Volume 6, Issue 3

The dependence of the U.S. power sector on water makes electricity generation exposed to hydrologic constraints in some regions. The U.S. power sector is in a state of transition, driven by technological innovations, energy markets, and regulations, and changes in the future electricity generation mix will have important implications for water use. Most models for long-term electricity sector projections do not have sufficient regional detail for analyzing water-related impacts and important decisions on electricity and water usage. In this paper we analyzed how water consumption and usage constraints affect the U.S. electricity generation sector. In addition, we investigated whether current CO 2 emissions mitigation policies such as the Regional Greenhouse Gas Initiative (RGGI) and greenhouse gas emissions (GHG) cap-and-trade program in California would improve or magnify electric sector water reliance. Finally, we analyzed what generation technologies will likely be deployed under different constraint assumptions.

Near surface complexities have been and remain the toughest challenge for oil and gas exploration on land, where most of the proven reserves are located. The same complexities are present for environmental applications, such as CO 2 sequestration or the quest for deep aquifers. In this paper I review a few of these continuing challenges and present examples of recent techniques and technologies that may contribute to their solution.

This study evaluates the size and cost of a solar aided feedwater heating (SAFWH) system necessary to reduce the emissions of a new coal-fired power plant to 1,400 pounds of carbon dioxide per megawatt-hour of gross electricity (1,400 lb CO 2 /MWh g ) produced by the plant. An Aspen Plus Model was used to determine the efficiency improvements which could be achieved through SAFWH and these results were used to size parabolic trough Concentrating Solar Power (CSP) Systems for three different steam conditions ranging from supercritical to advanced, ultra-supercritical. Thermal energy storage was included in the system to ensure 20–24 hours of the operation per day. Two geographic locations were evaluated in order to evaluate the effects of high and low solar resources. The combined costs of the solar field and the thermal storage system ranged from $30 to $70 million for a next-generation, advanced ultra-supercritical plant to between $119 and $276 million for a supercritical plant. The ranges in costs reflect a difference in solar resource quality at the two locations. More broadly, the results illustrate how increased power plant efficiency can dramatically reduce the size and cost of an SAFWH system required to meet an emissions limit of 1,400 lb CO 2 /MWh g .

This article provides an overview of the state of the art in hydraulic fracturing, a controversial topic of the last decade. To Frack or not to Frack, That is the Question [1]; this question was posed at a meeting of the Western Regional Society of Petroleum Engineers. The fact is, we have witnessed an intense debate over hydraulic fracturing’s economic benefits and its ill effects (perceived or real) during the past decade. Many, in particular those in the fossil energy industry, consider shale oil / gas, with the associated horizontal drilling and hydraulic fracturing, as one of the major developments in the oil and gas industry of the past two decades. Others, especially many environmentalists, consider fracking proponents as public enemy number one. Different sections of this paper attempt to highlight different scientific facts about hydraulic fracturing, the common-sense environmental concerns, and the respective economic ramifications. After a brief overview of the principals of hydraulic fracturing in section 1, we discuss the importance of hydraulic fracturing in section 2. This is followed by fracture characterization (section 3) and geomechanics (section 4). These sections examine natural fractures in the subsurface and how one can characterize them, how hydraulic fracturing helps to expand the natural fractures and/ or create new (stimulated) fractures, and the underlining rock mechanics properties and related stress regime. Section 5 addresses different environmental concerns about hydraulic fracturing. These include potential ground water contamination, amount of water used for hydraulic fracturing, the water disposal process, and methane emission concerns. Another environmental concern is induced seismicity or man-made earthquakes. Given the much publicized controversy on whether and to what extent hydraulic fracturing creates, section 6 is dedicated to covering this issue. Section 7 includes a case history from California, highlighting many of the topics discussed in other sections. The key message of this article is the best way to answer the question with which we began, namely to frack or not to frack, lies with science; the hope is, with sound scientific and engineering investigation, truth will prevail-- “ veritas omnia vincit .”