Capacity Value from Wind and Solar Sources in Systems with Variable Dispatchable Capacity—An Application in the Brazilian Hydrothermal System

The most robust methods to determine the capacity contribution from intermittent sources combine load curve, variable generation profile, and dispatchable generators’ data to calculate any new inserted variable source’s capacity value in the power system. However, these methods invariably adopt the premise that the system’s dispatchable generators’ capacity is constant. That is an unacceptable limitation when the energy mix has a large share of hydroelectric sources. Hydroelectric plants are dispatchable sources with variable maximum power output over time, varying mainly according to the reservoirs’ level. This article develops a method that makes it possible to calculate the capacity value from renewable resources when the dispatchable generation units of an electric system have variable capacity. The authors apply the method to calculate the capacity value from solar and wind sources in Brazil as an exercise. By abandoning the hypothesis of constant dispatchable capacity, the developed approach is in principle extensible for other energy-limited resources, such as batteries and concentrating solar power (CSP). This can be a strategy to incorporate energy-limited capacity sources into the planning and operation models as reliable capacity sources.

Multi-component supramolecular fibers with elastomeric properties and controlled drug release

Supramolecular fibers fabricated by co-axial electrospinning combine load-bearing properties and sustained drug release of hydrophobic and UPy-modified drugs.

Using Field-level Characteristics as Proxy Measures to Test for the Presence of Economies of Scale in Nonpoint Pollution Control

We use parametric and nonparametric methods to estimate correlations between average control cost and three field-level characteristics—field size and delivered phosphorous per field and per acre—as proxies for economies of scale in controlling nonpoint pollution. We combine load and delivery-ratio estimates for more than 12,000 fields in the Bear River Basin, Utah, with estimates of control costs and effectiveness of management practices from the literature. Results suggest a negative relationship between control cost and delivered phosphorous per field and per acre. Ranking fields by phosphorous load therefore prioritizes management-practice subsidies by economies of scale.

Qualification of UOE SAWL Linepipes With Enhanced Collapse Resistance for Ultra Deepwater Applications

Large diameter UOE pipes are being increasingly used for the construction of offshore pipelines. Since oil discoveries are moving towards ultra-deepwater areas, such as Pre-Salt in Brazil, collapse resistance is a key factor in the design of the pipelines. It is known that the cold forming, and the final expansion in the UOE linepipe manufacturing process, reduces the elastic limit of the steel in subsequent compression. Due to this, the DNV collapse formula includes a fabrication factor that derates by a 15% the yield strength of UOE Pipes. However, DNV also recognizes the effect of thermal treatments and the code allows for improvement of the fabrication factor when heat treatment or external cold sizing (compression) is applied, if documented. This paper presents the qualification of UOE pipes with enhanced collapse capacity focusing the use of a fabrication factor (αfab) equal to 1. TenarisConfab has performed a technology qualification process according to DNV-RP-A203 standard “Qualification Procedures for New Technology”. The main aspects of the qualification process are presented in this paper which included significant material and full scale testing, including combine load testing, and final analysis. The qualification process achieved successful results and this will allow use of a fabrication factor equal to 1 directly in deepwater and ultra-deepwater offshore pipeline projects with a possible reduction in material and offshore installation costs and also potentially enhancing the feasibility of many challenging offshore projects.