Current Energy Prices Research Articles

Assessment of Retrofit Measures for Industrial Halls: Energy Efficiency and Renovation Budget Estimation

The need for renovation is driven mostly by high energy prices and by the amortization of building envelope structures and building systems. Industrial buildings built before 1990s are usually poorly insulated and without ventilation heat recovery. When renovation is considered, it raises a question of what and to which extent to renovate, to achieve the optimal result for the investment. The current study focuses on the building envelope insulation and ventilation renovation options for hall-type industrial buildings. We have analyzed the impact of different renovation measures, regarding envelope insulation and ventilation systems, to the energy consumption and renovation budget for three typical buildings built between the 1960s and 1990s in Finland. The energy consumption calculations have been conducted with building energy and indoor climate simulation tool IDA-ICE. For the economic calculations, we have used the current Finnish energy prices and interest rates with moderate trends for the next 20 years to estimate the internal rate of return and net present value of the retrofit measures. The calculations have been done for two building sizes: a large hall, 137m x 66m, and for a smaller hall, 40m x 22m, both with an average height of 8m. The results show, that retrofitting the building envelope only for energy efficiency might not be beneficial when considering a payback period less than 20 years in the case of both large and small hall buildings. In case of smaller halls, some combinations of envelope retrofit can be also economically reasonable. Renovating the ventilation system by applying heat recovery and replacing lighting for energy efficient LEDs would be beneficial for all the initial building cases. Combination of supporting measures as a renovation package would be the most recommendable solution.

Discounted cash flow analysis of greenhouse-type solar kilns

This paper describes the overall discounted cash flow (DCF) analysis of two greenhouse-type solar kilns (Oxford and Boral) for hardwood drying processes. The financial performance of both the kilns was found to be mainly dominated by the costs/benefits associated with the model-predicted future thermal energy flows. All the costs and benefits were calculated based on the current energy prices, while adjusting all future cash flows (either costs or benefits) to their respective present values by incorporating appropriate inflation and discount rates. The overall results indicated that the net present cash benefit and the present drying energy benefit were larger for the Oxford kiln than those for the Boral kiln, by approximately 38% and 16%, respectively, while the present energy-loss cost was smaller for the Oxford kiln by 23% than that for the Boral kiln. A sensitivity analysis was carried out in order to assess the robustness of the results against the uncertain parameters. In general, the Oxford kiln design was found to be more cost-effective and environmentally beneficial than the Boral kiln design for hardwood drying.

Exergoeconomic Analysis of a Pumped Heat Electricity Storage System with Concrete Thermal Energy Storage

Within the last 25 years the share of renewable energy sources in electrical energy production in Germany has been rising considerably. The volatility of renewable energy sources results in an increasing mismatch between supply and demand of electrical energy creating the need for storage capacities. The storage of electrical energy via the detour of thermal energy can be realized by a relatively new technology known as Pumped Heat Electricity Storage systems. This paper examines the exergoeconomic performance of such a storage system. A sample system comprising a concrete thermal energy storage is introduced; unsteady operations are simulated and analyzed. Although the achieved efficiencies are reasonable economical operations of the analyzed Pumped Heat Electricity Storage System are currently not possible. For the analyzed operation scenario the exergetic system efficiency, electrical energy output to electrical energy input, amounts to 27.3 %. Considering the storage capacity and the lack of geological requirements the Pumped Heat Electricity Storage system can compete with pumped hydrostorage and compressed air energy storage. However, prices of the order of 60 ct/(kWh) are not competitive considering current energy prices. Based on improved system designs as well as rising energy prices we assess Pumped Heat Electricity Storage Systems as a potential alternative to established storage technologies.

Economic feasibility study of a fuel cell-based combined cooling, heating and power system for a data centre

The energy use of data centres is increasing as the data storage needs increase. One of the largest items in the energy use of these facilities is cooling. A fuel cell-based combined cooling, heating and power system can efficiently meet such a centre's need for cooling and in the meantime generate enough electricity for the centre and more. In this paper the economic feasibility of a fuel cell-based combined cooling, heating and power system that meets the energy demands of such a facility is investigated using operational data from an existing data centre in Stockholm, Sweden. The results show that although the system is not feasible with current energy prices and technology it may be feasible in the future with the projected changes in energy prices.

A VARX modelling of energy intensity interactions between China, the United States, Japan and EU

AbstractThis study attempts to predict energy intensity interactions between China, the United States, Japan and EU by developing a restricted VARX model by proposing energy intensities of the countries interact with each others, and gross domestic product (GDP) levels per capita and Organization of Petroleum Exporting Countries (OPEC) oil‐based current energy prices affect energy intensities of the countries based upon the direction of group causalities. There exist significant causal interactions between energy intensities of the countries up to lag five either increasing efficiency or not. China's current GDP level affects its own energy use and EU's energy intensity positively, on the other way; EU's current GDP level affects only China's energy intensity while Japan's current GDP level only affects its own energy intensity negatively, ceteris paribus. It is found that OPEC oil‐based current energy prices only affect the United States' energy intensity but not others' energy intensity, ceteris paribus, for the period of 1971–2009. Evaluating cumulative effects of energy intensities of all countries, it is found that each country has experienced higher energy intensity and consumed energy less efficiently even there have been existing new technology‐embodied equipments used and alternative energy sources developed in energy consumption for the years.

Poprawa efektywności energetycznej przy integrowaniu mikrosieci z inteligentnymi sieciami krajowymi

Technological development of distribution and transmission grids and building a so called smart grid also enable improving the efficiency of microgrids and microgenerators. Better coordination and scheduling of microgenerators operation make more effective adjustment to local conditions and achieving better overall energy efficiency possible. Due to smart communication interfaces the microgrids and microgenerators can also contribute to ancillary services. DOI: 10.12736/issn.2300-3022.2014405 1. Possible improvements of energy efficiency Small distributed sources are often equated with renewable energy sources and environmentally friendly electricity generation. However, only some of them, based on hydro, solar or wind energy, do not pollute the environment. Other types of small sources generate electricity by burning fossil fuels (coal or gas), and sometimes also agricultural or municipal waste. Combustion always produces CO2, NOx, sulfur compounds, and other pollution. Combustion in small sources is less controlled due to reduction of control systems costs (with respect to the generator cost and the electricity output). In addition, micro-plants are not equipped with exhaust aftertreatment systems. Electricity generation in combustion-based distributed sources produces much more pollution per output MWh than large power plants. Maintaining a certain level of power generation’s environmental impact nation-wide, with increased pollution emissions in some sources, will require reduction of the emissions in other sources. Costs and energy saved in one place will be spent in another place. Current energy policy basically promotes environmentally friendly sources, although in the case of micro-sources to obtain such preferences is almost impossible. It is expected that in the coming years the market will be flooded with inexpensive generation systems suitable to power certain loads (e.g. heating, lighting, or water pumping). An inexpensive generation system is usually devoid of control capabilities, and a significant portion of primary energy (e.g. wind, solar) is lost. But it was not relevant to users, because the primary energy is free, and inexpensive systems were quickly amortized. Microgrids can operate independently, powering specific appliances at households and farms, as well as in high-rise buildings in cities. Due to the national grid’s widespread accessibility it will become an alternative source of energy. The national grid will be used when the supply from a microsource is temporarily unavailable. With the significant increase in the number of microsources, their connecting to and disconnecting from the power system will impact the national power grids’ loads, even if they do not convert electricity, e.g. when heating with the sun or pumping water at a farm with a windmill. Providing individual customers with a control signal, for example the current energy price, will affect their decisions to draw electricity from the national grid. Microsources’ adjustment to electricity input to the grid, and adoption of simple and clear rules for energy purchase will be the microgrids’ natural further development. The next step will be to improve the efficiency of the whole process, starting from better use of primary energy up to optimum distribution of generated energy. Coordination of microsources’ operation in a microgrid, already at the stage of the primary energy’s conversion, allows better use of energy carriers with a lower exergy. Interoperation of several sources improves the microgrid’s overall efficiency. Also significant are energy losses in microgrids’ interconnections with the national grid. In Tab. 1. Primary energy conversion in microsources G. Blajszczak | Acta Energetica 4/21 (2014) | 56–61

How China’s current energy pricing mechanisms will impact its marginal carbon abatement costs?

Economic and social costs and benefits are critical factors affecting greenhouse gas abatement activities. Recognizing that energy prices are one of the most important factors influencing abatement costs, this study improved the basic China Energy and Environmental Policy Analysis (CEEPA) model by introducing a current energy pricing mechanism for China. The improved model was applied to generate marginal abatement cost (MAC) curves for China including the current energy pricing mechanism and to analyze MACs for the whole country and main abatement sectors in China under different energy pricing mechanisms. The results show that China MACs are sensitive to pricing mechanisms for electricity and refined oil. Ignoring the current regulation of these prices will lead to MAC underestimation, and price liberalization of these two energy sources could lead to a decrease in China MACs. Under a 50 % emission reduction target, if the electricity price regulation is ignored, the China MAC is underestimated by almost 16 %. Energy pricing reforms will lead to variations in sectoral abatement costs and overall abatement potential, and these impacts are projected to be large in the electricity sector. Under a 50 % reduction target, if the electricity price regulation is liberalized, MAC for the electricity sector nearly will decrease 50 %.

The influence of energy prices on adoption of clean technologies and recycling: Evidence from European SMEs

This paper examines the relative influence of energy prices on several environmental practices at firm level among SMEs. To that aim, we explore an EU-wide data-set providing information for 5194 SMEs in 27 European countries. We distinguish between recycling and purchasing and/or development of cleaner technologies and investigate whether the set of external and internal factors to the firm driving the adoption of least-integrated environmental innovation (recycling) differ from those influencing cleaner technologies (either purchased or in-house). The main findings stemming from a multivariate probit model suggest some significant differences among firms performing recycling practices and those purchasing and developing cleaner technologies. In particular, we find that current energy prices only increase the probability to adopt recycling practices while they have no significant effect on the most-integrated environmental innovation (developing cleaner technologies). Our results also indicate that market factors (proxied as expected increases in the demand for green products) are more relevant drivers of the least-advanced eco-innovation than of developing cleaner technologies. Interestingly, we find that higher technological and managerial capabilities are more effective in driving the adoption of cleaner technologies than in enhancing recycling solutions. A positive impact of cooperation and collaboration with universities and private agencies is found only on developing cleaner technologies in-house. This finding confirms the role of knowledge networks for the most-advanced innovative practice. Finally, neither existing nor future environmental regulations have significant impact on environmentally-friendly innovative practices while subsidies only increase the probability of purchasing cleaner technologies.

Investigating the residential energy consumption behaviors in Beijing: a survey study

This paper investigates the residents’ direct and indirect energy consumption behaviors in Beijing, as well as the impact of age, educational background and income level on the behaviors. The results show that, first, there are a high proportion of residents who may support the policies and activities about consumption behaviors adjustment towards energy-saving and low-carbon pattern, but currently the residents’ awareness and behaviors are still not desirable. Second, the promotion of energy-saving appliance is effective to drive the energy conservation and emission reductions, and the current energy prices are higher but not effective to curb energy consumption and carbon emissions. Third, the direct energy consumption behaviors of older respondents and those with higher education background and income level generally tend to be more energy conservative than the younger respondents and other education and income level groups. The survey results may provide significant policy implications for the government and energy-saving product suppliers.

Geographical context of energy prices in the European Union Member States with special emphasis on the Slovak Republic

Abstract The issue of energy prices presents an extremely topical subject with a major impact on human society. Energy demand is constantly increasing and most regions of the world are facing serious difficulties in ensuring sufficient energy supplies. However, not only global events affect energy prices in the particular country. National energy markets are highly specific and some local factors may also prove significant. In our contribution we focus on the Slovak Republic and try to analyze the major political and economic factors affecting the final price of energy, particularly of gas and electricity. We pay attention to the period from the accession of the country to the European Union in 2004 until 2011 characterised by ‘third liberalisation package’ that is associated with a wide range of major changes. Largely monopolized energy market has been gradually opening up to competition and the countries with regulated prices have been facing the increasing pressure to let the free market decide. Progressive liberalisation of energy markets enables consumers to use the energy services offered by various private companies. This new element operating in the energy sector is largely reflected in final energy prices. Thus, the main goal of this study is to highlight the price disparities between different energy commodities in European Union member states since we are at present witnesses to of significant regional disparities in energy prices. We try to analyze current energy prices with respect to GDP (regarding purchasing power parity as well) to ensure that resulting comparison would reflect the financial potential of the population. Demonstrating the effects of the economic crisis on energy prices in different countries will be another important aspect of this contribution.

Water and energy management in an automated irrigation district

An important modernization process providing pressurized irrigation systems to the traditional surface irrigation districts has taken place in Spain over the last 20 years However, an adverse consequence of modernization is the important increase in the energy cost in the modernized irrigation districts, which is aggravated by the current high energy prices. The Almudévar irrigation district (AID), a traditional surface irrigation district, was transformed into a pressurized sprinkler irrigation system in late 2010. The irrigation network was equipped with a high-level telemetry and remote control system that reaches the hydraulic valves of the irrigated blocks into which the plots are divided. Therefore, the telemetry system enables the centralized management of the irrigation scheduling from the district office. The district is divided into four independent networks with their own reservoirs and electric pump stations. A comparison of the land structure, crop patterns and irrigation management between the modernized AID in 2011 and the pre-modernization AID in 2006-2008 was performed. The temporal evolution of the irrigation water and energy demands in the 2011 irrigation season was analyzed with the available telemetry data from 2011. An irrigation performance index (SIPI) of the monthly and seasonal frequencies was computed for the main crops of the AID. Most irrigation events were performed during the low electricity tariff periods (P6 electric tariff) due to the centralized irrigation scheduling. Meteorological constraints had a low incidence in irrigation scheduling. Generally, a slight decrease in total irrigation deliveries was observed before and after medium-to-large precipitation events, but no changes in irrigation deliveries was observed with increases in wind speed. The exploitation of telemetry data in the AID has been an important tool to optimize the contracted electricity power in each tariff period and in decreasing the electric bill of the AID. This type of telemetry data analysis, similar to the analysis performed in the modernized AID in 2011, could be used in other water use associations as an important decision-making tool to improve water and energy management and to control the irrigation cost.

Real-time smart meters network for energy management

In this paper, an architecture of a low-cost ARM-based Smart Metering network is presented. The system is designed to be suitable for Smart Grids applications aimed to a more efficient energy use according to the article 13 of Directive 2006/32/EC. The network is composed by several slave smart meters that continuously monitor loads and energy generators to make available information in real-time such as power and energy consumption/generation and several power quality parameters communicating them via CAN bus to specific master device called data aggregator. This device, integrating the information coming from field devices (energy demands of loads, the current energy production and co-generator status), with information obtained through the web access (a prevision on the expected availability of energy produced by renewable sources, current and future energy price, customer remote setting), can take decisions to implement a suitable energy management aimed to cost saving or whatever else strategy chosen by customer. Data aggregator also allows checking current consumption locally, thanks to a display, and remotely, using the web browser access. To prevent external attacks a low computational burden protection software based on Message Authentication Code (MAC) has been implemented. Finally, characterization test of realized apparatus have shown good performance both in terms of communication delays and measurement uncertainty.

Operating value optimisation using simulation and mixed integer programming

Mining operations around the world will increasingly need to operate at greater depths. This significantly influences the complexity of ore extraction and ore transportation to the surface. The increase in mine depth leads to increases in haulage distance from mine areas to the mine surface. This results in an increase in energy costs to haul material further. Due to the increasing cost of future operations, the choice of the haulage method becomes an important factor in the optimisation of the mine plan. The haulage process is one of the most energy intensive activities in a mining operation, and thus, one of the main contributors to energy cost. This paper presents the comparison of the operating values of the mine plans at depth levels of 1000, 2000 and 3000 m for diesel and electric trucks, shaft and belt conveyor haulage systems for the current and a predicted future energy price scenario. The aim is to analyse the impact of energy requirements associated with each haulage method, as well as the use of alternative sequencing techniques as mine depth increases. This study is carried out using a combination of discrete event simulation and mixed integer programming (MIP) as a tool to improve decision-making in the process of generating and optimising the mine plans. Results show that energy cost increases across each haulage method at both current and future energy prices, with increasing depth. This study thus provides a broad and up to date analysis of the impact on operating values that may be experienced with the use of the main haulage systems available at present. Also, the study shows how the combination of discrete event simulation and MIP generates a good tool for decision support.

Construction of a fuel demand function portraying interfuel substitution, a system dynamics approach

Most of the recent numerical market partial equilibrium models of natural gas markets use imperfect competition assumptions. These models are typically embedded with a simple representation of the demand side, usually a single-variable, linear, inverse demand function, that does not capture any dynamic adjustment to past prices or energy substitution. To remedy this, we report an effort to construct an enhanced functional specification using the system dynamics-based model of [27,28]. This putty-clay model uses a vintage representation of capital stock to capture the effect of both past and current energy prices on fuel consumption. Using a re-calibrated version of this model, we first confirm the pertinence of this modeling framework to represent interfuel substitution at different fuel prices in the industrial sector. Building on these findings, a dynamic functional specification of the demand function for natural gas is then proposed and calibrated.

Affordability of energy cost increases for companies due to market-based climate policies: A survey in Taicang, China

This paper estimates the affordability of increased energy costs for Chinese companies due to the possible introduction of carbon pricing policies. The data were collected from 121 valid respondents in Taicang, China, using a multiple-bounded discrete choice (MBDC) format. Estimations indicate that a mean of 8.5% in energy cost increase would be acceptable for the surveyed companies on the whole. Companies from chemical and dyeing industries expressed a slightly higher affordability, with the mean of acceptable energy cost increase being 9.8% and 9.4% respectively. Econometric analysis identified two determinants of affordability for companies. One is the current energy price level, having a significant but negative relationship with affordability. The other is the energy management strategies of companies, significantly and positively associated with affordability. Calculations indicate that the mean of affordable energy cost increases for companies roughly equals a carbon price of 60 CNY/t-CO2 (about 9 USD/t-CO2). This result may be used as a referendum during the development of carbon tax policy and the establishment of a domestic carbon emissions trading scheme in China from the perspective of individual companies.

Solar assisted absorption cooling cycles for reduction of global warming: A multi-objective optimization approach

This work addresses the use of absorption cycles combined with solar energy for reducing the green house gas (GHG) emissions in the cooling sector. The problem of satisfying a given cooling demand at minimum cost and environmental impact is formulated as a bi-criterion non-linear optimization problem that seeks to minimize the total cost of the cooling application and its contribution to global warming. The latter metric, which is assessed following the principles of life cycle assessment (LCA), accounts for the impact caused during the construction and operation of the system. The concept of Pareto optimality is employed to discuss different alternatives for reducing the contribution to global warming that differ in their economic and environmental performance. We also analyze the effect of taxes on CO2 on the economic and environmental performance of the system. The capabilities of the proposed approach are illustrated through a case study that addresses the design of a solar assisted ammonia-water single effect absorption cooling system with 100kW of cooling capacity considering Barcelona weather conditions. We show that reducing the contribution to global warming considering the current energy prices and taxes on carbon dioxide emissions is technically viable but economically not appealing. We also discuss the conditions under which reducing the CO2 emissions could become economically attractive.

Optimal localisation of biofuel production on a European scale

This paper presents the development and use of an optimisation model suitable for analysis of biofuel production scenarios in the EU, with the aim of examining second generation biofuel production. Two policy instruments are considered – targeted biofuel support and a CO2 cost. The results show that over 3% of the total transport fuel demand can be met by second generation biofuels at a cost of approximately 65-73 EUR/MWh. With current energy prices, this demands biofuel support comparable to existing tax exemptions (around 30 EUR/MWh), or a CO2 cost of around 60 EUR/tCO2. Parameters having large effect on biofuel production include feedstock availability, fossil fuel price and capital costs. It is concluded that in order to avoid suboptimal energy systems, heat and electricity applications should also be included when evaluating optimal bioenergy use. It is also concluded that while forceful policies promoting biofuels may lead to a high biofuel share at reasonable costs, this is not a certain path towards maximised CO2 emission mitigation. Policies aiming to promote the use of bioenergy thus need to be carefully designed in order to avoid conflicts between different parts of the EU targets for renewable energy and CO2 emission mitigation.

Potential energy savings from cool roofs in Spain and Andalusia

Cool roofs are an inexpensive method to save energy and to improve the comfort level in buildings in mild and hot climates. A high scale implementation of cool roofs in Andalusia, in the south of Spain, could potentially save 295,000 kWh per year, considering only residential buildings with flat roofs using electrical heating. At the current energy prices, consumers can save 59 million euros annually in electricity costs and the emission of 136,000 metric tons of CO2 can be directly avoided every year from the production of that electricity. If radiative forcings are considered, Andalucía can potentially offset between 9.44 and 12 Mt of CO2. All the provinces in the rest of Spain are also studied in this paper. The biggest savings are achieved in Gran Canaria (48%), Tenerife (48%), Cádiz (36%), Murcia (33%), Huelva (30%), Málaga (29%), Almería (29%) and Sevilla (28%), where savings are greater than 2 euros per square meter of flat roof for old buildings with dark roofs. For the biggest cities the range of savings obtained are: between 7.4% and 11% in Madrid, between 12% and 18% in Barcelona and between 14% and 20% in Valencia.

Simultaneous saccharification and fermentation and economic evaluation of ultrasonic and jet cooking pretreatment of corn slurry

The potential of ultrasonics to replace hydrocooking in corn-to-ethanol plants was examined in this study. Batch and continuous experiments were conducted on corn slurry with sonication at a frequency of 20 kHz. Batch mode used a catenoidal horn operated at an amplitude of 144 μm peak-to-peak (p–p) for 90 s. Continuous experiments used a donut horn operating at inner radius amplitude of 12 μm p–p. Jet-cooked samples from the same ethanol plant were compared with ultrasonicated samples. The highest starch-to-ethanol conversion was obtained by the jet-cooked samples with a yield of 74% of the theoretical yield. Batch and continuous sonication achieved 71.2% and 68% conversion, respectively, however, statistical analysis showed no significant difference between the jet cooking and ultrasonication. On the basis of the similar performance, an economic analysis was conducted comparing jet cooking and ultrasonic pretreatment. The analysis showed that the capital cost for the ultrasonics system was ~10 times higher compared to the capital cost of a hydrocooker. However,due to the large energy requirements of hydrocookers, the analysis showed lower total overall costs for continuous ultrasonication than that for jet cooking, assuming the current energy prices. Because of the high utility cost calculated for jet cooking, it is concluded that ultrasonication poses as a more economical option than jet cooking. Overall, the study shows that ultrasonics is a technically and economically viable alternative to jet cooking in dry-grind corn ethanol plant.

The pricing of charging for electric vehicles in China—Dilemma and solution

The number of electric vehicles in China is expected to grow rapidly, triggering the nationwide large-scale construction of charging stations. At the same time, a reasonable charging price has not been established. This article records the views of station operators and EV users and calculates a charging pricing range. The price should not only ensure the profit of operators, but also help reduce EV users’ expenditure compared to using internal-combustion-engine vehicles. Based on current energy prices and battery costs, charging stations are unable to make profit, and the pricing shortfall is up to 0.78 RMB yuan(kWh) −1. Only with a 25% increase in energy price or 25% reduction in battery cost can charging stations become profitable. Several suggestions are proposed to improve station profits. First, ensuring a high station load is helpful to increase profits, and it is estimated the reasonable number of chargers in Beijing is approximately 6000, distributed among 672 stations. Second, the use of storage batteries for on/off-peak electricity self-management can also increase the annual profit by 600,000 RMB yuan. In addition, other methods like a jointed station alliance, multiple energy supplement approaches, vehicle-to-grid technology and state subsidy can also accelerate the development of the charging service industry.