Christopher Clack

Vibrant Clean Energy (VCE®) partnered with Energy Innovations to study the potential impact of a regional transmission organization (RTO) for the Southeastern United States (SE-RTO).

The modeling (using WIS:dom®-P) found that with an RTO the region could save $384 billion by 2040, create 285,000 full time jobs, reduce emissions by 37% and provide transparency in the region.

The team modeled four scenarios. Importantly, the first scenario mimicked the utilities’ integrated… Show more

Vibrant Clean Energy (VCE®) partnered with Energy Innovations to study the potential impact of a regional transmission organization (RTO) for the Southeastern United States (SE-RTO).

The modeling (using WIS:dom®-P) found that with an RTO the region could save $384 billion by 2040, create 285,000 full time jobs, reduce emissions by 37% and provide transparency in the region.

The team modeled four scenarios. Importantly, the first scenario mimicked the utilities’ integrated resource plans (IRPs) and found that an increase in thermal generation exceeded requirements and inflated costs. Conversely, the SE-RTO scenario reduced the dependency on thermal generation and shifted to low-cost variable generation.

One of the sensitivity scenarios studied an alternative IRP, which allowed for competitive build out and economic dispatch. This scenario produced approximately 60% of the savings of the SE-RTO. Finally, a fourth scenario determined the benefit of an SE-RTO when nuclear power plants remained online through 2040. This scenario was very slightly more expensive than the SE-RTO scenario, but had far fewer emissions.

Interestingly wind power, in the modeling, became an important contribution to the electricity mix. With it increasingly providing capacity requirements for winter demand profiles. Further, the modeling found that distributed energy resources (DERs) and their co-optimization provided 10% of the system savings. Show less

Vibrant Clean Energy (VCE®) partnered with Energy Innovations to study the potential impact of a regional transmission organization (RTO) for the Southeastern United States (SE-RTO).

The modeling (using WIS:dom®-P) found that with an RTO the region could save $384 billion by 2040, create 285,000 full time jobs, reduce emissions by 37% and provide transparency in the region.

The team modeled four scenarios. Importantly, the first scenario mimicked the utilities’ integrated… Show more

Vibrant Clean Energy (VCE®) partnered with Energy Innovations to study the potential impact of a regional transmission organization (RTO) for the Southeastern United States (SE-RTO).

The modeling (using WIS:dom®-P) found that with an RTO the region could save $384 billion by 2040, create 285,000 full time jobs, reduce emissions by 37% and provide transparency in the region.

The team modeled four scenarios. Importantly, the first scenario mimicked the utilities’ integrated resource plans (IRPs) and found that an increase in thermal generation exceeded requirements and inflated costs. Conversely, the SE-RTO scenario reduced the dependency on thermal generation and shifted to low-cost variable generation.

One of the sensitivity scenarios studied an alternative IRP, which allowed for competitive build out and economic dispatch. This scenario produced approximately 60% of the savings of the SE-RTO. Finally, a fourth scenario determined the benefit of an SE-RTO when nuclear power plants remained online through 2040. This scenario was very slightly more expensive than the SE-RTO scenario, but had far fewer emissions.

Interestingly wind power, in the modeling, became an important contribution to the electricity mix. With it increasingly providing capacity requirements for winter demand profiles. Further, the modeling found that distributed energy resources (DERs) and their co-optimization provided 10% of the system savings. Show less

Vibrant Clean Energy (VCE®) partnered with Energy Innovations to study the potential impact of a regional transmission organization (RTO) for the Southeastern United States (SE-RTO).

The modeling (using WIS:dom®-P) found that with an RTO the region could save $384 billion by 2040, create 285,000 full time jobs, reduce emissions by 37% and provide transparency in the region.

The team modeled four scenarios. Importantly, the first scenario mimicked the utilities’ integrated… Show more

Vibrant Clean Energy (VCE®) partnered with Energy Innovations to study the potential impact of a regional transmission organization (RTO) for the Southeastern United States (SE-RTO).

The modeling (using WIS:dom®-P) found that with an RTO the region could save $384 billion by 2040, create 285,000 full time jobs, reduce emissions by 37% and provide transparency in the region.

The team modeled four scenarios. Importantly, the first scenario mimicked the utilities’ integrated resource plans (IRPs) and found that an increase in thermal generation exceeded requirements and inflated costs. Conversely, the SE-RTO scenario reduced the dependency on thermal generation and shifted to low-cost variable generation.

One of the sensitivity scenarios studied an alternative IRP, which allowed for competitive build out and economic dispatch. This scenario produced approximately 60% of the savings of the SE-RTO. Finally, a fourth scenario determined the benefit of an SE-RTO when nuclear power plants remained online through 2040. This scenario was very slightly more expensive than the SE-RTO scenario, but had far fewer emissions.

Interestingly wind power, in the modeling, became an important contribution to the electricity mix. With it increasingly providing capacity requirements for winter demand profiles. Further, the modeling found that distributed energy resources (DERs) and their co-optimization provided 10% of the system savings. Show less

Close coordination between generation and transmission operations and planning is critical to cost effective and reliable energy production and delivery; such coordination, in the presence of ownership diversity, is indeed a primary and challenging goal of regional transmission organizations in the US and similar organizations worldwide. Optimizing these sectors separately overlooks potential synergies that may allow for more effective design and operation of power systems. Coordinated… Show more

Close coordination between generation and transmission operations and planning is critical to cost effective and reliable energy production and delivery; such coordination, in the presence of ownership diversity, is indeed a primary and challenging goal of regional transmission organizations in the US and similar organizations worldwide. Optimizing these sectors separately overlooks potential synergies that may allow for more effective design and operation of power systems. Coordinated expansion planning (CEP), where both generation and transmission decisions are coordinated, has become especially relevant to present day planning and operations. There are various reasons for this, some of which include the desire to obtain the most environmental and economic benefit from deeper penetration of renewable energy sources, the need for effective deployment of emerging storage technologies, opportunities to capture and harness the electrification of the transport sector, increased interdependencies with other sectors (e.g., gas), and accommodating increased shares of distributed energy resources in distribution grids. These changes result in increased short-term and long-term uncertainties, as well as an increased need for improved representation of multiscale temporal and spatial dynamics (e.g., representing hourly or sub-hourly intertemporal couplings in multi-decadal expansion models). The purpose of this work is to characterize the state-of-the-art in CEP models and identify technical challenges of grid development planning and research and development (R&D) needs for the new generation of these CEP models. Show less

The present EPRI report documents the possible considerations needed in advanced Coordinated Expansion Planning (CEP) for the future electricity and energy system. VCE® contributed to the report using its deep knowledge of modeling and grid integration techniques. The lengthy report touches on many aspects in developing and deploying models for the changing energy landscape. Most of the components are already included in the VCE® WIS:dom® Optimization modeling suite of tools. Scientific Paper… Show more

The present EPRI report documents the possible considerations needed in advanced Coordinated Expansion Planning (CEP) for the future electricity and energy system. VCE® contributed to the report using its deep knowledge of modeling and grid integration techniques. The lengthy report touches on many aspects in developing and deploying models for the changing energy landscape. Most of the components are already included in the VCE® WIS:dom® Optimization modeling suite of tools. Scientific Paper DOI: https://doi.org/10.1016/j.ijepes.2020.106089 Show less

The present study finds that electrifying transportation and heating (along with some other sectors) while decarbonizing the Colorado electricity sector will enable the reduction of economy-wide GHG emissions to below 70% of 2005 levels by 2040, while lowering both electricity and energy costs for all Coloradans. Personal vehicle fuel costs are reduced by over $600 per year (if an EV is used), household heating fuel costs are reduced by over $500 when electrified. In addition, all electricity… Show more

The present study finds that electrifying transportation and heating (along with some other sectors) while decarbonizing the Colorado electricity sector will enable the reduction of economy-wide GHG emissions to below 70% of 2005 levels by 2040, while lowering both electricity and energy costs for all Coloradans. Personal vehicle fuel costs are reduced by over $600 per year (if an EV is used), household heating fuel costs are reduced by over $500 when electrified. In addition, all electricity rates are lowered by 15%, meaning those that do not electrify also benefits with lower costs amounting to $98 per year.

The reduction in GHG emissions equates to Colorado exceeding all its target in HB19-1261 through 2040. The electrification of transportation and heating becomes essential in helping lower economy-wide emissions in an affordable manner. Their additions provides flexibility within the electricity grid over Colorado, which can enable more variable renewable energy sources.

The study was commissioned by Community Energy, Inc. as part of a series of studies to be released in 2019. Vibrant Clean Energy, LLC performed all the modeling using the WIS:dom® optimization model with publicly available data and assumptions. All salient inputs and outputs are provided, along with a report and a summary presentation. Show less

The present study finds that adding Electric Vehicles (EVs) to the Colorado electricity system will assist in reducing GHG emissions, while lowering energy costs for Coloradans. Fuel costs are reduced by nearly $600 per year, while slightly lowering electricity rates.

The reduction in GHG emissions equates to more than completely decarbonizing the electricity grid alone. The electrification of transportation becomes essential in helping lower economy-wide emissions in an affordable… Show more

The present study finds that adding Electric Vehicles (EVs) to the Colorado electricity system will assist in reducing GHG emissions, while lowering energy costs for Coloradans. Fuel costs are reduced by nearly $600 per year, while slightly lowering electricity rates.

The reduction in GHG emissions equates to more than completely decarbonizing the electricity grid alone. The electrification of transportation becomes essential in helping lower economy-wide emissions in an affordable manner. The addition of EVs provides flexibility within the electricity grid over Colorado, which can enable more variable renewable energy sources.

The study was commissioned by Community Energy, Inc. as part of a series of studies to be released in 2019. Vibrant Clean Energy, LLC performed all the modeling using the WIS:dom® optimization model with publicly available data and assumptions. All salient inputs and outputs are provided, along with a summarizing report and WIS:dom® description. Show less

Wind power installations have been increasing in recent years. Because wind turbines can influence local wind speeds, temperatures, and surface fluxes, weather forecasting models should consider their effects. Wind farm parameterizations do currently exist for numerical weather prediction models. They generally consider two turbine impacts: elevated drag in the region of the wind turbine rotor disk and increased turbulent kinetic energy production. The wind farm parameterization available in… Show more

Wind power installations have been increasing in recent years. Because wind turbines can influence local wind speeds, temperatures, and surface fluxes, weather forecasting models should consider their effects. Wind farm parameterizations do currently exist for numerical weather prediction models. They generally consider two turbine impacts: elevated drag in the region of the wind turbine rotor disk and increased turbulent kinetic energy production. The wind farm parameterization available in the Weather Research and Forecasting (WRF) Model calculates this drag and TKE as a function of hub-height wind speed. However, recent work has suggested that integrating momentum over the entire rotor disk [via a rotor-equivalent wind speed (REWS)] is more appropriate, especially for cases with high wind shear. In this study, we implement the REWS in the WRF wind farm parameterization and evaluate its impacts in an idealized environment, with varying amounts of wind speed shear and wind directional veer. Specifically, we evaluate three separate cases: neutral stability with low wind shear, high stability with high wind shear, and high stability with nonlinear wind shear. For most situations, use of the REWS with the wind farm parameterization has marginal impacts on model forecasts. However, for scenarios with highly nonlinear wind shear, the REWS can significantly affect results. Show less

America has officially entered the “coal cost crossover” – where existing coal is increasingly more expensive than cleaner alternatives. Today, local wind and solar could replace approximately 74 percent of the U.S. coal fleet at an immediate savings to customers. By 2025, this number grows to 86 percent of the coal fleet.

This analysis complements existing research into the costs of clean energy undercutting coal costs, by focusing on which coal plants could be replaced locally (within… Show more

America has officially entered the “coal cost crossover” – where existing coal is increasingly more expensive than cleaner alternatives. Today, local wind and solar could replace approximately 74 percent of the U.S. coal fleet at an immediate savings to customers. By 2025, this number grows to 86 percent of the coal fleet.

This analysis complements existing research into the costs of clean energy undercutting coal costs, by focusing on which coal plants could be replaced locally (within 35 miles of the existing coal plant) at a saving.

It suggests local decision-makers should consider plans for a smooth shut-down of these old plants—assessing their options for reliable replacement of that electricity, as well as financial options for communities dependent on those plants.

This report should begin a longer conversation about the most cost-effective replacement for coal, which may incl Show less

Replacing all of Colorado’s aging coal plants with a mix of wind, solar, natural gas and storage could save the state’s electric customers in excess of $250 million per year. Resulting in a cumulative saving of over $2.5 billion in through 2040, while reducing emissions by 510 million metric tons and increasing electric sector jobs. The $2.5 billion savings is in addition to all the coal-fired power plants having their debt repaid.

The removal of nearly 5,000 MW of coal is a turnover of… Show more

Replacing all of Colorado’s aging coal plants with a mix of wind, solar, natural gas and storage could save the state’s electric customers in excess of $250 million per year. Resulting in a cumulative saving of over $2.5 billion in through 2040, while reducing emissions by 510 million metric tons and increasing electric sector jobs. The $2.5 billion savings is in addition to all the coal-fired power plants having their debt repaid.

The removal of nearly 5,000 MW of coal is a turnover of about 25% of the entire Colorado electricity fleet. With such rich wind and solar resources, Colorado can take advantage and quickly remove high emitting technologies with much lower-cost alternatives, while equitably distributing costs and benefits.

The study was commissioned by Community Energy, Inc. as part of a series of studies to be released in early 2019. Vibrant Clean Energy, LLC performed all the modeling using the WIS:dom optimization model with publicly available data and assumptions. All salient inputs and outputs are provided, along with a summary presentation. DOI: https://doi.org/10.6084/m9.figshare.13087679 Show less

This study offers pathways and analysis of how Minnesota (MN) could transition from its current energy system to one that is decarbonized by 80% (from 2005 level) by 2050 [80×50]. The decarbonization would include the entire economy and is assumed to include energy efficiency measures, electrification, and generation changes. The study will model the entire United States (US) portion of the Eastern Interconnection along with electricity trade between the US, Mexico and Canada. The primary… Show more

This study offers pathways and analysis of how Minnesota (MN) could transition from its current energy system to one that is decarbonized by 80% (from 2005 level) by 2050 [80×50]. The decarbonization would include the entire economy and is assumed to include energy efficiency measures, electrification, and generation changes. The study will model the entire United States (US) portion of the Eastern Interconnection along with electricity trade between the US, Mexico and Canada. The primary purpose of the study is to determine how Minnesota can meet the goals of 80×50 under various scenarios. These scenarios will be evaluated against a baseline scenario that assumes minimal electrification and no additional climate policies beyond those already enacted into law. DOI: https://doi.org/10.6084/m9.figshare.13087670 Show less

(More authors than I could add - 32 in total) Models show that to avert dangerous levels of climate change, global carbon dioxide emissions must fall to zero later this century. Most of these emissions arise from energy use. Davis et al. review what it would take to achieve decarbonization of the energy system. Some parts of the energy system are particularly difficult to decarbonize, including aviation, long-distance transport, steel and cement production, and provision of a reliable… Show more

(More authors than I could add - 32 in total) Models show that to avert dangerous levels of climate change, global carbon dioxide emissions must fall to zero later this century. Most of these emissions arise from energy use. Davis et al. review what it would take to achieve decarbonization of the energy system. Some parts of the energy system are particularly difficult to decarbonize, including aviation, long-distance transport, steel and cement production, and provision of a reliable electricity supply. Current technologies and pathways show promise, but integration of now-discrete energy sectors and industrial processes is vital to achieve minimal emissions. Show less

In this study, Vibrant Clean Energy, LLC (VCE) analyzes alternative least-cost energy and capacity resource pathways to the continued operation of the Dynegy-Vistra coal power fleet in Southern Illinois, also known as “Zone 4” of the Midcontinent Independent System Operator (MISO)’s planning zones1 . The study’s primary purpose is to determine if DynegyVistra’s coal plants are necessary for resource adequacy and if subsidies Dynegy-Vistra has proposed for the plants are… Show more

In this study, Vibrant Clean Energy, LLC (VCE) analyzes alternative least-cost energy and capacity resource pathways to the continued operation of the Dynegy-Vistra coal power fleet in Southern Illinois, also known as “Zone 4” of the Midcontinent Independent System Operator (MISO)’s planning zones1 . The study’s primary purpose is to determine if DynegyVistra’s coal plants are necessary for resource adequacy and if subsidies Dynegy-Vistra has proposed for the plants are cost-effective.

To this end, the analysis evaluates the state of resource adequacy in Zone 4 and the surrounding region, the ability of the grid to deliver electricity every hour as needed, and the cost of electricity under each alternative pathway to keeping the Dynegy-Vistra coal plants in operation. DOI: https://doi.org/10.6084/m9.figshare.13087643 Show less

Stakeholders within Minnesota’s power sector convened during two workshops held in September 2016 and January 2017 to discuss a statewide strategy for energy storage deployment. The first workshop helped identified areas for more in depth analysis. Preliminary results from this analysis and real-world case studies were presented at the second workshop and used to guide a broader discussion around recommended next steps. Full report also available on the Energy Transition Labs, University of… Show more

Stakeholders within Minnesota’s power sector convened during two workshops held in September 2016 and January 2017 to discuss a statewide strategy for energy storage deployment. The first workshop helped identified areas for more in depth analysis. Preliminary results from this analysis and real-world case studies were presented at the second workshop and used to guide a broader discussion around recommended next steps. Full report also available on the Energy Transition Labs, University of Minnesota website.

VCE participated in the second workshop only, where they provided a system level analysis of the MISO footprint (with a focused effort on MN) to determine the pathways for future electricity grids and how storage participates in those futures. Presentation DOI: https://doi.org/10.6084/m9.figshare.13087610 Show less

A number of analyses, meta-analyses, and assessments, including those performed by the Intergovernmental Panel on Climate Change, the National Oceanic and Atmospheric Administration,
the National Renewable Energy Laboratory, and the International Energy Agency, have concluded that deployment of a diverse portfolio of clean energy technologies makes a transition to a low-carbon-emission energy system both more feasible and less costly than other pathways. In contrast, Jacobson et al… Show more

A number of analyses, meta-analyses, and assessments, including those performed by the Intergovernmental Panel on Climate Change, the National Oceanic and Atmospheric Administration,
the National Renewable Energy Laboratory, and the International Energy Agency, have concluded that deployment of a diverse portfolio of clean energy technologies makes a transition to a low-carbon-emission energy system both more feasible and less costly than other pathways. In contrast, Jacobson et al. [Jacobson MZ, Delucchi MA, Cameron MA, Frew BA (2015) Proc Natl Acad Sci USA 112(49):15060–15065] argue that it is feasible to provide “low-cost solutions to the grid reliability problem with 100% penetration of WWS [wind, water and solar power] across all energy sectors in the continental United States between 2050 and 2055”, with only electricity and hydrogen as energy carriers. In this paper, we evaluate that study and find significant shortcomings in the analysis. In particular, we point out that this work used invalid modeling tools, contained modeling errors, and made implausible and inadequately supported assumptions. Policy makers should treat with caution any visions of a rapid, reliable, and
low-cost transition to entire energy systems that relies almost exclusively on wind, solar, and hydroelectric power. Show less

The increased use of solar photovoltaic (PV) cells as energy sources on electric grids has created the need for more accessible solar irradiance and power production estimates for use in power modeling software. In the present paper, a novel technique for creating solar irradiance estimates is introduced. A solar PV resource dataset created by combining numerical weather prediction assimilation model variables, satellite data and high resolution ground-based measurements is also presented. The… Show more

The increased use of solar photovoltaic (PV) cells as energy sources on electric grids has created the need for more accessible solar irradiance and power production estimates for use in power modeling software. In the present paper, a novel technique for creating solar irradiance estimates is introduced. A solar PV resource dataset created by combining numerical weather prediction assimilation model variables, satellite data and high resolution ground-based measurements is also presented. The dataset contains ≈152,000 geographic locations each with ≈26,000 hourly time steps. The solar irradiance outputs are global horizontal irradiance (GHI), direct normal irradiance (DNI), and diffuse horizontal irradiance (DIF). The technique is developed over the United States by training a linear multiple multivariate regression scheme at ten locations. The technique is then applied to independent locations over the whole geographic domain. The irradiance estimates are input to a solar PV power modeling algorithm to compute solar PV power estimates for every 13-km grid cell. The dataset is analyzed to predict the capacity factors for solar resource sites around the USA for the three years of 2006 – 2008. Statistics are shown to validate the skill of the scheme at geographic sites independent of the training set. In addition, it is shown that more high quality, geographically dispersed, observation sites increase the skill of the scheme. Show less

Carbon dioxide emissions from electricity generation are a major cause of anthropogenic climate change. The deployment ofwind and solar power reduces these emissions, but is subject to the variability of the weather. In the present study, we calculatethe cost-optimized configuration of variable electrical power generators using weather data with high spatial (13-km) andtemporal (60-min) resolution over the contiguous US. Our results show that when using future anticipated costs for wind… Show more

Carbon dioxide emissions from electricity generation are a major cause of anthropogenic climate change. The deployment ofwind and solar power reduces these emissions, but is subject to the variability of the weather. In the present study, we calculatethe cost-optimized configuration of variable electrical power generators using weather data with high spatial (13-km) andtemporal (60-min) resolution over the contiguous US. Our results show that when using future anticipated costs for wind andsolar, carbon dioxide emissions from the US electricity sector can be reduced by up to 80% relative to 1990 levels, withoutan increase in the levelized cost of electricity. The reductions are possible with current technologies and without electricalstorage. Wind and solar power increase their share of electricity production as the system grows to encompass large-scaleweather patterns. This reduction in carbon emissions is achieved by moving away from a regionally divided electricity sectorto a national system enabled by high-voltage direct-current transmission Show less

The co-optimization carried out by Vibrant Clean Energy, LLC assessed the difference between purely cost-optimized futures, where expansion of wind, solar, natural gas and transmission was considered, and futures where carbon dioxide emissions are constrained. The case studies had time horizons of 2016, 2030, 2036 and 2050. The demand was grown to keep up with increasing electricity consumption over the MISO footprint. No connections to other markets were considered. DOI:… Show more

The co-optimization carried out by Vibrant Clean Energy, LLC assessed the difference between purely cost-optimized futures, where expansion of wind, solar, natural gas and transmission was considered, and futures where carbon dioxide emissions are constrained. The case studies had time horizons of 2016, 2030, 2036 and 2050. The demand was grown to keep up with increasing electricity consumption over the MISO footprint. No connections to other markets were considered. DOI: https://doi.org/10.6084/m9.figshare.13087598 Show less

The use of wind energy is growing around the world, and its growth is set to continue into the foreseeable future. Estimates of the wind speed and power are helpful to assess the potential of new sites for development and to facilitate electric grid integration studies. In the present paper, wind speed and power resource mapping analyses are performed. These resource mappings are produced on a 13 km, hourly model grid over the entire continental USA for the years of 2006–2014. The effects of… Show more

The use of wind energy is growing around the world, and its growth is set to continue into the foreseeable future. Estimates of the wind speed and power are helpful to assess the potential of new sites for development and to facilitate electric grid integration studies. In the present paper, wind speed and power resource mapping analyses are performed. These resource mappings are produced on a 13 km, hourly model grid over the entire continental USA for the years of 2006–2014. The effects of the rotor equivalent wind speed (REWS) along with directional shear are investigated. The total dataset (wind speed and power) contains ≈152,000 model grid points, with each location containing ≈78,000 hourly time steps. The resource mapping and dataset are created from analysis fields, which are output from an advanced weather assimilation model. Two different methods were used to estimate the wind speed over the rotor swept area (with rotor diameter of 100 m). First, using a single wind speed at hub height (80 m) and, second, the REWS with directional shear. The demonstration study shows that in most locations the incorporation of the REWS reduces the average available wind power. In addition, the REWS technique estimates more wind power production at night and less production in the day compared with the hub height technique; potentially critical for siting new wind turbines and plants. However, the wind power estimate differences are dependent on seasonality, diurnal cycle and geographic location. More research is warranted into these effects to determine the level at which these features are observed at actual wind plants. Show less

The spurt of growth in the wind energy industry has led to the development of many new technologies to study this energy resource and improve the efficiency of wind turbines. One of the key factors in wind farm characterization is the prediction of power output of the wind farm that is a strong function of the turbulence in the wind speed and direction. A new formulation for calculating the expected power from a wind turbine in the presence of wind shear, turbulence, directional shear and… Show more

The spurt of growth in the wind energy industry has led to the development of many new technologies to study this energy resource and improve the efficiency of wind turbines. One of the key factors in wind farm characterization is the prediction of power output of the wind farm that is a strong function of the turbulence in the wind speed and direction. A new formulation for calculating the expected power from a wind turbine in the presence of wind shear, turbulence, directional shear and direction fluctuations is presented. It is observed that wind shear, directional shear and direction fluctuations reduce the power producing capability, while turbulent intensity increases it. However, there is a complicated superposition of these effects that alters the characteristics of the power estimate that indicates the need for the new formulation. Data from two field experiments is used to estimate the wind power using the new formulation, and results are compared to previous formulations. Comparison of the estimates of available power from the new formulation is not compared to actual power outputs and will be a subject of future work. Show less

The importance of weather-driven renewable energies for the United States energy portfolio is growing. The main perceived problems with weather-driven renewable energies are their intermittent nature, low power density, and high costs.

In 2009, we began a large-scale investigation into the characteristics of weather-driven renewables. The
project utilized the best available weather data assimilation model to compute high spatial and temporal resolution power datasets for the renewable… Show more

The importance of weather-driven renewable energies for the United States energy portfolio is growing. The main perceived problems with weather-driven renewable energies are their intermittent nature, low power density, and high costs.

In 2009, we began a large-scale investigation into the characteristics of weather-driven renewables. The
project utilized the best available weather data assimilation model to compute high spatial and temporal resolution power datasets for the renewable resources of wind and solar PV. The coincident time series of electrical load and weather data on a 13-km grid is used to investigate optimal designs of electric power systems over the contiguous US. In the past two years, the team have expanded the sophisticated mathematical optimization tool that is based upon linear programming (1) with an economic objective.

We performed a simplified test where the US electric system consisted of wind, solar PV, nuclear,
hydroelectric and natural gas only with the addition of HVDC bulk transmission. The test shows that if the US meets its goals in price reduction of variable generation the US would only have dramatic reductions of carbon dioxide emissions that is cost effective with a national-scale interconnected system. The smaller the system the higher the carbon emissions and steeper the cost. Show less

The planning and design of an electric power system, including high-voltage direct-current transmission, is a complex optimization problem. The optimization must integrate and model the engineering requirements and limitations of the generation, while simultaneously balancing the system electric load at all times. The problem is made more difficult with the introduction of variable generators, such as wind and solar photovoltaics. In the present paper, we introduce two comprehensive linear… Show more

The planning and design of an electric power system, including high-voltage direct-current transmission, is a complex optimization problem. The optimization must integrate and model the engineering requirements and limitations of the generation, while simultaneously balancing the system electric load at all times. The problem is made more difficult with the introduction of variable generators, such as wind and solar photovoltaics. In the present paper, we introduce two comprehensive linear programming techniques to solve these problems. Linear programming is intentionally chosen to keep the problems tractable in terms of time and computational resources. The first is an optimization that minimizes the deviation from the electric load requirements. The procedure includes variable generators, conventional generators, transmission, and storage, along with their most salient engineering requirements. In addition, the optimization includes some basic electric power system requirements. The second optimization is one that minimizes the overall system costs per annum while taking into consideration all the aspects of the first optimization. We discuss the benefits and disadvantages of the proposed approaches. We show that the cost optimization, although computationally more expensive, is superior in terms of optimizing a real-world electric power system. The present paper shows that linear programming techniques can represent an electrical power system from a high-level without undue complication brought on by moving to mixed integer or nonlinear programming. In addition, the optimizations can be implemented in the future in planning tools. Show less

The increased use of solar photovoltaic cells as energy sources on electrical grids has created the need for accurate solar irradiance assessment over continental scales. In the present paper, we discuss a technique for computing solar irradiance estimations that utilizes numerical weather model variables, satellite data, and SURFRAD and ISIS network measurements. The numerical weather model used is the Rapid Update Cycle. The solar irradiance estimations found are more accurate than the solar… Show more

The increased use of solar photovoltaic cells as energy sources on electrical grids has created the need for accurate solar irradiance assessment over continental scales. In the present paper, we discuss a technique for computing solar irradiance estimations that utilizes numerical weather model variables, satellite data, and SURFRAD and ISIS network measurements. The numerical weather model used is the Rapid Update Cycle. The solar irradiance estimations found are more accurate than the solar irradiance fields provided by the satellites alone. Moreover, estimations are provided for the global horizontal, direct normal, and diffuse horizontal irradiance fields. The multivariate regression implemented allows accurate estimations of solar irradiance, but relies on high quality solar measurements at the surface over a geographically diverse domain. The technique developed in the present paper is also applicable to solar irradiance forecasts. Show less

Discussing the possibility and validity of a National Weather Driven Energy System. The complexities of such a system is simulated using the ESRL optimization code.

The potential for wind and solar energy to become a large percentage of total electricity production is dependent on how weather varies over geographic domains. A study of the characteristics of wind and solar energy generation systems as they vary with geographic size was conducted. The study used the 48 contiguous US states as a test domain alongside assimilated hourly weather data for 2006-8 and hourly electric load projected from 2006-8 to 2030. The model created optimizes the cost of the… Show more

The potential for wind and solar energy to become a large percentage of total electricity production is dependent on how weather varies over geographic domains. A study of the characteristics of wind and solar energy generation systems as they vary with geographic size was conducted. The study used the 48 contiguous US states as a test domain alongside assimilated hourly weather data for 2006-8 and hourly electric load projected from 2006-8 to 2030. The model created optimizes the cost of the national system when taking into account building the electricity producing stations, building the transmission lines, allowing for transmission losses and the fuel burned in the dispatch-able generation. It is shown that wind and solar energy utilization increases significantly with domain size, while the total atmospheric carbon release and total system costs are reduced. The transmission does not significantly alter the utilization of wind and solar, however, it does dramatically change the areal locations of the wind and solar generation plants. A similar scaling for global land and adjacent coastal areas, with no transmission constraints, shows that wind and solar energy systems are most effective on large geographic entities. Show less

A significant obstacle to the widespread use of wind and solar energy is the high variability. While this obstacle is significant for a small area, because of the possibility of low wind and solar energy production for a significant period every year, over larger areas renewable energy production can make use of the fact that there will always be wind or solar energy available somewhere in the domain. A key scientific question is how large does an area have to be such that wind and solar can… Show more

A significant obstacle to the widespread use of wind and solar energy is the high variability. While this obstacle is significant for a small area, because of the possibility of low wind and solar energy production for a significant period every year, over larger areas renewable energy production can make use of the fact that there will always be wind or solar energy available somewhere in the domain. A key scientific question is how large does an area have to be such that wind and solar can supply significant electricity production without large shortages? Results will be presented from a study that exams whether the continental US has enough areal scale such that the weather can drive large-scale wind and solar deployment? The study uses assimilated hourly weather data for 2006-8 and hourly electric load projected from 2006-8 to 2030. An optimization model developed for this study evaluates the cost of the national system when taking into account not only the cost of wind turbines and solar panels but also the costs of building the electricity producing stations, building the transmission lines, allowing for transmission losses and the fuel burned in the dispatch-able generation. While some results from this study are intuitive, others give surprising insights relevant to planning energy systems of the future. We show that wind and solar energy utilization increases with domain size, while the total atmospheric carbon release and total system costs are subsequently reduced. We show that transmission constraints do not significantly alter the utilization of wind and solar deployment, however, transmission dramatically affect the areal locations of the wind and solar generation plants. A similar scaling for global land and adjacent coastal areas, with no transmission constraints, shows that wind and solar energy systems are most effective on large geographic areas. The optimization model will be explained in greater detail and key results will be shared. Show less

A significant obstacle to the widespread use of wind and solar energy is the high variability. While this obstacle is significant for a small area, because of the possibility of low wind and solar energy production for a significant period every year, over larger areas renewable energy production can make use of the fact that there will always be wind or solar energy available somewhere in the domain. A key scientific question is how large does an area have to be such that wind and solar can… Show more

A significant obstacle to the widespread use of wind and solar energy is the high variability. While this obstacle is significant for a small area, because of the possibility of low wind and solar energy production for a significant period every year, over larger areas renewable energy production can make use of the fact that there will always be wind or solar energy available somewhere in the domain. A key scientific question is how large does an area have to be such that wind and solar can supply significant electricity production without large shortages? Results will be presented from a study that exams whether the continental US has enough areal scale such that the weather can drive large-scale wind and solar deployment? The study uses assimilated hourly weather data for 2006-8 and hourly electric load projected from 2006-8 to 2030. An optimization model developed for this study evaluates the cost of the national system when taking into account not only the cost of wind turbines and solar panels but also the costs of building the electricity producing stations, building the transmission lines, allowing for transmission losses and the fuel burned in the dispatch-able generation. While some results from this study are intuitive, others give surprising insights relevant to planning energy systems of the future. We show that wind and solar energy utilization increases with domain size, while the total atmospheric carbon release and total system costs are subsequently reduced. We show that changes to current transmission lines do not significantly alter the utilization of wind and solar deployment, however, changes in transmission dramatically affect the areal locations of the wind and solar generation plants. A similar scaling for global land and adjacent coastal areas, with no transmission constraints, shows that wind and solar energy systems are most effective on large geographic areas. Show less

Many question if it is possible to generate a significant portion of our required electricity in the U.S. from renewable sources, since the wind doesn’t always blow and the sun doesn’t always shine. Some claim that wind and solar require 100% fossil fuel backup. We investigate whether the continental U.S. has diverse enough weather to supply various levels of electricity given a national grid for transporting power, and also how much natural gas backup generation would be necessary in different… Show more

Many question if it is possible to generate a significant portion of our required electricity in the U.S. from renewable sources, since the wind doesn’t always blow and the sun doesn’t always shine. Some claim that wind and solar require 100% fossil fuel backup. We investigate whether the continental U.S. has diverse enough weather to supply various levels of electricity given a national grid for transporting power, and also how much natural gas backup generation would be necessary in different scenarios.
Show less

Determining the geographic scaling of weather driven renewable energy when introduced at large penetration levels within the US electrical generation mix. Different domain sizes were used to illustrate that as domain size shrinks, resource utilization decreases, due to variability and covariance issues.

Resonant absorption of fast magnetoacoustic (FMA) waves in an inhomogeneous, weakly dissipative, one-dimensional planar, strongly anisotropic and dispersive plasma is investigated. The magnetic configuration consists of an inhomogeneous magnetic slab sandwiched between two regions of semi-infinite homogeneous magnetic plasmas. Laterally driven FMA waves penetrate the inhomogeneous slab interacting with the localised slow or Alfvén waves present in the inhomogeneous layer and are partly… Show more

Resonant absorption of fast magnetoacoustic (FMA) waves in an inhomogeneous, weakly dissipative, one-dimensional planar, strongly anisotropic and dispersive plasma is investigated. The magnetic configuration consists of an inhomogeneous magnetic slab sandwiched between two regions of semi-infinite homogeneous magnetic plasmas. Laterally driven FMA waves penetrate the inhomogeneous slab interacting with the localised slow or Alfvén waves present in the inhomogeneous layer and are partly reflected, dissipated and transmitted by this region. The presented research aims to find the coefficient of wave energy absorption under solar chromospheric and coronal conditions. Numerical results are analysed to find the coefficient of wave energy absorption at both the slow and Alfvén resonance positions. The mathematical derivations are based on the two simplifying assumptions that i) nonlinearity is weak, and ii) the thickness of the inhomogeneous layer is small in comparison to the wavelength of the wave, i.e. we employ the so-called long wavelength approximation. Slow resonance is found to be described by the nonlinear theory, while the dynamics at the Alvén resonance can be described within the linear framework. We introduce a new concept of coupled resonances, which occurs when two different resonances are in close proximity to each other, causing the incoming wave to act as though it has been influenced by the two resonances simultaneously. Our results show that the wave energy absorption is heavily dependent on the angle of the incident wave in combination with the inclination angle of the equilibrium magnetic field. In addition, it is found that FMA waves are very efficiently absorbed at the Alvén resonance under coronal conditions. Under chromospheric conditions the FMA waves are far less efficiently absorbed, despite an increase in efficiency due to the coupled resonances. Show less

In the context of resonant absorption, nonlinearity has two different manifestations. The first is the reduction in amplitude of perturbations around the resonant point (wave energy absorption). The second is the generation of mean shear flows outside the dissipative layer surrounding the resonant point. Ruderman et al. [Phys. Plasmas 4, 75 (1997)] studied both these effects at the slow resonance in isotropic plasmas. Clack et al. [Astron. Astrophys. 494, 317 (2009)] investigated nonlinearity… Show more

In the context of resonant absorption, nonlinearity has two different manifestations. The first is the reduction in amplitude of perturbations around the resonant point (wave energy absorption). The second is the generation of mean shear flows outside the dissipative layer surrounding the resonant point. Ruderman et al. [Phys. Plasmas 4, 75 (1997)] studied both these effects at the slow resonance in isotropic plasmas. Clack et al. [Astron. Astrophys. 494, 317 (2009)] investigated nonlinearity at the Alfvén resonance; however, they did not include the generation of mean shear flow. In this present paper, we investigate the mean shear flow, analytically, and study its properties. We find that the flow generated is parallel to the magnetic surfaces and has a characteristic velocity proportional to ϵ1/2, where ϵ is the dimensionless amplitude of perturbations far away from the resonance. This is, qualitatively, similar to the flow generated at the slow resonance. The jumps in the derivatives of the parallel and perpendicular components of mean shear flow across the dissipative layer are derived. We estimate the generated mean shear flow to be of the order of 10 km s−1 in both the solar upper chromosphere and solar corona; however, this value strongly depends on the choice of boundary conditions. It is proposed that the generated mean shear flow can produce a Kelvin–Helmholtz instability at the dissipative layer which can create turbulent motions. This instability would be an additional effect, as a Kelvin–Helmholtz instability may already exist due to the velocity field of the resonant Alfvén waves. This flow can also be superimposed onto existing large scale motions in the solar upper atmosphere. Show less

The nonlinear theory of driven magnetohydrodynamics (MHD) waves in strongly anisotropic and dispersive plasmas, developed for slow resonance by Clack and Ballai [Phys. Plasmas 15, 2310 (2008)] and Alfvén resonance by Clack et al. [Astron. Astrophys. 494, 317 (2009)] , is used to study the weakly nonlinear interaction of fast magnetoacoustic (FMA) waves in a one-dimensional planar plasma. The magnetic configuration consists of an inhomogeneous magnetic slab sandwiched between two regions of… Show more

The nonlinear theory of driven magnetohydrodynamics (MHD) waves in strongly anisotropic and dispersive plasmas, developed for slow resonance by Clack and Ballai [Phys. Plasmas 15, 2310 (2008)] and Alfvén resonance by Clack et al. [Astron. Astrophys. 494, 317 (2009)] , is used to study the weakly nonlinear interaction of fast magnetoacoustic (FMA) waves in a one-dimensional planar plasma. The magnetic configuration consists of an inhomogeneous magnetic slab sandwiched between two regions of semi-infinite homogeneous magnetic plasmas. Laterally driven FMA waves penetrate the inhomogeneous slab interacting with the localized slow or Alfvén dissipative layer and are partly reflected, dissipated, and transmitted by this region. The nonlinearity parameter defined by Clack and Ballai (2008) is assumed to be small and a regular perturbation method is used to obtain analytical solutions in the slow dissipative layer. The effect of dispersion in the slow dissipative layer is to further decrease the coefficient of energy absorption, compared to its standard weakly nonlinear counterpart, and the generation of higher harmonics in the outgoing wave in addition to the fundamental one. The absorption of external drivers at the Alfvén resonance is described within the linear MHD with great accuracy. Show less

In the approximation of linear dissipative magnetohydrodynamics (MHD) it can be shown that driven MHD waves in magnetic plasmas with high Reynolds number exhibit a near resonant behaviour if the frequency of the wave becomes equal to the local Alfven (or slow) frequency of a magnetic surface. This near resonant behaviour is confined to a thin region, known as the dissipative layer, which embraces the resonant magnetic surface. Although driven MHD waves have small dimensionless amplitude far… Show more

In the approximation of linear dissipative magnetohydrodynamics (MHD) it can be shown that driven MHD waves in magnetic plasmas with high Reynolds number exhibit a near resonant behaviour if the frequency of the wave becomes equal to the local Alfven (or slow) frequency of a magnetic surface. This near resonant behaviour is confined to a thin region, known as the dissipative layer, which embraces the resonant magnetic surface. Although driven MHD waves have small dimensionless amplitude far away from the resonant surface, this near-resonant behaviour in the dissipative layer may cause a breakdown of linear theory. Our aim is to study the nonlinear effects in the Alfven dissipative layer. In the present paper, the method of simplified matched asymptotic expansions developed for nonlinear slow resonant waves is used to describe nonlinear effects inside the Alfven dissipative layer. The nonlinear corrections to resonant waves in the Alfven dissipative layer are derived and it is proved that at the Alfven resonance (with isotropic/anisotropic dissipation) wave dynamics can be described by the linear theory with great accuracy. Show less

The solar corona is a typical example of a plasma with strongly anisotropic transport processes. The main dissipative mechanisms in the solar corona acting on slow magnetoacoustic waves are the anisotropic thermal conductivity and viscosity [ Ballai et al., Phys. Plasmas 5, 252 (1998) ] developed the nonlinear theory of driven slow resonant waves in such a regime. In the present paper the nonlinear behavior of driven magnetohydrodynamic waves in the slow dissipative layer in plasmas with… Show more

The solar corona is a typical example of a plasma with strongly anisotropic transport processes. The main dissipative mechanisms in the solar corona acting on slow magnetoacoustic waves are the anisotropic thermal conductivity and viscosity [ Ballai et al., Phys. Plasmas 5, 252 (1998) ] developed the nonlinear theory of driven slow resonant waves in such a regime. In the present paper the nonlinear behavior of driven magnetohydrodynamic waves in the slow dissipative layer in plasmas with strongly anisotropic viscosity and thermal conductivity is expanded by considering dispersive effects due to Hall currents. The nonlinear governing equation describing the dynamics of nonlinear resonant slow waves is supplemented by a term which describes nonlinear dispersion and is of the same order of magnitude as nonlinearity and dissipation. The connection formulas are found to be similar to their nondispersive counterparts. Show less