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At least 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Comparing Resource Adequacy Metrics

As the penetration of variable generation (wind and solar) increases around the world, there is an accompanying growing interest and importance in accurately assessing the contribution that these resources can make toward planning reserve. This contribution, also known as the capacity credit or capacity value of the resource, is best quantified by using a probabilistic measure of overall resource adequacy. In recognizing the variable nature of these renewable resources, there has been interest in exploring the use of reliability metrics other than loss of load expectation. In this paper, we undertake some comparisons using data from the Western Electricity Coordinating Council in the western United States.

14 SOLAR ENERGY↗
DOE OSTI2024

South Asia Group for Energy - Sri Lanka

Sri Lanka set a target of generating 70% of its electricity from renewable energy sources by 2030. This goal includes the addition of 5.8 GW of renewable power capacity, comprising hydropower, solar, wind, and biomass, between 2023 and 2030, with an interim target of adding 2.5 GW of renewable capacity by 2026. To accomplish this, Sri Lanka's power grid needs significant transformation and modernization to handle the integration of variable renewable energy sources effectively. The South Asia Group for Energy (SAGE) is helping Sri Lanka's grid operator, the Ceylon Electricity Board (CEB), understand the gaps for operating the grid with higher renewable share and identifying technology and research requirements to establish a variable renewable energy control center.

ENERGY PLANNING, POLICY, AND ECONOMY,POWER TRANSMI↗
DOE OSTI2013

Fundamental Drivers of the Cost and Price of Operating Reserves

Operating reserves impose a cost on the electric power system by forcing system operators to keep partially loaded spinning generators available for responding to system contingencies variable demand. In many regions of the United States, thermal power plants provide a large fraction of the operating reserve requirement. Alternative sources of operating reserves, such as demand response and energy storage, may provide more efficient sources of these reserves. However, to estimate the potential value of these services, the cost of reserve services under various grid conditions must first be established. This analysis used a commercial grid simulation tool to evaluate the cost and price of several operating reserve services, including spinning contingency reserves and upward regulation reserves. These reserve products were evaluated in a utility system in the western United States, considering different system flexibilities, renewable energy penetration, and other sensitivities. The analysis demonstrates that the price of operating reserves depend highly on many assumptions regarding the operational flexibility of the generation fleet, including ramp rates and the fraction of fleet available to provide reserves.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2013

Fundamental Drivers of the Cost and Price of Operating Reserves

Operating reserves impose a cost on the electric power system by forcing system operators to keep partially loaded spinning generators available for responding to system contingencies variable demand. In many regions of the United States, thermal power plants provide a large fraction of the operating reserve requirement. Alternative sources of operating reserves, such as demand response and energy storage, may provide more efficient sources of these reserves. However, to estimate the potential value of these services, the cost of reserve services under various grid conditions must first be established. This analysis used a commercial grid simulation tool to evaluate the cost and price of several operating reserve services, including spinning contingency reserves and upward regulation reserves. These reserve products were evaluated in a utility system in the western United States, considering different system flexibilities, renewable energy penetration, and other sensitivities. The analysis demonstrates that the price of operating reserves depend highly on many assumptions regarding the operational flexibility of the generation fleet, including ramp rates and the fraction of fleet available to provide reserves.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2015

Renewable Electricity Grid Integration Roadmap for Mexico. Supplement to the IEA Expert Group Report on Recommended Practices for Wind Integration Studies

As a recognized leader in efforts to mitigate global climate change, the Government of Mexico (GOM) works proactively to reduce emissions, demonstrating strong political will and capacity to comprehensively address climate change. Since 2010, the U.S. government (USG) has supported these efforts by partnering with Mexico under the Enhancing Capacity for Low Emission Development Strategies (EC-LEDS) program. Through the program, the USG has partnered with Mexico’s Ministry of Energy (SENER), as well as other government agencies, to support GOM in reaching its clean energy and climate change goals. Specifically, the EC-LEDS program is supporting GOM’s clean energy goal of generating 35% of its electricity from renewable energy (RE) by 2024. EC-LEDS, through the U.S. Agency for International Development (USAID) and the U.S Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL), has been collaborating with SENER and GOM interagency working group—the Consejo Consultivo para las Energías Renovables (Consultative Council on Renewable Energy)—to create a grid integration roadmap for variable RE. 1 A key objective in creating a grid integration roadmap is assessing likely impacts of wind and solar energy on the power system and modifying planning and operations accordingly. This paper applies best practices in conducting a grid integration study to the Mexican context.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

Load Forecasting for the Moroccan Electricity Sector

The Moroccan electricity sector is undergoing rapid transformation as it seeks to increase its utilization of renewable energy from its abundant domestic supply. Key to implementing variable renewable energy is understanding current electricity demand and forecasting this demand on the long, medium, and short timescales. This report leverages existing Moroccan electricity sector data to build basic load forecasts on these timescales. Taking these forecasts, the report recommends next steps in terms of additional algorithms, mathematical models, data collection, and scenarios (such as vehicle electrification or high levels of distributed generation) that should be examined for advanced load forecasts.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

Multistage Stochastic optimization for mid-term integrated generation and maintenance scheduling of cascaded hydroelectric system with renewable energy uncertainty

The uncertainties resulting from the escalating penetration of renewable energy resources pose severe challenges to the efficient operation of modern power systems. Hydroelectricity is characterized by its flexibility, controllability, and reliability, and thus becomes one of the most ideal energy resources to hedge against such uncertainties. This paper studies the mid-term integrated generation and maintenance scheduling of a cascaded hydroelectric system (CHS) consisting of multiple cascaded reservoirs and hydroelectric units. To precisely describe the mid-term water regulation policies, the hydraulic coupling relationship and water-energy nexus of CHS are incorporated into the proposed optimization model. The uncertainties of natural water inflow and the power outputs of wind/solar energy generation are taken into consideration and captured via a stochastic process modeled by a scenario tree. A multistage stochastic optimization (MSO) approach is developed to coordinate the complementary operations of multiple energy resources, by optimizing the mid-term water resource management, generation scheduling, and maintenance scheduling of CHS. The proposed MSO model is formulated as a large-scale mixed-integer linear program that presents significant computational intractability. To address this issue, a tailored Benders decomposition algorithm is developed. Two real-world case studies are conducted to demonstrate the capability and characteristics of the proposed model and algorithm. The computational results show that the proposed MSO model can exploit the flexibility of hydroelectricity to efficiently respond to variable wind and solar power, and reserve water resources for the generation in peak months to reduce the consumption of fossil fuel. Furthermore, the proposed solution approach also exhibits promising computational efficiency when handling large-scale models.

13 HYDRO ENERGY↗
DOE OSTI2021

Resource Forecast and Ramp Visualization for Situational Awareness (RAVIS)

The Resource Forecast and Ramp Visualization for Situational Awareness (RAVIS) is an open-source tool for visualizing variable renewable resource forecasts and ramp alerts for significant up/down ramps in renewable resource and the consequent net-load. The modular dashboard of RAVIS contains configurable panes for viewing- probabilistic time series forecasts, ramp event alerts on the look-ahead timeline, spatially resolved resource sites and forecasts, and system simulation and market clearing data such as transmission lines utilization, nodal prices and available generation flexibility.

Krishnan, Venkat↗
DOE OSTI2024

Genome resources for three modern cotton lines guide future breeding efforts

Cotton ( Gossypium hirsutum L.) is the key renewable fibre crop worldwide, yet its yield and fibre quality show high variability due to genotype-specific traits and complex interactions among cultivars, management practices and environmental factors. Modern breeding practices may limit future yield gains due to a narrow founding gene pool. Precision breeding and biotechnological approaches offer potential solutions, contingent on accurate cultivar-specific data. Here we address this need by generating high-quality reference genomes for three modern cotton cultivars (‘UGA230’, ‘UA48’ and ‘CSX8308’) and updating the ‘TM-1’ cotton genetic standard reference. Despite hypothesized genetic uniformity, considerable sequence and structural variation was observed among the four genomes, which overlap with ancient and ongoing genomic introgressions from ‘Pima’ cotton, gene regulatory mechanisms and phenotypic trait divergence. Differentially expressed genes across fibre development correlate with fibre production, potentially contributing to the distinctive fibre quality traits observed in modern cotton cultivars. These genomes and comparative analyses provide a valuable foundation for future genetic endeavours to enhance global cotton yield and sustainability.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2012

Sub-Hour Solar Data for Power System Modeling From Static Spatial Variability Analysis: Preprint

High penetration renewable integration studies need high quality solar power data with spatial-temporal correlations that are representative of a real system. This paper will summarize the research relating sequential point-source sub-hour global horizontal irradiance (GHI) values to static, spatially distributed GHI values. This research led to the development of an algorithm for generatingcoherent sub-hour datasets that span distances ranging from 10 km to 4,000 km. The algorithm, in brief, generates synthetic GHI values at an interval of one-minute, for a specific location, using SUNY/Clean Power Research, satellite-derived, hourly irradiance values for the nearest grid cell to that location and grid cells within 40 km.

14 SOLAR ENERGY↗
DOE OSTI2018

Performance Analysis of a Biomass Gasifier Genset at Varying Operating Conditions

Abstract. An All Power Labs PP20 gasifier generation set (Berkeley, Calif.) was tested to evaluate its suitability for powering biomass conversion technologies (BCT) at remote forest operations sites. Feedstock of the species tanoak (), coast redwood (), and Douglas fir () were tested at moisture contents of 15% and 25% (wet basis). The PP20 was connected to a load bank with five different load profiles designed to simulate possible BCT loads. Two parameters of power quality, voltage variability, and frequency deviation, were determined to be within acceptable limits. The unit also successfully powered a remote biochar operation in Branscomb, California. Emissions of the PP20, when compared to diesel generator regulations, would meet non-methane hydrocarbons (NMHC) and NO X requirements but exceed the CO emissions limits by a factor of ten. The CO emissions could be reduced by adding a catalytic converter. The results indicate that it is possible to use a PP20 unit to provide electric power for the highly variable loads of a BCT system. Keywords: Bioenergy, Biomass conversion technology, Gasification, Renewable energy.

Agriculture↗
DOE OSTI2012

Hawaii Utility Integration Initiatives to Enable Wind (Wind HUI) (Final Technical Report)

To advance the state and nation toward clean energy, Hawaii is pursuing an aggressive Renewable Portfolio Standard (RPS), 40% renewable generation and 30% energy efficiency and transportation initiatives by 2030. Additionally, with support from federal, state and industry leadership, the Hawaii Clean Energy Initiative (HCEI) is focused on reducing Hawaii's carbon footprint and global warming impacts. To keep pace with the policy momentum and changing industry technologies, the Hawaiian Electric Companies are proactively pursuing a number of potential system upgrade initiatives to better manage variable resources like wind, solar and demand-side and distributed generation alternatives (i.e. DSM, DG).

17 WIND ENERGY↗
DOE OSTI2022

2022 FORCE Development Status Update

Due to the rapidly changing nature of the energy landscape in both the U.S. and abroad, including the increase in non-dispatchable variable renewable energy (VRE) deployment and the abundance of carbonbased dispatchable fuels, the Integrated Energy Systems (IES) program under the Department of Energy (DOE) has been engaged in determining whether IES could assist in providing nuclear power plants (NPPs) with a viable strategy for achieving future economic competitiveness. This includes enhanced dispatch flexibility for NPPs, thanks to thermal and electrical storage technology as well as the generation of ancillary commodities such as hydrogen, desalinated water, and synthetic fuels from the heat generated by NPPs. The technical and economic viability of these systems is of primary concern to the IES program, with the intent of providing insight to the wider nuclear energy community at large.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Existing Methods for Grid Strength Assessment and Role of Hydropower in Future Grids

The power system is undergoing rapid evolution with increasing penetration of inverter-based resources (IBRs), large loads, microgrids, and power electronic devices. Ensuring reliable and stable operation of the modern power grid is a multi-faceted challenge that requires detailed understanding of this complex system. Dynamic stability is a major concern in maintaining the security of power grids as the generation mixes and large loads transitions to include high shares of power electronic devices. The operation of IBRs in regions with low system strength and higher grid impedances has been found to be the main reason behind many of the power system instabilities that manifest themselves in various types of oscillations and interactions that, if not properly addressed and damped, can jeopardize the reliable operation of the power system. Weak grid conditions compound such stability problems, particularly when many IBRs operate in proximity to and connect to weak power grids. Therefore, it is important to assess grid strength for planning, integration and operation of IBRs for a given power system. In this report, we aim to understand and classify existing methodologies for grid strength assessment, along with their limitations and future needs. Further, we aim to utilize the huge untapped potential in utilizing hydro energy resources in addressing some of the pertinent challenges of grid strength and reliable operation of modern power systems. Hydropower, historically valued for its flexibility and dispatchability, now faces new constraints due to reduced share of synchronous machines in the generation mix and seasonal variability of available water resources. Yet, these same plants present untapped potential beyond energy generation - notably, as providers of critical grid services. This report explores how hydropower plants, particularly through operation as synchronous condensers, can play a pivotal role in strengthening the grid amid evolving system dynamics.

13 HYDRO ENERGY↗
DOE OSTI2016

Grid-Integrated Distributed Solar: Addressing Challenges for Operations and Planning, Greening the Grid

Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid. This document introduces a brief overview of common technical impacts of PV on distribution systems and operations, as well as emerging strategies for successfully addressing some of the priority issues.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2015

Three‐phase probabilistic load flow in radial and meshed distribution networks

With the introduction of higher levels of renewables and demand response programs, traditional deterministic power system tools fall short of expectations. Probabilistic load flow (PLF) takes into account the inconsistency or the unknown loads, and generation in the fundamental load flow analysis. This study proposes a PLF solution for both balanced and unbalanced, radial and weakly meshed networks without explicitly using the Y ‐bus matrix. It allows for discrete probability density functions as input variables without having to assume a predefined distribution. The nodal voltages and the power flows can be calculated independently from one another. The proposed method is applied to the IEEE 123 Node Test Feeder and the IEEE 13 Node Test Feeder in both its original radial configuration and a modified mesh configuration, including a load replaced with a wind turbine. The results are validated by comparison of the proposed method's solutions to those obtained using cumulants and Monte Carlo simulation. The proposed PLF method provides an accurate and practical way for finding the solution to stochastic problems occurring in power distribution systems allowing for real‐system data to be analysed.

Melhorn, Alexander C.↗