Engineering topics

Witt, Adam M.

Publications and source records attributed to Witt, Adam M..

9 records

DOE OSTI2020

Feasibility of Using Additive Manufacturing to Produce Axial Flow Hydropower Turbine Housing, Runner, and Draft Tube

Oak Ridge National Laboratory (ORNL) worked with AMJET Turbine Systems, LLC (ATS), to demonstrate additive manufacturing of components for low head hydro turbine/generator applications. Several different types of additive manufacturing systems were used. Components were finished and assembled for testing in a turbine. However, one of the processes, Big Area Additive Manufacturing (BAAM),produced components that did not adequately perform due to persistent leaks that were caused by porosity in the parts produced. Therefore, the BAAM system was eliminated from contention. Vacuum infusion of rein into the parts eventually solved the porosity problem.Components were installed in anATS-8 turbine to be tested on the Keokuk Dam for operationally testing the unit.

13 HYDRO ENERGY↗

DOE OSTI2020

Costs of mitigating the environmental impacts of hydropower projects in the United States

Developers are required to mitigate the environmental impacts of hydropower projects in the United States (U.S.) but there is very little accessible information on the associated costs. This work compiles and analyses a dataset of environmental impacts mitigation costs for 182 hydropower projects based on documents obtained from the U.S. Federal Energy Regulatory Commission (FERC). The analysis shows that environmental costs vary wildly across hydropower project classes and mitigation measures, even when normalized by plant capacity. Capital costs per kilowatt are generally higher for relicensed conventional hydropower plants, and lower for new and relicensed pumped storage hydropower plants, relative to other project classes. Smaller plants tend to spend a higher share of total project costs on mitigating environmental impacts than larger plants, and measures related to Aquatic Species, Project Operations, and Recreation have the highest capital cost per kilowatt. These findings mean that environmental costs could become a key decision variable for new hydropower developments in the U.S. due to the small scale of most of the remaining potential and the increasing stringency of environmental requirements. Therefore, technologies to reduce the environmental impacts and costs of hydropower would be important for future project developments.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Evidence-based indicator approach to guide preliminary environmental impact assessments of hydropower development

Global expansion of hydropower resources has increased in recent years to meet growing energy demands and fill worldwide gaps in electricity supply. However, hydropower induces significant environmental impacts on river ecosystems - impacts that are addressed through environmental impact assessment (EIA) processes. The need for effective EIA processes is increasing as environmental regulations are either stressed in developing countries undertaking rapid expansion of hydropower capacity or time- and resource-intensive in developed countries. Part of the challenge in implementing EIAs lies in reaching a consensus among stakeholders regarding the most important environmental factors as the focus of impact studies. To help address this gap, we developed a weight-of-evidence approach (and toolkit) as a preliminary and coarse assessment of the most relevant impacts of hydropower on primary components of the river ecosystem, as identified using river function indicators. Through a science-based questionnaire and predictive model, users identify which environmental indicators may be impacted during hydropower development as well as those indicators that have the highest levels of uncertainty and require further investigation. Furthermore, an assessment tool visualizes inter-dependent indicator relationships, which help formulate hypotheses about causal relationships explored through environmental studies. We apply these tools to four existing hydropower projects and one hypothetical new hydropower project of varying sizes and environmental contexts. We observed consistencies between the output of our tools and the Federal Energy Regulatory Commission licensing process (inclusive of EIAs) but also important differences arising from holistic scientific evaluations (our toolkit) versus regulatory policies. The tools presented herein are aimed at increasing the efficiency of the EIA processes that engender environmental studies without loss of rigor or transparency of rationale necessary for understanding, considering, and mitigating the environmental consequences of hydropower.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2019

An Assessment of Hydropower Environmental Mitigation Costs

This report provides an assessment of environmental mitigation costs for hydropower projects across the United States (U.S.) based on data extracted from Environmental Assessments (EA) submitted to the Federal Energy Regulatory Commission (FERC). EAs are required by the Federal Power Act (FPA) for hydropower license and relicense applications to weigh the “power” and “non-power” (i.e. environmental) benefits of their development and operation. For this analysis, we collected data from 184 EA documents reviewed by FERC between 1996 and 2018, and created a database of environmental protection, mitigation, and enhancement (PM&E) measures with their associated economic information. The data cover two hydropower relicense categories—103 Relicensed Conventional Hydropower Dams (RCHD) and 6 Relicensed Pumped Storage Hydropower (RPSH) projects—and three new development categories—57 hydropower retrofits at Non-Powered Dams (NPD), 11 New Stream-Reach Development (NSD) projects and 6 Pumped Storage Hydropower (NPSH) projects. For the analysis, we classify the PM&E measures into 11 Tier 1 categories. We evaluated capital and operations & maintenance (O&M) costs of PM&E measures on a $\$$/kW basis by project type and mitigation category, as well as their share in the total project levelized cost of energy (LCOE).

13 HYDRO ENERGY↗

DOE OSTI2019

A Checklist of River Function Indicators for hydropower ecological assessment

Hydropower generation has benefits for societies that seek low-carbon, renewable energy alternatives, but sustainable hydropower production will require an explicit consideration of potential tradeoffs between socioeconomic and environmental priorities. These tradeoffs are typically explored during a formal environmental impact assessment process that can be complex and controversial. The steps taken to address stakeholder concerns through impact hypotheses and field studies are not always transparent. We have designed a Checklist of River Function Indicators to facilitate stakeholder discussions during hydropower licensing and to support more transparent, holistic, and scientifically informed hydropower environmental analyses. Based on a database of environmental metrics collected from hydropower project studies documented by the Federal Energy Regulatory Commission (FERC), the International Hydropower Association, the Low Impact Hydropower Institute, and peer-reviewed scientific literature, our proposed Checklist of River Function Indicators contains 51 indicators in six categories. We have tested the usefulness of the Indicators by applying them to seven hydropower projects documented by FERC. Among the case study projects, 44 of the 51 Indicators were assessed according to the FERC documentation. Although each hydropower project presents unique natural resource issues and stakeholder priorities, the proposed Indicators can provide a transparent starting point for stakeholder discussions about which ecological impacts should be considered in hydropower planning and relicensing assessments.

13 HYDRO ENERGY↗

DOE OSTI2019

Instruction Manual: River Function Questionnaire

The River Function Questionnaire (Questionnaire) is a series of questions designed to help stakeholders determine the impacts of hydropower on a series of environmental indicators, i.e. river functions, that may need to be understood or addressed through additional field studies or environmental assessments. In order to provide a platform accessible to many users, the questionnaire was developed in Microsoft Excel with convenient macro-enabled interactive features. The Questionnaire was developed under the Department of Energy (DOE)-funded Environmental Metrics for Hydropower (EMH) project in FY 2018. This document provides an instruction manual that provides overall guidance and step-by-step instructions for use.

13 HYDRO ENERGY↗

DOE OSTI2018

Standard Modular Hydropower: Case Study on Modular Facility Design

Hydropower is a reliable, cost-effective, and widely deployed method of harnessing the power of river systems for human benefit.The undeveloped technical hydropower resource in the United States consists overwhelmingly of sites with small hydropower potential of less than 10 MW of installed capacity. Most existing hydropower projects and the bulk of proposed projects in the Federal Energy Regulatory Commission development pipeline are also small hydropower projects. However, the rate of development of new small hydropower projects is at a historical low because of the risks, costs, and uncertainty associated with project development. An acute challenge is the identification and mitigation of adverse environmental impacts, such as alterations to streamflow and water quality and the introduction of barriers that threaten geomorphologic processes and the resiliency of ecological communities. Success in new small hydropower development demands that low-cost, innovative approaches be developed to decrease the adverse environmental impacts of construction and operation.

13 HYDRO ENERGY↗

DOE OSTI2018

United States trends in non-powered dam electrification

Over the past two decades, retrofitting existing non-powered dams for electricity generation has been the primary hydropower development activity in United States. A total of 58 existing non-powered dams are currently licensed to produce an estimated 3.7 TWh of annual energy output from 888 MW of cumulative installed capacity. Here in this article we provide a review of development trends, focusing on the variety of dam types developed, strategies by type, cost data, environmental mitigation trends, and market drivers.

13 HYDRO ENERGY↗

DOE OSTI2018

Burden on hydropower units for short-term balancing of renewable power systems

There is a general need to change hydropower operational regimes to balance the growing contribution of variable renewable energy sources in power systems. Quantifying the burden on generation equipment is increasingly uncertain and difficult. Here, we propose a framework combining technical and economic indicators to analyze primary frequency control (PFC) on a timescale of seconds. We develop a model integrating hydraulic, mechanical, and electrical subsystems to characterize efficiency loss, wear and fatigue, regulation mileage, and frequency quality. We evaluate burden relief strategies under three idealized remuneration schemes for PFC, inspired by those used in Sweden, the USA, and China, respectively. We show how burden and compensation vary under future scenarios of renewable power systems. Here, our framework can be used by producers to develop favorable operation strategies that reduce burden and increase economic value, and by transmission system operators to provide insights on the relation between incentive structures and regulating performance.

13 HYDRO ENERGY↗