Renewable Natural Gas Research Articles

Thermophilic Fungi as the Microbial Agents of Choice for the Industrial Co-Fermentation of Wood Wastes and Nitrogen-Rich Organic Wastes to Bio-Methane.

The novel industrial approach of co-fermenting wood wastes with agricultural wastes that are rich in nitrogen such as animal manures to produce bio-methane (renewable natural gas) fuel via thermophilic anaerobic digestion mimics an analogous process occurring in lower termites, but it relies instead on thermophilic fungi along with other thermophilic microorganisms comprising suitable bacteria and archaea. Wood microbial hydrolysis under thermophilic temperatures (range of 55 °C to 70 °C) and aerobic or micro-aerobic conditions constitutes the first step of the two-step (hydrolysis and fermentation) dry thermophilic anaerobic digestion industrial process, designated as "W2M3+2", that relies on thermophilic fungi species, most of which grow naturally in wood piles. Eleven thermophilic fungi have been identified as likely agents of the industrial process, and their known growth habitats and conditions have been reviewed. Future research is proposed such that the optimal growth temperature of these thermophilic fungi could be increased to the higher thermophilic range approaching 70 °C, and a tolerance to partial anaerobic conditions can be obtained by modifying the fungal microbiome via a symbiotic existence with bacteria and/or viruses.

The development of data-intensive techno-economic models for the comparison of renewable natural gas production from six different biomass feedstocks for the decarbonization of energy demand sectors

Renewable natural gas (RNG) from biomass can be used as an alternative to natural gas. However, there is limited understanding of the economic viability of RNG production from a wide range of feedstocks. In this study, a comprehensive comparative techno-economic assessment of RNG production via gasification from six biomass feedstocks with a wide range of moisture contents and characteristics was conducted. The feedstocks studied are corn stover (CS), wheat straw (WS), whole forest (WF), forest residues (FR), cow manure (CM), and the organic fraction of municipal solid waste (OFMSW). The RNG production plants were simulated and the simulation results were used to develop techno-economic models for each feedstock to estimate the production cost of RNG. The pathways were compared in terms of RNG yield, RNG production quantity, electricity generation, as well as RNG production costs and cost components. Sensitivity analyses were conducted on a wide range of factors and effect of including cardon credit on the production cost were studied. RNG production costs from the gasification of the OFMSW and CS were lower than those of other feedstocks at 6.28 $/GJ and 6.32 $/GJ, respectively. If the avoided cost (as a source of revenue) of landfilling of the OFMSW or carbon credit (minimum 90 $/t CO2) is considered, the RNG production cost can be competitive with natural gas price (1.4 $/GJ). The information developed in study is critical for decision makers in policy formulation and investment decisions.

Assessment of the onshore storage capacity of hydrogen in Argentina’s natural gas fields

Increasing the proportion of electricity from renewable energy sources is critical for the reduction of CO 2 emissions required to meet the commitments of the Paris Agreement. However, intermittency in energy generation due to the daily and seasonal variability of wind and solar radiation is a major challenge. Addressing this issue requires the development of large-scale energy storage systems. Low-carbon hydrogen production and storage in geological reservoirs offers a potential seasonal energy storage solution. Here, we provide the first assessment of the underground storage capacity for hydrogen in Argentina and identify sites where future clusters of low-carbon hydrogen production could be co-located with suitable geological storage sites. We outline a production-based methodology that couples historical hydrocarbon production with remaining reserves to provide a reliable estimation of the amount of hydrogen that can be stored in each reservoir. Assuming a cushion gas requirement of 50%, our results show that a combined storage capacity of 2860 TWh of hydrogen exists. This far exceeds the requirements to meet the seasonal electricity demand for residential consumption in the country. The results of our sensitivity analysis show that the two most sensitive variables are temperature and compressibility, suggesting that high-pressure shallow reservoirs are most suitable for underground hydrogen storage. We additionally propose locations for two H 2 production and storage hubs that would permit the integration of storage sites with renewable developments and natural gas reserves that could be combined with carbon capture and storage to produce low-carbon hydrogen. Thematic collection: This article is part of the Hydrogen as a future energy source collection available at: https://www.lyellcollection.org/topic/collections/hydrogen

A Sustainable Approach to the Conversion of Waste into Energy: Landfill Gas-to-Fuel Technology

Landfill gas (LFG) is a methane-rich gas produced by the decomposition of organic waste in landfills. It has the potential to be a greenhouse gas, but it can also be a valuable source of energy. LFG can be used to generate electricity, heat, or fuel. Renewable natural gas, abundant in methane derived from organic matter or waste streams, can undergo processing to align with established specifications for conventional fossil natural gas pipelines and vehicle use. This article assesses the present state of understanding concerning the transformation of landfill gas into a valuable fuel resource. This study shows the methods for LFG collection and conversion into usable fuels, along with the environmental benefits and challenges associated with its utilization and usage. In this study, a thorough examination was conducted concerning the waste generated in residential communities, specifically within the rural districts of Adana, known as the Yedigoze region. This research focused on assessing the gas potential derived from these waste materials and their potential environmental implications when employed as a fuel source for municipal buses. The transitioning analysis of 50 diesel buses to compressed natural gas (CNG) buses resulted in a remarkable reduction of 950,625 kg of CO2 emissions in one year.

Carbon capture, circular utilization, and sequestration (CCCUS): A multifunctional technology coupling underground biomethanation with geothermal energy production

The urgent need to address climate change, driven by the increasing concentrations of greenhouse gases, has made it imperative for the world to focus on enhancing carbon emission mitigation and carbon utilization. Consequently, carbon-negative technologies have garnered significant attention, such as Carbon Capture, Utilization, and Storage (CCUS). In order to achieve the circular utilization of carbon and improve the economic viability of conventional carbon-negative technologies, this paper proposes the innovative concept of Carbon Capture, Circular Utilization, and Sequestration (CCCUS). This multifunctional carbon-negative technology couples underground biomethanation of carbon dioxide and hydrogen-rich industrial by-product gases with geothermal energy production. CCCUS also offers several additional functions, such as renewable natural gas storage, natural gas displacement, and carbon dioxide geological sequestration. Furthermore, a preliminary assessment of the techno-economic feasibility of CCCUS is undertaken. A numerical case study, conducted using the XGS gas storage in the Sichuan Basin, China, unveiled that over a 425-day period, the conversion ratio of carbon dioxide to methane in the working gas can achieve 98.9%. Moreover, the net present value (NPV) of CCCUS over a 30-year period is estimated to be approximately 4.67 × 108 CNY under the base scenario. These findings, along with field monitoring and laboratory experiments, preliminarily present evidence supporting the potential techno-economic feasibility of CCCUS. This paper offers a fresh perspective on the development of the circular carbon economy.

Genome-resolved correlation mapping links microbial community structure to metabolic interactions driving methane production from wastewater

Anaerobic digestion of municipal mixed sludge produces methane that can be converted into renewable natural gas. To improve economics of this microbial mediated process, metabolic interactions catalyzing biomass conversion to energy need to be identified. Here, we present a two-year time series associating microbial metabolism and physicochemistry in a full-scale wastewater treatment plant. By creating a co-occurrence network with thousands of time-resolved microbial populations from over 100 samples spanning four operating configurations, known and novel microbial consortia with potential to drive methane production were identified. Interactions between these populations were further resolved in relation to specific process configurations by mapping metagenome assembled genomes and cognate gene expression data onto the network. Prominent interactions included transcriptionally active Methanolinea methanogens and syntrophic benzoate oxidizing Syntrophorhabdus, as well as a Methanoregulaceae population and putative syntrophic acetate oxidizing bacteria affiliated with Bateroidetes (Tenuifilaceae) expressing the glycine cleavage bypass of the Wood–Ljungdahl pathway.

Development Progress of a 70% Efficient Hybrid SOFC-I.C. Engine Hybrid System for Stationary Applications up to 1 MW

Flexible and dispatchable, high-efficiency power generation supplied with carbon-neutral renewable fuels is needed to help enable defossilization of the electric grid. Pressurized, hybrid SOFC systems fueled with hydrogen, biogas, or renewable natural gas can generate clean power at ultra-high efficiency. This presentation presents an update on the development progress of a full-scale, hybrid system that targets low cost (<1000 $/kW) and ultra-high efficiency (70%-LHV) distributed power generation for applications up to 1 MW. The system features mature, metal-supported SOFC technology and the system design, control, hardware integration, and demonstration activities are funded by the U.S. DOE ARPA-E INTEGRATE Program. Some of the more novel aspects of the system include the intermediate operating cell temperature (600°C) and internal reforming capabilities which enable excellent thermal management and effectively reduce air preheater duty by >60% over more conventional SOFC systems operating near 800°C. Pressurization of the system decreases area specific resistance (ASR) and increases stack power density, thereby lowering capital cost. The use of a gasified diesel engine converts the residual chemical exergy in the anode tail-gas from the SOFC to drive auxiliaries and produce net additional power. Furthermore, the syngas engine enables a simple engine after-treatment for achieving ultra-low engine emissions (NOx, CO, PM, UHC). Updates on critical hardware advancements around pressurized multi-stack, 30 kW fuel cell modules, low-speed high efficiency rotating equipment, and ultra-high efficiency power electronics are provided. Results from experimental testing, system design and layout, and demonstration test facility capabilities are presented and discussed. The presentation concludes with a techno-economic outlook for such power generation systems in various stationary applications, as well as comparison with competing distributed generation technologies, such as solar PV-battery systems, microturbines, stationary engines, and non-hybridized SOFC technologies. Figure 1

Efficiency assessment of underground biomethanation with hydrogen and carbon dioxide in depleted gas reservoirs: A biogeochemical simulation

Underground biomethanation, which converts hydrogen and carbon dioxide to methane with the catalysis of methanogens in geological formations, has great potential for carbon dioxide utilization and sequestration, renewable natural gas production, and large-scale energy storage. However, the efficient conversion of hydrogen and carbon dioxide in a complex reservoir environment has not been explored. To address this issue, a novel biogeochemical model is developed for underground biomethanation that considers reservoir environment factors (e.g. pH, temperature, and salinity) and integrated into PHREEQC software. The biogeochemical model is validated with a laboratory experiment and utilized to investigate the effects of reservoir parameters and injection parameters on biomethanation efficiency in depleted gas reservoirs. Results show that the biomethanation efficiency is 94.2% after 360 days in both sandstone and carbonate reservoirs. Underground biomethanation can be completed in 30 days if initial biomass and optimum specific growth rate increase and decay rate decreases. Additionally, the optimal ratio of injected hydrogen and carbon dioxide for biomethanation is greater than 4:1 and increases with total pressure if it is above 70 atm. To improve the biomethanation efficiency, this study suggests utilizing geothermal energy and pre-injecting highly active methanogens cultured on the ground before mixed gas injection.

The more effective option to combat environmental degradation: Energy efficiency vs. renewable energy vs. natural gas?

Environmental degradation has become one of the major challenges facing the global community. This paper aims to explore the more effective options to combat environmental degradation by investigating the linearity and nonlinearity (trade openness set as a threshold variable) of energy efficiency, natural gas, renewable energy and ecological footprint. To this end, linear and non-linear panel models were constructed using panel data from 60 countries. The results of the linear analysis show that improving energy efficiency, and increasing the consumption of natural gas and renewable energy are conducive to inhibiting environmental degradation. Energy efficiency has the most significant negative correlation with ecological footprint, followed by renewable energy, and then natural gas, implying that improving energy efficiency and developing renewable energy is a more effective strategy to combat environmental degradation. The results of the nonlinear analysis show that there are threshold effects of trade openness between energy efficiency and ecological footprint, and between renewable energy and ecological footprint. The negative impact of both renewable energy and energy efficiency on the ecological footprint increases when trade openness exceeds the threshold. This suggests that, in terms of curbing environmental degradation, enhancing trade openness may further increase the negative impacts of energy efficiency and renewable energy on ecological footprint. At the same time, this confirms the positive role of trade openness in environmental protection.

The nature of carbon deposits and their formation pathways during catalytic supercritical water gasification of glycerol

Supercritical water gasification (SCWG) is a promising technology to convert wet biomass to renewable natural gas. The present study sheds light on the chemical composition and the formation mechanism of coke deposits on a Ru/CNF catalyst during continuous SCWG of glycerol in a fixed-bed reactor. SCWG experiments were performed using pristine carbon nanofibers (CNF) and 5 wt% Ru/CNF catalysts, which suffered from partial deactivation. Transmission electron microscopy (TEM) indicated a 34–42 % dispersion loss independently of the conditions, only partially explaining the activity loss observed during the test at very high space velocity. When operated under thermodynamic conditions, no deposits could be observed. A nanometric layer of deposits on the catalysts was present under intermediate conditions, while in the kinetic regime (conversion of glycerol down to 4 %), significant carbon deposition was observed. The chemical compositions of aqueous phases and organic deposits extracted from the catalysts and support showed that the presence of Ru enhanced the formation of unsaturated compounds from glycerol. In particular, molecules containing aromatic rings were detected. The space velocity significantly affected the composition of the coke deposits. The number of carbons in the molecules increased from 5–25 to 10–45 when moving away from the thermodynamic regime (full conversion), and the O/C ratio significantly decreased from 0.3–0.6 to 0.05–0.3, maintaining a very broad H/C ratio. The extracted organic deposits contained various aromatic compounds but were mostly represented by unsaturated aliphatic compounds. All these results were used to elucidate a reaction pathway for the formation of organic deposits from glycerol.

While some tout “renewable natural gas” as a way to mitigate climate change, others see a false solution

While some tout “renewable natural gas” as a way to mitigate climate change, others see a false solution

Enabling hydrate-based methane storage under mild operating conditions by periodic mesoporous organosilica nanotubes

Biomethane is a renewable natural gas substitute produced from biogas. Storage of this sustainable energy vector in confined clathrate hydrates, encapsulated in the pores of a host material, is a highly promising avenue to improve storage capacity and energy efficiency. Herein, a new type of periodic mesoporous organosilica (PMO) nanotubes, referred to as hollow ring PMO (HR-PMO), capable of promoting methane clathrate hydrate formation under mild working conditions (273 K, 3.5 MPa) and at high water loading (5.1 g water/g HR-PMO) is reported. Gravimetric uptake measurements reveal a steep single-stepped isotherm and a noticeably high methane storage capacity (0.55 g methane/g HR-PMO; 0.11 g methane/g water at 3.5 MPa). The large working capacity throughout consecutive pressure-induced clathrate hydrate formation-dissociation cycles demonstrates the material’s excellent recyclability (97% preservation of capacity). Supported by ex situ cryo-electron tomography and x-ray diffraction, HR-PMO nanotubes are hypothesized to promote clathrate hydrate nucleation and growth by distribution and confinement of water in the mesopores of their outer wall, along the central channels of the nanotubes and on the external nanotube surface. These findings showcase the potential for application of organosilica materials with hierarchical and interconnected pore systems for pressure-based storage of biomethane in confined clathrate hydrates.

Harvested winter rye energy cover crop: multiple benefits for North Central US

Cover crops (CCs) can reduce nitrogen (N) loss to subsurface drainage and can be reimagined as bioenergy crops for renewable natural gas production and carbon (C) benefits (fossil fuel substitution and C storage). Little information is available on the large-scale adoption of winter rye for these purposes. To investigate the impacts in the North Central US, we used the Root Zone Water Quality Model to simulate corn-soybean rotations with and without winter rye across 40 sites. The simulations were interpolated across a five-state area (IA, IL, IN, MN, and OH) with counties in the Mississippi River basin, which consists of ∼8 million ha with potential for rye CCs on artificially drained corn-soybean fields (more than 63 million ha total). Harvesting fertilized rye CCs before soybean planting in this area can reduce N loads to the Gulf of Mexico by 27% relative to no CCs, and provide 18 million Mg yr−1 of biomass-equivalent to 0.21 EJ yr−1 of biogas energy content or 3.5 times the 2022 US cellulosic biofuel production. Capturing the CO2 in biogas from digesting rye in the region and sequestering it in underground geologic reservoirs could mitigate 7.5 million Mg CO2 yr−1. Nine clusters of counties (hotspots) were identified as an example of implementing rye as an energy CC on an industrial scale where 400 Gg yr−1 of rye could be sourced within a 121 km radius. Hotspots consisted of roughly 20% of the region’s area and could provide ∼50% of both the N loss reduction and rye biomass. These results suggest that large-scale energy CC adoption would substantially contribute to the goals of reducing N loads to the Gulf of Mexico, increasing bioenergy production, and providing C benefits.

Post-hydrolysis versus side-stream ammonia stripping in semi-continuous two-stage anaerobic digestion of high nitrogen feedstock

With the increased popularity of two-stage anaerobic digesters, post-hydrolysis ammonia stripping (PHAS) has resurfaced as a new possible treatment configuration. This study discusses for the first time the semi-continuous operation of PHAS and compares it with the most used stripping configuration nowadays, side-stream ammonia stripping (SSAS), under similar conditions using air or renewable natural gas (RNG) as stripping mediums. Ammonia stripping operating conditions were set to pH 9.5, 55 °C, and flowrate of 100 L gas/L/hour. RNG removed 50–58% of ammonia while air removed 70–78%. Interestingly, the PHAS system showed more flexibility and resilience than the SSAS system when testing parameters were changed. Volumetric and specific biogas production from PHAS and SSAS scenarios averaged up to 1.91 and 1.26 L/L/day and 831 and 701 L biogas/ kg VS/day under organic loading rates of 2.61 and 1.8 g VS/L/day, respectively.

Development Progress of a 70% Efficient Hybrid SOFC-I.C. Engine Hybrid System for Stationary Applications up to 1 MW

Flexible and dispatchable, high-efficiency power generation supplied with carbon-neutral renewable fuels is needed to help enable defossilization of the electric grid. Pressurized, hybrid SOFC systems fueled with hydrogen, biogas, or renewable natural gas can generate clean power at ultra-high efficiency. In this summary, we provide an update on the development progress of a full-scale, hybrid system that targets low cost (<1000 $/kW) and ultra-high efficiency (70%-LHV) distributed power generation for applications up to 1 MW. The system features pressurized, metal-supported SOFC technology from Ceres Power which is integrated with a modified diesel engine which converts the residual chemical exergy in the anode tail-gas from the SOFC to drive auxiliaries and produce net additional power. Updates on critical hardware advancements around pressurized multi-stack, 30 kW fuel cell modules, low-speed high efficiency rotating equipment, and ultra-high efficiency power electronics are provided. A techno-economic outlook for such power generation systems in various stationary applications.

Environmental life cycle assessment of treatment and management strategies for food waste and sewage sludge

A consequential life cycle assessment (LCA) was utilized to compare the environmental impacts of food waste and sewage sludge management strategies. The strategies included a novel two-phase anaerobic digestion (AD) system and alternatives including landfill, waste-to-energy, composting, anaerobic membrane bioreactor, and conventional AD (wet continuous stirred-tank reactor [CSTR]). The co-management of food waste with sewage sludge was also considered for the two-phase AD system and for a conventional AD reactor. A multidimensional LCA approach was taken, considering the five-midpoint impact categories of global warming, smog, human health particulate, acidification, and eutrophication estimated using the U.S. EPA Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts. Co-management of food waste and sewage sludge using the novel two-phase AD system was shown to maximize energy recovery and had a net global warming benefit while reducing other environmental impacts compared with the alternative management strategies. It had similar relative environmental advantages across all categories as conventional AD, with the advantage of a smaller physical footprint. However, both approaches featured net environmental burdens when the background electric grid intensity fell below 0.25 kg CO2-eq kWh−1, as could be expected in a decarbonized electric future. Upgrading the biogas produced from AD to renewable natural gas can displace the use of fossil natural gas for other non-electricity energy requirements that are difficult to decarbonize and may extend the time period of significant environmental benefits of utilizing AD for organic waste management. Treatment of the nutrient-rich supernatant generated by the novel two-phase AD system could be an obstacle for utilities with stringent nutrient discharge limits. Future research and full-scale implementation are needed to demonstrate the benefits of the two-phase AD system predicted through this analysis.

Cost and Life Cycle Analysis for Deep CO2 Emissions Reduction for Steel Making: Direct Reduced Iron Technologies

Among heavy industrial sectors worldwide, the steel industry ranks first in carbon dioxide (CO2) emissions. Technologies that produce direct reduced iron (DRI) enable the industry to reduce emissions or even approach net‐zero CO2 emissions for steel production. Herein, comprehensive cradle‐to‐gate (CTG) life cycle analysis (LCA) and techno‐economic analysis (TEA) are used to evaluate the CO2 emissions of three DRI technologies. Compared to the baseline of blast furnace and basic oxygen furnace (BF–BOF) technology for steel making, using natural gas (NG) to produce DRI has the potential to reduce CTG CO2 emissions by 33%. When 83% or 100% renewable H2 is used for DRI production, DRI technologies can potentially reduce CO2 emissions by 57% and 67%, respectively, compared to baseline BF–BOF technology. However, the renewable H2 application for DRI increases the levelized cost of steel (LCOS). When renewable natural gas (RNG) and clean electricity are used for steel production, the CTG CO2 emissions of all the DRI technologies can potentially be reduced by more than 90% compared to the baseline BF–BOF technology, although the LCOS depends largely on the cost of RNG and clean electricity.

Evaluation of Hydrogen Blend Stability in Low-Pressure Gas Distribution

Natural gas distribution companies are developing ambitious plans to decarbonize the services that they provide in an affordable manner and are accelerating plans for the strategic integration of renewable natural gas and the blending of green hydrogen produced by electrolysis, powered with renewable electricity being developed from large new commitments by states such as New York and Massachusetts. The demonstration and deployment of hydrogen blending have been proposed broadly at 20% of hydrogen by volume. The safe distribution of hydrogen blends in existing networks requires hydrogen blends to exhibit similar behavior as current supplies, which are also mixtures of several hydrocarbons and inert gases. There has been limited research on the properties of blended hydrogen in low-pressure natural gas distribution systems. Current natural gas mixtures are known to be sufficiently stable in terms of a lack of chemical reaction between constituents and to remain homogeneous through compression and distribution. Homogeneous mixtures are required, both to ensure safe operation of customer-owned equipment and for safety operations, such as leak detection. To evaluate the stability of mixtures of hydrogen and natural gas, National Grid experimentally tested a simulated distribution natural gas pipeline with blends containing hydrogen at up to 50% by volume. The pipeline was outfitted with ports to extract samples from the top and bottom of the pipe at intervals of 20 feet. Samples were analyzed for composition, and the effectiveness of odorant was also evaluated. The new results conclusively demonstrate that hydrogen gas mixtures do not significantly separate or react under typical distribution pipeline conditions and gas velocity profiles. In addition, the odorant retained its integrity in the blended gas during the experiments and demonstrated that it remains an effective method of leak detection.

Production of Electricity at the European Union Level vs. Romania

The purpose of this paper is to carry out a quantitative analysis of the electricity production at the level of the European Union (EU) and in Romania, in the period of 2011-2020. To address the current environmental concerns, the package “Fit for 55” proposes that by 2050, most of the energy production will have to come from renewable sources, but the question is whether this desideratum can indeed be achieved. Among the methods used in scientific research, the quantitative analysis was selected and applied in this paper, in order to carry out a detailed statistical analysis on the trend of increase or decrease in the electricity production from different energy resources, and then comparative analysis was performed, so as to draw relevant conclusions in this respect. Through this study, it can be found that, at the level of the European Union, the electricity production from renewable energy resources is increasing, while that from solid fossil fuels is decreasing. In Romania, the same trend of increase and decrease can be observed, except on a smaller scale. Accordingly, the greatest increase in electricity production was recorded from renewable energy resources, for both the EU and Romania, while the biggest decrease in electricity production from fossil fuels. In order to address the decarbonization of the energy system in Romania, the hypothesis that the decrease in total electricity production is due to the decrease in electricity production from solid fossil fuels was tested. However, this hypothesis was only partially confirmed, since the production of electricity from other energy resources, apart from renewable resources and natural gas, also experienced a similar downward trend.

Investigation of the relationship between renewable energy, natural gas, and coal consumption with economic growth in Turkey: evidence from augmented ARDL approach.

Energy is an indispensable requirement for the sustainable development of countries. Turkey has been trying to increase the use of renewable sources in electricity energy production with the policies it has implemented recently. This study investigates the effect of disaggregate energy consumption on economic growth in Turkey via the Augmented ARDL. Robust results are obtained by Augmented ARDL in econometric analysis. In this context, it is to examine the impact of renewable energy, natural gas, and coal consumption. Considering the 2001 crisis in Turkey, we add a dummy variable to the cointegration equation. The paper employs the recently developed augmented ARDL approach in the presence of one structural break to investigate annual time series data during the period 1988-2018. The results obtained in this study showed that all variables were statistically significant eventually. Long-term estimation results suggest that among the energy sources examined in the study, on economic growth has a positive effect coal consumption, natural gas consumption, and renewable energy. Moreover, empirical results indicated that economic growth and energy consumption also contribute to environmental damage. On the contrary, natural gas both increases economic growth and is effective in increasing environmental quality. The fact that the positive effect of renewable energy sources on economic growth eventually is greater than natural gas is the most striking finding of the study. In line with these results, it can be said that Turkey can reduce its energy dependence by increasing the use of domestic and renewable energy sources and providing sustainable economic growth.