emissions, at high costs. The study concludes that carbon policies not only consist of an insurance against the risk of climate change but also improve the ambient air quality, as they have secondary benefits that compensate for part of the cost of carbon control. However, the stringency of the 2DS case is so demanding that the cost of climate policies is above benefits
Extreme value estimates using vibration energy harvesting
(Elsevier Ltd, 2018-09-11) Vathakkattil Joseph, George; Hao, Guangbo; Pakrashi, Vikram; Science Foundation Ireland; Tata Trusts
This paper establishes the possibility of utilizing energy harvesting from mechanical vibrations to estimate extreme value responses of the host structure and demonstrates the calibration of these estimates for excitation spectra typical to natural systems. For illustrative purposes, a cantilever type energy harvester is considered for wind excitation. The extreme value estimates are established through a Generalized Pareto Distribution (GPD). Classically well-known Kaimal and Davenport spectra for wind have been considered in this paper for comparison purposes. The applicability of GPD for processes with short-range dependence is explored in both linear and nonlinear systems. The work also demonstrates how return levels can be mapped using energy harvesting levels and indicates that vibration energy harvesting, in its own right, has the potential to be used for extreme value analysis and estimates. The work has impact on health monitoring and assessment of built infrastructure in various stages of repair or disrepair and exposed to nature throughout their lifetime.
From technology pathways to policy roadmaps to enabling measures – A multi-model approach
(Elsevier, 2017-07-21) Mulholland, Eamonn; Rogan, Fionn; Ó Gallachóir, Brian P.; Environmental Protection Agency; Science Foundation Ireland; Innovationsfonden, Denmark
Integrating a range of complementary energy models is becoming an increasingly common method for informing low carbon energy pathways at both national and global levels. Multi-modelling approaches facilitate improved understanding of the detailed technology pathways required to meet decarbonisation targets; however, to-date there has been limited attention on the policy roadmaps and enabling measures that might achieve these decarbonisation targets. This paper addresses this gap by developing a multi-model approach using an energy systems optimisation model, a sectoral simulation model together with scrutiny of individual policy measures to explore decarbonisation of the private car sector in the Irish transport system commensurate with an 80% reduction in national carbon emissions by 2050. The results comprise a cost optimal technology pathway for private cars in a future energy system constrained by a maximum level of carbon emissions, a policy roadmap identifying annual changes in energy efficiency, renewable energy and electrification, and a suite of enabling measures including changes to vehicle registration tax, a biofuel obligation on suppliers and a suite of measures to increase the share of electric vehicles in the fleet. The level of confidence in the different enabling measures to achieve the policy goals is compared and discussed.
Least cost energy system pathways towards 100% renewable energy in Ireland by 2050
(Elsevier B.V., 2020-07-03) Yue, Xiufeng; Patankar, Neha; Decarolis, Joseph; Chiodi, Alessandro; Rogan, Fionn; Deane, J. P.; Ó Gallachóir, Brian P.; Science Foundation Ireland; National Science Foundation; Engineering and Physical Sciences Research Council; NTR Foundation, Ireland; National Natural Science Foundation of China
Studies focusing on 100% renewable energy systems have emerged in recent years; however, existing studies tend to focus only on the power sector using exploratory approaches. This paper therefore undertakes a whole-system approach and explores optimal pathways towards 100% renewable energy by 2050. The analysis is carried out for Ireland, which currently has the highest share of variable renewable electricity on a synchronous power system. Large numbers of scenarios are developed using the Irish TIMES model to address uncertainties. Results show that compared to decarbonization targets, focusing on renewable penetration without considering carbon capture options is significantly less cost effective in carbon mitigation. Alternative assumptions on bioenergy imports and maximum variability in power generation lead to very different energy mixes in bioenergy and electrification levels. All pathways suggest that indigenous bioenergy needs to be fully exploited and the current annual deployment rate of renewable electricity needs a boost. Pathways relying on international bioenergy imports are slightly cheaper and faces less economic and technical challenges. However, given the large future uncertainties, it is recommended that further policy considerations be given to pathways with high electrification levels as they are more robust towards uncertainties.
A numerical and experimental investigation of the effect of side walls on hydrodynamic model testing in a wave flume
(Elsevier Ltd, 2019-08-15) Xie, N.; Hann, M.; Pemberton, R.; Iglesias, Gregorio; Greaves, D.; Engineering and Physical Sciences Research Council
The side wall effect was normally tackled by potential flow based numerical methods. It is well known that, due to the existence of the resonance frequency in the wave tank, the numerical methods over-predict the hydrodynamic forces when comparing with model experiments. Furthermore, in most of the previous studies on the effects of the side walls, the model was located at the centre of the tank, the disturbances on both sides of the model are symmetric, and the resonances of some of the responses such as wave surface elevation and motions may not be excited at the tank natural frequencies. In the present study, a Rankine source panel method is used to tackle the effects of the side walls and artificial damping is introduced in the free surface boundary condition to account for the viscous damping effect. Model experiments are carried out for a lifeboat model located at various positions in a wave flume. Numerical results of the wave forces, free surface elevations and motions of the model are compared with the model test measurements, and good agreement is found. It is shown that the inclusion of the artificial damping in the free surface boundary condition is effective, in particular for the model at off-centre position of the tank.
A perspective on novel cascading algal biomethane biorefinery systems
(Elsevier Ltd., 2020-02-15) Bose, Archishman; O'Shea, Richard; Lin, Richen; Murphy, Jerry D.; Science Foundation Ireland; Horizon 2020; Environmental Protection Agency; Gas Networks Ireland; Ervia, Ireland
Synergistic opportunities to combine biomethane production via anaerobic digestion whilst cultivating microalgae have been previously suggested in literature. While biomethane is a promising and flexible renewable energy vector, microalgae are increasingly gaining importance as an alternate source of food and/or feed, chemicals and energy for advanced biofuels. However, simultaneously achieving, grid quality biomethane, effective microalgal digestate treatment, high microalgae growth rate, and the most sustainable use of the algal biomass is a major challenge. In this regard, the present paper proposes multiple configurations of an innovative Cascading Algal Biomethane-Biorefinery System (CABBS) using a novel two-step bubble column-photobioreactor photosynthetic biogas upgrading technology. To overcome the limitations in choice of microalgae for optimal system operation, a microalgae composition based biorefinery decision tree has also been conceptualised to maximise profitability. Techno-economic, environmental and practical aspects have been discussed to provide a comprehensive perspective of the proposed systems.
A review of approaches to uncertainty assessment in energy system optimization models
(Elsevier Ltd., 2018-07-25) Yue, Xiufeng; Pye, Steve; DeCarolis, Joseph; Li, Francis G. N.; Rogan, Fionn; Ó Gallachóir, Brian P.; Science Foundation Ireland; National Science Foundation; Engineering and Physical Sciences Research Council; NTR Foundation, Ireland
Energy system optimization models (ESOMs) have been used extensively in providing insights to decision makers on issues related to climate and energy policy. However, there is a concern that the uncertainties inherent in the model structures and input parameters are at best underplayed and at worst ignored. Compared to other types of energy models, ESOMs tend to use scenarios to handle uncertainties or treat them as a marginal issue. Without adequately addressing uncertainties, the model insights may be limited, lack robustness, and may mislead decision makers. This paper provides an in-depth review of systematic techniques that address uncertainties for ESOMs. We have identified four prevailing uncertainty approaches that have been applied to ESOM type models: Monte Carlo analysis, stochastic programming, robust optimization, and modelling to generate alternatives. For each method, we review the principles, techniques, and how they are utilized to improve the robustness of the model results to provide extra policy insights. In the end, we provide a critical appraisal on the use of these methods.
SmarTEG: An autonomous wireless sensor node for high accuracy accelerometer-based monitoring
(MDPI, 2019-06-19) Magno, Michele; Sigrist, Lukas; Gomez, Andres; Cavigelli, Lukas; Libri, Antonio; Popovici, Emanuel M.; Benini, Luca
We report on a self-sustainable, wireless accelerometer-based system for wear detection in a band saw blade. Due to the combination of low power hardware design, thermal energy harvesting with a small thermoelectric generator (TEG), an ultra-low power wake-up radio, power management and the low complexity algorithm implemented, our solution works perpetually while also achieving high accuracy. The onboard algorithm processes sensor data, extracts features, performs the classification needed for the blade’s wear detection, and sends the report wirelessly. Experimental results in a real-world deployment scenario demonstrate that its accuracy is comparable to state-of-the-art algorithms executed on a PC and show the energy-neutrality of the solution using a small thermoelectric generator to harvest energy. The impact of various low-power techniques implemented on the node is analyzed, highlighting the benefits of onboard processing, the nano-power wake-up radio, and the combination of harvesting and low power design. Finally, accurate in-field energy intake measurements, coupled with simulations, demonstrate that the proposed approach is energy autonomous and can work perpetually.
The structural modification and rehydration behaviours of milk protein isolate powders: The effect of granule growth in the high shear granulation process
(Elsevier Ltd., 2016-05-30) Ji, Junfu; Cronin, Kevin; Fitzpatrick, John; Maguire, Pierce; Zhang, Hongzhou; Miao, Song; Department of Agriculture, Food and the Marine, Ireland
The effects of granule growth in high shear granulation on the structures and rehydration abilities of milk protein powders were investigated. In this study, milk protein isolate, as a model powder, was agglomerated in a high shear granulator. The formed granules with different sizes were used to compare the densities, granule shapes and subsequently the wettability, dispersibility and solubility. It is found that the small nuclei showed the most compacted structures. Then the primary agglomerates coalesced to create irregular secondary structures with lower density and higher porosity until the final agglomerates formed. The densely packed structures allowed the granules to be more easily wetted by water. The large granules showed quicker release of materials into water until reaching a critical size, where more mechanical energy is potentially required for further granule break down. All the agglomerated MPI granules solubilised much more slowly than the standard MPI powder.
Study of ocean thermal energy resources in Para’baya, West Sulawesi
(IOP Publishing Ltd., 2018) Wicaksono, Yoga Bagus; Putri, MR; Indonesia Endowment Fund for Education
Ocean thermal is one of the renewable energy resources. In 1981, a design of Ocean Thermal Energy Conversion (OTEC) pilot power plant was proven could produce electricity. The performance of OTEC depends on the possible temperature differences of the warm and cold seawater, at least 20°C. In the coastal of Para'baya, this requirement can be satisfied since the distance to reach the 1000 m depth is less than 10,000 m from the shore. The result of ocean thermal power calculation in Makassar Strait shows that Para'baya could produce higher power than any other place in west coast of Sulawesi, with an average power output of 120.35 kW. This ocean thermal study, in the coast of Para'baya, used sea surface temperatures (SST) data from the result of Long-term Indonesian Throughflow Model Simulation (LITHMOS) over 24 years (1982 – 2006), and sea temperature data at 1000 m depth from the World Ocean Atlas (WOA) 2009. The result shows that ocean thermal energy distributions in the Makassar Strait were affected by the combination of gust, wind direction, and sun position which varies in each season. Maximum ocean thermal power is reached during the first transitional season (March, April, May) with output power of 128 kW, and the minimum power is achieved during the dry season (June, July, August) with an output power of 114 kW.
A study on the effects of wave spectra on wave energy conversions
(Institute of Electrical and Electronics Engineers (IEEE), 2018) Prendergast, James; Li, Mingfang; Sheng, Wanan; China Scholarship Council; Hubei Provincial Department of Education; Wuhan University of Science and Technology; Science Foundation Ireland
This research work presents an investigation into the effects of wave spectra on energy conversion for wave energy converters and shows it may be important what theoretical spectrum should be used for a better assessment of a wave energy converter (WEC) in the given sea conditions in a proposed deployment site. To illustrate the problem and the solution, a slightly modified Reference Model 3 (RM3) self-referencing floating point absorber device is used for examining the effects of spectrum types on wave energy conversion. The compared wave spectra include the most used theoretical wave spectra, such as the standard JONSWAP and Bretschneider spectra, as well as the real sea spectrum from field measurements. From the analysis it is shown that the modified RM3 WEC extracts a similar amount of energy from the recorded sea conditions (measured at the AMETS site 2010) when the device is optimized to both the Bretschneider spectrum and the real sea spectrum while the use of the JONSWAP spectrum for optimization leads to an over-prediction in the annual energy production of 16.5%. This may be because, in many practical applications for wave energy development, the JONSWAP spectrum is often preferred by the developers for assessing the device power performance. However, the use of the narrower JONSWAP spectrum (compared to the Bretschneider spectrum) may lead to inaccurate optimization results and power performance data for the device. Therefore, using the correct wave spectrum shapes in the assessment and optimization of a device is suggested for a more accurate assessment and a better understanding of the overall power performance of the device.
Techno-economic data for a multi-model approach to decarbonisation of the Irish private car sector
(Elsevier Inc., 2017-10-07) Mulholland, Eamonn; Rogan, Fionn; Ó Gallachóir, Brian P.; Science Foundation Ireland; Innovationsfonden, Denmark; Environmental Protection Agency
These data and analyses support the research article “From technology pathways to policy roadmaps to enabling measures – A multi-model approach” Mulholland et al. (2017) [1]. This article uses 3 models – an optimization model of the Irish energy system (Irish TIMES), a simulation model of the Irish private transport sector (CarSTOCK), and a market share algorithm used to provide a behavior rich representation into the multi-modelling process. Each of these models are linked to provide a technology pathway, policy roadmap, and finally identify the enabling measures of the private transport sector in a low-carbon Ireland moving toward 2050. The article is organized in the same order, firstly providing the key modelling assumptions and operability of Irish TIMES, secondly for CarSTOCK, and finally for the market share algorithm. All data is supplied within this article.
Wave power extraction from a hybrid oscillating water column-oscillating buoy wave energy converter
(Elsevier B.V., 2020-08-23) Cui, Lin; Zheng, Siming; Zhang, Yongliang; Miles, Jon; Iglesias, Gregorio; European Regional Development Fund; National Natural Science Foundation of China
Oscillating water column (OWC) devices and oscillating buoys (OBs) are two of the main types of wave energy converters (WECs). In this paper a hybrid oscillating water column-oscillating buoy wave energy converter is proposed, which we have named OWCOB. The oscillating buoy is hinged at the outer wall of the oscillating water column. As waves propagate through the OWCOB, the water column within the OWC chamber moves up and down, producing air flow to propel a turbine. Meanwhile, the oscillation of the OB drives a separate hydraulic system. To solve the wave diffraction and radiation problems of the OWCOB and investigate its energy capture performance, an analytical model is developed based on linear potential flow theory and the eigenfunction matching method. Assuming that the PTOs of the OWC and OB are both linear, the wave power extraction of the OWCOB is evaluated in the frequency domain. Of the two configurations considered, the OWCOB with the OWC opening waveward and the OB hinged leeward is found to have a broader primary frequency band of wave power capture compared to the OWCOB with the OWC opening and the OB on the same side. Further, a thorough sensitivity analysis of power capture is carried out considering the main design parameters (size and submergence of the OWC opening, distance between the OWC and the OB, OB hinge elevation, OB radius), which can form the basis of an optimization study for a particular wave climate. Importantly, we find that the OWCOB performs generally better than stand-alone OWCs and OBs, not least in terms of frequency bandwidth.
Zero carbon energy system pathways for Ireland consistent with the Paris Agreement
(Taylor & Francis Group, 2018-04-26) Glynn, James; Gargiulo, Maurizio; Chiodi, Alessandro; Deane, Paul; Rogan, Fionn; Ó Gallachóir, Brian P.; Science Foundation Ireland; Environmental Protection Agency; Sustainable Energy Authority of Ireland; European Regional Development Fund; Higher Education Authority
The Paris Agreement is the last hope to keep global temperature rise below 2°C. The consensus agrees to holding the increase in global average temperature to well below 2°C above pre-industrial levels, and to aim for 1.5°C. Each Party’s successive nationally determined contribution (NDC) will represent a progression beyond the party’s then current NDC, and reflect its highest possible ambition. Using Ireland as a test case, we show that increased mitigation ambition is required to meet the Paris Agreement goals in contrast to current EU policy goals of an 80–95% reduction by 2050. For the 1.5°C consistent carbon budgets, the technically feasible scenarios' abatement costs rise to greater than €8,100/tCO2 by 2050. The greatest economic impact is in the short term. Annual GDP growth rates in the period to 2020 reduce from 4% to 2.2% in the 1.5°C scenario. While aiming for net zero emissions beyond 2050, investment decisions in the next 5–10 years are critical to prevent carbon lock-in.

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