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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

TRPV4 is involved in irisin-induced endothelium-dependent vasodilation

Highlights: • Irisin caused an increase in [Ca{sup 2+}]{sub i} due to extracellular Ca{sup 2+} influx rather than Ca{sup 2+} release in endothelial cells. • Pretreatment with TRPV4 channel inhibitor completely abolished irisin-induced increases in [Ca{sup 2+}]{sub i}. • Irisin induced endothelium-dependent vasodilation, however, it had no effect on endothelium-independent vasodilation. • Pretreatment with TRPV4 channel inhibitor fully abrogated irisin-induced vasodilation. Irisin, an exercise-induced myokine, induces conversion of white into brown adipocytes, promoting mitochondrial biogenesis and energy expenditure. Irisin has a vascular protective effect on endothelial function in animals, including humans. Defects in irisin signaling pathways result in endothelial dysfunction in obesity and diabetes. However, the mechanisms underlying the effects of irisin on endothelial function have not been elucidated. Transient receptor potential vanilloid subtype 4 (TRPV4) channels are one of the most important Ca{sup 2+}-permeable cation channels in vascular endothelial cells. In this study, we hypothesized that irisin may induce endothelium-dependent vasodilation by activating Ca{sup 2+} influx into endothelial cells via TRPV4 channels. In primary cultured rat mesenteric artery endothelial cells, irisin caused an increase in [Ca{sup 2+}]{sub i} due to extracellular Ca{sup 2+} influx rather than release from Ca{sup 2+} stores. Moreover, irisin-induced increases in [Ca{sup 2+}]{sub i} were completely abolished by a TRPV4 inhibitor. In addition, irisin induced endothelium-dependent vasodilation of rat mesenteric arteries. However, irisin had no effect on endothelium-independent vasodilation. Furthermore, irisin-induced vasodilation was fully abolished in the presence of a TRPV4 inhibitor, indicating the involvement of TRPV4 channels in endothelium-dependent vasodilation. This study provides the first evidence that irisin-induced endothelium-dependent vasodilation is related to the stimulation of extracellular Ca{sup 2+} influx via TRPV4 channels in rat mesenteric arteries.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Soluble dietary fiber improves energy homeostasis in obese mice by remodeling the gut microbiota

Intervention with dietary fibers is an important strategy to combat the global epidemic of obesity which is a consequence of energy imbalance. However, a possible role of the gut microbiota in effects of dietary fibers on energy homeostasis remains unclear. Here, we treated a high fat diet-induced obese (DIO) mouse model with soluble dietary fiber. Our results showed that soluble dietary fiber reduced body weight gain and the excessive accumulation of white fat tissue in DIO mice. Notably, soluble dietary fiber increased energy expenditure, but not change energy intake in DIO mice. In accordance, 16S rRNA sequencing revealed that the diversity of the gut microbiota was restored by soluble dietary fiber. Moreover, compared with controls, soluble dietary fiber resulted in a decreased ratio of Firmicutes/Bacteroidetes at the phylum level, and an increased relative abundance of the genera Roseburia at the genus level. Taken together, these findings indicate that soluble dietary fiber improves energy homeostasis and prevents obesity by increasing the diversity of the gut microbiota and the colonization of beneficial bacteria.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Ifi27 is indispensable for mitochondrial function and browning in adipocytes

Highlights: • Ifi27 is a brown fat-enriched gene and localizes to mitochondria. • The expression of Ifi27 is induced by β3-adrenergic agonist in adipose tissues. • Interferon-α signaling decreases Ifi27 level. • Ifi27 is physiologically required to maintain mitochondrial function and undergo browning. Brown adipose tissue (BAT) is specialized for energy expenditure, but the signaling pathways that regulate BAT metabolism and activity are incompletely understood. Interferon (IFN) signaling is a sophisticated defense mechanism to counteract viral infection. IFNs and interferon-stimulated genes (ISGs) are reported to exert profound effects on adipocytes. IFN-α inducible protein 27 (Ifi27/ISG12a) is a BAT-enriched gene, yet no any studies on its roles in BAT have been reported. Here, we show that Ifi27 protein localizes to mitochondria and the expression of Ifi27 can be induced by β3-adrenergic activation in adipose tissues. Knockdown of Ifi27 leads to reduced expression of key enzymes of tricarboxylic acid cycle (TCA), the subunits of electron transport chain (ETC) and uncoupling protein 1 (Ucp1) in brown and beige adipocytes. Moreover, the browning of subcutaneous white fat induced by β3-adrenergic agonist is also dramatically blocked. Ectopic expression of Ifi27 in brown adipocytes has the opposite effects. Together, these data indicate that Ifi27 regulates mitochondrial function and browning in adipocytes.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Leptin regulates the expression of angiopoietin-like 6

Highlights: • High-fat diet results in increased hepatic ANGPTL6 expression. • Leptin treatment upregulates ANGPTL6 expression in hepatocytes. • Exercise training decreases serum ANGPTL6 as well as leptin. Angiopoietin-like 6 (ANGPTL6) is a hepatokine that antagonizes obesity and insulin resistance by increasing energy expenditure. Despite its beneficial effects on metabolism, human studies have shown a paradoxical increase in ANGPTL6 level in the serum of patients with metabolic diseases, which has been interpreted as a compensatory upregulation. However, the regulatory mechanism of ANGPTL6 remains unclear. Since upregulation of ANGPTL6 is induced on metabolic stress, we investigated the hepatic expression of ANGPTL6 by leptin, a representative adipokine of obesity. Mice on a high-fat diet showed increased serum leptin levels and hepatic Angptl6 expression, which were attenuated by exercise training. A single leptin injection also induced hepatic ANGPTL6 expression and increased serum ANGPTL6 levels. In an in vitro model using primary hepatocytes, leptin treatment significantly upregulated ANGPTL6 expression at the mRNA and protein levels, as well as the amount of secreted ANGPTL6 protein in conditioned media. Similarly, exercise training on human participants also showed diminished serum levels of leptin and ANGPTL6. Altogether, these results strongly indicated that hepatic ANGPTL6 expression was determined by leptin.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Neuregulin-4 is an angiogenic factor that is critically involved in the maintenance of adipose tissue vasculature

Highlights: • Nrg4 is highly expressed in healthy adipocytes and down-regulated in obesity. • Nrg4 is an angiogenic growth factor. • Loss of Nrg4 caused reduction in adipose tissue blood vessels in mice. • Loss of Nrg4 caused overweight due to reduced energy expenditure in mice. • Loss of Nrg4 impaired metabolic health in mice even while consuming normal chow. Adipose tissue (AT) contains well-developed vascular networks. Pathological AT expansion often accompany the reduction in AT blood vessels, which further exacerbates adipocyte dysfunction due to hypoxia; however, it remains unclear whether AT vascular rarefaction is simply secondary to adipocyte hypertrophy, or if there is an actively regulated pathway that mediates impaired AT angiogenesis in obesity. We searched for growth factors whose expression in AT is down-regulated in obesity; accordingly, we identified neuregulin-4 (Nrg4), a member of the EGF family of proteins. Nrg4 is highly and preferentially expressed in healthy adipocytes, while its expression was substantially reduced in obesity. Nrg4 activated endothelial angiogenic functions and angiogenesis both in vitro and in vivo. Genetic loss of Nrg4 caused reduction in brown and white AT blood vessels, and induced overweight even while consuming normal chow. Conditional knockout of Nrg4 in brown adipocytes caused blood vessel reduction in brown but not in white AT, and was sufficient to induce obese phenotype. Our data demonstrated that Nrg4 plays a critical role in maintaining AT vasculature and its metabolic functions. Considering the substantial reduction of Nrg4 in obesity, disruption of Nrg4-mediated angiogenesis could be an active mechanism for the obesity-associated vascular rarefaction in AT, and thus Nrg4 is an attracting pharmacotherapeutic target in the prevention and/or treatment of obesity-related metabolic disorders.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Anti-obesity potential of Glycyrrhiza uralensis and licochalcone A through induction of adipocyte browning

Highlights: • G.uralensis or licochalcone A reduced body weight and inguinal fat weights in obese mice. • G.uralensis or licochalcone A increased brown fat population in inguinal white adipose tissue of obese mice. • G.uralensis and LicoA reduce obesity and recover metabolic homeostasis by inducing fat browning. The main function of brown adipose tissue is to dissipate surplus caloric intake into heat energy by thermogenesis, increasing energy expenditure. Inducible brown adipocytes can develop within white adipose tissue (WAT) through a process referred to as browning. Browning of white fat represents a promising strategy for treatment of obesity and the related complications. We investigated whether Glycyrrhiza uralensis and its ingredients modulated adipogenesis through adipocyte browning using 3T3-L1 adipocytes and a high-fat diet (HFD)-induced obesity mice model. Amongst extracts and fractions of G. uralensis, methyl dichloride (MeCl{sub 2}) fraction was the most effective to induce expression of uncoupling protein 1 (UCP1), a fat browning marker, in 3T3-L1 adipocytes. Ingredients of G. uralensis such as licochalcone A (LicoA), isoliquiritigenin, and liquiritigenin induced UCP1 expression in 3T3-L1 adipocytes. After inducing obesity in mice by 6-week HFD, MeCl{sub 2} fraction of G. uralensis or LicoA was intraperitoneally administered for additional 19 days. MeCl{sub 2} fraction or LicoA significantly reduced body weight gain and inguinal fat pad weights. Furthermore, MeCl{sub 2} fraction or LicoA improved metabolic disorders induced by HFD as the treatments decreased serum levels of glucose and cholesterol, and blocked insulin resistance. MeCl{sub 2} fraction or LicoA enhanced expression of brown fat markers such as UCP1, PRDM16, and PGC-1α and increased brown fat phenotype population in inguinal WAT of HFD-fed mice. Our results demonstrate that G. uralensis and LicoA are effective to reduce obesity and to recover metabolic homeostasis by inducing the brown fat phenotype.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Evaluation of alternatives for the evolution of palm oil mills into biorefineries

Six alternatives for the conversion of an average Colombian palm oil mill (30 t/h) of fresh fruit bunches (FFB) into biorefineries were evaluated. The alternatives studied were: (C1) Production of biogas from the Palm Oil Mill Effluents (POME), (C2) Composting of empty fruit bunches (EFB) and fiber, (C3) Biomass combustion for high pressure steam combined heat and power, (C4) Pellets production, (C5) Biochar production and, (C6) Biochar and bio-oil production. The available biomass could result in up to 125 kWh of electricity, 207 kg of compost, 125 kg of pellet, 44 kg of biochar and 63 kg of bio-oil per metric ton of FFB. The global warming potential (GWP), eutrophication potential (EP), net energy ratio (NER), capital expenditures (CAPEX), operational costs (OPEX), net present value (NPV) and internal rate of return (IRR) were calculated for all the alternatives. GHG reductions of more than 33% could be achieved. Anaerobic digestion and composting contributed to 30% reduction of the EP. The CAPEX for all of the biorefinery alternatives studied varies between 0.7 $/t and 2.8 $/t of FFB. The OPEX varies between 1.6 $/t and 7.3 $/t of FFB. The NPV for viable scenarios ranged between 2.5 million and 13.9 million US dollars. The IRR calculated varied between 3% and 56% and the payback periods were between 3 and 8 years. The total extra incomes reached values up to 15.2 $/t of FFB. Overall the pellets production biorefinery was the preferred alternative.

palm oil mill, biorefinery comparison, Life Cycle ↗
DOE OSTI2025

Integration of renewable energy generation and storage systems for emissions reduction in an islanded campus microgrid

Microgrid connected building communities are projected to play an integral part in the clean energy transition. These types of systems, when integrated with distributed energy resources (DERs) such as combined heat and power (CHP), district heating and cooling, renewable generation, and energy storage, can provide clean, reliable power to critical facilities and vulnerable communities. The intermittent nature of renewable generation is a challenge when integrating renewables into any grid system, but particularly in islanded microgrids. The University of Texas at Austin (UT) operates an islanded microgrid powered by a CHP plant, while also utilizing district heating and cooling systems and thermal energy storage (TES). High fidelity operating data was used to develop a validated reduced order model of UT’s integrated campus energy systems to serve as a testbed for use in a case study. Hypothetical renewable energy installations on land owned by UT in west Texas were modeled and integrated into the validated campus models along with battery energy storage (BES). Simulations showed that a combination of renewable energy from wind, and optimally controlled 24-hour thermal and battery storage systems could reduce carbon dioxide emissions on campus by 45.4%. The additional retrofit of burner systems to utilize hydrogen natural gas blends resulted in an overall annual emissions reduction of 54.7%. Carbon capture and storage eliminated the majority of the remaining emissions with increased plant energy expenditure. The presented simulations display the practical limitations of a CHP system complemented by renewable generation and short-term storage in eliminating emissions. Furthermore, results highlight the need for further research and development in long duration storage technologies and hydrogen fueled turbines to increase penetration of renewable energy and reduce emissions.

CHP↗
DOE OSTI2017

Crack detection in crystalline silicon solar cells using dark-field imaging

The high capital expenditure (capex) necessary to manufacture crystalline silicon PV modules negatively affects the levelized cost of electricity (¢/kWh) and critically impacts the rate at which the PV industry can scale up. Wafer, cell, and module fabrication with thin free-standing silicon wafers is one key to reduce capex. Thin wafers reduce capex associated with silicon refining and wafer fabrication, which together sum to 58% of the total capex of silicon module manufacturing. In addition, thin wafers directly and significantly reduce variable costs. However, introducing 50 μm thin free-standing wafers into today’s manufacturing lines result in cracking, creating a yield-based disincentive. Due to the brittle nature of silicon, wafer breakage is the major concern due to the high stress that is induced during processes in manufacturing lines. In this paper, we describe an improved method for edge micro-crack detection that can help enable low-capex, thin free-standing Si wafers. We present a method of detecting and measuring cracks along wafer edges by using a dark-field IR scattering imaging technique which enables detection of edge cracks at the micron scale.

14 SOLAR ENERGY↗
DOE OSTI2015

Assessment of external costs for transport project evaluation: Guidelines in some European countries

Many studies about the external costs generated by the transport system have been developed in the last twenty years. To standardize methodologies and assessment procedures to be used in the evaluation of the projects, some European countries recently have adopted specific guidelines that differ from each other in some aspects even sensibly. This paper presents a critical analysis of the British, Italian and German guidelines and is aimed at cataloguing the external cost types regarded and the assessment methods indicated as well as to highlight the differences of the results, in terms of applicability and reliability. The goal is to contribute to a European standardization process that would lead to the drafting of guidelines suited for all EU countries. - Highlights: • The analyzed guidelines agree on the methods to evaluate costs from air pollution, greenhouse gases and accidents. • They recommend respectively: dose-resp. approach; costs to reduce/permit emissions; whole direct, indirect and social costs. • For noise, DE guide indicates defensive expenditure or SP methods; IT guide, SP method; UK guide, the hedonic prices one. • For on territory impact, DE guide regards only the barrier effect; the IT one, also the soil consumption and system effects. • British guide proposes a qualitative methodology to estimate the impact on various landscapes and environments.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

The impact of municipal budgets and land-use management on the hazardous waste production of Malaga municipalities

Economic development and the search for competitiveness have become key issues in regions' economic success. However, despite the direct relationship between economic and environmental management, few land-use plans consider the latter aspect, and city managers delegate the responsibility for environmental impacts to state legislation and private initiatives. This myopic search for competitiveness has meant that a holistic view of environmental issues is often not integrated into municipal decision-making processes. Therefore, this study's objective was to determine the relevant direct and indirect relationships of land management and budgetary procedures of municipalities with overall production levels of hazardous waste. To this end, a primary tourist region, Málaga, was examined in terms of how this waste's environmental impacts can affect the region's vital tourism sector. This research used principal component analysis, regression by ordinary least squares, cluster analysis in two stages and a means test to compare the data for the Province of Malaga's subregions. The results confirm a positive relationship between municipal expenditure and waste production and highlight the environmental benefits of land use involving environmentally non-aggressive crops. The results also reveal a negative relationship between waste production and financial assets and a direct relationship between unproductive land and the production of hazardous waste. The findings also highlight the necessity of raising awareness about the need for collaboration between different agents, especially in the development of inter-municipal strategies.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

A novel green hydrogen production using water-energy nexus framework

The transformation of electrical energy to hydrogen via water electrolysis consumes considerable amount of fresh water and a productive use of nontraditional water sources enhances the reliability and resilience of energy and water systems. In this study, we have designed a solid oxide electrolysis cell (SOEC) system which is an evolving hydrogen production technology at high temperatures for water electrolysis. Here, the SOEC uses steam generated from flue gas as its feedstock and is fully integrated with numerous power production units, including coal and natural gas-fired power plants as its energy feedstock. While there is a hasten global shift away from fossil fuel, integrating its asset into this technology helps limit the risk and future losses of stranded assets and reduce the cost of investment in the new technologies. But high capital expenditures and doubt concerning the future cost and efficiency upgrade are obstacles to investing in water electrolysis. Such a detailed Levelized cost of hydrogen and techno-economic analysis is conducted to show the viability and environmental impacts of this novel technology. The results show SOEC efficiency of 97.4 % and 56.3 % as thermal-to-hydrogen efficiency of the system with a daily hydrogen production of 242,400 kg at $2.9–3.5/kg H 2 . The estimates show a positive gain prospect in this technology and techno-economic challenges.

08 HYDROGEN↗
DOE OSTI2023

Optimization under uncertainty of a hybrid waste tire and natural gas feedstock flexible polygeneration system using a decomposition algorithm

Market uncertainties motivate the development of flexible polygeneration systems that are able to adjust operating conditions to favor production of the most profitable product portfolio. However, this operational flexibility comes at the cost of higher capital expenditure. A scenario-based two-stage stochastic nonconvex Mixed-Integer Nonlinear Programming (MINLP) approach lends itself naturally to optimizing these trade-offs. This work studies the optimal design and operation under uncertainty of a hybrid feedstock flexible polygeneration system producing electricity, methanol, dimethyl ether, olefins or liquefied (synthetic) natural gas. A recently developed C++ based software framework (named GOSSIP) is used for modeling the optimization problem as well as its efficient solution using the Nonconvex Generalized Benders Decomposition (NGBD) algorithm. Two different cases are studied: The first uses estimates of the means and variances of the uncertain parameters from historical data, whereas the second assesses the impact of increased uncertain parameter volatility. The value of implementing flexible designs characterized by the value of the stochastic solution (VSS) is in the range of 260–405 M$ for a scale of approximately 893 MW of thermal input. Increased price volatility around the same mean results in higher expected net present value and VSS as operational flexibility allows for asymmetric exploitation of price peaks.

42 ENGINEERING↗
DOE OSTI2023

A novel method for co-optimizing battery sizing and charging strategy of battery electric bus fleets: An application to the city of Paris

Battery-electric buses (BEBs) are a promising technology for replacing diesel buses and reducing their environmental burden. However, their charging process can take several hours, depending on the charging technique and strategy, making them susceptible to schedule disruptions. Furthermore, the selection of the charging strategy and battery size can increase the total capital investment and operational expenses of a BEB fleet, which is a major obstacle to its adoption. Therefore, to minimize the total cost of ownership (TCO) and prevent schedule disruptions, it is essential to establish a well-defined approach to determine an appropriate battery size and charging strategy for BEB fleets. This paper presents a method for reducing the TCO of BEB by determining the optimal battery size and charging strategy for each bus while satisfying operating constraints. The method involves a two-step optimization algorithm that uses Dynamic Programming and Genetic Algorithm. Further, the study applies this approach to the bus fleet serving line 21 in Paris and generates the optimal battery sizing, charging strategy, and required charging infrastructure. The results indicate that 100 kWh batteries offer the best trade-off between capital and operational expenditure for the fleet deployment if used with 65–85 kW chargers at bus terminals.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2019

Improving estimates of transmission capital costs for utility-scale wind and solar projects to inform renewable energy policy

Estimating the overall costs of transmission needed to integrate variable renewable energy (VRE) onto the grid is challenging. An improved understanding of these transmission costs would support electricity system planning as VRE penetrations increase. This paper brackets VRE transmission capital costs using multiple approaches based on interconnection studies, actual transmission projects, capacity-expansion simulation models, and aggregated U.S. VRE-related transmission expenditures. Each approach possesses advantages and drawbacks, and combining the approaches lends confidence to the results. The resulting range of average levelized VRE transmission costs is 1– 10 dollars/MWh, which is generally lower than earlier estimates in the literature. These transmission capital costs can increase the direct plant-level levelized cost of VRE by 3%–33%, based on levelized costs of energy of 29– 56 dollars/MWh for utility-scale wind and 36–46 dollars/MWh for utility-scale solar. As VRE deployment continues to expand, policy makers can use this information to (1) assess the benefits of transmission avoidance and deferral when comparing distributed energy resources versus utility-scale projects, (2) evaluate the potential costs of large-scale public transmission investments, and (3) better analyze system-level costs of utility-scale VRE technologies. Future research can expand on the framework presented here by providing a review of operation and maintenance costs for transmission systems.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

Mexico and U.S. Power Systems Under Variations in Natural Gas Prices

This study examines the impact of natural gas prices on the power systems of Mexico and the United States. For this, we develop an integrated modeling framework by soft linking three different techno-economic bottom-up models of the power and energy systems, one partial equilibrium model of the natural gas sector, and a partial equilibrium model of the Mexican energy sector. Our results show several interesting results: high natural gas prices raise the use of carbon-intensive technologies in the short-term and boost renewable investments at longer time intervals, increasing emissions in earlier periods and reducing them thereafter. Regarding system costs, because of more capital-intensive green power and lower expenditures in raw energy carriers, capital costs rise and operating costs decrease in the long haul. Furthermore, we see an increase in natural gas demand when its price is low, reducing long-term capital and operating costs through cheaper energy inputs in natural gas facilities and a lower share of capital-intensive renewable facilities in the power system. Concerning emissions, low natural-gas prices decrease coal use in the United States, reducing anthropogenic emissions until the last stages of the optimization period. For Mexico, they show heterogeneous results across models. Policymakers can use this study's results to understand the influence of natural gas prices in the Mexican and United States energy sectors.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2025

Uplifting winds: The surprisingly positive community-wide impact of wind energy installations on property values

A primary concern of stakeholders when considering a new wind project is the potential negative effects wind turbines may have on home values. Yet, what has been surprisingly overlooked in the literature and general discourse around wind energy is that the well-researched positive economic development and fiscal and amenity benefits of wind energy (e.g., increased tax base, tax revenue, better public services and employment gains) might positively affect jurisdiction-wide housing values. With a focus on school districts in the United States, we compare home values in school districts with wind energy installations, before and after a wind energy installation becomes operational, to home values in other school districts located in the same county but without a wind energy installation to provide some of the first causal evidence on the relationship between wind energy projects and district-wide property values. We find that wind projects lead to economically meaningful increases in district-wide housing values of approximately 3 %, when those values are compared to similar homes located in school districts in same-county without wind energy. The effect is strongly correlated with wind project size. The mechanisms, our research suggests, are likely related to relatively large increases in school district per-pupil revenues and expenditures, which are also correlated with wind project size. We suggest other possible mechanisms for the increased values as well.

Attitudes↗
DOE OSTI2016

A modeling comparison of deep greenhouse gas emissions reduction scenarios by 2030 in California

California aims to reduce greenhouse gas (GHG) emissions to 40% below 1990 levels by 2030. We compare six energy models that have played various roles in informing the state policymakers in setting climate policy goals and targets. These models adopt a range of modeling structures, including stock-turnover back-casting models, a least-cost optimization model, macroeconomic/macro-econometric models, and an electricity dispatch model. Results from these models provide useful insights in terms of the transformations in the energy system required, including efficiency improvements in cars, trucks, and buildings, electrification of end-uses, low- or zero-carbon electricity and fuels, aggressive adoptions of zero-emission vehicles (ZEVs), demand reduction, and large reductions of non-energy GHG emissions. Some of these studies also suggest that the direct economic costs can be fairly modest or even generate net savings, while the indirect macroeconomic benefits are large, as shifts in employment and capital investments could have higher economic returns than conventional energy expenditures. These models, however, often assume perfect markets, perfect competition, and zero transaction costs. They also do not provide specific policy guidance on how these transformative changes can be achieved. Greater emphasis on modeling uncertainty, consumer behaviors, heterogeneity of impacts, and spatial modeling would further enhance policymakers' ability to design more effective and targeted policies. Here, this paper presents an example of how policymakers, energy system modelers and stakeholders interact and work together to develop and evaluate long-term state climate policy targets. Lastly, even though this paper focuses on California, the process of dialogue and interactions, modeling results, and lessons learned can be generally adopted across different regions and scales.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗