50 Matching Results

Search Results

Advanced search parameters have been applied.

Technical Potential of Solar Water Heating to Reduce Fossil Fuel Use and Greenhouse Gas Emissions in the United States

Description: Use of solar water heating (SWH) in the United States grew significantly in the late 1970s and early 1980s, as a result of increasing energy prices and generous tax credits. Since 1985, however, expiration of federal tax credits and decreased energy prices have virtually eliminated the U.S. market for SWH. More recently, increases in energy prices, concerns regarding emissions of greenhouse gases, and improvements in SWH systems have created new interest in the potential of this technology. SWH, which uses the sun to heat water directly or via a heat-transfer fluid in a collector, may be particularly important in its ability to reduce natural gas use. Dependence on natural gas as an energy resource in the United States has significantly increased in the past decade, along with increased prices, price volatility, and concerns about sustainability and security of supply. One of the readily deployable technologies available to decrease use of natural gas is solar water heating. This report provides an overview of the technical potential of solar water heating to reduce fossil fuel consumption and associated greenhouse gas emissions in U.S. residential and commercial buildings.
Date: March 1, 2007
Creator: Denholm, P.
Partner: UNT Libraries Government Documents Department

Transmission Benefits of Co-Locating Concentrating Solar Power and Wind

Description: In some areas of the U.S. transmission constraints are a limiting factor in deploying new wind and concentrating solar power (CSP) plants. Texas is an example of one such location, where the best wind and solar resources are in the western part of the state, while major demand centers are in the east. The low capacity factor of wind is a compounding factor, increasing the relative cost of new transmission per unit of energy actually delivered. A possible method of increasing the utilization of new transmission is to co-locate both wind and concentrating solar power with thermal energy storage. In this work we examine the benefits and limits of using the dispatachability of thermal storage to increase the capacity factor of new transmission developed to access high quality solar and wind resources in remote locations.
Date: March 1, 2012
Creator: Sioshansi, R. & Denholm, P.
Partner: UNT Libraries Government Documents Department

Simulating the Value of Concentrating Solar Power with Thermal Energy Storage in a Production Cost Model

Description: Concentrating solar power (CSP) deployed with thermal energy storage (TES) provides a dispatchable source of renewable energy. The value of CSP with TES, as with other potential generation resources, needs to be established using traditional utility planning tools. Production cost models, which simulate the operation of grid, are often used to estimate the operational value of different generation mixes. CSP with TES has historically had limited analysis in commercial production simulations. This document describes the implementation of CSP with TES in a commercial production cost model. It also describes the simulation of grid operations with CSP in a test system consisting of two balancing areas located primarily in Colorado.
Date: November 1, 2012
Creator: Denholm, P. & Hummon, M.
Partner: UNT Libraries Government Documents Department

Impacts of Array Configuration on Land-Use Requirements for Large-Scale Photovoltaic Deployment in the United States: Preprint

Description: Land use is often cited as an important issue for renewable energy technologies. In this paper we examine the relationship between land-use requirements for large-scale photovoltaic (PV) deployment in the U.S. and PV-array configuration. We estimate the per capita land requirements for solar PV and find that array configuration is a stronger driver of energy density than regional variations in solar insolation. When deployed horizontally, the PV land area needed to meet 100% of an average U.S. citizen's electricity demand is about 100 m2. This requirement roughly doubles to about 200 m2 when using 1-axis tracking arrays. By comparing these total land-use requirements with other current per capita land uses, we find that land-use requirements of solar photovoltaics are modest, especially when considering the availability of zero impact 'land' on rooftops. Additional work is need to examine the tradeoffs between array spacing, self-shading losses, and land use, along with possible techniques to mitigate land-use impacts of large-scale PV deployment.
Date: May 1, 2008
Creator: Denholm, P. & Margolis, R. M.
Partner: UNT Libraries Government Documents Department

Very Large-Scale Deployment of Grid-Connected Solar Photovoltaics in the United States: Challenges and Opportunities; Preprint

Description: This paper analyzes the potential for solar photovoltaics (PV) to be deployed on a very large scale and provide a large fraction of a system's electricity. It explicitly examines how the hourly availability of PV interacts with the limited flexibility of traditional electricity generation plants. The authors found that, under high penetration levels and existing grid-operation procedures and rules, the system will have excess PV generation during certain periods of the year. This excess PV generation results in increased costs, which can increase dramatically when PV provides on the order of 10%-15% of total electricity demand in systems that are heavily dependent on inflexible baseload steam plants. Measures to increase penetration of PV are also discussed, including increased system flexibility, increased dispatchable load, and energy storage.
Date: April 1, 2006
Creator: Denholm, P. & Margolis, R.
Partner: UNT Libraries Government Documents Department

Regional Per Capita Solar Electric Footprint for the United States

Description: In this report, we quantify the state-by-state per-capita 'solar electric footprint' for the United States. We use state-level data on population, electricity consumption, economic activity and solar insolation, along with solar photovoltaic (PV) array packing density data to develop a range of estimates of the solar electric footprint. We find that the solar electric footprint, defined as the land area required to supply all end-use electricity from solar photovoltaics, is about 181 m2 per person in the United States. Two key factors that influence the magnitude of the state-level solar electric footprint include how industrial energy is allocated (based on location of use vs. where goods are consumed) and the assumed distribution of PV configurations (flat rooftop vs. fixed tilt vs. tracking). The solar electric footprint is about 0.6% of the total land area of the United States with state-level estimates ranging from less than 0.1% for Wyoming to about 9% for New Jersey. We also compare the solar electric footprint to a number of other land uses. For example, we find that the solar electric footprint is equal to less than 2% of the land dedicated to cropland and grazing in the United States.
Date: December 1, 2007
Creator: Denholm, P. & Margolis, R.
Partner: UNT Libraries Government Documents Department

Value of Concentrating Solar Power and Thermal Energy Storage

Description: This paper examines the value of concentrating solar power (CSP) and thermal energy storage (TES) in four regions in the southwestern United States. Our analysis shows that TES can increase the value of CSP by allowing more thermal energy from a CSP plant?s solar field to be used, by allowing a CSP plant to accommodate a larger solar field, and by allowing CSP generation to be shifted to hours with higher energy prices. We analyze the sensitivity of CSP value to a number of factors, including the optimization period, price and solar forecasting, ancillary service sales, capacity value and dry cooling of the CSP plant. We also discuss the value of CSP plants and TES net of capital costs.
Date: February 1, 2010
Creator: Sioshansi, R. & Denholm, P.
Partner: UNT Libraries Government Documents Department

Summary of: Simulating the Value of Concentrating Solar Power with Thermal Energy Storage in a Production Cost Model (Presentation)

Description: Concentrating solar power (CSP) deployed with thermal energy storage (TES) provides a dispatchable source of renewable energy. The value of CSP with TES, as with other potential generation resources, needs to be established using traditional utility planning tools. Production cost models, which simulate the operation of grid, are often used to estimate the operational value of different generation mixes. CSP with TES has historically had limited analysis in commercial production simulations. This document describes the implementation of CSP with TES in a commercial production cost model. It also describes the simulation of grid operations with CSP in a test system consisting of two balancing areas located primarily in Colorado.
Date: February 1, 2013
Creator: Denholm, P. & Hummon, M.
Partner: UNT Libraries Government Documents Department

Costs and Emissions Associated with Plug-In Hybrid Electric Vehicle Charging in the Xcel Energy Colorado Service Territory

Description: The combination of high oil costs, concerns about oil security and availability, and air quality issues related to vehicle emissions are driving interest in plug-in hybrid electric vehicles (PHEVs). PHEVs are similar to conventional hybrid electric vehicles, but feature a larger battery and plug-in charger that allows electricity from the grid to replace a portion of the petroleum-fueled drive energy. PHEVs may derive a substantial fraction of their miles from grid-derived electricity, but without the range restrictions of pure battery electric vehicles. As of early 2007, production of PHEVs is essentially limited to demonstration vehicles and prototypes. However, the technology has received considerable attention from the media, national security interests, environmental organizations, and the electric power industry. The use of PHEVs would represent a significant potential shift in the use of electricity and the operation of electric power systems. Electrification of the transportation sector could increase generation capacity and transmission and distribution (T&D) requirements, especially if vehicles are charged during periods of high demand. This study is designed to evaluate several of these PHEV-charging impacts on utility system operations within the Xcel Energy Colorado service territory.
Date: May 1, 2007
Creator: Parks, K.; Denholm, P. & Markel, T.
Partner: UNT Libraries Government Documents Department

Evaluation of Utility System Impacts and Benefits of Optimally Dispatched Plug-In Hybrid Electric Vehicles (Revised)

Description: Hybrid electric vehicles with the capability of being recharged from the grid may provide a significant decrease in oil consumption. These ''plug-in'' hybrids (PHEVs) will affect utility operations, adding additional electricity demand. Because many individual vehicles may be charged in the extended overnight period, and because the cost of wireless communication has decreased, there is a unique opportunity for utilities to directly control the charging of these vehicles at the precise times when normal electricity demand is at a minimum. This report evaluates the effects of optimal PHEV charging, under the assumption that utilities will indirectly or directly control when charging takes place, providing consumers with the absolute lowest cost of driving energy. By using low-cost off-peak electricity, PHEVs owners could purchase the drive energy equivalent to a gallon of gasoline for under 75 cents, assuming current national average residential electricity prices.
Date: October 1, 2006
Creator: Denholm, P. & Short, W.
Partner: UNT Libraries Government Documents Department

Enabling Greater Penetration of Solar Power via the Use of CSP with Thermal Energy Storage

Description: At high penetration of solar generation there are a number of challenges to economically integrating this variable and uncertain resource. These include the limited coincidence between the solar resource and normal demand patterns and limited flexibility of conventional generators to accommodate variable generation resources. Of the large number of technologies that can be used to enable greater penetration of variable generators, concentrating solar power (CSP) with thermal energy storage (TES) presents a number of advantages. The use of storage enables this technology to shift energy production to periods of high demand or reduced solar output. In addition, CSP can provide substantial grid flexibility by rapidly changing output in response to the highly variable net load created by high penetration of solar (and wind) generation. In this work we examine the degree to which CSP may be complementary to PV by performing a set of simulations in the U.S. Southwest to demonstrate the general potential of CSP with TES to enable greater use of solar generation, including additional PV.
Date: November 1, 2011
Creator: Denholm, P. & Mehos, M.
Partner: UNT Libraries Government Documents Department

Supply Curves for Solar PV-Generated Electricity for the United States

Description: Energy supply curves attempt to estimate the relationship between the cost of an energy resource and the amount of energy available at or below that cost. In general, an energy supply curve is a series of step functions with each step representing a particular group or category of energy resource. The length of the step indicates how much of that resource is deployable or accessible at a given cost. Energy supply curves have been generated for a number of renewable energy sources including biomass fuels and geothermal, as well as conservation technologies. Generating a supply curve for solar photovoltaics (PV) has particular challenges due to the nature of the resource. The United States has a massive solar resource base -- many orders of magnitude greater than the total consumption of energy. In this report, we examine several possible methods for generating PV supply curves based exclusively on rooftop deployment.
Date: November 1, 2008
Creator: Denholm, P. & Margolis, R.
Partner: UNT Libraries Government Documents Department

Break-Even Cost for Residential Solar Water Heating in the United States: Key Drivers and Sensitivities

Description: This paper examines the break-even cost for residential rooftop solar water heating (SWH) technology, defined as the point where the cost of the energy saved with a SWH system equals the cost of a conventional heating fuel purchased from the grid (either electricity or natural gas). We examine the break-even cost for the largest 1,000 electric and natural gas utilities serving residential customers in the United States as of 2008. Currently, the break-even cost of SWH in the United States varies by more than a factor of five for both electricity and natural gas, despite a much smaller variation in the amount of energy saved by the systems (a factor of approximately one and a half). The break-even price for natural gas is lower than that for electricity due to a lower fuel cost. We also consider the relationship between SWH price and solar fraction and examine the key drivers behind break-even costs. Overall, the key drivers of the break-even cost of SWH are a combination of fuel price, local incentives, and technical factors including the solar resource location, system size, and hot water draw.
Date: February 1, 2011
Creator: Cassard, H.; Denholm, P. & Ong, S.
Partner: UNT Libraries Government Documents Department

Preliminary Assessment of Plug-in Hybrid Electric Vehicles on Wind Energy Markets

Description: This report examines a measure that may potentially reduce oil use and also more than proportionately reduce carbon emissions from vehicles. The authors present a very preliminary analysis of plug-in hybrid electric vehicles (PHEVs) that can be charged from or discharged to the grid. These vehicles have the potential to reduce gasoline consumption and carbon emissions from vehicles, as well as improve the viability of renewable energy technologies with variable resource availability. This paper is an assessment of the synergisms between plug-in hybrid electric vehicles and wind energy. The authors examine two bounding cases that illuminate this potential synergism.
Date: April 1, 2006
Creator: Short, W. & Denholm, P.
Partner: UNT Libraries Government Documents Department

Production Cost Modeling for High Levels of Photovoltaics Penetration

Description: The goal of this report is to evaluate the likely avoided generation, fuels, and emissions resulting from photovoltaics (PV) deployment in several U.S. locations and identify new tools, methods, and analysis to improve understanding of PV impacts at the grid level.
Date: February 1, 2008
Creator: Denholm, P.; Margolis, R. & Milford, J.
Partner: UNT Libraries Government Documents Department

PHEV Impacts on Regional Systems (Poster)

Description: This poster, submitted for the CU Energy Initiative/NREL Symposium on October 3, 2006 in Boulder, Colorado, looks at the impacts, emissions, and avoided gasoline due to plug-in hybrid electric vehicles (PHEVs).
Date: October 3, 2006
Creator: Parks, K.; Denholm, P. & Markel, T.
Partner: UNT Libraries Government Documents Department

Solar Deployment System (SolarDS) Model: Documentation and Sample Results

Description: The Solar Deployment System (SolarDS) model is a bottom-up, market penetration model that simulates the potential adoption of photovoltaics (PV) on residential and commercial rooftops in the continental United States through 2030. NREL developed SolarDS to examine the market competitiveness of PV based on regional solar resources, capital costs, electricity prices, utility rate structures, and federal and local incentives. The model uses the projected financial performance of PV systems to simulate PV adoption for building types and regions then aggregates adoption to state and national levels. The main components of SolarDS include a PV performance simulator, a PV annual revenue calculator, a PV financial performance calculator, a PV market share calculator, and a regional aggregator. The model simulates a variety of installed PV capacity for a range of user-specified input parameters. PV market penetration levels from 15 to 193 GW by 2030 were simulated in preliminary model runs. SolarDS results are primarily driven by three model assumptions: (1) future PV cost reductions, (2) the maximum PV market share assumed for systems with given financial performance, and (3) PV financing parameters and policy-driven assumptions, such as the possible future cost of carbon emissions.
Date: September 1, 2009
Creator: Denholm, P.; Drury, E. & Margolis, R.
Partner: UNT Libraries Government Documents Department

Modeling the U.S. Rooftop Photovoltaics Market

Description: Global rooftop PV markets are growing rapidly, fueled by a combination of declining PV prices and several policy-based incentives. The future growth, and size, of the rooftop market is highly dependent on continued PV cost reductions, financing options, net metering policy, carbon prices and future incentives. Several PV market penetration models, sharing a similar structure and methodology, have been developed over the last decade to quantify the impacts of these factors on market growth. This study uses a geospatially rich, bottom-up, PV market penetration model--the Solar Deployment Systems (SolarDS) model developed by the National Renewable Energy Laboratory--to explore key market and policy-based drivers for residential and commercial rooftop PV markets. The identified drivers include a range of options from traditional incentives, to attractive customer financing options, to net metering and carbon policy.
Date: September 1, 2010
Creator: Drury, E.; Denholm, P. & Margolis, R.
Partner: UNT Libraries Government Documents Department

Impacts of Commercial Electric Utility Rate Structure Elements on the Economics of Photovoltaic Systems

Description: This analysis uses simulated building data, simulated solar photovoltaic (PV) data, and actual electric utility tariff data from 25 cities to understand better the impacts of different commercial rate structures on the value of solar PV systems. By analyzing and comparing 55 unique rate structures across the United States, this study seeks to identify the rate components that have the greatest effect on the value of PV systems. Understanding the beneficial components of utility tariffs can both assist decision makers in choosing appropriate rate structures and influence the development of rates that favor the deployment of PV systems. Results from this analysis show that a PV system's value decreases with increasing demand charges. Findings also indicate that time-of-use rate structures with peaks coincident with PV production and wide ranges between on- and off-peak prices most benefit the types of buildings and PV systems simulated. By analyzing a broad set of rate structures from across the United States, this analysis provides an insight into the range of impacts that current U.S. rate structures have on PV systems.
Date: June 1, 2010
Creator: Ong, S.; Denholm, P. & Doris, E.
Partner: UNT Libraries Government Documents Department

Impact of Different Economic Performance Metrics on the Perceived Value of Solar Photovoltaics

Description: Photovoltaic (PV) systems are installed by several types of market participants, ranging from residential customers to large-scale project developers and utilities. Each type of market participant frequently uses a different economic performance metric to characterize PV value because they are looking for different types of returns from a PV investment. This report finds that different economic performance metrics frequently show different price thresholds for when a PV investment becomes profitable or attractive. Several project parameters, such as financing terms, can have a significant impact on some metrics [e.g., internal rate of return (IRR), net present value (NPV), and benefit-to-cost (B/C) ratio] while having a minimal impact on other metrics (e.g., simple payback time). As such, the choice of economic performance metric by different customer types can significantly shape each customer's perception of PV investment value and ultimately their adoption decision.
Date: October 1, 2011
Creator: Drury, E.; Denholm, P. & Margolis, R.
Partner: UNT Libraries Government Documents Department

Sensitivity of Utility-Scale Solar Deployment Projections in the SunShot Vision Study to Market and Performance Assumptions

Description: The SunShot Vision Study explored the potential growth of solar markets if solar prices decreased by about 75% from 2010 to 2020. The ReEDS model was used to simulate utility PV and CSP deployment for this present study, based on several market and performance assumptions - electricity demand, natural gas prices, coal retirements, cost and performance of non-solar renewable technologies, PV resource variability, distributed PV deployment, and solar market supply growth - in addition to the SunShot solar price projections. This study finds that utility-scale solar deployment is highly sensitive to solar prices. Other factors can have significant impacts, particularly electricity demand and natural gas prices.
Date: April 1, 2013
Creator: Eurek, K.; Denholm, P.; Margolis, R. & Mowers, M.
Partner: UNT Libraries Government Documents Department

Grid Parity for Residential Photovoltaics in the United States: Key Drivers and Sensitivities; Preprint

Description: In this report, we analyze PV break-even costs for U.S. residential customers. We evaluate some key drivers of grid parity both regionally and over time. We also examine the impact of moving from flat to time-of-use (TOU) rates, and we evaluate individual components of the break-even cost, including effect of rate structure and various incentives. Finally, we examine how PV markets might evolve on a regional basis considering the sensitivity of the break-even cost to four major drivers: technical performance, financing parameters, electricity prices and rates, and policies. We find that electricity price rather than technical parameters are in general the key drivers of the break-even cost of PV. Additionally, this analysis provides insight about the potential viability of PV markets.
Date: August 1, 2012
Creator: Ong, S.; Denholm, P. & Clark, N.
Partner: UNT Libraries Government Documents Department