Forecasting Model of Electricity Demand in the Nordic Countries

A model implemented in order to describe the electricity demand on hourly basis for the Nordic countries. The objective of this project is to use the demand data simulated from the model as input data in the price forecast model, EMPS model, at Vattenfall. The time horizon is 5 years, 6 years including the current year. After different models tried out, the final model is described by fundamental and autoregressive time variant variables, an ARX model. The variable of temperature is described by historical data from 46 years which are used to create an idea of the outcome variation depending on the weather. Non parametric bootstrap of the residuals is used when adding noise to the simulation. The ARX parameters was estimated by prediction error method but a two-step estimation was also tried, by first estimating the fundamental parameters and then model the rest of the demand by an AR process. The second method was supposed to increase the weight on the fundamental variables. Results of the simulation Indicates of a realistic description of the electricity demand which is an improvement of the earlier demand input to the EMPS model but the difference is not always seen in the outcome of the price forecast. The results are discussed in Chapter 5

Modelling electricity prices: from the state of the art to a draft of a new proposal

In the last decades a liberalization of the electric market has started; prices are now determined on the basis of contracts on regular markets and their behaviour is mainly driven by usual supply and demand forces. A large body of literature has been developed in order to analyze and forecast their evolution: it includes works with different aims and methodologies depending on the temporal horizon being studied. In this survey we depict the actual state of the art focusing only on the recent papers oriented to the determination of trends in electricity spot prices and to the forecast of these prices in the short run. Structural methods of analysis, which result appropriate for the determination of forward and future values are left behind. Studies have been divided into three broad classes: Autoregressive models, Regime switching models, Volatility models. Six fundamental points arise: the peculiarities of electricity market, the complex statistical properties of prices, the lack of economic foundations of statistical models used for price analysis, the primacy of uniequational approaches, the crucial role played by demand and supply in prices determination, the lack of clearcut evidence in favour of a specific framework of analysis. To take into account the previous stylized issues, we propose the adoption of a methodological framework not yet used to model and forecast electricity prices: a time varying parameters Dynamic Factor Model (DFM). Such an eclectic approach, introduced in the late ‘70s for macroeconomic analysis, enables the identification of the unobservable dynamics of demand and supply driving electricity prices, the coexistence of short term and long term determinants, the creation of forecasts on future trends. Moreover, we have the possibility of simulating the impact that mismatches between demand and supply have over the price variable. This way it is possible to evaluate whether congestions in the network (eventually leading black out phenomena) trigger price reactions that can be considered as warning mechanisms.

Tre essay om elektrisitetspriser

The thesis explores how the Nord Pool power market prices forward-looking information. Specifically, the thesis investigates the efficiency, or the biasedness, of the derivatives side of the power market, how temperature is priced by the market, and how to account for uncertainty in future information. The thesis consists of an introductory chapter which comprises the context and background for the three studies, including a summary. Using data on current and future-looking information from futures prices, the thesis brings new evidence on how the efficiency of the futures market at Nord Pool has developed. Furthermore, the thesis investigates relationship between the relationship between temperature and power prices and the price forecasting information implied in weather forecasts.The thesis provides new insight into the effect of future looking information on the electricity spot prices. The findings indicate that futures on the Nord Pool spot price has been unbiased estimates of the future spot price since 2008. Furthermore, the effect of temperature on price were investigated and were found to be seasonally dependent, different across Norwegian price zones, and different across price quantiles. Also, the information from temperature forecasts is beneficial to use in price forecasts for up to 9 days ahead, but the uncertainty in temperature forecasts has to be accounted for

Forecasting summer-time overheating in UK homes using time series models

Heatwaves are projected to become more frequent, intense and long-lasting in the UK and the prevalence of overheating in dwellings is set to increase. As a result, occupants will experience increased levels of thermal discomfort, heat stress and heat-related morbidity and mortality. Since the use of mechanical air conditioning in dwellings is unsustainable, and not widely affordable, it is of utmost importance to understand when heat related health risks are anticipated in free-running dwellings. This is crucial for vulnerable occupants, such as the elderly, for whom the accurate detection of future heat risks could prepare them (or their carers) for timely mitigation, for example, through additional window ventilation or the use of shading. Many countries deploy Heat-Health Warning Systems (HHWS) to alert their populations, however, these generally apply to a wide area and are based exclusively on regional weather forecasts. Consequently, HHWSs are unable to identify where, when, or to what extent individual buildings (and their occupants) will be affected. Previous studies have investigated the use of time series forecasting models, with the majority considering the use of Model Predictive Control. There is, however, no rigorous scientific evidence to support the belief that such models can provide accurate predictions in free-running dwellings during heatwaves and over multi-day forecasting horizons. This thesis therefore examines the use of black-box forecasting models to provide reliable predictions of the impending indoor temperatures in UK homes. Having established the viability of this approach, the application of such models in the context of an indoor Heat-Health Warning System (iHHWS) has been explored. This research led to five main findings: (i) linear AutoRegressive forecasting models with eXogenous inputs (ARX), i.e. weather forecasts, can provide satisfactory accuracies during heatwaves for time horizons up to 72 h ahead; (ii) more complex semi-parametric Generalized Additive Models (GAMs) were not capable of significantly improving the forecasting accuracy at forecasting horizons over 6 h (iii) logistic GAMs can predict the window opening state with adequate discrimination, however, integration of the window state into forecasting models did not improve their accuracy; (iv) forecasting models could be usefully incorporated within an iHHWS, however, the warning lead-time should be constrained to less than 24 h in order to guarantee high confidence in such a system; (v) a weighted metric such as the Cumulative Heat Index (CHI) could further reduce the risks of false or missed warnings, increasing the dependability of the iHHWS.</div

Performance and economic analysis of hybrid microhydro systems

Microhydro (MHP) systems usually employ unregulated turbines and an electronic load controller, a demand-side control device. Existing analytical models for such systems are lacking details, especially supply-side flow control, for performance simulation at hourly or sub-hourly scales. This work developed stochastic models for downscaling of streamflow and an empirical model of MHP systems. We integrated these models within the framework of Hybrid2 tool to simulate the long-term performance of a tri-hybrid system consisting of hydropower, solar PV and wind turbine. Based on an additive model of time series decomposition, we develop a Multiple Input Single Output (MISO) model in order to synthesize an hourly time series of streamflow. The MISO model takes into account daily precipitation dataset as well as regional hydrological characteristics. The model employs a constrained Monte-Carlo Markov Chain (MCMC) algorithm which is validated against an hourly time series of flow data at Blue River at Blue, Oklahoma. A non-dimensional performance model of MHP systems is developed based on empirical data from Nepal. Three design configurations are presented for a case study. The results show that, along with a small pond that can store water for an hour at the rated capacity of MHP system, a hybrid system with half the size of the battery bank can supply the load year around at Thingan Project in Nepal. This system meets the availability requirements of the Multi-Tier Framework for measuring energy access for household supply. The new proposed system is marginal in the economic sense as well. This project can never recover the initial capital cost at a current rate of the tariff which is about 7 cents/kWh. Other O&M risks aside, the sensitivity analysis suggests that the system may barely recover the initial capital cost, excluding the subsidy, at twice the existing rate of tariff and half the interest rate. This study aspires to come up with better techniques to simulate hybrid microhydro systems and enhance their design and operation through more effective utilization of resources