Is the choice of renewable portfolio standards random?

This study investigated factors influencing the adoption or intention to adopt renewable portfolio standards (RPS) by individual states in the United States (U.S). Theory of adoption of innovation was applied as a conceptual framework. A logistic model was used to achieve the task. Gross state product (GSP), growth rate of population (GRP), political party dominancy, education level, natural resources expenditure, and share of coal in electricity generation were used as explanatory variables. Results indicated that the model predicts the dependent variable (state's choice of adopting or not adopting RPS) 82 times correctly out of 100. Results also suggested that education followed by political party dominancy, GSP and GRP are shown to have large impacts on the probability of RPS adoption.     

Supply amount and marginal price of renewable electricity under the renewables portfolio standard in Japan

The Renewables Portfolio Standard (RPS) in Japan requires that approximately 1.35% of each retail supplier's electricity sales in FY2010 come from renewable energy sources (RES), for example, photovoltaics, wind, biomass, geothermal, and small hydropower. To help retail suppliers and renewable generators develop effective strategies, this study provides a quantitative analysis of the impact of this measure. We assume the supply conditions for electricity generation from renewable energy sources (RES-E) based on regional resource endowments, and we derive the cost-effective compositions of renewable portfolios, RES-E certificate prices, and additional costs to retail suppliers. The future prospects of RES-E are assessed based on technology, region, and year up to FY2010. The analysis reveals that wind power and biomass power generated from municipal waste will provide the majority of the total supply of RES-E under the RPS. It also indicates that the marginal price of RES-E certificates will be approximately 5.8 JPY/kWh (5.2 USc/kWh) in FY2010, in the case wherein the marginal price of electricity is assumed to be 4 JPY/kWh (3.6 USc/kWh). In order to elaborate on this further, sensitivity analyses for some parameters of RES and the price of electricity are provided. The dynamic supply curves of RES-E certificates are also indicated.     

Weighing the costs and benefits of state renewables portfolio standards in the United States: A comparative analysis of state-level policy impact projections

State renewables portfolio standards (RPS) have emerged as one of the most important policy drivers of renewable energy capacity expansion in the U.S. As RPS policies have been proposed or adopted in an increasing number of states, a growing number of studies have attempted to quantify the potential impacts of these policies, focusing primarily on cost impacts, but sometimes also estimating macroeconomic, risk reduction, and environmental effects. This article synthesizes and analyzes the results and methodologies of 31 distinct state or utility-level RPS cost-impact analyses completed since 1998. Together, these studies model proposed or adopted RPS policies in 20 different states. We highlight the key findings of these studies on the projected costs of state RPS policies, examine the sensitivity of projected costs to model assumptions, evaluate the reasonableness of key input assumptions, and suggest possible areas of improvement for future RPS analyses. We conclude that while there is considerable uncertainty in the study results, the majority of the studies project modest cost impacts. Seventy percent of the state RPS cost studies project retail electricity rate increases of no greater than 1%. Nonetheless, there is considerable room for improving the analytic methods, and therefore accuracy of these estimates.     

Promoting renewables in the energy sector of Tajikistan

Energy technology transfer can allow countries to move quickly to environmentally sound and sustainable practices. Integration of Renewable Energy Sources (RES) technologies in the energy sector of these countries can play a key role towards sustainability. The level of penetration of RES technologies remains seriously in arrears in Tajikistan, although the country has great RES potential. The aim of the paper is to look deeply into the most appropriate RES technology, which can be gradually introduced in the energy sector of Tajikistan and supported through demonstrations, business workshops, guides for installers with technical details and design proposals. The multi-dimensional methodology adopted included transparent decision support processes, using linguistic variables, taking into consideration the specific conditions prevailing in Tajikistan, as well as policy and technical proposal for the further development of the local market. Based on the results, the emphasis is laid on decentralized heat production, though the promotion of Solar Water Heaters, which seems to be an attractive energy option, with multiple benefits for the country.     

Carbon mitigation in the electric power sector under cap-and-trade and renewables policies

In Europe, CO₂ emissions from the electric power sector and energy intensive industries are capped under a cap-and-trade system (i.e., the EU ETS). When other indirect measures are taken to impact emissions in a specific sector under the cap (such as a push for renewables in the electric power sector), this has implications on the overall allowance price, and on CO₂ emissions both from this specific sector and the other sectors under the cap. The central contribution of this paper is the derivation of impact curves, which describe these interactions, i.e., the impact on allowance price and the shift of emissions across sectors. From a set of detailed simulations of the electric power system operation, a so-called “emission plane” is obtained, from which impact curves can be derived. Focus is on interactions between CO₂ abatement through fuel switching and measures affecting the residual electricity demand (such as deployment of renewables) in the electric power sector, as well as on interactions with other sectors, both in a short-term framework. A case study for Central-Western Europe is presented. The analysis reveals a substantial impact of renewables on CO₂ emissions, and hence on emissions shifts across sectors and/or on the CO₂ price.     

Land-use requirements and the per-capita solar footprint for photovoltaic generation in the United States

In this report, we estimate the state-by-state per-capita “solar electric footprint” for the United States, defined as the land area required to supply all end-use electricity from solar photovoltaics (PV). We find that the overall average solar electric footprint is about 181 m² per person in a base case scenario, with a state- and scenario-dependant range from about 50 to over 450 m² per person. 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). We also compare the solar electric footprint to a number of other land uses. For example, we find that the base case solar electric footprint is equal to less than 2% of the land dedicated to cropland and grazing in the United States, and less than the current amount of land used for corn ethanol production.     

美国可再生能源配额制最新进展及对我国的启示

到目前为止,美国已有30个州依据本州资源、市场、政策背景制定并实施了可再生能源配额制,产生效果不尽相同。为了识别配额制特点及其作用和影响,本文在概述美国配额制最新进展基础上,选取德克萨斯州、加利福尼亚州、新墨西哥州和麻萨诸塞州为例,比较其设计和运行特点,为我国设计实施配额制政策提供借鉴。     

Analysis of renewable energy development to power generation in the United States

Renewable energy resources have historically played a small role for electricity generation in the US. However, concerns such as security of energy supply, limitations and price fluctuations of fossil fuels, and threats of climate changes have encouraged US policy makers to think and debate about diversification strategy in the energy supply and promotion of renewables. The current paper discusses the role of renewable portfolio in the US energy action plan during 2010–2030. A system dynamics model is constructed to evaluate different costs of renewable energy utilization by 2030. Results show that while renewables will create a market with near 10 billion $ worth (in the costs level) in 2030, the total value of renewable energy promotion and utilization in the US will be more than 170 billion $(in the costs level) during 2010–2030.     

Rejecting renewables: The socio-technical impediments to renewable electricity in the United States

If renewable power systems deliver such impressive benefits, why do they still provide only 3 percent of national electricity generation in the United States? As an answer, this article demonstrates that the impediments to renewable power are socio-technical, a term that encompasses the technological, social, political, regulatory, and cultural aspects of electricity supply and use. Extensive interviews of public utility commissioners, utility managers, system operators, manufacturers, researchers, business owners, and ordinary consumers reveal that it is these socio-technical barriers that often explain why wind, solar, biomass, geothermal, and hydroelectric power sources are not embraced. Utility operators reject renewable resources because they are trained to think only in terms of big, conventional power plants. Consumers practically ignore renewable power systems because they are not given accurate price signals about electricity consumption. Intentional market distortions (such as subsidies), and unintentional market distortions (such as split incentives) prevent consumers from becoming fully invested in their electricity choices. As a result, newer and cleaner technologies that may offer social and environmental benefits but are not consistent with the dominant paradigm of the electricity industry continue to face comparative rejection.     

Evaluation of numerical weather prediction for intra-day solar forecasting in the continental United States

Numerical weather prediction (NWP) is generally the most accurate tool for forecasting solar irradiation several hours in advance. This study validates the North American Model (NAM), Global Forecast System (GFS), and European Centre for Medium-Range Weather Forecasts (ECMWF) global horizontal irradiance (GHI) forecasts for the continental United States (CONUS) using SURFRAD ground measurement data. Persistence and clear sky forecasts are also evaluated. For measured clear conditions all NWP models are biased by less than 50 W m⁻². For measured cloudy conditions these biases can exceed 200 W m⁻² near solar noon. In general, the NWP models (especially GFS and NAM) are biased towards forecasting clear conditions resulting in large, positive biases.Mean bias errors (MBE) are obtained for each NWP model as a function of solar zenith angle and forecast clear sky index, kt^∗, to derive a bias correction function through model output statistics (MOS). For forecast clear sky conditions, the NAM and GFS are found to be positively biased by up to 150 W m⁻², while ECMWF MBE is small. The GFS and NAM forecasts were found to exceed clear sky irradiances by up to 40%, indicating an inaccurate clear sky model. For forecast cloudy conditions (kt^∗ < 0.4) the NAM and GFS models have a negative bias of up to −150 W m⁻². ECMWF forecasts are most biased for moderate cloudy conditions (0.4 < kt^∗ < 0.9) with an average over-prediction of 100 W m⁻².MOS-corrected NWP forecasts based on solar zenith angle and kt^∗ provide an important baseline accuracy to evaluate other forecasting techniques. MOS minimizes MBE for all NWP models. Root mean square errors for hourly-averaged daytime irradiances are also reduced by 50 W m⁻², especially for intermediate clear sky indices. The MOS-corrected GFS provides the best solar forecasts for the CONUS with an RMSE of about 85 W m⁻², followed by ECMWF and NAM. ECMWF is the most accurate forecast in cloudy conditions, while GFS has the best clear sky accuracy.     

中美水电标准中水电站技术供水系统要求的对比分析

在中国水电"走出去"的过程中,国外用户对中国标准体系的认可度较低的问题日益凸显,影响了中国水电全产业链"走出去"的进程和国外项目的顺利推进.本文作者通过对中美相关标准中水电站技术供水系统要求的对比,分析了两国标准在技术细节上的优劣性,为中国水电标准的推广提供了一个样本和借鉴.     

A preliminary assessment of avian mortality at utility-scale solar energy facilities in the United States

Despite the benefits of reduced toxic and carbon emissions and a perpetual energy resource, there is potential for negative environmental impacts resulting from utility-scale solar energy (USSE) development. Although USSE development may represent an avian mortality source, there is little knowledge regarding the magnitude of these impacts in the context of other avian mortality sources. In this study we present a first assessment of avian mortality at USSE facilities through a synthesis of available avian monitoring and mortality information at existing USSE facilities. Using this information, we contextualize USSE avian mortality relative to other forms of avian mortality at 2 spatial scales: a regional scale (confined to southern California) and a national scale. Systematic avian mortality information was available for three USSE facilities in the southern California region. We estimated annual USSE-related avian mortality to be between 16,200 and 59,400 birds in the southern California region, which was extrapolated to between 37,800 and 138,600 birds for all USSE facilities across the United States that are either installed or under construction. We also discuss issues related to avian–solar interactions that should be addressed in future research and monitoring programs.     

Exploring the impact of permitting and local regulatory processes on residential solar prices in the United States

This article statistically isolates the impacts of city-level permitting and other local regulatory processes on residential PV prices in the United States. We combine data from two “scoring” mechanisms that independently capture local regulatory process efficiency with the largest dataset of installed PV prices in the United States. We find that variations in local permitting procedures can lead to differences in average residential PV prices of approximately $0.18/W between the jurisdictions with the least-favorable and most-favorable permitting procedures. Between jurisdictions with scores across the middle 90% of the range (i.e., 5th percentile to 95th percentile), the difference is $0.14/W, equivalent to a $700 (2.2%) difference in system costs for a typical 5-kW residential PV installation. When considering variations not only in permitting practices, but also in other local regulatory procedures, price differences grow to $0.64–$0.93/W between the least-favorable and most-favorable jurisdictions. Between jurisdictions with scores across the middle 90% of the range, the difference is equivalent to a price impact of at least $2500 (8%) for a typical 5-kW residential PV installation. These results highlight the magnitude of cost reduction that might be expected from streamlining local regulatory regimes.     

Efficient power generating portfolio in Brazil: Conciliating cost,emissions and risk

The main purpose of this paper is to assess efficiency of the Brazilian electricity generation mix proposed in the 2020 Decennial Plan for Energy Expansion (DPEE 2020). It evaluates estimated costs, risks and CO₂ emissions following the mean–variance portfolio theory. The efficiency frontier is estimated for three CO₂ prices scenarios: no CO₂ prices, low CO₂ price and high CO₂ price. The planned portfolio in Brazil presented in the DPEE 2020 is relatively close to the efficient frontier, however there is still room for risk mitigation by diversifying the energy portfolio. As there is currently no CO₂ price in Brazil, the tendency is that diversification increases fossil fuel share in the energy mix, but the introduction of a CO₂ price can be an option to promote renewables. This type of large general market framework can contribute to reduce market uncertainties by reducing the level of government′s discretionary activism.     

Evaluating renewable portfolio standards and carbon cap scenarios in the U.S. electric sector

This report examines the impact of renewable portfolio standards (RPS) and cap-and-trade policy options on the U.S. electricity sector. The analysis uses the National Renewable Energy Laboratory's Regional Energy Deployment System (ReEDS) model that simulates the least-cost expansion of electricity generation capacity and transmission in the U.S. to examine the impact of a variety of emissions caps—and RPS scenarios both individually and combined. The generation mix, carbon emissions, and electricity price are examined for various policy combinations simulated in the modeling.     

When renewable portfolio standards meet cap-and-trade regulations in the electricity sector: Market interactions,profits implications,and policy redundancy

Emission trading programs (C&T) and renewable portfolio standards (RPS) are two common tools used by policymakers to control GHG emissions in the energy and other energy-intensive sectors. Little is known, however, as to the policy implications resulting from these concurrent regulations, especially given that their underlying policy goals and regulatory schemes are distinct. This paper applies both an analytical model and a computational model to examine the short-run implications of market interactions and policy redundancy. The analytical model is used to generate contestable hypotheses, while the numerical model is applied to consider more realistic market conditions. We have two central findings. First, lowering the CO₂ C&T cap might penalize renewable units, and increasing the RPS level could sometimes benefit coal and oil and make natural gas units worse off. Second, making one policy more stringent would weaken the market incentive, which the other policy relies upon to attain its intended policy target.     

Technical and economic performance of residential solar water heating in the United States

This paper examines the regional, technical, and economic performance of residential rooftop solar water heating (SWH) technology in the U.S. It focuses on the application of SWH to consumers in the U.S. currently using electricity for water heating, which currently uses over 120 billion kWh per year. The variation in electrical energy savings due to water heating use, inlet water temperature and solar resource is estimated and applied to determine the regional “break-even” cost of SWH where the life-cycle cost of SWH is equal the life-cycle energy savings. For a typical residential consumer, a SWH system will reduce water heating energy demand by 50–85%, or a savings of 1600–2600 kWh per year. For the largest 1000 electric utilities serving residential customers in the United States as of 2008, this corresponds to an annual electric bill savings range of about $100 to over $300, reflecting the large range in residential electricity prices. This range in electricity prices, along with a variety of incentives programs corresponds to a break-even cost of SWH in the United States varying by more than a factor of five (from less than $2250/system to over $10,000/system excluding Hawaii and Alaska), despite a much smaller variation in the amount of energy saved by the systems (a factor of approximately one and a half). We also consider the relationships between collector area and technical performance, SWH price and solar fraction (percent of daily energy requirements supplied by the SWH system) and examine the key drivers behind break-even costs.     

A comparison of CO2 emissions from fossil and solar power plants in the United States

We present estimates of the lifetime carbon dioxide emissions from coal-fired, photovoltaic, and solar thermal power plants in the United States. These CO₂ estimates are based on a net energy analysis derived from both operational systems and detailed design studies. It appears that energy-conservation measures and shifting from fossil to renewable energy sources have significant long-term potential to reduce CO₂ production caused by energy generation. The implications of these results for a national energy policy are discussed.     

Managing carbon regulatory risk in utility resource planning: Current practices in the Western United States

Concerns about global climate change have substantially increased the likelihood that future policy will seek to minimize carbon dioxide emissions. As such, even today, electric utilities are making resource planning and investment decisions that consider the possible implications of these future carbon regulations. In this article, we examine the manner in which utilities assess the financial risks associated with future carbon regulations within their long-term resource plans. We base our analysis on a review of the most recent resource plans filed by 15 electric utilities in the Western United States. Virtually all of these utilities made some effort to quantitatively evaluate the potential cost of future carbon regulations when analyzing alternate supply- and demand-side resource options for meeting customer load. Even without federal climate regulation in the US, the prospect of that regulation is already having an impact on utility decision-making and resource choices. That said, the methods and assumptions used by utilities to analyze carbon regulatory risk, and the impact of that analysis on their choice of a particular resource strategy, vary considerably, revealing a number of opportunities for analytic improvement. Though our review focuses on a subset of US electric utilities, this work holds implications for all electric utilities and energy policymakers who are seeking to minimize the compliance costs associated with future carbon regulations.     

Potential emissions reductions from grandfathered coal power plants in the United States

A two-tiered approach to environmental regulation in the United States has long allowed existing coal-fired power plants to emit air pollutants at far higher rates than new facilities. The potential for reducing the emissions of existing coal-fired facilities is quantified via two hypothetical scenarios: the installation of available retrofit control technologies, or the imposition of New Source Performance Standards (NSPS). Available control technologies could have reduced year 2005 emissions by 56% for NO_x and 72% for SO₂ for a cost of $11.3 billion/year (2004$), likely yielding far larger benefits to human health. Slightly more emission reductions would be achieved by upgrading or replacing existing facilities to achieve the NSPS emissions limits required of all new facilities. Potential CO₂ reductions are more speculative due to the emerging nature of carbon capture and efficiency retrofit technologies. Recent policies such as the Cross-State Air Pollution Rule would likely achieve most of the NO_x and SO₂ reduction potential identified by the scenario analyses for grandfathered facilities. However, escalating obstacles to new generation capacity may perpetuate the reliance on an aging fleet of power plants, resulting in higher rates of coal consumption and CO₂ emissions than could be achieved by new or retrofit units.