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Opportunities for wastewater heat recovery in Hungary and its role in the circular economy
Views:416Most of the energy content of wastewater can be found in wastewater heat, however, its recovery is limited. In this article, the current situation, future opportunities of wastewater heat recovery are presented based on secondary data collection, mentioning the constraints and main influencing factors of sustainable implementation of heat recovery systems in Hungary. Besides, the already existing systems are described. As regards the capacities of treatment plants, 103 of the 574 domestic plants have a capacity of over 20,000 Population Equivalent (PE), of which 25 plants have a capacity of over 100,000 PE. According to our calculations, in big cities/capitals (20.000 – 100.000, and over 100.000 inhabitants), it may be possible to recover wastewater heat sustainably in several places. In small towns (5.000 – 20.000 inhabitants), wastewater heat recovery can be technologically and economically sustainable only in the presence of agricultural or industrial plants with high and continuous wastewater feed into the pipeline system. Taking into account the temperature conditions at each place of use and their estimated fluctuations, it can be said that proper, careful planning, sizing and implementation have a crucial effect on the efficiency of microbiological activity in the treatment plants. In bigger cities, of course, the effect of the temperature drop of one main collector may be minimal, however, in smaller and medium-sized settlements, excessive heat extraction may result in complete inhibition or cessation of nitrification. In Hungarian case studies, the maximum acceptable temperature drop is approx. 2-3 °C. It can be stated that energy recovery from wastewater may be very promising considering the size and temperature limitations. Therefore, the rational recovery of wastewater heat can be an important part of the implementation of circular economy and sustainable energy utilization in wastewater management, resulting in significant energy savings and pollutant reduction.
JEL CODE: Q25
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The most relevant factors and trends in energy cooperation between Kazakhstan and China, focused on renewable energy sources (RES)
Views:541This paper analyses the good political and legal environments, mutually beneficial strategic policy, along with level of economic development and growth, superior geographical conditions and cultural integration degree of the important effecting factors of the energy cooperation between Kazakhstan and China. By using the main points listed above this article refers to related trade and investment theories, and it’s divided into two aspects: Kazakhstan's export of Chinese energy products with time series data 1998-2014 and China's investment in Kazakhstan's energy sector with time series data 1998-2016 to construct the vector autoregressive model (VAR).We selected relevant variables and data to construct an econometric model from the perspectives of trade and investment to make an empirical analysis on the influencing factors of energy cooperation between Kazakhstan and China. Our results show that China's demand for large-scale market and for opening to the outside world as well as Kazakhstan’s great energy potential are the most important factors their cooperation. It can be stated that in our days Kazakh legislation is suitable for promoting the Chinese energy investments, but in the long run it would be beneficial to mobilize national capital especially in RES investments and research. In the end, we found the most important reserves in competitiveness of electricity and heat (both from fossil and renewable energy sources) are power grid consolidation and waste heat utilization in the short run.
JEL CODE: F14; Q43
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Bioenergy: Risks to food-, energy- and environmental security
121-130Views:256There are growing opportunities and demands for the use of biomass to provide additional renewables, energy for heat, power and fuel, pharmaceuticals and green chemical feedstocks. However, the worldwide potential of bioenergy is limited, because all land is multifunctional, and land is also needed for food, feed, timber and fiber production, and for nature conservation and climate protection. The recent expansion of the bioenergy industries together with a strong increase in many commodity prices has raised concerns over the land use choices between energy needs and food and feed. New systems of energy production must be developed based on cost of environmental damage due to production and use of fossil energy and certain chemicals and materials. This article presents risks to food and energy security, estimates of bioenergy potential and the challenges of the environmental and social impact associated with expansions in bioenergy production.
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Enhancing the effectiveness of thermal water consumption via heat pumping
53-58Views:156Renewable technologies and the extension of their scope of usage basically has to face the general obstacles like any other novelties newly introduced to the market. In the case of environmentally friendly and clean technologies we must consider another critical aspect: the knowledge and the trust of the potential future users. To influence these people first we must extend their knowledge regarding renewable energies so they will be able to change their own approach about them. Usually the most crucial factor is the economic efficiency which determines the attitude of the majority of the users. Even the ones whose decision making process is highly based on the environmental patterns. In the case of any technology, the economic aspect is significantly influenced by its operational effectiveness. So this analysis – besides the direct economic matters – aims to examine how the performance of thermal water heating in greenhouses can be improved by using heat pumping.
JEL classification: Q42
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Energy alternatives in large-scale wastewater treatment
141-146Views:216In my article, after describing the characteristics of recent wastewater treatment activity, I introduce different traditional and innovative energetic opportunities of the compulsory waste management activities at large-scale operational level, covering national and international examples. Furthermore, the wastewater-based biomethane production and the certain plant’s energy self-sufficiency are highlighted topics as well. In the former case, it is possible to utilize the wastewater-based biomethane as fuel (and even to operate own vehicle fleet), while the second one gives the opportunity for the internal usage of produced electricity and waste heat, which can also result in significant cost-savings. As an additional option, algae-based wastewater post treatment is presented, based on the conditions of a Hungarian wastewater treatment plant, which biogas production efficiency and thus energy self-sufficiency has developed favourably due to the technological improvements. These plants may have a twofold role in the future: they are responsible for the compulsory waste management activity and on the other hand they can serve as excellent raw material mines.
JEL Code: Q25
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