Overcoming challenges in the classification of deep geothermal potential

The geothermal community lacks a universal definition of deep geothermal systems. A minimum depth of 400 m is often assumed, with a further sub-classification into middle-deep geothermal systems for reservoirs found between 400 and 1000 m. Yet, the simplistic use of a depth cut-off is insufficient to uniquely determine the type of resource and its associated potential. Different definitions and criteria have been proposed in the past to frame deep geothermal systems. However, although they have valid assumptions, these frameworks lack systematic integration of correlated factors. To further complicate matters, new definitions such as hot dry rock (HDR), enhanced or engineered geothermal systems (EGSs) or deep heat mining have been introduced over the years. A clear and transparent approach is needed to estimate the potential of deep geothermal systems and be capable of distinguishing between resources of a different nature. In order to overcome the ambiguity associated with some past definitions such as EGS, this paper proposes the return to a more rigorous petrothermal versus hydrothermal classification. This would be superimposed with numerical criteria for the following: depth and temperature; predominance of conduction, convection or advection; formation type; rock properties; heat source type; requirement for formation stimulation and corresponding efficiency; requirement to provide the carrier fluid; well productivity (or injectivity); production (or circulation) flow rate; and heat recharge mode. Using the results from data mining of past and present deep geothermal projects worldwide, a classification of the same, according to the aforementioned criteria is proposed

INTERIM REPORT IMPROVED METHODS FOR INCORPORATING RISK IN DECISION MAKING

This paper reports observations and preliminary investigations in the first phase of a research program covering methodologies for making safety-related decisions. The objective has been to gain insight into NRC perceptions of the value of formal decision methods, their possible applications, and how risk is, or may be, incorporated in decision making. The perception of formal decision making techniques, held by various decision makers, and what may be done to improve them, were explored through interviews with NRC staff. An initial survey of decision making methods, an assessment of the applicability of formal methods vis-a-vis the available information, and a review of methods of incorporating risk and uncertainty have also been conducted

The Built Environment in a Changing Climate

The papers included in this Special Issue tackle multiple aspects of how cities, districts, and buildings could evolve along with climate change and how this would impact our way of conceiving and applying design criteria, policies, and urban plans. Despite the multidisciplinary nature of the collection, some transversal take-home messages emerge: • Today’s energy-efficient paradigms may lose their virtuosity in the future unless accurate estimates of future scenarios are used to design modelling platforms and to inform legislative frameworks; • Acting at the local scale is key. Future climate change adaptation will be implemented at the local level. Overlooking regional and local specificities will contribute to inaccurate and inefficient action plans. As such, the smaller scale will become vital in predicting future urban metabolic rates and corresponding comfort-driven strategies; • Energy poverty, heat vulnerability, and social injustice are emerging as critical factors for planning and acting for future-proof cities on par of micro- and meso-climatological factors; • Given that the impacts of climate change will persist for many years, adaptation to this phenomenon should be prioritized by removing any prominent barrier and by enabling combinations of different mitigation technologies. These topics will receive a global reach in few decades, since also developing and underdeveloped countries are starting their fight against local climate change, with cities at the forefront

A Renewable Energy Plan for Mozambique

Mozambique has among the lowest uses of electricity in the world. Yet virtually all of the electricity it does produce from Cahora Bassa Dam on the Zambezi is shipped to its wealthy neighbor, South Africa. As the government prepares to build another costly large dam on the Zambezi that will also power South Africa rather than homes and businesses in Mozambique, a new report lays out a saner plan for developing renewable energy sources across the nation that would share the energy wealth more equitably; diversify the national electricity grid to help the nation adapt to climate change (which is expected to significantly affect large hydro), and build a clean energy sector that would also spare the Zambezi

Climate-Related Investing Across Asset Classes

Responsible investment -- understood as the incorporation of environmental, social, and governance (ESG) information into investment analysis -- is a discipline that allows investors to:- Better assess long-term risks and opportunities in their portfolios; and- Better align their investment strategies with opportunities to create longterm wealth for investors and society alike.It is a tool for investors who seek to improve long-term financial returns through enhanced ESG analysis. It also appeals to mission or impact investors, who seek to achieve defined social and/or environmental goals while achieving targeted rates of return. In both cases, investors use responsible investment as a tool to improve their ability to achieve their goals.Climate change is among the most important issues addressed by today's responsible investment universe. The physical risks of climate change, the likelihood of major changes in political and regulatory investment environments as a result of climate change, the opportunities associated with a radical global transformation to a low-carbon economy -- these issues create far-reaching implications for investors as they make decisions about their investment strategies, and as they evaluate particular fund managers and investment opportunities. New ideas, products, and methods have entered the market to address the long-term implications of climate change.This short handbook takes as its premise that a climate lens reveals risks and opportunities across all elements of an investor's portfolio. Every asset class offers investors an opportunity to pursue climate-friendly investments, to mitigate exposure to climate risk, and to engage stakeholders to improve climate-related performance across the range of investment opportunities

AFB/open cycle gas turbine conceptual design study

Applications of coal fired atmospheric fluidized bed gas turbine systems in industrial cogeneration are identified. Based on site-specific conceptual designs, the potential benefits of the AFB/gas turbine system were compared with an atmospheric fluidized design steam boiler/steam turbine system. The application of these cogeneration systems at four industrial plant sites is reviewed. A performance and benefit analysis was made along with a study of the representativeness of the sites both in regard to their own industry and compared to industry as a whole. A site was selected for the conceptual design, which included detailed site definition, AFB/gas turbine and AFB/steam turbine cogeneration system designs, detailed cost estimates, and comparative performance and benefit analysis. Market and benefit analyses identified the potential market penetration for the cogeneration technologies and quantified the potential benefits