scholarly journals Prediction Error and Forecasting Interval Analysis of Decision Trees with an Application in Renewable Energy Supply Forecasting

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xin Zhao ◽  
Xiaokai Nie

Renewable energy has become popular compared with traditional energy like coal. The relative demand for renewable energy compared to traditional energy is an important index to determine the energy supply structure. Forecasting the relative demand index has become quite essential. Data mining methods like decision trees are quite effective in such time series forecasting, but theory behind them is rarely discussed in research. In this paper, some theories are explored about decision trees including the behavior of bias, variance, and squared prediction error using trees and the prediction interval analysis. After that, real UK grid data are used in interval forecasting application. In the renewable energy ratio forecasting application, the ratio of renewable energy supply over that of traditional energy can be dynamically forecasted with an interval coverage accuracy higher than 80% and a small width around 22, which is similar to its standard deviation.

Author(s):  
Almas Heshmati ◽  
Shahrouz Abolhosseini

This chapter reviews relevant literature on the current state and effectiveness of developing renewable energy on energy security in general, and on energy security in the European Union (EU) in particular. The chapter elaborates on primary energy import sources, possible alternatives, and how energy security is affected by the sources of supply. It also gives an analysis of the effects of the Ukrainian crisis, the isolation of Iran on diversification sources, and on European energy security. It examines EU’s energy policy, analyses the best motivation for a new energy policy direction within Europe, and suggests alternative solutions for enhanced energy supply security. The aim is to suggest suitable solutions for energy security in Europe through energy supply diversification. Supply diversification includes alternative energy corridors for reducing dependency on Russia as a supplier and enhancing the power generated by renewable energy sources under the European Union 2020 strategy.


Author(s):  
Seyedeh Asra Ahmadi ◽  
Seyed Mojtaba Mirlohi ◽  
Mohammad Hossein Ahmadi ◽  
Majid Ameri

Abstract Lack of investment in the electricity sector has created a huge bottleneck in the continuous flow of energy in the market, and this will create many problems for the sustainable growth and development of modern society. The main reason for this lack of investment is the investment risk in the electricity sector. One way to reduce portfolio risk is to diversify it. This study applies the concept of portfolio optimization to demonstrate the potential for greater use of renewable energy, which reduces the risk of investing in the electricity sector. Besides, it shows that investing in renewable energies can offset the risk associated with the total input costs. These costs stem from the volatility of associated prices, including fossil fuel, capital costs, maintenance, operation and environmental costs. This case study shows that Iran can theoretically supply ~33% of its electricity demand from renewable energy sources compared to its current 15% share. This case study confirms this finding and predicts that Iran, while reducing the risk of investing in electricity supply, can achieve a renewable energy supply of ~9% with an average increase in supply costs. Sensitivity analysis further shows that with a 10% change in input cost factors, the percentage of renewable energy supply is only partially affected, but basket costs change according to the scenario of 5–32%. Finally, suggestions are made that minimize risk rather than cost, which will bring about an increase in renewable energy supply.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2728
Author(s):  
Chun-Nan Chen ◽  
Chun-Ting Yang

The Taiwanese government has set an energy transition roadmap of 20% renewable energy supply by 2025, including a 20 GW installed PV capacity target, composed of 8 GW rooftop and 12 GW ground-mounted systems. The main trend of feed-in tariffs is downwards, having fallen by 50% over a ten-year period. Predicting the future ten-year equity internal rate of return (IRR) in this study, we examine the investability of PV systems in Taiwan when subsidies and investment costs descend. We have found that the projected subsidies scheme favours investment in small-sized PV systems. Unless the investment costs of medium-sized PV systems fall or subsidies rise over the next decade, investing in medium-sized PV systems will be less attractive. Nonlinear and linear degradation causes slight IRR differences when using higher-reliability modules.


Buildings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 100 ◽  
Author(s):  
Elaheh Jalilzadehazhari ◽  
Georgios Pardalis ◽  
Amir Vadiee

The majority of the single-family houses in Sweden are affected by deteriorations in building envelopes as well as heating, ventilation and air conditioning systems. These dwellings are, therefore, in need of extensive renovation, which provides an excellent opportunity to install renewable energy supply systems to reduce the total energy consumption. The high investment costs of the renewable energy supply systems were previously distinguished as the main barrier in the installation of these systems in Sweden. House-owners should, therefore, compare the profitability of the energy supply systems and select the one, which will allow them to reduce their operational costs. This study analyses the profitability of a ground source heat pump, photovoltaic solar panels and an integrated ground source heat pump with a photovoltaic system, as three energy supply systems for a single-family house in Sweden. The profitability of the supply systems was analysed by calculating the payback period (PBP) and internal rate of return (IRR) for these systems. Three different energy prices, three different interest rates, and two different lifespans were considered when calculating the IRR and PBP. In addition, the profitability of the supply systems was analysed for four Swedish climate zones. The analyses of results show that the ground source heat pump system was the most profitable energy supply system since it provided a short PBP and high IRR in all climate zones when compared with the other energy supply systems. Additionally, results show that increasing the energy price improved the profitability of the supply systems in all climate zones.


2008 ◽  
Vol 33 (7) ◽  
pp. 1475-1490 ◽  
Author(s):  
G.J. Dalton ◽  
D.A. Lockington ◽  
T.E. Baldock

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