A multi-period optimization model for energy planning with CO2 emission consideration

A novel deterministic multi-period mixed-integer linear programming (MILP) model for the power generation planning of electric systems is described and evaluated in this paper. The model is developed with the objective of determining the optimal mix of energy supply sources and pollutant mitigation options that meet a specified electricity demand and CO₂ emission targets at minimum cost. Several time-dependent parameters are included in the model formulation; they include forecasted energy demand, fuel price variability, construction lead time, conservation initiatives, and increase in fixed operational and maintenance costs over time. The developed model is applied to two case studies. The objective of the case studies is to examine the economical, structural, and environmental effects that would result if the electricity sector was required to reduce its CO₂ emissions to a specified limit.     

Evaluating the impact of uncertainty and variability on the value chain optimization of a forest biomass power plant using Monte Carlo Simulation

Mathematical programming models have been used to optimize the design and management of forest bioenergy supply chains. A deterministic mathematical model is beneficial for making optimum decisions; however, its applicability to real-world problems may be limited because it does not capture all the complexities, including uncertainties in the parameters, in the supply chain. In this paper, a combination of Monte Carlo Simulation and optimization model is used to evaluate the impact of uncertainty in biomass quality, availability and cost, and electricity prices on the supply chain of a forest biomass power plant. The optimization model is a deterministic mixed integer non-linear model with monthly time steps over a 1-year planning horizon. Variability in biomass quality, i.e. moisture content (MC) and higher heating value (HHV), based on the historical data of a real case study is studied in detail and fitted probability distributions are used in the model, while for electricity prices different scenarios are considered. The results show that the impact of variability in the MC on profit is higher than that of uncertainty in HHV. It is observed that the annual profit ranges between $13.3 million and $17.9 million in the presence of all possible uncertainties while its average is $15.5 million. Uncertainty in biomass availability and cost and electricity price results in the risks of having annual profit of less than $14 million and low monthly storage levels.     

Securing water for wetland conservation: a comparative analysis of policy options to protect a national nature reserve in China

This study evaluates four policy options to secure the water supply needed for wetland conservation in Qixinghe--a national wetland nature reserve in China--using four criteria: cost effectiveness, probability of success in achieving the water-saving goal, political feasibility, and farmer acceptance. This multi-criteria analysis framework reveals the ecological, economic, and socio-political trade-offs for policymakers when choosing among the four policy options. Results suggest that upgrading irrigation infrastructure in the area surrounding the wetland (Option I) is the most politically feasible option, but it is the second best option in terms of cost effectiveness. Constructing a dam to store and control floodwater (Option II) is the most reliable for achieving the water-saving goal. It is also the farmers' most favored strategy. But this option is the least cost effective and receives little support from local governments. Promoting farmers' adoption of water-saving practices (Option III) is the most cost effective, but it is less reliable for achieving the water-saving goal than Options I or II. Converting paddy crops to dry-land crops (Option IV) is politically infeasible and least reliable for achieving the water-saving goal. The overall ranking of the four options is determined using the policymakers' revealed weights on the four criteria. Option I is ranked first, followed by Options II, III, and IV.     

Mitigation of power sector environmental emissions through energy efficiency improvements: the case of Pakistan

This paper assesses the potential of selected efficient electrical appliances for avoiding power generation and for mitigation of selected air pollutants from the power sector in Pakistan from technical as well as national, utility and user perspectives. The study shows that about 14, 21 and 35% of the total CO₂, SO₂and NO_xemissions in the business as usual (BAU) case could be avoided by the adoption of selected efficient appliances during 1997–2015 from the national perspective, while the corresponding figures from the user perspective are 12, 17 and 29%, respectively. All selected efficient appliances would be cost effective to the users if electricity prices were set at the long-run marginal cost of supply.1998 Academic Press     

The political economy of power generation in Zimbabwe since 1980

This article presents a historical analysis of the power generation choices in Zimbabwe since independence in 1980; their causes and consequences. In the early 1980s, the electricity supply choices of the country were dictated by a policy of self-sufficiency, and least-cost supply options (e.g. imports and hydropower) were rejected at a not negligible economic cost. At the end of the 1980s, a new political environment and pressures from the World Bank prompted substantial changes towards least-cost alternatives. In the early 1990s, security of supply motives still played an important role and financial constraints were severe. At present, however, there is little evidence that imported power is still as cheap a source of electricity as it was about 15 years ago. This situation together with the ongoing trend towards higher discount rates imply that thermal power, in particular coal-fired power, will dominate future electricity supply investments in Zimbabwe.     

WATER SUPPLY AND URBAN GROWTH PLANNING: A PARTNERSHIP1

ABSTRACT As urban expansion outstrips water supplies, the usual solution is to build pipelines to bring in water from sources farther afield. Such water supplies may act as either a leader of urban development or as a follower. In either case, this engineering approach to the provision of water has fostered less than optimal utilization of regional water and land resources for urban growth. More efficient utilization of these resources is achieved when water supply development and urban growth planning are conjoint activities. Water supply planners and land use planners, working together, are able to generate and evaluate the full range of urban development options, including water demand management through conservation. Preferred regional growth plans are achieved using the best mix of water supply and urban growth. The result is a reduced rate of water supply development and a reduction of urban expansion on prime lands. This partnership approach is demonstrated for the Calgary Region under two levels of water conservation.     

Sizing and performance analysis of standalone hybrid photovoltaic/battery/hydrogen storage technology power generation systems based on the energy hub concept

In this study, the optimal sizing and performance analysis of a standalone integrated solar power system equipped with different storage scenarios to supply the power demand of a household is presented. One of the main purposes when applying solar energy resource is to face the increasing environmental pollutions resulting from fossil fuel based electricity sector. To this end, and to compare and examine two energy storage technologies (battery and hydrogen storage technology), three storage scenarios including battery only, hydrogen storage technology only and hybrid storage options are evaluated. An optimization framework based on Energy Hub concept is used to determine the optimum sizes of equipment for the lowest net present cost (NPC) while maintaining the system reliability. It was determined that the most cost effective and reliable case is the system with hybrid storage technology. Also, the effects of solar radiation intensity, the abatement potential of CO₂ emissions and converting excess power to hydrogen on the system’s performance and economics, were investigated and a few noticeable findings were obtained.     

Relative Value of Water for Hydropower and Municipal Supply in Southeastern Reservoirs

Population growth in the Southeast has driven withdrawals for municipal water beyond the limits of local supplies. With few options left for development of virgin sources, a number of urban areas are looking toward demand management and additional supplies by reallocating storage in reservoirs that were built primarily or in part for hydropower. Hydropower has become a lesser part of the mix of energy sources, and the question arises as to value of water for that purpose relative to its value for municipal use. Three cases are used to examine the issue. Effects of withdrawal for municipal water supply on output of electric energy are estimated. Benefits of foregone energy are evaluated using the least cost alternative for replacement, and benefits for municipal water are estimated using costs for development of new sources. Benefits for use as municipal water are found to be considerably higher than benefits for hydroelectric energy at existing prices, even higher than the least cost alternative for replacement. Given the spatial distribution of the cases, that finding would appear to hold in general across the region.     

Integrated Modeling of Water Supply and Demand under Management Options and Climate Change Scenarios in Chifeng City,China

Water resource management is becoming increasingly challenging in northern China because of the rapid increase in water demand and decline in water supply due to climate change. We provide a case study demonstrating the importance of integrated watershed management in sustaining water resources in Chifeng City, northern China. We examine the consequences of various climate change scenarios and adaptive management options on water supply by integrating the Soil and Water Assessment Tool and Water Evaluation and Planning models. We show how integrated modeling is useful in projecting the likely effects of management options using limited information. Our study indicates that constructing more reservoirs can alleviate the current water shortage and groundwater depletion problems. However, this option is not necessarily the most effective measure to solve water supply problems; instead, improving irrigation efficiency and changing cropping structure may be more effective. Furthermore, measures to increase water supply have limited effects on water availability under a continuous drought and a dry‐and‐warm climate scenario. We conclude that the combined measure of reducing water demand and increasing supply is the most effective and practical solution for the water shortage problems in the study area.     

Economics of Energy Conservation in Developing Countries and Analysis of Investment Incentives

This paper analyzes the economics of energy conservation in developing countries, compares the cost of energy conservation with the cost of enhancing domestic energy supply, and examines the effect of government investment incentive policies on the financial feasibility of energy conservation projects. A representative sample of 21 projects from six Indian industries shows that investing in energy conservation is more economical to a country than investing in domestic energy supply. Moreover, the nature of the conservation effort, i.e. housekeeping improvements, waste heat recovery or process change, is more important in determining the economics of energy conservation than is the type of industry. Analysis of government investment incentives shows that most of them are effective in making uneconomical energy conservation projects financially feasible and that the most effective incentive for the private investor to invest in energy conservation is the removal of fuel subsidies.     

MUNICIPAL WATER CONSERVATION ALTERNATIVES1

ABSTRACT: The municipal water conservation options available to meet the goals of a national water conservation policy are evaluated. Water conservation with water conservation devices is shown to offer many significant advantages over education and pricing and metering as a method of accomplishing water conservation goals. Current constraints on the use of water conservation devices are outlined, and their elimination is suggested if the nation's water conservation goals are to be met.     

Irrigation water management policies: Allocation and pricing principles and implementation experience

Food security and sustainable development require efficient use of water resources, especially in irrigation. Economic pricing can be an effective tool to achieve more efficient water use, provided it is supported by other policies in implementation. Applying various water pricing and cost recovery arrangements is suggested for efficient allocation. Any adverse impact on farmers’ incomes must be addressed and more reliable service must accompany higher prices. Experience from several countries suggests a variety of implementation issues. Essential complements to water pricing are water distribution rules and technological choices at critical nodes in the delivery system that allow farmers flexibility in conserving water in response to higher prices. Among supporting institutions, water users associations seem a higher priority than water markets.     

Seeking calm water: Exploring policy options for India's water future

This paper seeks to identify some promising policy options which could be part of a strategic and holistic effort to address India's future water challenges. Significant increases in agricultural water productivity would be a major factor in reducing the need for developing new water sources. Crop diversification, appropriately targeted to account for the present agricultural systems and available water resources, will increase productivity. Furthermore, much more emphasis needs to be placed on effective management of the groundwater resources through renewed efforts to enhance artificial recharge and conservation. Also, efforts should be revived to improve the existing surface irrigation systems. In particular, systems could be reconfigured to provide a more reliable water supply and allow effective community level management, where appropriate. Finally, while some of the increasing demands from domestic and industrial users will be met by the development of groundwater and reallocation of water from the agricultural sector, this will not be sufficient. Given that such conditions are emerging in states with high economic growth and relatively water scarce basins, this will require the further development of water resources. In some cases, these conditions along with the demand for reliable water for high value crops, will be part of the justification for inter‐basin transfers.     

Urban water demand and climate change

This paper presents a methodology for improved understanding of options for managing urban water demands under the uncertainties associated with climate change. It combines a sensitivity analysis of water supply with forecasts of water demand and examines how conservation efforts may offset deficits which result from climate change. It presents a case study of Nassau County, New York State, USA, that concludes that deficits projected for warmer climate scenarios can probably be alleviated by increased conservation. For scenarios of decreased precipitation, more extreme measures (eg rationing) may be necessary, illustrating the prudence of considering climate change in planning studies for communities which already experience water supply problems.     

VALUING URBAN WATER ACQUISITIONS1

ABSTRACT: Municipalities typically seek additional water supplies whenever prospective population and economic growth suggests the inadequacy of currently available water supply. The benefit of supply enhancement is usually construed as avoiding debilitating water scarcity. A more effective approach to planning is to compare the benefits and costs of supply augmentation. The net present value of benefits for a supply increase in a representative Texas community is calculated for alternative scenarios relating to population growth, rate growth, and the temporal distribution of the increased supply. Consumer surplus measures are sensitive to all three of these factors and vary from $0 to over $4000 per acre-foot. A notable finding is that the added supply may offer zero values in cases where real water prices increase at an annualized rate of 4 percent (or greater) which is half the rate occurring in Texas from 1981–1985.     

Assessing the value of CO2 capture ready in new-build pulverised coal-fired power plants in China

Making new plants CO₂ capture ready (CCR) would enable them to retrofit to capture CO₂ at a later date at lower cost when the appropriate policy and/or economic drivers are in place. In order to understand the economic value and investment characteristics of making new plants CCR in China, a typical 600 MW pulverised coal-fired ultra-supercritical power plant, locating in Guangdong province, was examined. Combined with an engineering assessment, costs were estimated for different CCR scenarios. To analyze CCR investment opportunities, the paper applies a cash flow model for valuing capture options and CCR investment. Results were obtained by Monte-Carlo simulation, based on engineering surveys and an IEA GHG CCR study, as well as plant performance information and expert projections on carbon prices, coal prices and electricity prices.CCR investments are justified by factors such as higher retrofitting probabilities, lower early closure probabilities and fair economic return. However, the economic case for CCR largely depends on two factors: (a) whether the original plant is retrofittable without CCR; and (b) the type of investments made, for example, investments essential to CCR tend to be more economic than additional non-essential CCR features such as clutched low pressure turbines. The carbon price and discount rate were found to have significant impacts on the economics of CCR. Overall, it appears that the value of the ‘capture options’ that CCR generates for retrofitting CCS is significant, and so could justify a modest CCR investment, even assuming the original plant is retrofittable without CCR. It was also found the value of CCR might be significantly understated if the range of potential retrofitting dates is artificially constrained.     

TRICK OR TREAT? AN OFFER TO OBTAIN METERED WATER1

ABSTRACT: In this paper we examine the possible reasons why individuals who live in homes facing a flat monthly rate for water accept or reject an offer to have water metering devices installed at no cost to them. A logit model is used to model the discrete choice of acceptance. Since the demand for metering is directly tied to water demand, we estimate demand models for unmetered households in the Reno/Sparks metropolitan area using contingent data obtained by presenting households with hypothetical prices they might encounter under a metering system. Conditional logit and demand models are then used to examine the potential for metering to promote water conservation in the arid Reno/Sparks, Nevada metropolitan area.     

Evaluation of different CHP options for refinery integration in the context of a low carbon future

This study presents a comparison of different concepts for delivering combined heat and power (CHP) to a refinery in Norway. A reference case of producing high pressure steam from natural gas in boilers and electricity in a combined cycle power plant, is compared to a: (1) natural gas fueled CHP without any CO₂ capture; (2) hydrogen fueled CHP with hydrogen produced from steam methane reforming (SMR); (3) hydrogen fueled CHP with hydrogen produced from autothermal reforming (ATR); and finally (4) natural gas fueled CHP with postcombustion CO₂ removal. The options are compared on the basis of first law efficiency, emissions of CO₂ and a simplified cash flow evaluation. Results show that in terms of efficiency the standard natural gas fueled CHP performs better than the reference case as well as the options with carbon capture. The low carbon options in turn offer lower emissions of greenhouse gases while maintaining the same efficiency as the reference case. The cash flow analysis shows that for any option, a certain mix of prices is required to produce a positive cash flow. As expected, the relationship between natural gas price and electricity price affects all options. Also the value of heat and CO₂ emissions plays an important role.     

Controlling groundwater pumping online

Groundwater over-pumping is a major problem in several countries around the globe. Since controlling groundwater pumping through water flow meters is hardly feasible, the surrogate is to control electricity usage. This paper presents a framework to restrict groundwater pumping by implementing an annual individual electricity quota without interfering with the electricity pricing policy. The system could be monitored online through prepaid electricity meters. This provides low transaction costs of individual monitoring of users compared to the prohibitive costs of water flow metering and monitoring. The public groundwater managers' intervention is thus required to determine the water and electricity quota and watch the electricity use online. The proposed framework opens the door to the establishment of formal groundwater markets among users at very low transaction costs. A cost–benefit analysis over a 25-year period is used to evaluate the cost of non-action and compare it to the prepaid electricity quota framework in the Batinah coastal area of Oman. Results show that the damage cost to the community, if no active policy is implemented, amounts to (−$288) million. On the other hand, the implementation of a prepaid electricity quota with an online management system would result in a net present benefit of $199 million.     

CONSERVATION PRACTICES AND ATTITUDES AMONG MARYLAND WATER SUPPLY MANAGERS1

ABSTRACT: In addition to offsetting water supply shortages, water conservation is recognized as serving many purposes, ranging from reduced energy consumption to lower capital costs. Since the discussion of these benefits has been a recent development and has generally excluded local water supply managers, a question arises as to whether supply managers are implementing conservation programs to exploit these benefits. A survey of the managers at 35 Maryland water utilities provides insight into the prevailing attitude toward conservation in a water rich eastern state. The results indicate that most managers continue to view conservation only as a short term response to temporary supply shortages. Only 12 Maryland utilities have undertaken any form of water conservation activity and just two systems have ongoing, comprehensive conservation programs. Institutional, perceptual, economic, political, and time constraints all contribute to the managers’attitudes and general inaction. If water conservation is to be widely practiced, these issues must be addressed and the benefits attributed to conservation must be better documented and articulated to supply managers.