IoT Sensor Challenges for Geothermal Energy Installations Monitoring: A Survey.

Geothermal energy installations are becoming increasingly common in new city developments and renovations. With a broad range of technological applications and improvements in this field, the demand for suitable monitoring technologies and control processes for geothermal energy installations is also growing. This article identifies opportunities for the future development and deployment of IoT sensors applied to geothermal energy installations. The first part of the survey describes the technologies and applications of various sensor types. Sensors that monitor temperature, flow rate and other mechanical parameters are presented with a technological background and their potential applications. The second part of the article surveys Internet-of-Things (IoT), communication technology and cloud solutions applicable to geothermal energy monitoring, with a focus on IoT node designs, data transmission technologies and cloud services. Energy harvesting technologies and edge computing methods are also reviewed. The survey concludes with a discussion of research challenges and an outline of new areas of application for monitoring geothermal installations and innovating technologies to produce IoT sensor solutions.

Return connectedness and multiscale spillovers across clean energy indices and grain commodity markets around COVID-19 crisis.

The aim of this paper is to examine the return connectedness and multiscale spillovers between the Clean Energy Index and the grain commodity market around COVID-19. Using daily data from January 4, 2017 to July 1, 2022, a time-varying parametric vector autoregressive (TVP-VAR) connectedness approach is first used to reveal connectedness patterns before and during COVID-19. We further used Baruník and Krehlík (2018)'s frequency domain spillover method to assess connectedness in different domain horizons. Our results show spillover effects over time and frequency, with COVID-19 significantly affecting the connectedness of the whole system. Dynamic connectedness peaks significantly after sudden bursts of COVID-19, validating the reported uncertainty. We also documented higher spillover levels in the short term than in the medium and long term. In addition, We find that (i) most clean energy indices are positively affected by the COVID-19 outbreak; (ii) the NASDAQ OMX Bio/Clean Fuels Index and NASDAQ OMX Geothermal Index send spillovers to all grain commodities throughout the sample period, while the WilderHill Clean Energy Index and NASDAQ OMX Wind Energy Index indices are the largest recipients of spillovers from other markets regardless of time horizon; (iii) the OMX Bio/Clean Fuels and OMX Geothermal Energy indices dominate spillover shocks to grain commodity markets. This is the first study to analyse the connectedness and time-frequency dynamics of returns in the green energy index and the grain commodity market. These results provide valuable insights to investors and key policymakers, especially at a time of more significant uncertainty.

A Monte Carlo based approach to the resource assessment of Jamaica's geothermal energy potential.

The Eastern Caribbean chain of islands is commonly known to exhibit high-enthalpy systems for geothermal energy exploitation. The northernmost Caribbean Community member state of Jamaica possesses physical manifestations of 12 hot springs across the island. Previous investigations indicate that of the potential 12 hot springs, Bath, Windsor and Milk River springs have cogent geothermometry of their thermal fluids with estimated temperature ranges of (80-102°C), (128-156°C), and (158-206°C), respectively. The paper provides numerical findings for each geothermal system of interest and performs Monte Carlo simulations to optimize calculated findings. The determined quantitative findings are considered under the context of environmental savings and policy regime conditions for driving geothermal energy development. The three areas of interest are situated within the Rio Minho Basin, the Dry Harbour Mountains and the Blue Mountain South Basin. Through the consideration of a 25-year lifetime for production, a collective total of 94.81 MWe of geothermal power reserves can be absorbed into the national energy mix, displacing an estimated 0.38 million barrels of oil imports, resulting in approximately 0.44 million tonnes of carbon dioxide emissions being avoided per year. This article is part of the theme issue 'Developing resilient energy systems'.

Environmental benefits from geothermal energy use with a well doublet located in the Szczecin Trough (NW Poland).

The article presents environmental aspects related to the use of geothermal waters of the Lower Jurassic in the area of the Szczecin Trough. The research area located in the north-western part of the country has been successfully using underground waters of the Lower Jurassic since the 1990s to generate thermal energy at two geothermal heating plants located in Pyrzyce and Stargard. In the case of the area in question, it was proposed a hypothetical geothermal doublet located in the vicinity of the city of Choszczno, for which numerical simulations were carried out for different variants of the locations of the wells and the intake capacity. On the basis of the obtained results, the environmental effect that could be achieved in the case of the analyzed investment was estimated. Reduction in pollutants emission might be expected on the global scale. Even taking into account the emission linked to the electricity consumed (more than 81% of electricity in 2020 in Poland was produced based on fossil fuels, the share of had coal is about half of them). Local reduction in emission is obvious, and it is strictly related to the amount of reduction of fuels consumption. Taking into account the health resorts and thermal pools that utilize groundwater operating in the Polish Lowlands, the chemical composition of the underground waters extracted in the region of Choszczno was also analyzed, and the possibilities of their use for therapeutic and balneotherapeutic purposes were indicated.

Total Site Heat Integration benefiting from geothermal energy for heating and cooling implementations.

Geothermal energy is a promising renewable energy source that has been developed by many countries in recent years. It can be utilised to meet various energy demand. This paper studies the performance of integrating geothermal energy in the Locally Integrated Energy Sector (LIES). The heating and cooling demand of various processes should be satisfied, and heat among processes should be recovered. This is done by using Grand Composite Curves and Total Site Profiles to visually illustrate how much load is required for utility systems. The geothermal utility system and steam utility system are compared. The integration plan for geothermal energy under different temperatures are studied. An illustrative case shows that by using this type of renewable energy under a specific and favourable condition, above 70% of steam utility load can be saved. The working cycle of using a geothermal utility system is studied by using the Time Slice model. The heat recovery plan for normal operation, mineral scaling, and cleaning periods are optimised. The minimum temperature for heat storage can also be identified.

Using DNA-barcoded Malaise trap samples to measure impact of a geothermal energy project on the biodiversity of a Costa Rican old-growth rain forest.

We report one year (2013-2014) of biomonitoring an insect community in a tropical old-growth rain forest, during construction of an industrial-level geothermal electricity project. This is the first-year reaction by the species-rich insect biodiversity; six subsequent years are being analyzed now. The site is on the margin of a UNESCO Natural World Heritage Site, Área de Conservación Guanacaste (ACG), in northwestern Costa Rica. This biomonitoring is part of Costa Rica's ongoing efforts to sustainably retain its wild biodiversity through biodevelopmental integration with its societies. Essential tools are geothermal engineering needs, entomological knowledge, insect species-rich forest, government-NGO integration, common sense, DNA barcoding for species-level identification, and Malaise traps. This research is tailored for integration with its society at the product level. We combine an academic view with on-site engineering decisions. This biomonitoring requires alpha-level DNA barcoding combined with centuries of morphology-based entomological taxonomy and ecology. Not all desired insect community analyses are performed; they are for data from subsequent years combined with this year. We provide enough analysis to be used by both guilds now. This biomonitoring has shown, for the first year, that the geothermal project impacts only the biodiversity within a zone less than 50 m from the project margin.

Health effects associated with short-term exposure to hydrogen sulfide from geothermal power plants: a case-crossover study in the geothermal areas in Tuscany.

OBJECTIVE: Thirty-four geothermal power plants for the production of electricity are currently active in the geothermal areas in Tuscany. The present study aimed to investigate the association between short-term exposure to hydrogen sulfide (H2S) and acute health outcomes. METHODS: This study used individual data on non-accidental, cardiovascular and respiratory mortality, urgent hospital admissions (HA) and emergency department (ED) visits for cardiorespiratory diseases occurring from 2000 to 2017. All cases were georeferenced and matched to daily H2S data, derived from 18 monitoring sites. A case-crossover design following the matched pair interval approach was applied and conditional logistic regression models were fitted to estimate odds ratios and their 90% confidence intervals, adjusting for a set of time-dependent variables, such as influenza epidemics, holidays and temperature. RESULTS: A total of 8054 deaths, 30,527 HA and 15,263 ED visits occurred. Mortality for non-accidental (OR = 1.11, 90% CI 1.02-1.22) and cardiovascular causes (OR = 1.22, 90% CI 1.03-1.44) were associated with an increase of 10 µg/m3 of H2S daily levels only among men. Hospital admissions for respiratory diseases were positively associated with H2S exposure: OR = 1.11 (90% CI 1.00-1.22) among women. No associations were observed in ED visits analyses. CONCLUSIONS: In this case-crossover study in the Tuscan geothermal areas, short-term exposure to H2S was weakly associated with some mortality and morbidity outcomes. Our findings did not show a clear pattern as the results were not homogeneous between mortality and morbidity data or between men and women.

Quantitative assessment of the environmental risks of geothermal energy: A review.

Over recent decades, the use of geothermal energy for heating supply and power generation has increased significantly across the world, owing to its low carbon emissions. However, a series of emerging environmental risks from geothermal energy development and operation have been drawing increasing attention from governments and the publics. In this context, the present study provides an overview of methods for quantitatively assessing the environmental risks of geothermal energy. These include seismic hazards, human health, ecological damage and economic loss. The constraints on constructing assessment frameworks are also discussed. Furthermore, a preliminary concept for an integrated framework is proposed to assess environmental risks of geothermal energy comprehensively from multiple perspectives. To enhance the accuracy and reliability of the proposed framework, a data-sharing platform needs to be built to develop multi-disciplinary modeling further.

Clay Composites for Thermal Energy Storage: A Review.

The development of novel materials and approaches for effective energy consumption and the employment of renewable energy sources is one of the current trends in modern material science. With this respect, the number of researches is focused on the effective harvesting and storage of solar energy for various applications. Phase change materials (PCMs) are known to be able to store thermal energy of the sunlight due to adsorption and release of latent heat through reversible phase transitions. Therefore, PCMs are promising as functional additives to construction materials and paints for advanced thermoregulation in building and industry. However, bare PCMs have limited practical applications. Organic PCMs like paraffins suffer from material leakage when undergoing in a liquid state while inorganic ones like salt hydrates lack long-term stability after multiple phase transitions. To avoid this, the loading of PCMs in porous matrices are intensively studied along with the thermal properties of the resulted composites. The loading of PCMs in microcontainers of natural porous or layered clay materials appears as a simple and cost-effective method of encapsulation significantly improving the shape and cyclic stability of PCMs. Additionally, the inclusion of functional clay containers into construction materials allows for improving their mechanical and flame-retardant properties. This article summarizes the recent progress in the preparation of composites based on PCM-loaded clay microcontainers along with their future perspectives as functional additives in thermo-regulating materials.

Spatial Distribution of Partner-Seeking Men Who Have Sex With Men Using Geosocial Networking Apps: Epidemiologic Study.

BACKGROUND: Geosocial networking apps have made sexual partner-seeking easier for men who have sex with men, raising both challenges and opportunities for human immunodeficiency virus and sexually transmitted infection prevention and research. Most studies on men who have sex with men geosocial networking app use have been conducted in large urban areas, despite research indicating similar patterns of online- and app-based sex-seeking among men who have sex with men in rural and midsize cities. OBJECTIVE: The goal of our research was to examine the spatial distribution of geosocial networking app usage and characterize areas with increasing numbers of partner-seeking men who have sex with men in a midsize city in the South. METHODS: Data collection points (n=62) were spaced in 2-mile increments along 9 routes (112 miles) covering the county encompassing the city. At each point, staff logged into 3 different geosocial networking apps to record the number of geosocial networking app users within a 1-mile radius. Data were collected separately during weekday daytime (9:00 AM to 4:00 PM) and weekend nighttime (8:00 PM to 12:00 AM) hours. Empirical Bayesian kriging was used to create a raster estimating the number of app users throughout the county. Raster values were summarized for each of the county's 208 Census block groups and used as the outcome measure (ie, geosocial networking app usage). Negative binomial regression and Wilcoxon signed rank sum tests were used to examine Census block group variables (eg, median income, median age) associated with geosocial networking app usage and temporal differences in app usage, respectively. RESULTS: The number of geosocial networking app users within a 1-mile radius of the data collection points ranged from 0 to 36 during weekday daytime hours and 0 to 39 during weekend nighttime hours. In adjusted analyses, Census block group median income and percent Hispanic ethnicity were negatively associated with geosocial networking app usage for all 3 geosocial networking apps during weekday daytime and weekend nighttime hours. Population density and the presence of businesses were positively associated with geosocial networking app usage for all 3 geosocial networking apps during both times. CONCLUSIONS: In this midsize city, geosocial networking app usage was highest in areas that were more population-dense, were lower income, and had more businesses. This research is an example of how geosocial networking apps' geospatial capabilities can be used to better understand patterns of virtual partner-seeking among men who have sex with men.

Geothermal activity helps life survive glacial cycles.

Climate change has played a critical role in the evolution and structure of Earth's biodiversity. Geothermal activity, which can maintain ice-free terrain in glaciated regions, provides a tantalizing solution to the question of how diverse life can survive glaciations. No comprehensive assessment of this "geothermal glacial refugia" hypothesis has yet been undertaken, but Antarctica provides a unique setting for doing so. The continent has experienced repeated glaciations that most models indicate blanketed the continent in ice, yet many Antarctic species appear to have evolved in almost total isolation for millions of years, and hence must have persisted in situ throughout. How could terrestrial species have survived extreme glaciation events on the continent? Under a hypothesis of geothermal glacial refugia and subsequent recolonization of nongeothermal regions, we would expect to find greater contemporary diversity close to geothermal sites than in nongeothermal regions, and significant nestedness by distance of this diversity. We used spatial modeling approaches and the most comprehensive, validated terrestrial biodiversity dataset yet created for Antarctica to assess spatial patterns of diversity on the continent. Models clearly support our hypothesis, indicating that geothermally active regions have played a key role in structuring biodiversity patterns in Antarctica. These results provide critical insights into the evolutionary importance of geothermal refugia and the history of Antarctic species.

A multi-objective optimization approach for the selection of working fluids of geothermal facilities: Economic, environmental and social aspects.

The selection of the working fluid for Organic Rankine Cycles has traditionally been addressed from systematic heuristic methods, which perform a characterization and prior selection considering mainly one objective, thus avoiding a selection considering simultaneously the objectives related to sustainability and safety. The objective of this work is to propose a methodology for the optimal selection of the working fluid for Organic Rankine Cycles. The model is presented as a multi-objective approach, which simultaneously considers the economic, environmental and safety aspects. The economic objective function considers the profit obtained by selling the energy produced. Safety was evaluated in terms of individual risk for each of the components of the Organic Rankine Cycles and it was formulated as a function of the operating conditions and hazardous properties of each working fluid. The environmental function is based on carbon dioxide emissions, considering carbon dioxide mitigation, emission due to the use of cooling water as well emissions due material release. The methodology was applied to the case of geothermal facilities to select the optimal working fluid although it can be extended to waste heat recovery. The results show that the hydrocarbons represent better solutions, thus among a list of 24 working fluids, toluene is selected as the best fluid.

Distribution drivers and physiological responses in geothermal bryophyte communities.

PREMISE OF STUDY: Our ability to explain community structure rests on our ability to define the importance of ecological niches, including realized ecological niches, in shaping communities, but few studies of plant distributions have combined predictive models with physiological measures. METHODS: Using field surveys and statistical modeling, we predicted distribution drivers in geothermal bryophyte (moss) communities of Lassen Volcanic National Park (California, USA). In the laboratory, we used drying and rewetting experiments to test whether the strong species-specific effects of relative humidity on distributions predicted by the models were correlated with physiological characters. KEY RESULTS: We found that the three most common bryophytes in geothermal communities were significantly affected by three distinct distribution drivers: temperature, light, and relative humidity. Aulacomnium palustre, whose distribution is significantly affected by relative humidity according to our model, and which occurs in high-humidity sites, showed extreme signs of stress after drying and never recovered optimal values of PSII efficiency after rewetting. Campylopus introflexus, whose distribution is not affected by humidity according to our model, was able to maintain optimal values of PSII efficiency for 48 hr at 50% water loss and recovered optimal values of PSII efficiency after rewetting. CONCLUSIONS: Our results suggest that species-specific environmental stressors tightly constrain the ecological niches of geothermal bryophytes. Tests of tolerance to drying in two bryophyte species corresponded with model predictions of the comparative importance of relative humidity as distribution drivers for these species.

On the origin of life.

The origin of life is a very rich field, filled with possibilities and ripe for discovery. RNA replication requires chemical energy and vesicle division is easy to do with mechanical energy. These requirements point to a surface lake, perhaps at some time following the period of concentrated cyanide chemistry that gave rise to nucleotides, amino acids and (maybe) fatty acids. A second requirement follows specifically from the nature of the RNA replication cycle, which requires generally cool to moderate temperatures for the copying chemistry, punctuated by brief periods of high temperature for strand separation. Remarkably, lakes in a geothermal active area provide just such a fluctuating temperature environment, because lakes similar to Yellowstone can be generally cool (even ice covered in winter), but they contain numerous hydrothermal vents that emit streams of hot water. Protocells in such an environment would occasionally be swept into these hot water streams, where the transient high temperature exposure would cause RNA strand separation. However, the protocells would be quickly mixed with surrounding cold water, and would therefore cool quickly, before their delicate RNA molecules could be destroyed by heat. Because of the combination of favorable chemical and physical environments, this could be the most likely scenario for the early Earth environment that nurtured the origin of life.

Incorporating land-use requirements and environmental constraints in low-carbon electricity planning for California.

The land-use implications of deep decarbonization of the electricity sector (e.g., 80% below 1990 emissions) have not been well-characterized quantitatively or spatially. We assessed the operational-phase land-use requirements of different low-carbon scenarios for California in 2050 and found that most scenarios have comparable direct land footprints. While the per MWh footprint of renewable energy (RE) generation is initially higher, that of fossil and nuclear generation increases over time with continued fuel use. We built a spatially explicit model to understand the interactions between resource quality and environmental constraints in a high RE scenario (>70% of total generation). We found that there is sufficient land within California to meet the solar and geothermal targets, but areas with the highest quality wind and solar resources also tend to be those with high conservation value. Development of some land with lower conservation value results in lower average capacity factors, but also provides opportunity for colocation of different generation technologies, which could significantly improve land-use efficiency and reduce permitting, leasing, and transmission infrastructure costs. Basing siting decisions on environmentally-constrained long-term RE build-out requirements produces significantly different results, including better conservation outcomes, than implied by the current piecemeal approach to planning.

Actinomadura amylolytica sp. nov. and Actinomadura cellulosilytica sp. nov., isolated from geothermally heated soil.

Two aerobic, Gram-positive actinomycetes, designated YIM 77502(T) and YIM 77510(T), were isolated from geothermally heated soil of Tengchong county, Yunnan province, south-west China. The taxonomic position of strains YIM 77502(T) and YIM 77510(T) were investigated by a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains YIM 77502(T) and YIM 77510(T) belong to the genus Actinomadura. Both strains form extensively-branched substrate and aerial mycelia which differentiated into short spore chains. The cell wall of the two strains contained meso-diaminopimelic acid, while the whole-cell sugars detected were glucose, madurose, mannose and rhamnose. The polar lipid profile of strain YIM 77502(T) was found to consist of diphosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylinositol, two unidentified phospholipids and an unidentified polar lipid, while strain YIM 77510(T) consisted of diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylinositol. The respiratory quinones of strains YIM 77502(T) and YIM 77510(T) were MK-9(H6) and MK-9(H8). The major fatty acids (>10 %) of strain YIM 77502(T) were C17:0, iso-C16:0, C17:010-methyl and iso-C18:0, and those of strain YIM 77510(T) were iso-C16:0, C17:010-methyl and iso-C18:0. The G+C contents of strains YIM 77502(T) and YIM 77510(T) were determined to be 71.3 and 70.2 mol%, respectively. The DNA-DNA hybridization values of strains YIM 77502(T), YIM 77510(T) and their closest phylogenetic neighbours Actinomadura echinospora BCRC 12547(T) and Actinomadura umbrina KCTC 9343(T) were less than 70 %. Based on the morphological and physiological properties, and phylogenetic analyses, strains YIM 77502(T) and YIM 77510(T) are considered to represent two novel species of the genus Actinomadura, for which the names Actinomadura amylolytica sp. nov. (type strain YIM 77502(T) = DSM 45822(T) = CCTCC AA 2012024(T)) and Actinomadura cellulosilytica sp. nov. (type strain YIM 77510(T) = DSM 45823(T) = CCTCC AA 2012023(T)) are proposed.

Geothermal Gases--Community Experiences, Perceptions, and Exposures in Northern California.

Lake County, California, is in a high geothermal-activity area. Over the past 30 years, the city of Clearlake has reported health effects and building evacuations related to geothermal venting. Previous investigations in Clearlake revealed hydrogen sulfide at levels known to cause health effects and methane at levels that can cause explosion risks. The authors conducted an investigation in multiple cities and towns in Lake County to understand better the risk of geothermal venting to the community. They conducted household surveys and outdoor air sampling of hydrogen sulfide and methane and found community members were aware of geothermal venting and some expressed concerns. The authors did not, however, find hydrogen sulfide above the California Environmental Protection Agency air quality standard of 30 parts per billion over one hour or methane above explosive thresholds. The authors recommend improving risk communication, continuing to monitor geothermal gas effects on the community, and using community reports and complaints to monitor and document geothermal venting incidents.

Origins and emergent evolution of life: the colloid microsphere hypothesis revisited.

Self-replicating molecules, in particular RNA, have long been assumed as key to origins of life on Earth. This notion, however, is not very secure since the reduction of life's complexity to self-replication alone relies on thermodynamically untenable assumptions. Alternative, earlier hypotheses about peptide-dominated colloid self-assembly should be revived. Such macromolecular conglomerates presumably existed in a dynamic equilibrium between confluent growth in sessile films and microspheres detached in turbulent suspension. The first organic syntheses may have been driven by mineral-assisted photoactivation at terrestrial geothermal fields, allowing photo-dependent heterotrophic origins of life. Inherently endowed with rudimentary catalyst activities, mineral-associated organic microstructures can have evolved adaptively toward cooperative 'protolife' communities, in which 'protoplasmic continuity' was maintained throughout a graded series of 'proto-biofilms', 'protoorganisms' and 'protocells' toward modern life. The proneness of organic microspheres to merge back into the bulk of sessile films by spontaneous fusion can have made large populations promiscuous from the beginning, which was important for the speed of collective evolution early on. In this protein-centered scenario, the emergent coevolution of uncoded peptides, metabolic cofactors and oligoribonucleotides was primarily optimized for system-supporting catalytic capabilities arising from nonribosomal peptide synthesis and nonreplicative ribonucleotide polymerization, which in turn incorporated other reactive micromolecular organics as vitamins and cofactors into composite macromolecular colloid films and microspheres. Template-dependent replication and gene-encoded protein synthesis emerged as secondary means for further optimization of overall efficieny later on. Eventually, Darwinian speciation of cell-like lineages commenced after minimal gene sets had been bundled in transmissible genomes from multigenomic protoorganisms.

Heat exchange characteristics of underground and pavement buried pipes for bridge deck heating conditions.

Geothermal energy is increasingly employed across diverse applications, with bridge deck snow melting emerging as a notable utilization scenario. In Jinan city, China, a project is underway to utilize ground source heat pumps (GSHPS) for heating bridges. However, essential operational parameters, including fluid medium, temperature, and heat exchange details, are currently lacking. This study addresses the thermal design challenges associated with ground heat exchangers (GHE) for bridge heating through a combination of numerical modeling and field experiments. Utilizing software Fluent, a refined three-dimensional multi-condition heat transfer numerical analysis was carried out. Field tests based on actual operating conditions were also conducted and the design parameters were verified. The results indicate that an inlet temperature of 5°C and an aqueous solution of ethylene glycol with a mass concentration of 35% as the heat exchange medium are suitable for the GSHPS in Jinan; Moreover, the influence of backfill material and operation time on the heat transfer efficiency was revealed and the suitable material with 10% bentonite and 90% SiO2 was suggested; Finally, based on the influence of the pipe spacing on the heating characteristics of bridge deck, the transition spacing of 0.2 m is given for the temperature response of the bridge deck. This comprehensive study contributes valuable insights through simulation and experimental analysis of the thermal environment variation, aiming to advance the development of GSHPS for bridge deck heating in Jinan, China.

Stationarity and cycles in the energy consumption in the United States.

The purpose of this paper is twofold: analyzing stationarity of energy consumption by source in the United States and studying their cycles and pairwise synchronization. We study a panel of nine time series of monthly energy consumption for the period 1973-2022. Four of the series (namely coal, natural gas, petroleum, and nuclear electric power consumption) are non-renewables, whereas the remaining ones (hydroelectric power, geothermal, biomass, solar, and wind energy consumption) are renewable energy sources. We employ a nonparametric, panel stationarity testing approach. The results indicate that most of the series may be trend-stationarity, with nuclear and geothermal energy consumption being the only exceptions. Additionally, a study on potential cycles in the series of energy consumption by source is carried out, and subsequently we analyze pairwise concordance between states of different energy sources and between states of energy sources and the business cycle. Significant correlations are detected in the latter analysis, which are positive in the case of fossil fuel sources and negative for two renewable sources, namely geothermal and biomass energy consumption.