A financial model for publicly-owned electric utilities

Supply planning by electric utilities is fraught with uncertainty. An essential tool for the evaluation of the riskiness of alternative supply plans is a financial simulation model. Sophisticated models of investor-owned utilities have been employed by both regulatory bodies and utilities. However, such models have not been developed for publicly-owned utilities. This paper details the reasons why models of investor-owned utilities are inappropriate for use by publicly-owned utilities. A financial model of a publicly-owned electric utility is presented and applied. Finally, uses and abuses of financial models are discussed.     

Introducing OTEC to mainland utilities

The adoption of advanced technology by a large electric utility must be preceded by a lengthy assessment process involving cost, performance, reliability, technology availability, environmental impact, legal, institutional, and other factors. Over the past 25 years, the most important technological development to take place in the electric utility business has been that of nuclear power generation. This technology, though proven technically, has encountered significant problems. The time to site and construct a nuclear plant has grown because of environmental and regulatory restrictions. The absence of a national policy with respect to nuclear waste disposal and fuel recycling has created what appears to utility planners to be a very unfavorable political environment. For these and other reasons, the capital cost of nuclear plants has been steadily increasing and utility managements have begun to look to other fuel technologies such as coal.In this paper, we examine the major factors which a large utility considers in evaluating any potentially important new energy system. Briefly, we review U.S. electric utility experience with technological innovation and identify the major problem areas facing industry from one utility's point of view. We then discuss the feasibility and appeal of ocean thermal energy conversion (OTEC) technology and describe the steps which one utility executes in determining the need for new capacity and the planning process which results in the construction and operation of a new plant. These steps are then applied to OTEC.Tentatively, we have concluded that the current U.S. Government OTEC program leaves OTEC an unlikely candidate for meaningful U.S. mainland applications within the century. We recommend a specific development strategy which will produce performance and cost data needed by potential investors in, and by operators of, electric utilities.     

A regional linear logit fuel demand model for electric utilities

We investigate a short-term forecasting and simulation model of utility fuel demand based on the linear logit model. The forecasting properties of the model are surprisingly good for such a simple econometric model of factor demand. The model ignores the distinctive characteristics of electric utilities (load curves, wheeling, etc.) yet produces remarkably good forecasts at both the national and regional levels. Because the model is based on neoclassical theory it can be used for simulations, making it more useful, and less ad hoc, than a pure forecasting model.     

Novel model reduction techniques for refinery-wide energy optimisation

The oil refining industry mainly uses linear programming (LP) modelling tools for refinery optimisation and planning purposes, on a daily basis. LPs are attractive from the computational time point of view; however these models have limitations such as the nonlinearity of the refinery processes is not taken into account. In addition, building the LP model can be an arduous task that requires collecting large amounts of data. The main aim of this work is to develop approximate models to replace the rigorous ones providing a good accuracy without compromising the computational time, for refinery optimisation. The data for deriving approximate models has been generated from rigorous process models from a commercial software, which is extensively used in the refining industry. In this work we present novel model reduction techniques based upon optimal configuration of artificial neural networks to derive approximate models and demonstrate how these models can be used for refinery-wide energy optimisation.     

A Swedish integrated pulp and paper mill—Energy optimisation and local heat cooperation

Heat cooperation between industries and district heating companies is often economically and environmentally beneficial. In this paper, energy cooperation between an integrated Swedish pulp and paper mill and two nearby energy companies was analysed through economic optimisations. The synergies of cooperation were evaluated through optimisations with different system perspectives. Three changes of the energy system and combinations of them were analysed. The changes were process integration, extending biofuel boiler and turbine capacity and connection to a local heat market. The results show that the single most promising system change is extending biofuel and turbine capacity. Process integration within the pulp and paper mill would take place through installing evaporation units that yield less excess heat but must in this particular case be combined with extended biofuel combustion capacity in order to be beneficial. Connecting to the local heat market would be beneficial for the pulp and paper mill, while the studied energy company needs to extend its biofuel capacity in order to benefit from the local heat market. Furthermore, the potential of reducing CO₂ emissions through the energy cooperation is shown to be extensive; particularly if biofuel and turbine capacity is increased.     

Modelling the existing Irish energy-system to identify future energy costs and the maximum wind penetration feasible

In this study a model of the Irish energy-system was developed using EnergyPLAN based on the year 2007, which was then used for three investigations. The first compares the model results with actual values from 2007 to validate its accuracy. The second illustrates the exposure of the existing Irish energy-system to future energy costs by considering future fuel prices, CO₂ prices, and different interest rates. The final investigation identifies the maximum wind penetration feasible on the 2007 Irish energy-system from a technical and economic perspective, as wind is the most promising fluctuating renewable resource available in Ireland. It is concluded that the reference model simulates the Irish energy-system accurately, the annual fuel costs for Ireland's energy could increase by approximately 58% from 2007 to 2020 if a business-as-usual scenario is followed, and the optimum wind penetration for the existing Irish energy-system is approximately 30% from both a technical and economic perspective based on 2020 energy prices. Future studies will use the model developed in this study to show that higher wind penetrations can be achieved if the existing energy-system is modified correctly. Finally, these results are not only applicable to Ireland, but also represent the issues facing many other countries.     

Photovoltaics and electric utilities

We determine the long-term value of a grid-connected, residential photovoltaic (PV) systems. The value of the PV electricity is defined as the full avoided cost, consistent with the Public Utilities Regulatory Policies Act of 1978. A case study approach to three utility systems is used. The avoided cost is computed using a long range utility planning approach to measure revenue requirement changes in response to the time-phased introduction of PV systems into the grid. The changing value of PV electricity over a 20-year period from 1985 is presented, and the fuel and capital savings due to PV are analyzed and translated into a measure of breakeven capital investment.     

Development and implementation of an optimisation model for biofuels supply chain

Biofuels supply chain comprises a wide set of activities involving a rather complex set of parameters. Cultivation of the raw materials is closely related to the agricultural sector whereas the production of the final product presumes the operation of a conversion plant. The distribution network aims at delivering the final product close to the consumption. The extent of the involvement of each one of the previously mentioned sectors is the result of strategic and operational planning of the whole supply chain and, in the general case, determines the efficiency of the biofuels sector. Taking also into account the very rapidly changing opinions related to the environmental behaviour of the whole biofuels supply chain, it becomes very clear that the parameters in the sector are continuously changing. Therefore, the consideration of an integrated supply chain appropriately modelled is believed to be very critical and could result in the optimal solution per case, economically and/or environmentally speaking. In this paper the development of a mathematical model for the optimal design and operation of Biofuels Supply Chain is proposed as an integrated approach that can take into account both technical and economic parameters affecting the performance of the whole value chain. Model implementation would facilitate and support the decision taking in various planning and operational issues such as infrastructure investments, the quantities of raw materials to be cultivated, the quantities of biofuels to be produced in the domestic market or imported, identifying the best available solution for the optimal design and operation of the biofuels supply chain.     

Renewable energy resources and technologies applicable to Ireland

The energy consumed in Ireland is primarily achieved by the combustion of fossil fuels. Ireland's only indigenous fossil fuel is peat; all other fossil fuels are imported. As fossil fuels continually become more expensive, their use as an energy source also has a negative impact on the environment. Ireland's energy consumption can be separated into three divisions: transportation, electricity generation and heat energy. Ireland however has a vast range of high quality renewable energy resources. Ireland has set a target that 33% of its electricity will be generated from renewable sources by 2020 [I. Government. Delivering a Sustainable Energy Future for Ireland; 2007.]. The use of biomass, wind and ocean energy technologies is expected to play a major part in meeting this target. The use of renewable energy technologies will assist sustainable development as well as being a solution to several energy related environmental problems. This paper presents the current state of renewable energy technologies and potential resources available in Ireland. Considering Ireland's present energy state, a future energy mix is proposed.     

A further assessment of the Hong Kong Government's proposed post-2008 regulatory regime for local electricity utilities

The current regulatory contract between the Hong Kong Government and the two local power suppliers will expire in 2008. To elicit constructive ways to refine this regulatory contract upon its expiration in two years, the Hong Kong Government recently issued a public consultation paper. An earlier viewpoint by Woo, Horowitz and Tishler (2006) warns that if the proposals provided in this consultation paper are fully adopted, it will do more harm than benefiting the industry. While its concern is valid, that viewpoint has not suggested specific improvements of the existing arrangement, and how incumbent firms’ incentives to invest will not be harmed under the new arrangement. Hence, this viewpoint contributes to Hong Kong electricity policy debate by filling this gap, with the hope of aiding the regulator to better regulate the market in the years after the current contract's expiration.     

A critical assessment of the Hong Kong Government's proposed post-2008 regulatory regime for local electricity utilities

In December 2005, the Hong Kong Government issued a “Consultation Paper on Future Development of the Electricity Markets in Hong Kong: Stage II Consultation,” proposing a post-2008 regulatory regime upon the expiration of the existing regulatory contract between the Hong Kong Government and each of the two local electricity utilities. We assess the proposal using the criteria of safe, reliable, and environmentally friendly service at the lowest rates that will allow the utilities reasonable returns on their investments. We caution that if fully adopted, the highly risky proposal may lead to less-reliable service without the compensating benefits to the environment.     

International benchmarking and regulation: an application to European electricity distribution utilities

Due to a shortage of data and increased international mergers, national energy regulators are looking to international benchmarking analyses for help in setting price controls within incentive regulation. We present an international benchmarking study of 63 regional electricity distribution utilities in six European countries that aims to illustrate the methodological and data issues encountered in the use of international benchmarking for utility regulation. The study examines the effect of the choice of benchmarking methods using DEA, COLS and SFA models. We discuss what problems of international benchmarking are highlighted by the study and how they can be overcome.     

适用于农村采暖系统的防垢剂

介绍了采暖系统防垢剂的阻垢机理和适用于农村采暖系统的防垢剂种类。水质稳定剂已广泛地应用在工业循环冷却水的处理上，但在民用采暖系统应用得很少，广大农村冬季采暖如采用防垢剂将节约大量能源，延长供暖系统寿命，具有重要意义。     

A heterogeneous dynamic model for the simulation and optimisation of the steam methane reforming reactor

In the current paper the dynamic behaviour of an industrial heterogeneous catalytic packed-bed reactor for the steam reforming of methane is examined. The model consists of a set of partial differential equations describing the physico-chemical processes that take place both in solid and gas phases accounting for diffusional limitations within the catalyst particles. The model was validated against literature data, while the heat provided to the reactor wall was optimised in terms of the optimal H₂ yield using a quadratic wall temperature profile. The values of the physico-chemical properties were adjusted to the severe operating conditions (high pressures and temperatures) of the reactor accounting for multicomponent gas mixture properties. It is shown that the 2-phase reactor concept along with the optimised wall temperature profile capture very well the dynamic conversion, the temperature and the partial pressure profiles both at bed and at particle level.     

The statistical smoothing of power delivered to utilities bymultiple wind turbines

A relationship for estimating the spectrum of the power delivered from multiple wind turbines from the spectrum of the power delivered by a single wind turbine is derived. It is assumed in the derivation that the wind power time series of each wind turbine is stationary and can be related to time series or neighboring wind turbines by a spatial coherence function. The multiple wind turbine power spectra is derived for two cases: operation at rated power and operation at below rated power. The theoretical results are compared with measurement data, showing excellent agreement     

Assessment of externalities related to global and local air pollutants with the NEEDS-TIMES Italy model

This work is aimed to illustrate the potentiality of the multi-region NEEDS-TIMES modelling platform, in the economic evaluation of the environmental damages due to air pollution. In particular the effects of external costs on the least-cost optimised energy system configuration were analysed in a national case study with the NEEDS-TIMES Italy model, considering the externalities related to local and global air pollutants (NO_x, SO₂, VOC, particulates and GHGs). Different scenarios were compared to emphasise the role of external costs in the achievement of strategic environmental targets. The main results obtained are discussed, focusing on the changes in energy fuel mix as well as in local air pollutants and GHG emissions, highlighting the main conclusions in terms of policy strategies.     

Thermophysical properties of some paraffins applicable to thermal energy storage

An experimental study has been conducted with the aim to investigate and evaluate thermophysical properties of technical grade paraffins appropriate for solar energy storage applications.The results obtained involve the kinetics of phase transition and latent heat of phase change, the thermal cycling stability at heating and cooling and specific heat for the temperature range of application.A method for the automatic computer controlled thermal cycling has been developed. The dynamic mode of precise uniform rising and lowering of the temperature at various rates has been accomplished. Nine hundred thermal cycles have been carried out on two different mixtures of technical grade paraffins, varied by their composition.The change of the DSC kinetics measured by Mettler TA 3000 and the relative thermodynamic values of the phase transitions were not registered after cycling. The calculated enthalpies of three paraffin mixtures were found to depend on their oil content and the distribution of atoms defined by chemical and gas chromatographic analyses.     

Modelling a hydropower plant with reservoir with the micropower optimisation model (HOMER)

Hydropower with water accumulation is an interesting option to consider in hybrid systems, because it helps dealing with the intermittence characteristics of renewable energy resources. The software HOMER (version Legacy) is extensively used in research works related to these systems, but it does not include a specific option for modelling hydro with reservoir. This paper describes a method for modelling a hydropower plant with reservoir with HOMER by adapting an existing procedure used for modelling pumped storage. An example with two scenarios in southern Brazil is presented for illustrating and validating the method explained in this paper. The results validate the method by showing a direct correspondence between an equivalent battery and the reservoir. The refill of the reservoir, its power output as a function of the flow rate and installed hydropower capacity are effectively simulated, indicating an adequate representation of a hydropower plant with reservoir is possible with HOMER.