The crucial relationship among energy commodity prices: Evidence from the Spanish electricity market

The main purpose of this article is twofold to analyze: (a) the long-term relation among the commodities prices and between spot electricity market price and commodity prices, and (b) the short-term dynamics among commodity prices and between electricity prices and commodity prices. Data between 2002 and 2005 from the Spanish electricity market was used. Econometric methods were used in the analysis of the commodity spot price, namely the vector autoregression model, the vector error correction model and the granger causality test. The co-integration approach was used to analyze the long-term relationship between the common stochastic trends of four fossil fuel prices. One of the findings in the long-term relation is that the prices of fuel and the prices of Brent are intertwined, though the prices of Brent ten to “move” to reestablish the price equilibrium. Another finding is that the price of electricity is explained by the evolution of the natural gas series.     

Optimal operation of autonomous microgrid including wind turbines

This paper gives a novel hybrid optimization method to find optimal sitting and operation of an autonomous MG at the same time. The operation is optimized via finding the optimal droop gain parameters of DGs. The optimization problem is formulated as a multi-objective problem where the objectives are applied to minimize the fuel consumption of DGs and to improve the voltage profile and stability of MG subject to operational and security constraints. A hybrid algorithm, named HS-GA, is developed to solve the paper optimization problem. A new formulation of power flow is derived to run the proposed algorithm where the steady state frequency of system, reference frequency, reference voltage and droop coefficients of DGs, based on a droop controller, are considered as optimization variables. The performance of the paper approach is compared with other optimization and non-optimization methods in MG with 33and 69 buses using MATLAB. The performance of the proposed method is compared with a method that the parameters of DGs are pre-determined without conducting any optimization process. The results show, which optimized droop parameters improves the operation of the MG.     

The effect of residential solar photovoltaic systems on home value: A case study of Hawai‘i

An investment in solar photovoltaic (PV) is considered a home improvement, and should be reflected in home sales prices. However, uncertainty about PV policies and information asymmetries may result in an imperfect pass-through. Hawai‘i serves as an illustrative case study to assess the impact of PV on home prices because Hawai‘i has the highest number of PV installations per capita nationwide. Applying a hedonic pricing model using home resale and PV building permit data from 2000 to 2013 for Oʻahu, I find that the presence of PV adds on average 5.4% to the value of a home. The value of PV exceeds total average installed costs because many of Hawai‘i's electricity circuits have reached legal limits for PV installations and thus many neighborhoods could technically no longer install additional PV capacity. Therefore, the value of the system goes beyond its capital investment—on average, by $5000—to incorporate expected electricity savings.     

Causalities between CO2, electricity,and other energy variables during phase I and phase II of the EU ETS

The topic of this article is the analysis of the interplay between daily carbon, electricity and gas price data with the European Union Emission Trading System (EU ETS) for CO₂ emissions. In a first step we have performed Granger causality tests for Phase I of the EU ETS (January 2005 until December 2007) and the first year of Phase II of the EU ETS (2008). The analysis includes both spot and forward markets—given the close interactions between the two sets of markets. The results show that during Phase I coal and gas prices, through the clean dark and spark spread, impacted CO₂ futures prices, which in return Granger caused electricity prices. During the first year of the Phase II, the short-run rent capture theory (in which electricity prices Granger cause CO₂ prices) prevailed. On the basis of the qualitative results of the Granger causality tests we obtained the formulation testable equations for quantitative analysis. Standard OLS regressions yielded statistically robust and theoretically coherent results.     

Correlation between Chinese and international energy prices based on a HP filter and time difference analysis

To establish a reasonable system and mechanism for Chinese energy prices, we use the Granger causality test, Hodrick–Prescott (HP) filter and time difference analysis to research the pricing relationship between Chinese and international energy prices. We find that Chinese and international crude oil prices changed synchronously while Chinese refined oil prices follow the changes of international oil prices with the time difference being about 1 month to 2 months. Further, Australian coal prices Granger causes Chinese coal prices, and there is a high correlation between them. The U.S. electricity price is influenced by the WTI crude oil price, the U.S. gasoline price and the HenryHub gas price. Due to the unreasonable price-setting mechanism and regulation from the central government, China′s terminal market prices for both electricity and natural gas do not reflect the real supply–demand situation. This paper provides quantitative results on the correlation between Chinese and international energy prices to better predict the impact of international energy price fluctuations on China′s domestic energy supply and guide the design of more efficient energy pricing policies. Moreover, it provides references for developing countries to improve their energy market systems and trading, and to coordinate domestic and international energy markets.     

The large-scale integration of wind generation: Impacts on price,reliability and dispatchable conventional suppliers

This work examines the effects of large-scale integration of wind powered electricity generation in a deregulated energy-only market on loads (in terms of electricity prices and supply reliability) and dispatchable conventional power suppliers. Hourly models of wind generation time series, load and resultant residual demand are created. From these a non-chronological residual demand duration curve is developed that is combined with a probabilistic model of dispatchable conventional generator availability, a model of an energy-only market with a price cap, and a model of generator costs and dispatch behavior. A number of simulations are performed to evaluate the effect on electricity prices, overall reliability of supply, the ability of a dominant supplier acting strategically to profitably withhold supplies, and the fixed cost recovery of dispatchable conventional power suppliers at different levels of wind generation penetration. Medium and long term responses of the market and/or regulator in the long term are discussed.     

Time variation in European carbon pass-through rates in electricity futures prices

The European Union Emissions Trading Scheme is a means to price emission allowances. Electricity market prices should reflect these market prices of emission allowances as they are a cost factor for power producers. The pass-through rate is the fraction of the emission allowance price that is passed through to electricity market prices. It is often measured and presented as an average or a fixed estimate over some time period. However, we expect that the pass-through rates should actually vary over time as electricity supply curves reflect the marginal costs of different producers that differ in emission intensity. We apply a Kalman Filter approach to observe pass-through rates in Germany and U.K. and find strong support for time varying instead of fixed pass-through rates. Although policy makers are interested in the impact of a policy on average, our results indicate that one needs to be careful with the time-frame over which pass-through rates are measured for policy evaluation, as an incorrect chosen evaluation period could cause an under- or overestimation of the pass-through rate. In addition, our model helps to provide policy makers with insight in the development of pass-through rates when market circumstances change with respect to power production.     

Effects of stochastic energy prices on long-term energy-economic scenarios

In view of the currently observed energy prices, recent price scenarios, which have been very moderate until 2004, also tend to favor high future energy prices. Having a large impact on energy-economic scenarios, we incorporate uncertain energy prices into an energy systems model by including a stochastic risk function. Energy systems models are frequently used to aid scenario analysis in energy-related studies. The impact of uncertain energy prices on the supply structures and the interaction with measures in the demand sectors is the focus of the present paper.

For the illustration of the methodological approach, scenarios for four EU countries are presented. Including the stochastic risk function, elements of high energy price scenarios can be found in scenarios with a moderate future development of energy prices. In contrast to scenarios with stochastic investment costs for a limited number of technologies, the inclusion of stochastic energy prices directly affects all parts of the energy system. Robust elements of hedging strategies include increasing utilization of domestic energy carriers, the use of CHP and district heat and the application of additional energy-saving measures in the end-use sectors. Region-specific technology portfolios, i.e., different hedging options, can cause growing energy exchange between the regions in comparison with the deterministic case.     

Intra‐Urban migration and housing submarkets: theory and evidence

In the 1950s and 1960s a group of housing economists at Columbia University developed a framework for the analyses of urban housing markets which was based around the concept of housing submarkets and household migration. There is now widespread agreement amongst housing economists that submarkets should be adopted as a working hypothesis but the concept has been reformulated in terms of intra‐urban relative house price differentials. The accepted test for submarket existence uses a hedonic model of house prices which assumes market equilibrium. This paper returns to an analysis of submarkets which focuses on spatial migration patterns. By examining household intra‐urban mobility patterns in the Glasgow housing market it is possible to demonstrate that submarkets tend to be self‐contained. The analysis also suggests that the current standard statistical tests may be incomplete and in the case of Glasgow underestimate the number of submarkets.     

浅谈变压器节能运行的容量选择

本文介绍了一种更为准确的方法来确定变压器的最佳经济容量,依据最佳容量选择变压器,能使其运行在最佳经济区域,从而达到减少电能损耗的目的。并且本文还就现行电费收取方式的不合理而导致电能浪费这一现象,提出改革的建议。