Search Results (4)

The article aims at reviewing the drop regions (DR) of the launch vehicles (LV) separating parts (SP) and methods of their determination. The DRs include sea and land areas; going beyond them is associated with a number of environmental, economic, and political factors. Their combination dictates the need to ensure the safety of the people, transport, infrastructure, and environment from the negative impact of LV SPs and fuel residues. The Monte Carlo method is mostly used to determine the impact areas. It enables an estimation of the probability of the SPs of LVs falling in certain areas, constituting the DRs. These points are varied according to a set of different initial parameters. The methods of controlling the impact areas are contingently divided into engineering (based on a change in the design appearance of the LV), mathematical (which includes the changes in or optimization of the LV’s trajectory or its SP), and “soft landing” (implying the return of the LV’s to the spaceport or to a certain prepared area). The present analysis can be used as a starting point when choosing a method for determining and controlling the projected LVs and the SPs’ area of impact. Full article

The policy decision of extending electric power transmission lines to connect a remote area to a primary grid vs. developing local electricity generation resources must be informed by studies considering both alternatives’ economic and environmental outcomes. Such analysis must also consider the uncertainty of several factors such as fuel prices, the cost and performance of renewable and conventional power generation technologies, and the value of environmental benefits. This paper presents a method for this analysis, making two main contributions to the literature. First, it shows how to characterize the two alternatives (i.e., main-grid extension vs. local power generation) in detail for precise quantification of their capital and operating costs while guaranteeing that they are both adequate to meet forecast demand and operating reserves. Second, it shows how to properly account for the economic and environmental implications of renewable energy intermittency and uncertainty through the optimization of capital investments and hourly operations. The method is illustrated by applying this analysis method to Saudi Arabia, where the government is struggling to outline a strategy to meet residential and commercial loads reliably and sustainably in the country’s remote, scattered, isolated areas. To meet this demand, the Saudi government is considering two main alternatives: (1) extending the primary power transmission grid; or (2) installing an optimal combination of off-grid distributed generation (DG) resources, including solar PV, wind, diesel, oil, heavy fuel oil, and Li-ion batteries, to generate the electricity locally. Results suggest that under most scenarios of capital costs, fuel prices, and costs of air pollution, developing a microgrid with a large share of wind and solar power is more cost-effective than extending a primary grid 150 km or more away. Extending a primary grid powered by gas-fired combined-cycle power plants is more economical only if the load is not very high, the distance is not more than 350 km, and oil prices are relatively high compared to natural gas. Full article

Stand-alone hybrid power plants based on renewable energy sources are becoming a more and more interesting alternative. However, their management is a complex task because there are many variables, requirements and restrictions as well as a wide variety of possible scenarios. Though a proper sizing of the power plant is necessary to obtain a competitive cost of the energy, smart management is key to guarantee the power supply at a minimum cost. In this work, a novel hybrid power plant control strategy is designed, implemented and simulated under a wide variety of scenarios. Thereby, the proposed control algorithm aims to achieve maximum integration of renewable energy, reducing the usage of non-renewable generators as much as possible and guaranteeing the stability of the microgrid. Different scenarios and case studies have been analyzed by dynamic simulation to verify the proper operation of the power plant controller. The main novelties of this work are: (i) the stand-alone hybrid power plant management regarding a battery energy storage system as a part of the spinning reserve, (ii) the characterization of the largest loads as non-priority loads, (iii) the minimization of the needed spinning reserve and fuel consumption from diesel generators. Full article

Among the renewable energy sources, increasing the use of biomass (agricultural by-products) could be important from both an environmental and a climate protection perspective, but in many cases this is not a part of the current practice. Especially in developing countries, a large amount of agricultural waste suitable for energy use remains unused, remaining on the arable land or being burned in the field. Complicating matters is the fact that some countries have significant fossil energy reserves. This is also the case in Kosovo, which has the largest reserves of coal reserves (lignite) in southeastern Europe. An important question is how polluting and non-climate-friendly fossil fuels are to be replaced when they are available cheaply and in large quantities. The function of the political and economic models used in Europe has local specificity. It is not possible to copy the good solutions introduced by each country because of differences in the economic systems and farmers. Previous research has paid little attention to the producer conditions for available waste biomass sales. Studies have not examined the sales attitudes of farmers, or under what conditions they are willing to sell a larger proportion of the straw produced—of course, in such a way that they also meet the needs of animal husbandry, nutrients, and carbon supply. Using binary logistics regression and descriptive statistics not yet used in previous research, we analyzed the factors that influence farmers’ willingness to sell, sales barriers, and incentives. According to the respondents, the biggest barriers to selling straw are the lack of a market (74.1%) and baling machines (50.9%), while the main incentives may be a good price (75%) and a guaranteed contract (67.8%). The farmers surveyed believe that, in a safe market, with a multiyear contractual agreement, they would sell more than half of their straw for biomass energy production. The use of straw in animal husbandry is declining due to the introduction of new technological solutions, so the use of straw for energy purposes is an increasingly topical issue in the rapidly developing southeastern European countries as well. Based on our research results, it can be stated that the majority of farmers are willing to sell more than 50% of the amount of straw produced for energy purposes if the business model and state regulations are appropriate. Full article