Sex: Male
Education:
- Doctor of Philosophy in Mechanical Engineering, De La Salle University
- Master of Science in Mechanical Engineering, De La Salle University
- Bachelor of Science in Mechanical Engineering, De La Salle University
Field of Specialization
Transport Policy
Energy Policy
Energy Economics
Alternative Fuels
Emission Inventories
Researches:
Article title: Societal cost-benefit analysis of electric vehicles in the Philippines with the inclusion of impacts to balance of payments
Authors: Neil Stephen Lopez, Lew Andrew Tria, Leo Allen Tayo, Rovinna Janel Cruz, Carlos Oppus, Paul Cabacungan, Igmedio Isla Jr., Arjun Ansay, Teodinis Garcia Kevien Cabarrubias-Dela Cruz, Jose Bienvenido Manuel Biona
Publication title: Renewable and Sustainable Energy Reviews 150:111492, October 2021
Abstract:
Countries globally have committed to deploy electric vehicles immensely within the decade. However, these deployments at an early stage come at a huge cost to governments. The high ownership costs of electric vehicles require them to be supported by subsidies, tax exemptions and other incentives – not to mention the costs of installing new charging infrastructure. Several cost-benefit studies have looked into various components, and this present work aims to contribute to the literature by estimating the impact to the country's trade deficit or surplus. While ownership cost parity between electric vehicles and internal combustion vehicles might be farfetched, the modeling results in this study show that electric vehicles can achieve societal cost-benefit parity with internal combustion vehicles within the decade. This finding can provide a strong justification for subsidies and incentives provided to electric vehicles. To conclude, the authors provide some policy implications supporting the local production of electric vehicles.
Full text available upon request to the author
Article title: Optimizing Regional Electricity Trading with Carbon Emissions Pinch Analysis
Authors: Neil Stephen A. Lopez, Dominic C. Y. Foo, Raymond R. Tan
Publication title: Energy 237(6):121544, July 2021
Abstract:
The global effort to decarbonize electricity production requires the concurrent phaseout of fossil fuel-fired power plants coupled with the installation of new renewable energy capacity. The requirement for the latter capacity may be prohibitive in cases where deep greenhouse gas emissions cuts are sought. Electricity trading among countries provides an opportunity to aggregate electricity sources and demands and reduce incremental new renewable energy generation. Carbon emissions limits of each country can be met if a renewable energy certification system is in place. In this work, a modified Carbon Emissions Pinch Analysis (CEPA) approach is developed to determine the minimum renewable energy target for a group of countries with an electricity trading agreement. CEPA is implemented here both graphically and via the Automated Targeting Model (ATM). The effectiveness of this approach for carbon-constrained energy planning is illustrated using three case studies, which include a case study based on countries in the Association of Southeast Asian Nations (ASEAN). The case study results show that electricity trading can reduce new aggregated renewable energy capacity by 9 TWh. Furthermore, the case studies demonstrate reduced investments in renewable energy generation capacity and avoiding energy assets from being stranded in some cases.
Full text available upon request to the author
Article title: Modeling Electric Vehicle Charging Demand with the Effect of Increasing EVSEs: A Discrete Event Simulation-Based Model
Authors: Neil Stephen Lopez, Adrian Allana and Jose Bienvenido Manuel Biona
Publication title: Energies 14(13):3734, June 2021
Abstract:
Electric vehicle (EV) use is growing at a steady rate globally. Many countries are planning to ban internal combustion engines by 2030. One of the key issues needed to be addressed before the full-scale deployment of EVs is ensuring energy security. Various studies have developed models to simulate and study hourly electricity demand from EV charging. In this study, we present an improved model based on discrete event simulation, which allows for modeling characteristics of individual EV users, including the availability of electric vehicle supply equipment (EVSE) outside homes and the charging threshold of each EV user. The model is illustrated by simulating 1000 random electric vehicles generated using data from an actual survey. The results agree with previous studies that daily charging demands do not significantly vary. However, the results show a significant shift in charging schedule during weekends. Moreover, the simulation demonstrated that the charging peak demand can be reduced by as much as 11% if EVSEs are made more available outside homes. Interestingly, a behavioral solution, such as requiring users to fully utilize their EV’s battery capacity, is more effective in reducing the peak demand (14–17%). Finally, the study concludes by discussing a few potential implications on electric vehicle charging policy.
Full text link https://tinyurl.com/ym2z8ufj
Article title: Modeling Traffic Flow, Energy Use, and Emissions Using Google Maps and Google Street View: The Case of EDSA, Philippines
Authors: Joshua Ezekiel Rito, Neil Stephen Lopez, and JoseBienvenido Manuel Biona
Publication title: Sustainability 13(12):6682, June 2021
Abstract:
The general framework of the bottom-up approach for modeling mobile emissions and energy use involves the following major components: (1) quantifying traffic flow and (2) calculating emission and energy consumption factors. In most cases, researchers deal with complex and arduous tasks, especially when conducting actual surveys in order to calculate traffic flow. In this regard, the authors are introducing a novel method in estimating mobile emissions and energy use from road traffic flow utilizing crowdsourced data from Google Maps. The method was applied on a major highway in the Philippines commonly known as EDSA. Results showed that a total of 370,855 vehicles traveled along EDSA on average per day in June 2019. In comparison to a government survey, only an 8.63% error was found with respect to the total vehicle count. However, the approximation error can be further reduced to 4.63% if cars and utility vehicles are combined into one vehicle category. The study concludes by providing the limitations and opportunities for future work of the proposed methodology.
Full text link https://tinyurl.com/448ywd99
Article title: Comparison of Driving Forces to Increasing Traffic Flow and Transport Emissions in Philippine Regions: A Spatial Decomposition Study
Authors: Geoffrey Udoka Nnadiri, Anthony S. F. Chiu, Jose Bienvenido Manuel Biona and Neil Stephen Lopez
Publication title: Sustainability 13(11):6500, June 2021
Abstract:
The warming of the climate system has raised a lot of concerns for decades, and this is traceable to human activities and energy use. Conspicuously, the transportation sector is a great contributor to global emissions. This is largely due to increasing dependence on private vehicles and a poorly planned public transportation system. In addition to economic impacts, this also has significant environmental and sustainability implications. This study demonstrates a novel approach using spatial logarithmic mean Divisia index (LMDI) to analyze drivers of traffic flow and its corresponding CO2 emissions in regions through an illustrative case study in the Philippines. Population growth is revealed as the main driver to traffic flow in most regions with the exception of a few regions and the national capital which are driven by economic activity. The economic activity effect shows positive trends contributing positively to traffic flow which is greatly linked to income level rise and increase in vehicle ownership. Concerning the impacts, results revealed that an increase in economic activity generally causes traffic intensity to decrease, and switching to more sustainable modes is not a guarantee to reduce carbon emissions. The authors recommend increasing equity on the appropriation of transport infrastructure projects across regions, quality improvement of public transport services and promoting mixed-use development.
Full text link https://tinyurl.com/yc6dsjk2
Article title: Spatiotemporal Comparison of Drivers to CO2 Emissions in ASEAN: A Decomposition Study
Authors: Edwin Bernard F. Lisaba, Jr. and Neil Stephen A. Lopez
Publication title: Sustainability 13(11):6183, May 2021
Abstract:
The Southeast Asian region is one of the most vulnerable to climate change given its geographical location and economic situation. This study aims to conduct a combination of spatial and temporal analyses in order to understand differences between member nations in terms of driving factors to changing emissions. The logarithmic mean Divisia index (LMDI) method was used in order to estimate carbon dioxide emissions due to population, economic activity, economic structure, and energy intensity effects from the year 1990 to 2018. In conducting the study, spatial analysis showed that Singapore was the only country to effectively lessen carbon emissions, due to population and energy intensity, in comparison to the others. Additionally, temporal analysis showed that the ASEAN initially developed at the same rate, before countries such as Singapore, Malaysia, and Thailand, started becoming more economically active, as shown by their economic activity. Finally, results have shown that some countries, especially the Philippines and Indonesia, have undergone significant changes in economic structure, which significantly affected carbon emissions. The results also highlight the increasing per capita emissions as income levels rise. The paper concludes by presenting a summary of the findings and some policy recommendations.
Full text link https://tinyurl.com/2p8hztna
Article title: Production- and consumption-based energy use in the ASEAN: Lessons from the Tiger and the cubs
Authors: Neil Stephen Lopez, Vincent Moreau, Krista Danielle Yu, Anthony S. F. Chiu, Ming Xu
Publication title: Journal of Cleaner Production 304(1):126986, July 2021
Abstract:
Energy-intensive activities have been increasingly outsourced to developing countries. Many researchers investigated this trend, and in recent years, consumption-based accounting of energy use and emissions have gained attention. This study contributes to this literature by analyzing the effect of changing the accounting method for energy use on the resulting drivers identified from a decomposition analysis study. Specifically, the analysis is done on the increasing energy use in six ASEAN countries. The authors argue that since policy recommendations on energy and emissions are anchored significantly on these drivers, their sensitivity to the accounting approach used must be understood. The results show that the effect is not the same for all countries, and they can be grouped into 3 categories. The findings provide insights and raise questions regarding the sustainability of growing economies in the ASEAN region. To conclude, the results are reflected on from both a national and international perspective, and potential policy implications are discussed.
Full text available upon request to the author
Article title: Uncovering the significant socio-economic attributes of low- and high-emission countries using rough sets
Authors: Neil Stephen Lopez, Meta Mouy, Aaron Don Africa
Publication title: Clean Technologies and Environmental Policy, March 2021
Abstract:
Drivers to global carbon emissions have been widely investigated in the scientific literature. However, most previous studies have been limited to supervised learning approaches such as decomposition analysis. Thus, the effects of more specific socio-economic factors such as research expenditure, poverty incidence, education level and trading of goods have seldom been probed into, and often, drivers significantly vary from country to country. However, it is hypothesized in this study that patterns can be derived among high- and low-emission countries using a more detailed approach. Thus, a novel approach using rough sets is developed to uncover the effects of detailed socio-economic attributes to the emissions of 194 countries and regions. A significant advantage of rough set theory is its ability to work with incomplete data sets. As comprehensive as they are, global data sets such as that of the World Bank would still have gaps especially in less developed countries. The rough set model developed in this study has a validity of 94%. The most significant factors for low-income countries are having low to mid agricultural exports and having mid to high pump prices for diesel. For high-income countries, this was having high gross domestic product per capita. Overall, the most interesting insight from this study is that countries do not simply grow as they increase emissions, but also evolve. As countries develop, they also change their priority sectors, policies and demographics. Moreover, the findings suggest that the understanding of low-emission countries benefits more from a comprehensive study. High-emission countries have been well studied in the literature already. Graphical abstract
Full text link https://tinyurl.com/2p8a5jmn
Article title: Identification of key sugarcane harvester features using the Analytic Hierarchy Process
Authors: J A Gonzaga, E Dela Cruz, N S Lopez
Publication title: IOP Conference Series Materials Science and Engineering 1109(1):012010, March 2021
Abstract:
The Philippine sugarcane industry is worth roughly 88 billion pesos and employs around 700,000 Filipinos. However, the competitiveness of the local industry ($0.17 per lb sugar) is currently under threat from international producers ($0.14 per lb sugar) because of the upcoming ASEAN 2015 integration. One of the major blockages to cost effectiveness is the low productivity of the local industry. This may be addressed with the use of a semi-automated mechanical harvester. As a preliminary study, the present work captures the expert preferences of various stakeholders in the selection of a semi-automated mechanical harvester. This is done using the Analytic Hierarchy Process (AHP) surveying tool. The study assumes the following important factors: a) Ease of use, b) Productivity, c) Adaptability to different terrains, d) with Lifter, and e) with Topper. Using a survey with a series of pairwise comparison questions, it is able to quantify even qualitative factors affecting decision making. The priorities of the surveyed stakeholders are averaged and discussed in the results section. Widely used in policy making and planning, the paper introduces the use of the AHP tool to commercial machinery design. The model may be expanded and improved to consider other key factors.
Full text link https://tinyurl.com/2za42c2e
Article title: Decomposition analysis of Japan’s CO2 emissions
Authors: J A Dela Vega, J A Gonzaga, L A Gan Lim, N S Lopez
Publication title: IOP Conference Series Materials Science and Engineering 1109(1):012060, March 2021
Abstract:
Studies have been conducted to uncover the underlying factors of global CO2 emissions. One method to quantify the driving forces of carbon dioxide emissions is decomposition analysis. In this paper, the logarithmic mean Divisia index (LMDI) method was used to investigate the driving forces of carbon dioxide emissions in Japan for the period of 1990-2017. As one of the world’s leading economies, it also contributes one of the highest CO2 emissions globally. Results highlighted the flaw of energy structure as one major factor affecting CO2 emission intensity. Another notable finding is how the state of the economy played a pivotal role in the shift of carbon emission levels. Potential policy recommendations were also introduced to establish a better power structure for electricity generation in the country.
Full text link https://tinyurl.com/2p8crknx
Article title: Decision tree analysis of commuter mode choice in Baguio City, Philippines
Authors: I H V Gue,, J Soliman, M De Guzman, R Cabredo, A Fillone, N S Lopez and J B M Biona
Publication title: IOP Conference Series Materials Science and Engineering 1109(1):012059, March 2021
Abstract:
Transportation is a multidisciplinary system. Solving its issues would require the knowledge of social, economic, engineering, environmental, and technological disciplines. Emerging techniques used in problem-solving involve the use of machine learning techniques. In this study, a machine learning technique, decision tree, is used for mode choice analysis in Baguio City, Philippines. Using data from a household survey, the developed model uncovers the most significant factors affecting mode choice of residents in the city. The results highlight the role of income, which is related to the individuals’ career level and stage in life. Interestingly, a mid-level income group seems to be highly inclined towards private vehicle use. To conclude, the authors note that the primary advantage of a decision tree is its simplicity and straightforward results interpretation, which is paramount in policymaking. For future work, the authors recommend exploring larger decision tree models for mode choice and conducting a validation interview of the insights obtained from the study.
Full text link https://tinyurl.com/2p8b5ta7
Article title: Using Logarithmic Mean Divisia Index method (LMDI) to estimate drivers to final energy consumption and emissions in ASEAN
Authors: E B Lisaba and N S Lopez
Publication title: IOP Conference Series Materials Science and Engineering 1109(1):012070, March 2021
Abstract:
The ASEAN is currently trying to mitigate the amount of CO 2 emissions per country. This is not only to contribute to the worldwide goal of lessening greenhouse gases, but to also ensure the safety of its member states by combatting the effects of climate change. The effects as stated by the IPCC, such as rising water levels, rising ambient temperature, and an increase in the frequency of tropical storms, can greatly endanger members of the ASEAN. It must be noted that a majority of its members are archipelagic, have areas of extreme poverty, and rely on agriculture for production. Therefore, the temporal logarithmic mean Divisia index (LMDI) has been conducted in order to determine the possible drivers that cause the changes in CO 2 emissions per year for all ASEAN member countries. The drivers of CO 2 were divided into the population, economic activity, energy intensity, and energy structure effects. CO 2 emissions per fuel type were calculated using their respective emission factors. Knowing which drivers constitute the most CO 2 emissions in a country would help pinpoint which areas could be worked on. It was found that Indonesia, Brunei Darussalam, and Lao PDR had the most impressive decrease in CO 2 emissions due to energy intensity and structure effects. A majority of the other countries have either stayed constant or even increased CO 2 emission output per year from each effect. Therefore, general policies based on the success of these countries that could be applied for each member country are recommended in this study.
Full text available upon request to the author
Article title: Energy equity analysis in Metro Manila using household expenditure data
Authors: Christian Roice Tayag and Neil Stephen Lopez
Publication title: IOP Conference Series Materials Science and Engineering 1109(1):012043, March 2021
Abstract:
Energy poverty in the Philippines has been prevalent, but current energy equity metrics in the Philippines are done only on a national level. Lorenz curve and Gini coefficient are concepts traditionally applied in economics to measure wealth inequality. In this paper, the authors will adapt the methodology used by Jacobson to measure energy inequality in Metro Manila for 2015 using energy expenses of households retrieved from the Family Income and Expenditure Survey conducted and published by the Philippine Statistics Authority every three years containing energy expenses, income, and socio-economic identifiers of a household. The main energy resources listed in the survey are electricity, LPG, kerosene, fuelwood, charcoal, and biomass residue. To translate energy expenses to energy consumption, historical costs available from public records are used in conjunction with the fuels’ calorific values. From there, Lorenz curves and Gini coefficients are calculated for districts and cities in Metro Manila. Further comparison reveals the relationship of income and energy consumption Gini coefficients in the region. Based on the results, the authors include recommendations to improve the use of Lorenz curve and Gini coefficient as a metric in quantifying energy equity.
Full text link https://tinyurl.com/2p993yj5
Article title: Transport Emissions Modeling using Google Maps: An alternative approach for vehicle flow analysis
Authors: J E Rito, and N S Lopez
Publication title: IOP Conference Series Materials Science and Engineering 1109(1):012069, March 2021
Abstract:
Continuous measurements of transport emissions are considered key issues for air pollution management in the transportation sector. In some instances, researchers may come across difficulties in doing transport emissions modeling such as overcomplexities and laborious methodologies. In this regard, the authors are introducing a novel method of doing a transport emissions modeling by utilizing Google Maps data. By getting the average travel time of a road segment and the corresponding length, the average speed can be obtained. This speed will be used to identify the flow of vehicles in terms of Passenger Car Unit (PCU) through a speed-flow curve on the basis of a Roadside Frictions Index (RSFI). PCU percentages are derived from the actual counting of vehicles using the street view features of Google Maps. Once the PCU count and the PCU percentages are established, the actual number of vehicle flow per type can now be determined. Consequently, emissions loads are calculated by multiplying the vehicle flow and road length to emissions factors derived from reliable sources.
Full text link https://tinyurl.com/yxm9ebfn
Article title: Multi-sector decomposition analysis of Philippine CO 2 emissions
Authors: E A S Ng and N S A Lopez
Publication title: IOP Conference Series Materials Science and Engineering 1109(1):012047, March 2021
Abstract:
Global CO 2 emissions are rising due to the rising energy demand and the extent to which this is fed by fossil fuels. The LMDI method of IDA is a valuable tool for determining the contributing driving forces behind emissions in a particular time frame, region, or economy. This study applies the techniques of spatial LMDI across the industry sectors of the 2017 Philippine economy to understand the effects of value share, energy intensity, energy structure, and fuel types on carbon emissions per sector. A combination of IEA, PSA, and IPCC data are used in order to ascertain these effects based on the Kaya identity. Results and tabulated and visualized in Cartesian scatter plots. Trends identified include the negative relationship between value share and energy intensity effects and between oil use and natural gas use effects. Outliers to these trends and in the Figures were also highlighted and elucidated. The study recommended increased use of natural gas due to its lower emission factor vs oil and coal, government assistance to low-value sectors in procurement of more efficient equipment, and bespoke solutions per sector based on the given data herein.
Full text link https://tinyurl.com/2p873tjy
Article title: Computational Fluid Dynamics Simulation of Indoor Air Quality and Thermal Stratification of an Underfloor Air Distribution System (UFAD) with Various Vent Layouts
Authors: Neil Stephen Lopez, Selena Kay Galeos, Brian Raphael Calderon, David Roy Dominguez, Bryan Joseph Uy, Rupesh Iyenga
Publication title: Fluid Dynamics and Materials Processing 17(2):333-347, January 2021
Abstract:
The underfloor air distribution (UFAD) system has not been able to penetrate the residential and commercial air conditioning industry significantly until now. To date, the most notable applications are found in datacenters because of their more demanding thermal stratification and cooling requirements. In addition to highlighting the advantages of the UFAD system over the traditional overhead (OH) system, this study compares various ventilation layouts for a UFAD system. Four different UFAD ventilation layouts are compared and one OH layout. The results show that using multiple swirl-type diffusers creates a more uniform floor-to-knee temperature and less air recirculation than the rectangular grille-type diffusers. Placing the return vents on the sides of the room creates a cooler environment by isolating recirculating air to a smaller space. At the end of the study, a design guide matrix is presented to summarize how the supply and return vent layout affects air conditioning performance.
Full text available upon request to the author
Article title: Towards more sustainable transport in Metro Manila: A case study of household vehicle ownership and energy consumption
Authors: Monorom Ritha, ,Krister Ian Daniel Z. Roquel, Neil Stephen A. Lopez,Alexis M. Fillone, Jose Bienvenido Manuel M. Biona
Publication title: Transportation Research Interdisciplinary Perspectives 6:100163, July 2020
Abstract:
Improvement of residential areas with low accessibility to crucial destinations (e.g., hospitals, schools, markets, and recreation centers) is expected to improve traffic flow and reduce energy consumption and CO2 emissions. This study intends to evaluate the multi-criteria accessibility measure of residential areas to key destinations in Metro Manila, using the gravity method and applying it to understand its impact on household vehicle ownership and energy consumption. The main findings suggest that improving residential area access to key services and facilities (i.e., hospitals, schools, markets, and recreation centers) not only enhances the equitable development of society but also discourages household vehicle dependency. Additionally, the highest multi-criteria accessibility is observed for areas with the presence of high rail line density, specifically in the most populated part of Metro Manila because of many educational institutions, medical centers and hospitals, and markets and shopping malls are located around the train stations and along the rail lines. Furthermore, households living in an area with high multi-criteria accessibility are less likely to acquire and use vehicles. A 1% improvement of accessibility reduced the energy consumption by 38.470 MJ/month-vehicle, CO2 emission by 2.851 kg/month-vehicle, and vehicle kilometers traveled by 12.043 km/month-vehicle. Based on the empirical findings, policy implications recommend building more key facilities in residential areas having the lowest accessibility. The lowest accessibility areas are also geospatially visualized to support policymakers and urban planners.
Full text link https://tinyurl.com/4re92vmr
Article title: Development of small area population estimation models for a developing, densely populated metropolitan area and its applications: A case study of Metro Manila
Authors: Monorom Rith, Jimwell L. Soliman, Neil Stephen A. Lopez, Alexis M. Fillone and Jose Bienvenido M. Biona
Publication title: Engineering and Applied Science Research 47(2): 21-5, June 2020
Abstract:
Projection of population in a small area is essential for the government to design proactive policies to support a variety of planning processes and making decisions. The private sector can use this information to do customer demand forecasting and market site targets on a small scale. However, most developing countries do not have this level of data for the development of small area population estimation models. The thrust of this study is to develop a linear regression-based small area population estimation model using recent census data of Metro Manila. The R 2 values of the developed population and household estimation models are 0.975 and 0.994, respectively, while the respective mean absolute errors (MAEs) are 9.76% and 7.98%. The developed models were then applied to project a small area population. The area of Metro Manila with a population density of more than 50,000 persons/km 2 will increase from 5.78% in 2010 to 9.23% in 2020, 15.14% in 2030, 21.76% in 2040, and 31.31% in 2050. The projected population within Metro Manila will increase from 11.89 million in 2010 to 29.16 million in 2050, with an average annual growth rate of 3.63% from 2010 to 2050. During this time, the population density will rise from 19,137 persons/km 2 in 2010 to 49,243 persons/km 2 in 2050. The total number of households is projected to increase from 2.89 million in 2010 to 7.49 million in 2050, which is a 2.59-fold increase.
Full text link https://tinyurl.com/3pvsuc9w
Article title: Cost-benefit analysis of alternative vehicles in the Philippines using immediate and distant future scenarios
Authors: Neil Stephen Lopez, Jimwell Soliman, Jose Bienvenido ManuelBiona, Lewis Fulton
Publication title: Transportation Research Part D: Transport and Environment 82:102308, May 2020
Abstract:
Alternative vehicle technologies promise a sustainable future by reducing carbon emissions and pollution. However, their widespread adoption tends to be slow due to high costs and uncertainties in benefits. Using a life cycle-based approach, this study calculates ownership savings and societal benefits for various alternative vehicle technologies against their baseline vehicle technology (e.g. gasoline or diesel). The assessment is performed from a developing country context – in the Philippines. Furthermore, immediate and distant future scenarios are modeled. The immediate future scenario assesses costs and benefits if the shift is to happen now, while the distant future scenario considers the effect of widespread autonomous driving and ridesharing. The results of the study echo the significant societal benefits from electric- and fuel cell-powered vehicles found in literature, but they are hindered by high ownership costs. In the immediate future, the diesel hybrid electric vehicle can potentially have both positive societal and operational costs for public transportation. For a gasoline-powered private passenger car, a simple shift to diesel, 20% biodiesel or 85% methanol can be beneficial. In the distant future, it is expected that autonomous, rideshared vehicles can potentially lure people away from driving their own vehicles, because of lower costs per passenger-kilometer while sustaining the privacy and comfort of a private car.
Full text available upon request to the author
Article title: Numerical simulation of thermal stratification and air quality in an underfloor air distribution system (UFAD)
Authors: Neil Stephen Lopez, Selena Kay Galeos, Brian Raphael Calderon, David Roy Dominguez, Bryan Joseph Uy and Rupesh Iyengar
Publication title: IOP Conference Series Earth and Environmental Science 463(1):012021, April 2020
Abstract:
The penetration of underfloor air distribution systems (UFAD) in residential and commercial air conditioning has been rather slow. The most notable applications would be on data centers, where thermal stratification requirements are more demanding. The present study supports and strengthens recent work in the design and development of UFAD systems, by augmenting literature on proper vent positioning and design. In UFAD systems where thermal stratification is more pronounced, significant energy savings may be achieved through proper positioning of supply and return vents. Using a validated numerical simulation model in ANSYS CFX, four UFAD vent layouts are investigated with regards to their implications on thermal stratification and indoor air quality. Results show that not only ventilation layout, but also vent type selection can significantly affect the performance of a UFAD system. Spreading multiple, smaller supply diffusers is preferable than having large supply diffusers on the perimeter of the rooms, both from a temperature distribution and indoor air quality perspective. Notably, air flow is significantly poor in the perimeter layout, causing warmer temperature at the center of the room.
Full text link https://tinyurl.com/yvpy9ahs
Article title: Determinants of individual vehicle type choice and energy consumption in a heavy traffic metropolis of Southeast Asia featuring the case of Metro Manila
Authors: Monorom Rith, Neil Stephen Lopez, Alexis M. Fillone and Jose Bienvenido M. Biona
Publication title: Engineering and Applied Science Research 47(1):56-65, March 2020
Abstract:
Sustained economic growth with insufficient public transport in metropolitan areas encourages private vehicle dependency, thereby increasing petroleum oil consumption and greenhouse gas (GHG) production. One way to mitigate these issues is to encourage private vehicle users to own smaller fuel-efficient vehicles. This paper intends to explore determinants (i.e., socioeconomic characteristics, travel behavior, vehicle attributes and purchasing conditions, vehicle and gas prices, and built environment characteristics) of individual vehicle type owners and energy consumption in Metro Manila. The data sample of 846 observations and a copula-based joint discrete-continuous framework were employed. The findings highlighted that individuals using bank auto loans are more likely to choose SUVs than cars, thereby consuming more energy. Furthermore, people located in high population density areas and those with road-based public transport line dense areas prefer cars to SUVs. An increase in gas and vehicle cost contributes to energy saving and discourages SUV dependency. The developed models were also applied for a "what-if" scenario analysis to quantify the competing options as an innovative perspective for crafting proactive transportation policies. Understanding the determinants of vehicle type ownership and energy consumption is the precursor of designing consistent transportation policies to mitigate petroleum oil consumption and mobile emissions.
Full text link https://tinyurl.com/kepz3p2e
Article title: The combustion and emission characteristics of the diesel engine operated on a dual producer gas-diesel fuel mode
Authors: Monorom Rith, Bernard Buenconsejo3, Jeremias A. Gonzaga1, H. W. Gitano-Briggs4, Neil S. Lopez1 and Jose Bienvenido M. Biona
Publication title: Engineering and Applied Science Research 46(4): 360-370, December 2019
Abstract:
Producer gas is a low energy density gaseous fuel converted from carbonaceous materials through a thermochemical process. The gas can be exploited to operate a diesel engine on a dual-fuel mode to partially reduce diesel fuel use. The present study intends to investigate the impacts of gas flow rate and diesel injection timing (DIT) on a diesel engine operated on a dual-fuel mode at a high engine speed of 3,000 rpm. The findings highlight that the peak pressure occurred later and was lower at a higher gas flow rate. The peak pressure was higher and advanced when the DIT was advanced and the engine load was increased. Large increases in CO2, HC, and CO concentrations were found in the dual-fuel mode, specifically at low loads. Unlike the findings using a medium engine speed, the specific NOX emissions were higher for the dual-fuel mode operation. Based on these empirical results, a dual-fuel engine should be operated at a high engine load and a gas flow rate of 10 kg/h. A slightly advanced DIT is required-roughly 3 degrees of crank angle. Furthermore, a dual producer gas-diesel engine should not be operated at the maximum gas flow rate.
Full text link https://tinyurl.com/3mtne7fx
Article title: Evaluation of political risk factors influencing energy supply disruption
Authors: J Soliman, N S Lopez and J B M Biona
Publication title: IOP Conference Series Earth and Environmental Science 268(1):012123, July 2019
Abstract:
High dependence on imported energy supply makes a country vulnerable to risks of supply disruption. Disruptions can be in the form of government policies, external conflicts, and natural calamities. Several indicators quantifying the probability of supply disruption were proposed in past studies based on a defined set of criteria. However, factors influencing the behavior of energy exports vary per country. In this study, 12 political risk components were investigated and correlated with historical oil-export data to assess the main drivers dictating export behavior. A case study was conducted on Philippine crude oil suppliers from 2001 to 2015, and three countries were elaborated for further discussion. Results showed that oil exports are strongly correlated with internal and external conflicts in Saudi Arabia; internal conflicts in Venezuela; and socioeconomic conditions in Russian Federation. The study recommends utilizing the developed methodology to aid estimation of energy security costs based on various political risk scenarios.
Full text available upon request to the author
Article title: Assessing sustainability of long-term energy supply using desirability functions
Authors: Jimwell L. Soliman, Neil Stephen A. Lopez, Jose Bienvenido Manuel M. Biona
Publication title: Energy Procedia 158:3723-3728, February 2019
Abstract:
The depletion of fossil fuels due to high energy demand poses an imminent threat to energy security. Sustainability of energy sources is prioritized to minimize the economic impact of oil supply disruptions. Several energy security indices and indicators had been developed to quantitatively assess the security of supply. However, studies concerning the cost of such risks were limited. Thus, a modification to currently used supply sustainability indicators is needed to express the risk score as a probability of disruption. In this study, a modification was applied using desirability function to convert the scores into scales. Long-term energy security was assessed based on reserves-to-production ratio and share in world export. A case study on the crude oil imports of the Philippines from 2007 to 2016 was conducted to demonstrate the proposed methodology. The desirability scores were weighted based on the share of each supplier to the total crude oil import. During the 10-year period, integrated sustainability risk scores reflecting a proxy probability varying from 1 to 8% were computed due to changes in suppliers and import shares. The study recommends consistent importation of crude oil from sustainable countries to minimize the sustainability risk.
Full text available upon request to the author
Article title: A Systematic Approach to the Optimal Planning of Energy Mix for Electric Vehicle Policy
Authors: Aristotle Ubando, Ivan Henderson Gue, Monorom Rith, Jeremias Gonzaga, et al.
Publication title: Chemical Engineering Transactions 76(2019):1147-1152, January 2019
Abstract:
Electric vehicle offers a cleaner and sustainable alternative to transportation as it eliminates direct carbon dioxide emission through the conventional internal combustion engine. With the increase in the global population and economic development, the demand for transportation and the adoption of electric vehicles is unprecedented. However, the adoption of electric vehicle on a national-scale requires long-term planning of infrastructure development, and energy generation and distribution. The study focuses on the development of a systematic mathematical programming approach in the optimal planning of the energy mix of the additional power generation capacity arising from the adoption of the electric vehicle in a developing country. The study considers the 2030 horizon which includes, the cost of power generation and distribution per energy mix, and the forecasted commissioning and decommissioning of energy plants. The study proposes a fuzzy mixed-integer non-linear programming model in the optimal planning of the energy mix for the adoption of EV while minimizing carbon footprint, minimizing the total capital cost, and minimizing the electricity cost. A case study in the adoption of electric vehicle in the Philippines will be utilized to demonstrate the capability of the model. In addition, a comparison of the electricity cost of the business as usual (BAU) scenario and this study has been evaluated. The results show that the various renewable energy technologies for power generation are selected initially from 2019 to 2022 and 2029 to 2030, while the fossil-fuel based power plants were utilized from 2023 to 2028. The results revealed the electricity cost from the study is relatively lower than the BAU scenario. The results of the model are intended to aid and guide policymakers in the potential adoption of electric vehicles, especially in the energy planning sector.
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Article title: Decomposing drivers of transportation energy consumption and carbon dioxide emissions for the Philippines: the case of developing countries
Authors: Neil Stephen Lopez, Anthony S. F. Chiu & Jose Bienvenido Manuel Biona
Publication title: Frontiers in Energy 12(1), July 2018
Abstract:
Global CO 2 emissions increased by 57.9% from 1990 to 2014, of which 21% is known to be from the transportation sector. In line with policy development, driving forces to energy consumption and emissions may be determined using decomposition analysis techniques. However, the detail of information required to perform such studies for the transportation sector in developing countries can be challenging. An attempt was made in this study to formulate a decomposition analysis framework considering data availability and limitation in developing countries. Furthermore, a suggestion of adjusting transport activity data using average oil price was proposed. An illustrative case study in the Philippines revealed that the most significant driver was transport activity, followed by energy intensity, and then population growth, which was both similar and contrary to all previous studies performed in developed and rapidly urbanizing countries, which pointed out to transport activity as the primary contributing force. For the Philippines, transport activity was an inhibiting force, whereas energy intensity was the primary contributing factor. The difference could be explained by the differences in mode shares and quality of life between countries. Looking at private vehicle ownership data, it is observed that growth rates are higher in the rural, than in the urban centers. Deriving from the findings, developing a comprehensive public transport plan is recommend for future growth areas, expansion and modernization of public transport services in the city, and strategic deployment of transport policies.
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Article title: “I Drive outside of Peak Time to Avoid Traffic Jams—Public Transport Is Not Attractive Here.” Challenging Discourses on Travel to the University Campus in Manila
Authors: Robin Hickman, Neil Lopez, Mengqiu Cao, Beatriz Mella Lira and Jose Bienvenido Manuel Biona
Publication title: Sustainability 10(5):1462, May 2018
Abstract:
One of the major narratives in transport policy internationally concerns the promotion of private versus public modes. The Global North has many examples where public transport, walking and cycling networks are well developed, yet examples from the Global South are less evident. There is a historical failure of replicating policies and practices from the Global North, particularly in perpetuating the highway building model, often unsuitable to the cultural contexts in the Global South. This paper examines individual attitudes and discourses concerning travel to De La Salle University campus, in Metro Manila, the Philippines. 42 participants are surveyed using Q methodology. Four discourses are developed, reflecting attitudes to growing automobility in Manila, public transport service provision, the difficulties of travelling in the city and the aspiration for increased comfort whilst travelling. Manila provides an example of the complexities in moving towards greater sustainable travel in the southeast Asian context where levels of private car usage are already high. It is hoped that a greater awareness of the problems of the current travel experiences might lead to us to seek different narratives, where transport systems can be developed which better serve social equity and environmental goals.
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Article title: Electricity trading and its effects on global carbon emissions: A decomposition analysis study
Authors: Neil Stephen A. Lopez, Jose Bienvenido Manuel M. Biona, Anthony S. F. Chiu
Publication title: Journal of Cleaner Production 195(10): 532-539, September 2018
Abstract:
The emissions trading system is one of the primary instruments of the European region to achieve emissions reduction targets. As an alternative, some scholars investigate the potential role of electricity trading on emissions reduction as well. Acknowledging the fact that renewable sources and technical expertise may be concentrated in a few geographical areas, cross-border electricity trading provides a means to exploit these renewable resources, and therefore increase the potential for cleaner production of electricity. In the research presented in this paper, we decompose the effects of electricity trading to changes in CO2 emissions of the top 20 electricity trading countries in the European region. We compare the contributions of electricity imports and exports to changes in carbon emissions with those of traditional drivers, e.g. energy intensity, economic activity and population growth. A novel identity function was formulated in this paper to include the effects of electricity imports and exports in the decomposition analysis, using the logarithmic mean divisia index. Our results show that the European region offset approximately 10.3 MtCO2 from 1990 to 2014 due to electricity trading. This is because of large clean energy exports from France, Sweden and Switzerland. However, some countries have been adversely affected by electricity exporting, significantly increasing their emissions. In some countries, the increases in carbon emissions due to electricity exporting even outweighed increases due to population growth. To conclude, we discuss policy and wider implications for sustainable practice of electricity trading in the context of emissions reduction.
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Article title: Driving forces of Iran's CO2 emissions from energy consumption: An LMDI decomposition approach
Authors: Babak Mousavi, Neil Stephen A. Lopez, Jose Bienvenido Manuel Biona, Anthony S. F. Chiu, Markus Blesl
Publication title: Applied Energy 206:804-814, November 2017
Abstract:
In order to address climate change in an effective manner, it is essential to quantify driving forces of CO2 emissions in the fossil-fuel rich countries. Iran is among the top ten CO2 emitting countries. Moreover, it has the largest natural gas reserve and the fourth largest oil reserve in the world. However, there is a lack of comprehensive analytical studies on quantifying the contributions of key drivers to Iran’s CO2 emissions. This study fills this gap and performs in a systematic manner three variations of decomposition analyses on driving forces of carbon emissions from 2003 to 2014 due to energy consumption of the industry, driving forces of carbon intensity of the electricity generation, and key drivers of carbon emissions due to total fossil fuel combustion. In addition, the other novelty of this study is inclusion of the effect of electricity import and export in the decomposition analysis, which opens important avenues for analysis of emissions’ driving factors in countries currently engaged, or will engage in electricity trade. In the discussion of results, we take an international perspective and discuss findings pertaining to Iran as a fuel-rich country. Furthermore, we demonstrate real applications of decomposition analysis in policymaking using real experiences of Iran. Major findings highlight that the main driver to Iran’s CO2 emissions is increased consumption, which was responsible for an additional 201.5 MtCO2 since 2004, while technology-related improvements (e.g. energy mix) were only able to offset 7.7 MtCO2. Additional natural gas capacity, especially in the transport sector helps improve the energy mix, but would require more. Insights on electricity trading and hydropower are also presented, before we end with appropriate policy implications.
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Article title: Decomposition analysis of Philippine CO2 emissions from fuel combustion and electricity generation
Authors: Ana Karmela Sumabat, Neil Stephen Lopez, Krista Danielle Yu, Han Hao, Richard Li, Yong Geng, Anthony S. F. Chiu
Publication title: Applied Energy 164:795-804, February 2016
Abstract:
In order to address climate change and attain sustainable growth, there is a need to quantify driving factors in CO2 emissions in the developing countries. While information for accounting of Philippine CO2 emissions are abound, there is a lack of analytical studies on the driving forces. In this study, the logarithmic mean Divisia index (LMDI) is used to quantify the driving forces of changes in Philippine CO2 emissions from 1991 to 2014. The top-down approach described from 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines was used to estimate CO2 emissions from national fuel combustion and electricity generation. Results affirm the negative impacts of economic growth and higher standard of living to CO2 emissions, and reveal the significant damages inconsistent energy structures deliver to the emissions performance of a country. This has never been highlighted in previous studies in ASEAN and other developing countries. Policies to protect the energy structure from fluctuating oil prices, to improve energy planning capabilities, and to promote industrial symbiosis are recommended. On the other hand, the contribution of economic activity and energy intensity to CO2 emissions offset each other.
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Article title: Design of modified Magnus wind rotors using computational fluid dynamics simulation and multi-response optimization
Authors: Neil Lopez, Brian Mara, Brian Mercado, Luigi Mercado, Miguel Pascual, and Michael Angelo Promentilla
Publication title: Journal of Renewable and Sustainable Energy 7(6):063135, November 2015
Abstract:
Concerns on climate change and dwindling fossil fuel supply have renewed interest on alternative ways of harnessing renewable energy. Using rotating cylinders to generate lift from a fluid stream, a Magnus rotor can produce up to 10 times more lift compared to an airfoil. However, it is also producing more drag. Recent studies have demonstrated improvement on the aerodynamic efficiency of a Magnus rotor through the application of surface modifications such as grooves, bumps, dimples, and even changing the shape of the cylinder into a frustum. However, it is unknown which is most desirable among those modifications; moreover, if some may be combined for even better performance. This present study seeks to fill the mentioned research gap with the aid of computer simulation tool ANSYS CFX. Simulation results showed that modifying cylinder shape into a frustum generates the most lift force. However, it is also increasing the drag on the cylinder. Interestingly, a helical groove may be employed around the frustum cylinder to mitigate the increase in drag, making the two modifications a promising combination. Multiple response surface analysis using desirability function was used to investigate the sensitivity of the rotor design to the different modifications. Furthermore, a new perspective is introduced wherein the rotor may be able to withstand more drag in exchange for more lift. For lift generation purposes, bumps are not desirable.
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