Combined Heat And Power System Research Articles

Assessing the Effects of Uncertain Energy and Carbon Prices on the Operational Patterns and Economic Results of CHP Systems

In the power and heat sectors, the uncertainty of energy and carbon prices plays a decisive role in the rationale for decommissioning/repurposing coal-fired CHP (combined heat and power) systems and on investment decisions of energy storage units. Therefore, there is a growing need for advanced methods that incorporate the stochastic disturbances of energy and carbon emission prices into the optimization process of an energy system. In this context, this paper proposes an integrated method for investigating the effects of uncertain energy and carbon prices on the operational patterns and financial results of CHP systems with thermal energy storage units. The approach combines mathematical programming and Monte Carlo simulation. The computational process generates feasible solutions for profit maximization considering the technical constraints of the CHP system and the variation of energy and carbon emission prices. Four scenarios are established to compare the operational patterns and economic performance of a CHP system in 2020 and 2030. Results show that in 2020, there is an 80% probability that the system’s annual profit will be less than or equal to €30.98 M. However, at the same probability level, the annual profit in 2030 could fall below €11.88 M. Furthermore, the scenarios indicate that the incorporation of a thermal energy storage unit leads to higher expected profits (€0.74 M in 2020 and €0.71 M in 2030). This research shows that coal-fired CHP plant operators will face costly risks and potentially greater challenges in the upcoming years with the increasing regulatory and financial pressure on CO2 emissions and the EU’s plan of phasing out fossil fuels from electricity and heat generation.

Optimization of a 30 kW SOFC combined heat and power system with different cycles and hydrocarbon fuels

Solid oxide fuel cells (SOFCs) could generate power cleanly and efficiently by using a wide range of fuels. Through the recovery and utilization of the energy in the SOFC tail gas, SOFC combined heat and power (CHP) systems achieve efficient cascade utilization of fuels. In this article, an efficient 30 kW SOFC CHP system with multiple cycles is designed based on a commercial kw-level SOFC device. The energy and substances could be recycled at multiple levels in this system, which makes the system do not need external water supply anymore during working. Meanwhile, the performance, fuel applicability, flexibility and reliability of the system are investigated. Finally, an optimized operating condition is confirmed, in which the electrical efficiency is 54.0%, and the thermoelectric efficiency could reach 88.8% by using methanol as fuel.

Synthesize a Sustainable Supply Chain of Biomass to Electricity via Mathematical Approach

The huge amount of biomass waste and palm oil mill effluent (POME) generated during oil extraction has prompted the need for a more sustainable framework in waste management. Since oil palm biomass waste is rich in lignocellulosic content, it can be potential to be converted into green energy such as bioelectricity via different pathway of processes such as the thermal conversion pathway and biochemical conversion pathway. This study proposes a mathematical approach to synthesise a sustainable supply chain of biomass to electricity by implementing the combined heat and power (CHP) system in palm oil mill. The optimum pathway of supply chain based on the technical, economical, and environmental aspects is generated. The purpose of this approach is to assists the industry players or owners to make decision in choosing the location of the pre-treatment technology, transportation method, location of power plant and configuration of CHP. A generic superstructure is first developed to achieve the objective. Then, a series of generic mathematical equations will then be formulated based on the pathways demonstrated in the generic superstructure. The mathematical equations involve general mass and energy balance, cost computation and carbon emission. The fuzzy optimisation concept will be adopted in this research to trade-off the conflicting objectives (maximize profit and minimize carbon footprint) in order to generate the optimum pathway. A palm oil-based bioelectricity supply chain case study in Selangor, Malaysia is solved to illustrate the presented approach. According to the optimised result in this case study, a total of 3,753.36 MW of bioelectricity can be generated per year. The result proved that the optimum pathway is feasible by comparing with the existing oil palm biomass-based power plant in Sarawak, where only 375 MW of electricity is generated by oil palm biomass. On the other hand, RM 7.25 million per year of net profit is estimated with a payback period of 2.81 years. Moreover, the CHP system is able to achieve 570 million kg CO2 per year.

MW cogenerated proton exchange membrane fuel cell combined heat and power system design for eco-neighborhoods in North China

Buildings account for most of the greenhouse gas (GHG) emissions causing global warming. The development of eco-neighborhood can improve the energy efficiency of buildings and reduce GHG emissions. A combined heat and power (CHP) system based on proton exchange membrane fuel cells (PEMFCs) is designed to supply electricity and thermal for eco-neighborhood in North China with low GHG emissions. Effects of different inlet parameters, such as PEMFC inlet pressure and current density, on multi-stack CHP system performance are discussed. Coupled with a dynamic load scenario, the adaptability of the designed PEMFC-CHP system is studied through PI control with an electricity-led strategy and a thermal-led strategy. Both strategies can effectively reduce GHG emissions and the eco-neighborhood with PEMFC-CHP system is more environmental friendly compared to conventional energy supply. The electricity-led strategy can satisfy the energy consumption of the eco-neighborhood but with thermal waste. The energy consumption for most of the time during a year can be satisfied by the PEMFC-CHP system under the thermal-led strategy, but the electricity gap exists as the thermal demand is lower. Under the electricity-led strategy, the GHG emission reduction of the eco-neighborhood under electricity-led strategy and thermal-led strategy are around 7000 ton and 5000 ton per year, respectively.

Heat transfer and economic analyses of using various nanofluids in shell and tube heat exchangers for the cogeneration and solar-driven organic Rankine cycle systems

Abstract This project attempts to evaluate the effect of nanofluids on thermal performance and the economic parameters of shell and tube heat exchangers. First, two thermodynamic processes including combined heat and power (CHP) system and solar-driven organic Rankine cycle (ORC) are simulated using the Aspen HYSYS. The CHP and ORC systems can produce 25 MW and 175.8 kW of electrical power, respectively. Thereafter, to use the nanofluids in the heat exchangers of these systems, the thermophysical specifications are modeled in the MATLAB software and validated with previous investigations. For this purpose, four kinds of nanofluids consisting of Al2O3/H2O, TiO2/H2O, Cu/H2O and Ag/H2O are utilized. According to the results, by adding the nanoparticles to the base fluid, the thermal conductivity, viscosity, heat transfer coefficient and density increase and the heat capacity reduces. The economic assessment and parametric analysis on concentration of the nanoparticles are conducted. The variations of concentration of nanoparticles are taken to be 0.5–4%. It was found that in ORC system, by employing 1% concentration of Ag/H2O, Cu/H2O, Al2O3/H2O and TiO2/water nanofluids, the overall cost is reduced by 3.1%, 1.9%, 1.2% and 0.9%, respectively. Also, in CHP system, at a concentration of 2% for Ag/water, Cu/water Al2O3/water and TiO2/water nanofluids, the total cost decreases by 4.4%, 3%, 1% and 0.5%, respectively. It was denoted that the utilization of nanofluids in thermodynamic cycles can considerably reduce the total cost of heat exchangers and the whole process.

Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger

We analyzed the potential of thermoelectrics for electricity generation in a combined heat and power (CHP) waste heat recovery system. The state-of-the-art organic Rankine cycle CHP system provides hot water and space heating while electricity is also generated with an efficiency of up to 12% at the MW scale. Thermoelectrics, in contrast, will serve smaller and distributed systems. Considering the limited heat flux from the waste heat source, we investigated a counterflow heat exchanger with an integrated thermoelectric module for maximum power, high efficiency, or low cost. Irreversible thermal resistances connected to the thermoelectric legs determine the energy conversion performance. The exit temperatures of fluids through the heat exchanger are important for the system efficiency to match the applications. Based on the analytic model for the thermoelectric integrated subsystem, the design for maximum power output with a given heat flux requires thermoelectric legs 40–70% longer than the case of fixed temperature reservoir boundary conditions. With existing thermoelectric materials, 300–400 W/m2 electrical energy can be generated at a material cost of $3–4 per watt. The prospects of improvements in thermoelectric materials were also studied. While the combined system efficiency is nearly 100%, the balance between the hot and cold flow rates needs to be adjusted for the heat recovery applications.

Optimal Planning for the Cogeneration Energy System using Energy Hub Model

Cogeneration or combined heat and power (CHP) energy system could concurrently produce electrical and heat energies. Nonetheless, its integration in energy planning would need to consider interactions with other energy carriers, energy storages, and transmission networks. Previous works have used energy hub (EH) modelling to optimise the energy flow in a CHP energy system with predetermined energy components. In this paper, an Optimal Cogeneration Model (OCM) is proposed to consider the EH design which (1) enables the flexible selection between different energy transformation technologies, then (2) minimises the cost and environmental emission constraints concerning the technical characteristics and operating conditions of the selected EH components. Mixed-integer linear programming (MILP) has been used to model the optimisation problem in GAMS software. Based on the case study, an EH with CHP and energy storage system (ESS) has been developed with the minimised total annual cost (TAC) of 27.02 x 106 MYR/y for a pharmaceutical facility. The research output - the developed OCM serves as an integrated analysis tool for potential cogenerators to plan and determine the economic feasibility of CHP implementation.

Technical, economic and environmental analyses of combined heat and power (CHP) system with hybrid prime mover and optimization using genetic algorithm

In this study, a new arrangement of combined heat and power (CHP) system with combination of two prime mover has been investigated. The proposed system includes gas engine (GE) and gas turbine (GT) with different capacities. Because of the importance of pollution and global warming topics, the main purposes of this study are reducing the fuel consumption, increase of system efficiency and consequently reducing production of pollutants. Then, by changing parameters such as the generator's capacity, part load operation, pressure ratio, compression ratio, and the output temperature of the combustion chamber, the CHP system is optimized by using the genetic algorithm method. In the next step, two new parameters for comparing the efficiency of hybrid system relative to the common CHP system is introduced. Also, the emission reduction at different operating modes are evaluated. The results show that the use of the proposed CHP system with hybrid prime mover will increase the efficiency by 10%. The optimization results also suggest that the proposed system reduces the operational costs about 67.52% and fuel energy saving ratio about 49.08%. In addition, the rate of return and the payback period are calculated 30% and 3.67 years, respectively.

Techno-economic assessment of a hybrid RO-MED desalination plant integrated with a solar CHP system

In this study, an existing thermal multi-effect distillation (MED) plant was assumed to be integrated with reverse osmosis (RO) desalination system in a way that both heat and electricity demands of the hybrid RO-MED plant could be provided by a solar combined heat and power (CHP) system composed of parabolic trough concentrators (PTCs). For this purpose, the climatic conditions of Bushehr province (latitude 28.7621° N; longitude 51.5150° E), located in the south of Iran, was considered as the case study, and the water demand of 1,000 m3/day was assumed. In the first step, new algorithms were developed to integrate RO and MED desalination plants, and an incorporated thermal energy storage (TES) system was designed using the MATLAB program. Additionally, the whole system including the RO-MED plant and the solar CHP system was mathematically modeled and their performance was technically and economically evaluated. To perform this, four scenarios including recovery values for RO and MED as 50% and 30% (scenario 1), 50% and 35% (scenario 2), 55% and 30% (scenario 3), and 55% and 35% (scenario 4) were deemed. The results revealed that, first of all, the fourth scenario yields the highest total recovery amounts in all considered shares of freshwater production between two desalination plants. Secondly, under this scenario, the optimum total recovery can be obtained when each desalination plant produces 50% of the required freshwater, leading to a 15% rise in total recovery in hybrid mode, compared to the use of a single MED unit. Moreover, it was found that the integration of the TES unit can extend the working hours of the system by 30% under daylight irradiation. From calculations, the number of required PTCs in the solar field was calculated as 188 with a total aperture area of 17,869 m2. The economic evaluation of the designed system illustrated that the integration of a RO plant with an existing MED system could reduce the total cost of the produced freshwater for 6700 people from 2.08 US$/m3 for a single solar-powered MED plant to 1.918 US$/m3 for the solar-powered RO-MED plant.

Thermodynamic optimization on supercritical carbon dioxide Brayton cycles to achieve combined heat and power generation

The development of combined heat and power (CHP) systems based on the supercritical carbon dioxide (SCO2) Brayton cycle is important to enhance the energy utilization efficiency and satisfy different energy demands. Therefore, this study summarizes and compares the SCO2 CHP configurations in terms of back-pressure heating (system without pre-cooler (PC)) and extraction heating CHP types (system with PC). The configurations proposed in previous studies and new configurations proposed in this work are involved. Thermodynamic analysis models are developed, and the genetic algorithm is used to optimize the multi-parameters of SCO2 CHP configurations to reach the highest exergy efficiency. For the back-pressure CHP type, the configuration based on the SCO2 recompression–reheat cycle has the highest exergy efficiency of 44.1%, which can generate 219.5 MW of power under the selected heat load of 300 MW. For the extraction CHP type, the demands of 300 MW heat and 315 MW electricity are selected as the comparison condition. Under the comparison condition, the energy and exergy efficiencies of the configuration E-2 proposed in this study are respectively 73.9% and 40.8%. The configuration E-2 is integrated by the recompression-intercooling cycle, high-pressure extraction heating and reheat. Moreover, exergy losses and destruction within the SCO2 CHP system are analyzed to reveal its energy-saving mechanism in this study.

Feasibility Study and Economic Analysis of a Fuel-Cell-Based CHP System for a Comprehensive Sports Center with an Indoor Swimming Pool

Unlike a general commercial building, heating for a building with an indoor swimming pool is highly energy-intensive due to the high energy demand for swimming water heating. In Korea, the conventional heating method for this kind of building is to use boilers and heat storage tanks that have high fuel costs and greenhouse gas emissions. In this study, a combined heat and power (CHP) system for such a building using the electricity and waste heat from a Phosphoric Acid Fuel Cell (PAFC) system was designed and analyzed in terms of its primary energy saving, CO2 reduction, fuel cell and CHP efficiency, and economic feasibility. The mathematical model of the thermal load evaluation was used with the 3D multi-zone building model in TRNSYS 18 software (Thermal Energy System Specialists, LLC, Madison, MI, USA) to determine the space heating demand and swimming pool heat losses. The energy efficiency of the fuel cell unit was evaluated as a function of the part-load ratio from the operating data. The fundamental components, such as the auxiliary boiler, thermal storage tank, and heat exchanger are also integrated for the simulation of the system’s operation. The result shows that the system has a high potential to improve the utilization efficiency of fuel cell energy production. Referring to the local condition of the energy market in Korea, an economic analysis was also carried out by using a specific FC-CHP capacity at 440 kW. The economic benefit is significant in comparison with a conventional heating system, especially for the full-time operating (FTO) mode. The net profit made by comparison with the conventional energy supply system is about 178,352 to 273,879 USD per year, and the payback period is expected to be 6.9 to 10.7 years under different market conditions.

The tests of micro-CHP prototype with SI engine powered by LPG and natural gas

This paper presents the experimental results of a Combined Heat and Power (CHP) prototype based on a SI V-twin internal combustion engine driving a synchronous generator. The paper presents the criteria that were used to select the combustion engine and the electrical generator for the prototype. The internal combustion engine has been adapted to be fuelled by natural gas or LPG, with the possibility of controlling the load in two ways, i.e. by changing the throttle position (quantitatively) and/or the value of the excess air ratio by changing the fuel dose at a constant throttle position (qualitatively). The applied method of control allows to improve the efficiency of the engine especially in the range of partial loads. The experimental tests were carried out at a constant speed of 1500 rpm. During the tests, the fuel consumption of the internal combustion engine, the composition of the exhaust gas at the outlet of the exhaust system, the electrical parameters of the synchronous generator and the temperature at selected locations of the CHP system instance were measured. According to the obtained results, there was a slight increase in the efficiency of electricity generation with the application of the developed method of control of the combustion engine. The maximum power generation efficiency for Natural Gas (NG) was higher compared to LPG by more than 2 percentage points.

Renewable Energy-Based Systems on a Residential Scale in Southern Coastal Areas of Iran: Trigeneration of Heat, Power, and Hydrogen

The use of small-scale Combined Heat and Power (CHP) to meet the electrical and thermal needs of buildings has grown exponentially and plans have been made in Iran to expand these systems. In view of the above, in the present work, for the first time, sensitivity analysis has been performed on the parameters of natural gas price, annual interest rate, and the price of pollutant penalties. The CHP system studied included fuel cell, biomass generator, solar cell, wind turbine, and gas boiler. The techno-econo-enviro simulations were performed by HOMER software and the study area was Abadan. The use of a dump load to convert excess electricity into heat and heat recovery in a biomass generator and fuel cell are other advantages presented by the present work. The minimum Cost of Energy (COE) is 1.16 $/kWh. The results also showed that the use of biomass generators was economical when the annual interest rate was 30 %. The significant effect of using dump load on the required heat supply and the lowest price per kg of hydrogen produced equal to $ 35.440 are other results of the present work. In general, the results point to the superiority of solar radiation potential over wind energy potential of the study area and the prominent role of dump load in providing heat on a residential scale is clearly seen. Also, for the current situation, using biomass is not cost-effective.

Renewable hydrogen and ammonia for combined heat and power systems in remote locations: Optimal design and scheduling

AbstractUsing hydrogen (H) and ammonia (NH) for renewable energy storage has the potential to enable economical power and heat supply with high renewable penetrations, especially in remote locations which are characterized by high energy costs. In this work we assess the economic competitiveness of renewable combined heat and power (CHP) systems in Mahaka HI, Nantucket MA, and Northwest Arctic Borough (NWAB) AK by optimally designing these systems for scenarios in which power and heat can be purchased over a range of historical energy prices as well as when 100% renewable supply is required. We use a combined optimal design and scheduling model which minimizes annualized net present cost by determining optimal technology selection and size simultaneously with optimal schedules for each period of a system operating horizon aggregated from full year hourly resolution data via a consecutive temporal clustering algorithm. We find that renewable generation meets at least 85% of power demands and 75% of heat demands under the lowest energy prices investigated. Higher conventional energy prices lead to increased renewable penetration which is facilitated by renewable NH as a seasonal energy storage medium, as are 100% renewable CHP systems. NH is used for power generation with heat cogeneration in all three locations, as well as directly for heating in NWAB. On an annual cost basis, NH‐enabled 100% renewable CHP is only 3% more expensive in Mahaka and NWAB than systems which can purchase energy at the lowest prices, while it is 15% more expensive in Nantucket.

Combined heat and power as a platform for clean energy systems

Many regions and countries including Europe, China, Japan, and Canada are expanding their combined heat and power (CHP) systems, often coupled with renewable fuels, to provide platforms for clean energy. In the United States, however, CHP market shares are. A cost-benefit analysis of CHP systems in Georgia (an industry-heavy state in the Southeastern U.S.) suggests that the benefits from reduced fuel costs and steam production far exceed the CHP installation and O&M costs. We estimate other benefits, as well, including jobs, cleaner air, public health, and a 2–13% reduction in Georgia’s total carbon emissions. However, the capital-intensive nature of CHP systems can be difficult for host industries, and utilities are reluctant to purchase their excess electricity. Possible approaches to address these barriers include clean energy portfolio standards, regulatory reform, financial incentives such as tax credits. By developing a comprehensive case study methodology for evaluating the expansion of CHP systems, analysts can examine the costs and benefits of cogeneration in other regions with their particular industry profiles, fuel costs, and policies. Analysis of key stakeholders and policy options adds social and behavioral insights for the design of effective government interventions to capture the economic and social benefits of CHP systems.

A novel energy-water nexus based CHP operation optimization model under water shortage

A combined heating and power (CHP) system is a distributed energy system with the high energy efficiency and low pollutant emissions. CHP system was capable of supplying the electricity and heat to the users simultaneously and thus was widely applied in the industrial field. However, a large amount of water was exhausted during energy supply process in order to realize the temperature drop of system equipment and steam generation of waste heat boiler. Under the context of global water shortage crisis, the exploration in the relationship between the energy production and water consumption in CHP system was critical, with the aim of reducing water consumption amounts while meeting the user demand and maximizing system benefit as possible. This study selected the CHP system in an industrial park of Jinan City (Shandong Province, China) as the example, where hourly water consumption data of the CHP system throughout the year was available based on the site survey and literature review. The water consumption at each month was fitted firstly and determined to follow a normal distribution. Then, the water-consumption quota under various water guarantee rates was calculated by aid of mean value and variance coefficient. Finally, the relationship between energy supply and water consumption and the maximum water availability were innovatively incorporated into traditional CHP operation optimization model, where a novel energy-water nexus based CHP operation optimization model was formulated. The obtained results demonstrated that with the increase in the guarantee rate, the energy provision of the equipments and total system profit would increase, indicating that the water resource plays an important role in energy generation process. Compared with traditional operation optimization model, energy-water nexus based optimization model realized the balance between water resource protection and energy demand satisfaction and ensured normal operation of CHP system under strict water availability in the future.

Agro-Industrial Symbiosis and Alternative Heating Systems for Decreasing the Global Warming Potential of Greenhouse Production

Greenhouses require large amounts of energy, which is the dominant factor making greenhouses more emission intensive than open-field cultivation. Alternative heating systems, such as combined heat and power (CHP), biogas, and industrial waste heat, are continuously being researched for reducing the environmental impacts of greenhouses. This paper assesses utilizing industrial waste heat and CO2 enrichment in greenhouses as an example to propose “agro-industrial symbiosis” (AIS), to refer to a symbiotic co-operation between agricultural and industrial partners. The global warming potentials (GWPs) of greenhouse production using different heating systems are inadequately compared in the literature, which is the research gap addressed herein. Additionally, potential emission reductions of greenhouse production with industrial waste heat are yet to be assessed via lifecycle assessment (LCA). A comparative LCA of Finnish greenhouse tomato and cucumber production using various heating systems was conducted. Naturally, replacing fossil fuels with bioenergy and renewables significantly decreases the GWP. CHP systems result in decreased GWP only when using biogas as the energy source. Additionally, utilizing industrial waste heat and CO2 resulted in a low GWP. These results are applicable worldwide to guide political decision-making and clean energy production in the horticultural sector.

Energy, Exergy and economic analyses of a combined heat and power generation systems with a gas turbine and a horizontal axis wind turbine

Using the Combined Heat and Power (CHP) systems are known as one of the most effective ways to raise the power coefficient and reduce fuel consumption and operational costs. In this study, a CHP system with the prime movers of a gas turbine and a horizontal axis wind turbine under the strategy of providing electric charge has been investigated based on the first and second laws of thermodynamics. This study aims to evaluate the effect of a wind turbine on the CHP system. The results show that the proposed CHP system has significant advantages compared to the CHP system working without the wind turbine. The best operating condition for the wind turbine is at the wind speed of 12 m/s, the pitch angle of 5ο and the tip speed ratio of 3. Moreover, the effects of the wind speed and tip speed ratio on the exergy efficiency of the total system become considerable when the gas turbine works at the high-pressure ratios (more than 10) and the combustion chamber temperature below 1250οc. Also, it is shown this integrated system can reduce operational costs and fuel consumption by 55 % and 60%, respectively. Finally, regarding the interest rate, the payback period will be equal to 5.4 years.

State-by-State comparison of combined heat and power to photovoltaic installations at manufacturing facilities with heat and power loads

Manufacturing facilities with large electricity and steam loads commonly meet those loads with a grid and boiler (GB) system configuration. In this study, two alternatives, a natural gas turbine cycle driven combined heat and power (CHP) system configuration and a grid boiler system augmented with photovoltaics (GB-PV), are investigated sustainable manufacturing in reference to the GB system configuration. For this purpose, their discounted payback period (DPP), carbon dioxide (CO2) and nitrogen oxides (NOx) emission reductions, and primary fossil energy impacts are calculated. The major contribution of this study is that it directly compares the application of both CHP and PV technologies at an assumed manufacturing facility in all 50 states of the United States. This highlights the location-specific impacts of the facility. The examined manufacturing facility utility requirements are 5 MW of power and over 12,000 kg/h of 250 kPa and 400 K saturated steam. A DPP of less than 25 years, the technology lifetime, is found in 44 states for the CHP system configuration and 6 states for the GB-PV system configuration. GB-PV and CHP cost-effectively reduce CO2 in 44 and 38 states, respectively. CHP is better for NOx reduction, whereas GB-PV is better for primary fossil energy reduction.

Multi-objective optimization of an integrated biomass waste fixed-bed gasification system for power and biochar co-production

In this work, an integrated biomass waste gasification combined heat and power (CHP) system is simulated and analyzed based on a multi-scale first-principles numerical model, which consists of a 1D fixed-bed gasifier model and a 1D hybrid peripheral fragmentation and shrinking-core biomass particle model. The simulations are based on a 15kW gasification CHP system and the numerical model is validated by two different groups of experimental data, and the maximum deviation is 2.56% in syngas H2 composition prediction. A multi-objective optimization framework of the integrated biomass waste gasification CHP system is formulated that considers 3 objectives: economic benefit, greenhouse gas emission, and potential health impact caused by PM emission. The best-compromised solution from the Pareto front leads to $142.8/day economic benefit, 694.3 kg CO2eq/day mitigation, and 57.67 Singapore Pollutant Standards Index score. The impacts of the three objectives on decision variables (i.e., feedstock flowrate, feedstock moisture content, and equivalent ratio) are analyzed by investigating 21 different weighted single-objective problems.