Energy Return on Investment for Norwegian Oil and Gas from 1991 to 2008

Post-evaluation analysis on urban coal, oil and gas resources comprehensive utilization governance project: A case study in Fuxian, China

China's energy and chemical enterprises in the resource-based urban cities face challenges of climate change targets. Coal, Oil and Gas Resources Comprehensive Utilization (COGRCU) project can address the carbon and hydrogen imbalance between conventional methanol from coal and natural gas. Moreover, it can improve energy conversion rates and carbon resource recovery. Therefore, it is a better way for energy and chemical enterprises to transition to sustainable development and advocated by enterprises in resource-based cities. In practice, the actual benefits of the COGRCU project are often different from those expected from prior assessments, and the main factors contributing to the differences need to be identified. Therefore, it is necessary to propose a post-evaluation methodology for the COGRCU project to assist energy and chemical enterprises in identifying these constraints and optimize project management. This study considers energy and monetary flows, combines emergy-based energy return on investment (EmEROI) and cost-benefit analysis (CBA), and proposes a post-evaluation methodology of the COGRCU project based on the case study of YC Group's Fuxian COGRCU project in Fuxian County. In addition, the emergy per unit money, emergy per unit labor, and bio-resources emergy per unit area of Yan'an City are measured. Results showed that indirect energy and labor input emergy are the primary contributors to improving the projects' energy efficiency. Operating costs reduction are the key factors for improving economic benefits. The indirect energy has the highest impact on the project's EmEROI, followed by labor, direct energy, and environmental governance. Several policy recommendations are raised, including strengthening policy support, such as advancing the formulation and revision of fiscal and tax policies, improving project assets and human resource management, and increasing environmental governance efforts.

A Comprehensive Societal Energy Return on Investment Study of Portugal Reveals a Low but Stable Value

Energy return on investment (EROI) is a ratio of the energy obtained in relation to the energy used to extract/produce it. The EROI of fossil fuels is globally decreasing. What do the declining EROIs of energy sources imply for society as a whole? We answer this question by proposing a novel EROI measure that describes, through one parameter, the efficiency of a society in managing energy resources over time. Our comprehensive societal EROI measure was developed by (1) expanding the boundaries of the analysis up to the useful stage; (2) estimating the amount of energy embodied in the energy-converting capital; (3) considering non-conventional sources such as the muscle work of humans and draught animals; and (4) considering the influence of imported and exported energy. We computed the new EROI for Portugal as a case study. We find a considerably lower EROI value, at around 3, compared to those currently available, which is stable over a long-time range (1960–2014). This suggests an independence of EROI from economic growth. When estimated at the final stage, using conventional methods (i.e., without applying the four novelties here introduced), we find a declining societal EROI. Therefore, our results imply that the production of new and more efficient final-to-useful energy converting capital has historically kept societal EROI around a stable value by offsetting the effects of the changing returns of energy sources at the primary and final stages. This will be crucial in the successful transition to renewables.

Deriving EROI for Thirty Large Oil Companies Using the CO2 Proxy from 1999 to 2018

Energy Return on Investment (EROI, sometimes EROEI) is one of the most important indices for evaluating the efficacy of a primary energy source. It is generally defined as the relation between the energy extracted from a given resource and the energy costs diverted from society to extract it. In this paper, the EROI of 30 oil companies was calculated using the CO₂ emitted by the companies and declared in Sustainability and/or Annual Reports as required by law, to estimate the energy used for the production process over a time span of 20 years (1999–2018). The resulting EROI estimates for the companies analyzed are rather homogeneous and, except in some cases, these values are relatively constant over time. These values agree (although sometimes somewhat lower than) estimates derived by other methods.

Landscape social-metabolism in food-energy-water systems: Agricultural transformation of the Upper Snake River Basin

This paper applies a social metabolism framework and energy flow analysis for evaluating agroecosystem and land use transitions in food-energy-water systems using the Upper Snake River Basin (USBR), Idaho, USA as a case-study. The study area is one of the primary agricultural regions of the State of Idaho. Dairy products are the primary agricultural outputs of the region; therefore, we modified a biomass accounting framework to explicitly incorporate the role of manure in the agroecosystem. Despite the increase of cropland between 2002 and 2012 in the basin, a decrease in energy input was observed for crop production. An increase in the industrial energy inputs for dairy production, on the other hand, showed that the basin is a clear example of a metabolic industrialized farm system - an example of land use intensification. We compare the energy return on investments (EROIs) as an indicator of agroecosystem transition for both crop and dairy production during the period 2002 to 2012. Contrary to our expectations, the analysis suggests that livestock production is a relatively energy efficient process in land management in the basin. This is due to the reuse of nutrient by-products from livestock as well as the refuse and residues from crop farming. At the same time, the findings provide insights on the percentage of manure to be reinvested as compost that would improve energy production efficiency. However, the reuse of manure, as it is managed in the basin, may have a negative implication on the nutrient balance of the agroecosystem that needs further investigation. Nonetheless, there is market potential for the reuse and reinvestment of biomass to make energy production in the basin more efficient.

Energy Return on Investment (EROI) for Forty Global Oilfields Using a Detailed Engineering-Based Model of Oil Production

Studies of the energy return on investment (EROI) for oil production generally rely on aggregated statistics for large regions or countries. In order to better understand the drivers of the energy productivity of oil production, we use a novel approach that applies a detailed field-level engineering model of oil and gas production to estimate energy requirements of drilling, producing, processing, and transporting crude oil. We examine 40 global oilfields, utilizing detailed data for each field from hundreds of technical and scientific data sources. Resulting net energy return (NER) ratios for studied oil fields range from ≈2 to ≈100 MJ crude oil produced per MJ of total fuels consumed. External energy return (EER) ratios, which compare energy produced to energy consumed from external sources, exceed 1000:1 for fields that are largely self-sufficient. The lowest energy returns are found to come from thermally-enhanced oil recovery technologies. Results are generally insensitive to reasonable ranges of assumptions explored in sensitivity analysis. Fields with very large associated gas production are sensitive to assumptions about surface fluids processing due to the shifts in energy consumed under different gas treatment configurations. This model does not currently include energy invested in building oilfield capital equipment (e.g., drilling rigs), nor does it include other indirect energy uses such as labor or services.

The implications of the declining energy return on investment of oil production

Declining production from conventional oil resources has initiated a global transition to unconventional oil, such as tar sands. Unconventional oil is generally harder to extract than conventional oil and is expected to have a (much) lower energy return on (energy) investment (EROI). Recently, there has been a surge in publications estimating the EROI of a number of different sources of oil, and others relating EROI to long-term economic growth, profitability and oil prices. The following points seem clear from a review of the literature: (i) the EROI of global oil production is roughly 17 and declining, while that for the USA is 11 and declining; (ii) the EROI of ultra-deep-water oil and oil sands is below 10; (iii) the relation between the EROI and the price of oil is inverse and exponential; (iv) as EROI declines below 10, a point is reached when the relation between EROI and price becomes highly nonlinear; and (v) the minimum oil price needed to increase the oil supply in the near term is at levels consistent with levels that have induced past economic recessions. From these points, I conclude that, as the EROI of the average barrel of oil declines, long-term economic growth will become harder to achieve and come at an increasingly higher financial, energetic and environmental cost.