Ajay Gupta | Massachusetts Institute of Technology (MIT) (original) (raw)

Papers by Ajay Gupta

Due to its light-weighting potential and utility in fuel cells, scandium incorporation is importa... more Due to its light-weighting potential and utility in fuel cells, scandium incorporation is important to achieving decarbonization and energy efficiency. Forecasting scandium supply and demand is complex due to lack of public data and uncertainty in potential new market sectors such as automobiles and commercial airplanes. Consultants provide forecasts, but the underlying assumptions are unclear, and results differ by firm. We explore global supply and demand of scandium oxide in 2030 using public data and information from government, consultants, and literature to analyze two possible scenarios: business-as-usual share of scandium products in sectors and an assumed additional 10% share, including new applications. For supply, in addition to current producers, planned and proposed scandium oxide suppliers are assessed and ranked to match demand scenarios. Current production is 14-23 tonnes per annum, if proposed projects are built by 2030 the maximum total is approximately 1,800 tonnes. The business-as-usual scenario would result in 38 tonnes of production per annum in 2030. The assumed additional 10% share scenario suggests supply would be sufficient to meet all demand at 260 tonnes in 2030, except in automobiles, which could use 5,300 tonnes. Scandium oxide production would need to expand by 3,700 tonnes in 2030 over proposed projects to meet the additional 10% share. Adoption is not ensured if price and supply volatility remain. The most critical drivers of future scandium oxide demand are its price and availability.

Journal of Cleaner Production, 2022

Techno-economic analysis (TEA) evaluates technical performance and economic feasibility of techno... more Techno-economic analysis (TEA) evaluates technical performance and economic feasibility of technologies in development. TEAs are inherently uncertain, and analysts use tools such as Monte Carlo Analysis to characterize this. Future prices of inputs and products are integral for analysis and historical data provide key information to forecast and quantify uncertainty. In traditional Monte Carlo Analysis, historical prices are calibrated to a distribution, from which a sample is used throughout the project lifetime, however, variability in prices tends to average out over time, and in practice, are sampled many times over the project. Alternate approaches are stochastic mean-reversion methods and Monte Carlo resampling over defined time periods. Time-increment is determined by the nature of firms’ contracts for purchasing and selling materials. For a case study of a TEA for recovering rare earths from hard drives, we quantify how choice of time-increment affects uncertainty in profitability arising from price uncertainties. One result is using daily, monthly, or annual prices using mean-reversion yields different distributions of expected net present value: standard deviations of 26%, 33% and 39% respectively. Our conclusions are that mean-reversion methods are preferable, and that it is important to gather information on time scales of purchases and sales to accurately estimate uncertainty.

Sustainability, 2011

This is a review of the literature available on data for the EROI (prior to this special issue) o... more This is a review of the literature available on data for the EROI (prior to this special issue) of the following 12 sources of fuel/energy: oil and natural gas, coal, tar sands, shale oil, nuclear, wind, solar, hydropower, geothermal, wave/tidal and corn ethanol. Unfortunately, we found that few studies have been undertaken since the 1980s, and such as have been done are often marked more by advocacy than objectivity. The most recent summary of work and data on the EROI of fuels was conducted in the summer of 2007 at SUNY ESF and appeared on The Oil Drum website and in a readable summary by Richard Heinberg. This paper summarizes the findings of that study, and also those preceding and subsequent to it where available. It also summarizes issues raised by some concerning the findings of these studies and with the calculations within. While there are many who believe that such EROI studies are critical to understanding our financial and social future there seems to be very little interest by governments and industries in supporting this research or in using or promulgating such research as has been done. We view this as critical as our main fuels are progressively depleted and as we are faced with making extremely important decisions on a very meager analytical and data base, and with few scientists trained to cut through the reams of insufficiently analyzed energy advocacy saturating our media and the blogosphere.

Energy Policy, 2014

Large quantities of high quality energy appears to contribute to social wellbeing. LEI examines t... more Large quantities of high quality energy appears to contribute to social wellbeing. LEI examines the quantity, efficiency and distribution of energy within the system. EROI SOC of o25:1, o100 GJ/capita and LEIo0.2 point to poor/moderate quality of life. A threshold of well-being is: EROI SOC of 20-30:1, 100-200 GJ/capita and LEI 0.2-0.4. Improvement in well-being levels off at: EROI SOC 430:1, 4200 GJ/capita and LEI40.4.

Large quantities of high quality energy appears to contribute to social wellbeing. LEI examines t... more Large quantities of high quality energy appears to contribute to social wellbeing. LEI examines the quantity, efficiency and distribution of energy within the system. EROI SOC of o25:1, o100 GJ/capita and LEIo0.2 point to poor/moderate quality of life. A threshold of well-being is: EROI SOC of 20-30:1, 100-200 GJ/capita and LEI 0.2-0.4. Improvement in well-being levels off at: EROI SOC 430:1, 4200 GJ/capita and LEI40.4.

Forestry (SUNY-ESF), examines the energy used by modern economies over time. This work centers on... more Forestry (SUNY-ESF), examines the energy used by modern economies over time. This work centers on assessing the relation of energy costs of modern day society and its relation to GDP. A focus of this report is energy return on investment (EROI) and some important characteristics of our major energy sources over time. We find the EROI for each major fossil fuel resource (except coal) has declined substantially from the middle of the last century. Most renewable and nonconventional energy alternatives have substantially lower EROI values than conventional fossil fuels. Declining EROI, at the societal level, means that an increasing proportion of energy output is diverted to getting the energy needed to run an economy with less discretionary funds available for "non-essential" projects. The declining EROI of traditional fossil fuel energy sources and this eventual effect on the world economy are likely to result in a myriad of unforeseen consequences. We offer this report as a window into the EROI of global energy sources, the effect of policy and world events on past, present, and future EROI values, the EROI of renewable, non-conventional and imported energy sources, and provide a brief discussion on how declining EROI values may influence the economies of select developed and developing nations. The increasing energy cost of oil: Drake's first well, Spindletop (Courtesy Texas Energy Museum), Thunderhorse (courtesy of Andyminicooper), a modern pumpjack and refinery.

This is a review of the literature available on data for the EROI (prior to this special issue) o... more This is a review of the literature available on data for the EROI (prior to this special issue) of the following 12 sources of fuel/energy: oil and natural gas, coal, tar sands, shale oil, nuclear, wind, solar, hydropower, geothermal, wave/tidal and corn ethanol. Unfortunately, we found that few studies have been undertaken since the 1980s, and such as have been

Posted by Nate Hagens on April 15, 2008-11:00am in The Oil Drum: Net Energy Topic: Supply/Product... more Posted by Nate Hagens on April 15, 2008-11:00am in The Oil Drum: Net Energy Topic: Supply/Production Tags: charles hall, eroei, eroi, net energy, oil sands, oil shale, tar sands [list all tags] This is third in a series of six guest posts by Professor Charles Hall of the SUNY College of Environmental Science and Forestry describing the energy statistic, "EROI" for various fuels. As has been discussed often on this site, net energy analysis is a vitally important concept-just as we primarily care about our take home pay which is our salary minus the taxes, we should care about our 'take home' energy, which is what is left after energy costs have been accounted for. As important as it is, this measure is not easy to quantify, as: a)data is almost always measured in $ as opposed to energy terms, b) parsing non-energy inputs (and outputs) into energy terms is difficult, and c) analysis boundaries (including environmental impacts) are very disparate. As such, there is not (has not yet been) a consistent formula for EROI applied to all energy studies that has led to policymakers and analysts speaking the same language in useful ways. The lead paper in this months Royal Academy of Sweden's journal AMBIO will be about such an EROI framework, and we will link to it when it comes online. Professor Hall has been working in this area for over 30 years. Below are net energy analysis from Hall's group on the unconventional oil sources from tar sands and oil shaletwo resources that theoretically are enormous in energy scale, but practically are limited by flow rates, costs, and externalities. Just how limited is the subject of todays two-part informative post is below the fold. Remember, any specific numerical help via referenced literature, personal experience or knowledge to better inform Dr. Hall and his students would be appreciated. Definition Oil sands, also called tar sands, consist of bitumen mixed with sand. Bitumen or " very heavy " oil is composed of carbon rich, hydrogen poor, long chain molecules and is in a semi-solid or solid form. It has not been " cooked properly " by geological processes to yield the lighter fractions we The Oil Drum: Net Energy | Unconventional Oil: Tar Sands and Shale Oil-EROI on the Web, Part 3 of 6

Thesis Chapters by Ajay Gupta

Books by Ajay Gupta

A Comprehensive Guide to Solar Energy Systems: with special focus on photovoltaic systems, 2017

Materials are critical to any economy. They are integral to the systems that provide energy to in... more Materials are critical to any economy. They are integral to the systems that provide energy to industry and society such as PV technology. Also, the energy costs of developing critical materials can seriously impact the PV industry. Assessing precisely what these costs are is extremely difficult, especially for secondary ores and uncommon materials used by the industry. While PV module efficiency is increasing, the energy costs of securing materials for development is increasing as well. Not all materials are likely constrained and there are ways to improve efficiencies. Today, obtaining materials of PV-grade purity relies heavily on fossil fuels, for which energy costs are also increasing. One of our most critical needs if we are to achieve a better understanding of a future involving a continued rapid-upscale of PV electricity, is better information about material availability in the long term and the energy costs associated with that.

A Comprehensive Guide to Solar Energy Systems: with special focus on photovoltaic systems, 2017

As the world moves through an energy transition of immense scale, the concept of Energy Return on... more As the world moves through an energy transition of immense scale, the concept of Energy Return on Investment (EROI or ERoEI) is increasing being studied. In this chapter the focus is on the EROI of PV modules and systems. EROI refers to the ratio of the usable energy returned during a system’s lifetime to all the invested energy needed to make this energy usable. It is a relatively new area of study and is related to Net Energy Analysis and Life Cycle Assessment. The higher the EROI of a fuel technology, the more valuable it is in terms of producing economically useful energy output. A higher EROI allows more net energy to be available to the economy; and to some degree, all economic activity relies on energy. In this chapter the EROI of PV systems are evaluated and illustrated, based on a variety of studies and in terms of technologies and the impact on economies. EROI can be used to rank the quality of fuels in terms of economics and here PV is evaluated in comparison to other fuels used for electricity generation.

Due to its light-weighting potential and utility in fuel cells, scandium incorporation is importa... more Due to its light-weighting potential and utility in fuel cells, scandium incorporation is important to achieving decarbonization and energy efficiency. Forecasting scandium supply and demand is complex due to lack of public data and uncertainty in potential new market sectors such as automobiles and commercial airplanes. Consultants provide forecasts, but the underlying assumptions are unclear, and results differ by firm. We explore global supply and demand of scandium oxide in 2030 using public data and information from government, consultants, and literature to analyze two possible scenarios: business-as-usual share of scandium products in sectors and an assumed additional 10% share, including new applications. For supply, in addition to current producers, planned and proposed scandium oxide suppliers are assessed and ranked to match demand scenarios. Current production is 14-23 tonnes per annum, if proposed projects are built by 2030 the maximum total is approximately 1,800 tonnes. The business-as-usual scenario would result in 38 tonnes of production per annum in 2030. The assumed additional 10% share scenario suggests supply would be sufficient to meet all demand at 260 tonnes in 2030, except in automobiles, which could use 5,300 tonnes. Scandium oxide production would need to expand by 3,700 tonnes in 2030 over proposed projects to meet the additional 10% share. Adoption is not ensured if price and supply volatility remain. The most critical drivers of future scandium oxide demand are its price and availability.

Journal of Cleaner Production, 2022

Techno-economic analysis (TEA) evaluates technical performance and economic feasibility of techno... more Techno-economic analysis (TEA) evaluates technical performance and economic feasibility of technologies in development. TEAs are inherently uncertain, and analysts use tools such as Monte Carlo Analysis to characterize this. Future prices of inputs and products are integral for analysis and historical data provide key information to forecast and quantify uncertainty. In traditional Monte Carlo Analysis, historical prices are calibrated to a distribution, from which a sample is used throughout the project lifetime, however, variability in prices tends to average out over time, and in practice, are sampled many times over the project. Alternate approaches are stochastic mean-reversion methods and Monte Carlo resampling over defined time periods. Time-increment is determined by the nature of firms’ contracts for purchasing and selling materials. For a case study of a TEA for recovering rare earths from hard drives, we quantify how choice of time-increment affects uncertainty in profitability arising from price uncertainties. One result is using daily, monthly, or annual prices using mean-reversion yields different distributions of expected net present value: standard deviations of 26%, 33% and 39% respectively. Our conclusions are that mean-reversion methods are preferable, and that it is important to gather information on time scales of purchases and sales to accurately estimate uncertainty.

Sustainability, 2011

This is a review of the literature available on data for the EROI (prior to this special issue) o... more This is a review of the literature available on data for the EROI (prior to this special issue) of the following 12 sources of fuel/energy: oil and natural gas, coal, tar sands, shale oil, nuclear, wind, solar, hydropower, geothermal, wave/tidal and corn ethanol. Unfortunately, we found that few studies have been undertaken since the 1980s, and such as have been done are often marked more by advocacy than objectivity. The most recent summary of work and data on the EROI of fuels was conducted in the summer of 2007 at SUNY ESF and appeared on The Oil Drum website and in a readable summary by Richard Heinberg. This paper summarizes the findings of that study, and also those preceding and subsequent to it where available. It also summarizes issues raised by some concerning the findings of these studies and with the calculations within. While there are many who believe that such EROI studies are critical to understanding our financial and social future there seems to be very little interest by governments and industries in supporting this research or in using or promulgating such research as has been done. We view this as critical as our main fuels are progressively depleted and as we are faced with making extremely important decisions on a very meager analytical and data base, and with few scientists trained to cut through the reams of insufficiently analyzed energy advocacy saturating our media and the blogosphere.

Energy Policy, 2014

Large quantities of high quality energy appears to contribute to social wellbeing. LEI examines t... more Large quantities of high quality energy appears to contribute to social wellbeing. LEI examines the quantity, efficiency and distribution of energy within the system. EROI SOC of o25:1, o100 GJ/capita and LEIo0.2 point to poor/moderate quality of life. A threshold of well-being is: EROI SOC of 20-30:1, 100-200 GJ/capita and LEI 0.2-0.4. Improvement in well-being levels off at: EROI SOC 430:1, 4200 GJ/capita and LEI40.4.

Large quantities of high quality energy appears to contribute to social wellbeing. LEI examines t... more Large quantities of high quality energy appears to contribute to social wellbeing. LEI examines the quantity, efficiency and distribution of energy within the system. EROI SOC of o25:1, o100 GJ/capita and LEIo0.2 point to poor/moderate quality of life. A threshold of well-being is: EROI SOC of 20-30:1, 100-200 GJ/capita and LEI 0.2-0.4. Improvement in well-being levels off at: EROI SOC 430:1, 4200 GJ/capita and LEI40.4.

Forestry (SUNY-ESF), examines the energy used by modern economies over time. This work centers on... more Forestry (SUNY-ESF), examines the energy used by modern economies over time. This work centers on assessing the relation of energy costs of modern day society and its relation to GDP. A focus of this report is energy return on investment (EROI) and some important characteristics of our major energy sources over time. We find the EROI for each major fossil fuel resource (except coal) has declined substantially from the middle of the last century. Most renewable and nonconventional energy alternatives have substantially lower EROI values than conventional fossil fuels. Declining EROI, at the societal level, means that an increasing proportion of energy output is diverted to getting the energy needed to run an economy with less discretionary funds available for "non-essential" projects. The declining EROI of traditional fossil fuel energy sources and this eventual effect on the world economy are likely to result in a myriad of unforeseen consequences. We offer this report as a window into the EROI of global energy sources, the effect of policy and world events on past, present, and future EROI values, the EROI of renewable, non-conventional and imported energy sources, and provide a brief discussion on how declining EROI values may influence the economies of select developed and developing nations. The increasing energy cost of oil: Drake's first well, Spindletop (Courtesy Texas Energy Museum), Thunderhorse (courtesy of Andyminicooper), a modern pumpjack and refinery.

This is a review of the literature available on data for the EROI (prior to this special issue) o... more This is a review of the literature available on data for the EROI (prior to this special issue) of the following 12 sources of fuel/energy: oil and natural gas, coal, tar sands, shale oil, nuclear, wind, solar, hydropower, geothermal, wave/tidal and corn ethanol. Unfortunately, we found that few studies have been undertaken since the 1980s, and such as have been

Posted by Nate Hagens on April 15, 2008-11:00am in The Oil Drum: Net Energy Topic: Supply/Product... more Posted by Nate Hagens on April 15, 2008-11:00am in The Oil Drum: Net Energy Topic: Supply/Production Tags: charles hall, eroei, eroi, net energy, oil sands, oil shale, tar sands [list all tags] This is third in a series of six guest posts by Professor Charles Hall of the SUNY College of Environmental Science and Forestry describing the energy statistic, "EROI" for various fuels. As has been discussed often on this site, net energy analysis is a vitally important concept-just as we primarily care about our take home pay which is our salary minus the taxes, we should care about our 'take home' energy, which is what is left after energy costs have been accounted for. As important as it is, this measure is not easy to quantify, as: a)data is almost always measured in $ as opposed to energy terms, b) parsing non-energy inputs (and outputs) into energy terms is difficult, and c) analysis boundaries (including environmental impacts) are very disparate. As such, there is not (has not yet been) a consistent formula for EROI applied to all energy studies that has led to policymakers and analysts speaking the same language in useful ways. The lead paper in this months Royal Academy of Sweden's journal AMBIO will be about such an EROI framework, and we will link to it when it comes online. Professor Hall has been working in this area for over 30 years. Below are net energy analysis from Hall's group on the unconventional oil sources from tar sands and oil shaletwo resources that theoretically are enormous in energy scale, but practically are limited by flow rates, costs, and externalities. Just how limited is the subject of todays two-part informative post is below the fold. Remember, any specific numerical help via referenced literature, personal experience or knowledge to better inform Dr. Hall and his students would be appreciated. Definition Oil sands, also called tar sands, consist of bitumen mixed with sand. Bitumen or " very heavy " oil is composed of carbon rich, hydrogen poor, long chain molecules and is in a semi-solid or solid form. It has not been " cooked properly " by geological processes to yield the lighter fractions we The Oil Drum: Net Energy | Unconventional Oil: Tar Sands and Shale Oil-EROI on the Web, Part 3 of 6

A Comprehensive Guide to Solar Energy Systems: with special focus on photovoltaic systems, 2017

Materials are critical to any economy. They are integral to the systems that provide energy to in... more Materials are critical to any economy. They are integral to the systems that provide energy to industry and society such as PV technology. Also, the energy costs of developing critical materials can seriously impact the PV industry. Assessing precisely what these costs are is extremely difficult, especially for secondary ores and uncommon materials used by the industry. While PV module efficiency is increasing, the energy costs of securing materials for development is increasing as well. Not all materials are likely constrained and there are ways to improve efficiencies. Today, obtaining materials of PV-grade purity relies heavily on fossil fuels, for which energy costs are also increasing. One of our most critical needs if we are to achieve a better understanding of a future involving a continued rapid-upscale of PV electricity, is better information about material availability in the long term and the energy costs associated with that.

A Comprehensive Guide to Solar Energy Systems: with special focus on photovoltaic systems, 2017

As the world moves through an energy transition of immense scale, the concept of Energy Return on... more As the world moves through an energy transition of immense scale, the concept of Energy Return on Investment (EROI or ERoEI) is increasing being studied. In this chapter the focus is on the EROI of PV modules and systems. EROI refers to the ratio of the usable energy returned during a system’s lifetime to all the invested energy needed to make this energy usable. It is a relatively new area of study and is related to Net Energy Analysis and Life Cycle Assessment. The higher the EROI of a fuel technology, the more valuable it is in terms of producing economically useful energy output. A higher EROI allows more net energy to be available to the economy; and to some degree, all economic activity relies on energy. In this chapter the EROI of PV systems are evaluated and illustrated, based on a variety of studies and in terms of technologies and the impact on economies. EROI can be used to rank the quality of fuels in terms of economics and here PV is evaluated in comparison to other fuels used for electricity generation.