A New Zealand Electricity Market Model: Assessment of the Effect of Climate Change on Electricity Production and Consumption.

In this paper, we introduce an electricity market model and use it to explore the effect of climate change on electricity output and prices. It is calibrated to the New Zealand Electricity Market, and includes multiple generation fuels, uncertain fuel availability, and storage options. The model is formulated in continuous time, which mimics the many short trading periods that are common to electricity spot markets, while properly incorporating forward-looking generation decision making. Specifically, it is used to estimate the effects of changes that may arise in characteristics of fuels -water and gas- as a consequence of climate change and climate change policies. The model does this under the polar cases of a competitive market structure and monopoly. There are three key findings from the results. First, the results illustrate the importance of allowing for volatility and including management of storage in electricity market models. Second, they suggest that reductions in average hydro fuel availability will reduce welfare significantly. Increases in the volatility of hydro fuel availability will also affect welfare, but to a very small extent. Third, the value of reservoir expansion is sensitive to the distribution of hydro fuel availability. Finally, the effects of a carbon tax are also reported.dynamic optimisation, electricity spot market performance, stochastic fuel availability, storage options, climate change

A new and integrated hydro-economic accounting and analytical framework for water resources: A case study for North China

Water is a critical issue in China for a variety of reasons. China is poor of water resources with 2300 m3 of per capita availability, which is less than of the world average. This is exacerbated by regional differences; e.g. North China's water availability is only about 271 m3 of per capita value, which is only of the world's average. Furthermore, pollution contributes to water scarcity and is a major source for diseases, particularly for the poor. The Ministry of Hydrology [1997. China's Regional Water Bullets. Water Resource and Hydro-power Publishing House, Beijing, China] reports that about 65–80% of rivers in North China no longer support any economic activities. Previous studies have emphasized the amount of water withdrawn but rarely take water quality into consideration. The quality of the return flows usually changes; the water quality being lower than the water flows that entered the production process initially. It is especially important to measure the impacts of wastewater to the hydro-ecosystem. Thus, water consumption should not only account for the amount of water inputs but also the amount of water contaminated in the hydro-ecosystem by the discharged wastewater. In this paper we present a new accounting and analytical approach based on economic input–output modelling combined with a mass balanced hydrological model that links interactions in the economic system with interactions in the hydrological system. We thus follow the tradition of integrated economic–ecologic input–output modelling. Our hydro-economic accounting framework and analysis tool allows tracking water consumption on the input side, water pollution leaving the economic system and water flows passing through the hydrological system thus enabling us to deal with water resources of different qualities. Following this method, the results illustrate that North China requires 96% of its annual available water, including both water inputs for the economy and contaminated water that is ineligible for any uses

Investment in Electricity Markets with Asymmetric Technologies

We study competition between hydro and thermal electricity generators under de- mand uncertainty. Producers compete in quantities and each is constrained: the ther- mal generator by capacity and the hydro generator by water availability. We analyze a two-period game emphasizing the incentives for capacity investments by the ther- mal generator. We characterize both Markov perfect and open-loop equilibria. In the Markov perfect equilibrium, investment is discontinuous in initial capacity and higher than it is in the open-loop equilibrium. However, since there are two distortions in the model, equilibrium investment can be either higher or lower than the ecient investment.Electricity markets; Dynamic game; Duopoly; Capacity investment.

Efficient bidding for hydro power plants in markets for energy and ancillary services

In order to preserve stability of electricity supply generators must provide ancillary services in addition to energy production. Hydroelectric resources have significant ancillary service capability because of their dynamic flexibility. This paper suggests a solution for optimal bidding for hydro units operating in simultaneous markets for energy and ancillary services by estimating water shadow price from operating parameters of the hydro unit, expectations on prices of energy and ancillary services, and water availability. The model implications are illustrated on a numerical example of a hydro unit operating in markets of New York Independent System Operator. Participation in ancillary services market increases or decreases water shadow price depending on water availability. As a result of participation in ancillary services markets, a unit with water availability given by a capacity factor of 0.6 increases the value of existing generating capacity by 25% and nearly doubles the value of incremental generating capacity

Optimasi Operasi Pembangkit Listrik Tenaga Air (PLTA) Menggunakan Linear Programming Dengan Batasan Ketersediaan Air

One of hydro power plant operational problem is how to maximize available water resouces to gather optimal electric power generation. Water availability which is limited and can be stored in a reservoir will influence electrical energy generated by the plant. This paper present a new approach of short term optimization of hydro power plant operation. The objective function is to maximize energy which is produced by power plant on scheduling operation period, with consider water resource availability in reservoir as operational constraint. The optimization problem is formulated in Linear Programming Method, in which this method is a commonly used to solve optimization problem in hydro power plant. Based on simulation results on Ketenger Hydro Power Plant using water flow data on June 1st 2013 shows that this method can be used to solve hydro power plant operation optimization problem well. Electrical energy as main objective function is maximized and all prevailing constrain is satisfied. On this short term operation (24 hour) simulation, total energy can be produced is 96121,55 kWh, or 1427 kWh (1,51%) greater comparing with real generation condition with 96694 kWh

Environmental Impact Assessment of Power Generation Systems at GSM (Global Systems for Mobile Communication) Base Station Site

Hybrid power systems were used to minimize the environmental impact of power generation at GSM (global systems for mobile communication) base station sites. This paper presents the comparative environmental impact assessment of a diesel gas (DG) and hybrid (PV/wind/hydro/diesel) power system for the base station sites. The assessment was based on theoretical modeling of the power stations using Hybrid Optimization Model for Electric Renewables (HOMER) software. The model was designed to provide an optimal system configuration based on hour-by-hour data for energy availability and demands. Energy source, energy storage and their applicability in terms of performance are discussed. The proposed hybrid (solar, wind & hydro) + DG system was simulated using the model which results in eight different topologies: hybrid (solar, wind & hydro) + DG, hybrid (solar & hydro) + DG, hybrid (wind & hydro) + DG, hydro only + DG, hybrid (solar & wind) + DG, solar only + DG, wind only + DG, DG. From the simulation results, it is shown that a 69% renewable energy penetration in the designed hybrid PV/wind/hydro/diesel system reduces the quantity of different air pollutants relative to the case of a diesel-only system. Details of the comparisons are presented

Integration of hydrological and economic approaches to water and land management in Mediterranean climates: an initial case study in agriculture

A distinction is commonly drawn in Hydrology between ‘green’ and ‘blue water’ in accounting for total water availability in semi-arid regions. The criterion underlying this classification is important for successful water management, because it reveals how much natural water is and/or could be used by households, industry and, especially, agriculture. The relative share of green and blue water is generally treated as a constant. In recent years, a growing hydro-geological literature has focused on a phenomenon that significantly affects the stability of the green/blue water ratio. This is the increase in land cover density and its impact on runoff in regions with a Mediterranean climate, such as the Ebro Basin in Spain. We seek to carry this knowledge over into the parameters of disciplines concerned with the economic valuation of water and territorial resources, and translate it into the language used by water management professionals in the expectation that this contribution will improve the way we assess and account for real water availability. The heart of the matter is that the increasing density of forest cover produces both positive and negative environmental and economic impacts, presenting new economic and environmental problems that must be examined and assessed in a hydrological-economic context. We will show that these positive and negative effects are sufficiently important to merit attention, whether they are measured in physical or economic terms. Finally, we make an initial proposal for the economic valuation of some of the effects produced by these hydrological changes.blue water; green water; hydro-economic framework; water resources accounting

The costs of uncoordinated infrastructure management in multi-reservoir river basins

Though there are surprisingly few estimates of the economic benefits of coordinated infrastructure development and operations in international river basins, there is a widespread belief that improved cooperation is beneficial for managing water scarcity and variability. Hydro-economic optimization models are commonly-used for identifying efficient allocation of water across time and space, but such models typically assume full coordination. In the real world, investment and operational decisions for specific projects are often made without full consideration of potential downstream impacts. This paper describes a tractable methodology for evaluating the economic benefits of infrastructure coordination. We demonstrate its application over a range of water availability scenarios in a catchment of the Mekong located in Lao PDR, the Nam Ngum River Basin. Results from this basin suggest that coordination improves system net benefits from irrigation and hydropower by approximately 3–12% (or US$12-53 million/yr) assuming moderate levels of flood control, and that the magnitude of coordination benefits generally increases with the level of water availability and with inflow variability. Similar analyses would be useful for developing a systematic understanding of the factors that increase the costs of non-cooperation in river basin systems worldwide, and would likely help to improve targeting of efforts to stimulate complicated negotiations over water resources

Modelling the role of groundwater hydro-refugia in East African hominin evolution and dispersal.

Water is a fundamental resource, yet its spatiotemporal availability in East Africa is poorly understood. This is the area where most hominin first occurrences are located, and consequently the potential role of water in hominin evolution and dispersal remains unresolved. Here, we show that hundreds of springs currently distributed across East Africa could function as persistent groundwater hydro-refugia through orbital-scale climate cycles. Groundwater buffers climate variability according to spatially variable groundwater response times determined by geology and topography. Using an agent-based model, grounded on the present day landscape, we show that groundwater availability would have been critical to supporting isolated networks of hydro-refugia during dry periods when potable surface water was scarce. This may have facilitated unexpected variations in isolation and dispersal of hominin populations in the past. Our results therefore provide a new environmental framework in which to understand how patterns of taxonomic diversity in hominins may have developed