Brian H. Bowen

A new long-term hydro production scheduling method for maximizing the profit of hydroelectric systems

This paper presents a new long-term hydrothermal production scheduling method. The proposed method maximizes the profit of hydroelectric plants, based on the monthly energy requirement of the system, instead of minimizing the production cost of thermal units. It is shown that different forms of composite thermal marginal costs will lead to the same hydro production schedule. Thus a linear marginal cost, the simplest form, is sufficient for long-term hydrothermal scheduling. A linear hydro marginal profit is also sufficient for this purpose. An immediate conclusion is that an actual composite thermal cost function, which is complicated by thermal unit availability, may not be needed for the long-term optimal hydrothermal scheduling. Due to this simplification, traditional long and mid-term hydrothermal scheduling, a complicated problem, becomes easier to solve. The method can be used by the owners of independent hydro plants in a region for long-term hydroelectric scheduling under both deregulation and competition. A case study shows that the model allocates successfully and efficiently the hydroelectric resources to peak demand periods with negligible computation time.

Modeling electricity trade policy for the twelve nations of the Southern African Power Pool (SAPP)

Abstract The benefits from a centralized and competitive dispatch, compared with existing bilateral electricity trade agreements are determined to be about

On convexity issues of short-term hydrothermal scheduling

100 million per year in the 12-nation Southern African Power Pool (SAPP). Generation, transmission, and costing variables are uniquely incorporated into a short-term cost minimizing mixed integer linear programming model, to determine the optimal unit commitment and dispatch across this 12-nation pool of the Southern African Development Community (SADC) region of Africa. Costs are minimized from increasing the use of existing hydropower facilities in the Democratic Republic of Congo (DRC), Zambia, and Mozambique and reducing fuel costs primarily in South Africa.

An enhanced model of capacity expansion with CO 2 cap-and-trade and EOR CO 2 re-emergence

This paper introduces a convex and normally constrained hydrothermal scheduling method. Convexity is achieved by using a hydro water loss term and a piece-wise linear representation of the relationship between water head and volume. A basic technique is developed for obtaining normal constraints, developed for the first time in this paper, by converting the conditional constraints into unconditional constraints. An example of the conditional constraints is the hydrothermal unit on/off status being expressed as a function of the unit minimum up/down times. Unit start-up and shut-down variables are summed over the minimum-up time and the minimum-down time and the summations are being limited to one. In each case this is to prevent immature unit start-up or shut-down. This allows the hydrothermal scheduling problem to become an ordinary mixed integer problem that can be solved by using standard commercial mixed integer programming solvers. These solvers can be purchased on the market for a few thousand dollars, far below the prices of the specially designed hydrothermal scheduling software products from consulting firms. The algorithm developed in this paper is tested for different cases with good results, especially for small hydrothermal systems.

Preserving low cost electricity while improving the riverine environment: A case study of Ghana’s Akosombo hydro complex

This paper describes an enhanced model of power production under CO2 cap-and-trade regulation. Re-emergence of CO2 from EOR (enhanced oil recovery) processing is considered, and the net CO2 release is quantified accordingly. New cost data is used to reflect the cost increase in the past few years. Binary variables are used for new construction of power plants, transmission, CO2 pipelines, and retrofitting, while continuous variables are used for representing others such as power production, CO2 generation, etc. The objective is to minimize regional cost of meeting demand under potential CO2 cap-and-trade regulation in the United States. In case studies, 28 nodes are used to represent production and demand in five States including Indiana and its surrounding states. Seventy sequestration sites are chosen for the 28 nodes, including EOR, ECBM (enhanced coal bed methane) and aquifers.

Preserving low cost electricity while improving the riverine environment: Part two — Model results

This paper presents the strategy for development of a stochastic programming model of the operation and capacity additions to a large hydro/thermal electricity generation complex. The proposed model minimizes the incremental costs of operating the complex so as to return river flows to pre-dam patterns. The paper focuses on a representative year made up of wet and dry seasons far enough into the future to allow adjustment of thermal and hydro generating capacities and the initial level of the reservoir, but not the capacity of the reservoir itself. The model was run first to find the operating and investment strategies which minimize electricity costs, and then run so as to minimize cost subject to equating seasonal reservoir inflows to seasonal outflows - so called ldquorun of river, RORrdquo operation. Using data from Ghanapsilas Akosombo/Kpong complex, likely outcomes of the model are presented and compared, based on existing capacities of the system.

Clean coal initiatives in Indiana

This paper reports on a case study for Ghanas thermal/hydroelectric generation system that evaluates the incremental cost of returning dam outflows to pre-dam or near pre-dam conditions. This mode of operation is termed Run of River (ROR) operation. It appears that two key factors — the availability of alternatives for economically expanding hydro generation and the existence of well developed markets for energy and electricity — have a large influence on the increase in cost of ROR operation relative to the least cost operating rules.

Economic benefits and strategic new international transmission in the Southern African power pool (SAPP) and West African power pool (WAPP)

Purpose – Indiana is listed among the top ten coal states in the USA and annually mines about 35 million short tons (million tons) of coal from the vast reserves of the US Midwest Illinois Coal Basin. The implementation and commercialization of clean coal technologies is important to the economy of the state and has a significant role in the states energy plan for increasing the use of the states natural resources. Coal is a substantial Indiana energy resource and also has stable and relatively low costs, compared with the increasing costs of other major fuels. This indigenous energy source enables the promotion of energy independence. The purpose of this paper is to outline the significance of clean coal projects for achieving this objective.Design/methodology/approach – The paper outlines the clean coal initiatives being taken in Indiana and the research carried out at the Indiana Center for Coal Technology Research.Findings – Clean coal power generation and coal for transportation fuels (coal‐to‐liqu...

Planning India's long-term energy shipment infrastructures for electricity and coal

This work discusses the Purdue long-term expansion model (LTEM), which is used in both the SAPP and WAPP policy planning. This policy is a 20-year planning system for energy and reserve trade between countries, which minimizes the present value of electricity generation costs, and generation/transmission capacity expansion costs. Modeling demonstrations consistently indicate the importance of several particular international transmission lines in Africa. Also expansions on existing lines and the addition of new proposed lines are indicated as providing the most cost effective investments for improving reliability of supplies across Africa.