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  • Author: Andres Siirde x
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Efficiency Assessment of Support Mechanisms for Wood-Fired Cogeneration Development in Estonia

There are various support mechanisms for wood-fired cogeneration plants, which include both support for cogeneration development and stimulation for increasing consumption of renewable energy sources. The efficiency of these mechanisms is analysed in the paper. Overview of cogeneration development in Estonia is given with the focus on wood-fired cogeneration. Legislation acts and amendments, related to cogeneration support schemes, were described.

For evaluating the efficiency of support mechanisms an indicator - fuel cost factor was defined. This indicator includes the costs related to the chosen fuel influence on the final electricity generation costs without any support mechanisms.

The wood fuel cost factors were compared with the fuel cost factors for peat and oil shale. For calculating the fuel cost factors, various data sources were used. The fuel prices data were based on the average cost of fuels in Estonia for the period from 2000 till 2008. The data about operating and maintenance costs, related to the fuel type in the case of comparing wood fuel and oil shale fuel were taken from the CHP Balti and Eesti reports. The data about operating and maintenance costs used for peat and wood fuel comparison were taken from the Tallinn Elektrijaam reports.

As a result, the diagrams were built for comparing wood and its competitive fuels. The decision boundary lines were constructed on the diagram for the situation, when no support was provided for wood fuels and for the situations, when various support mechanisms were provided during the last 12 years.

The Impact of Pollution Charges, Ash Handling and Carbon Dioxide on the Cost Competitiveness of the Fuel Sources Used for Energy Production in Estonia

The goal of this paper is to estimate the effects of pollution charges, ash handling and of the carbon dioxide quota trade on the competitiveness of natural gas, oil shale, peat and wood chips in Estonia for 2010 and 2015.

The pollution charges and levels are calculated based on the Environmental Charges Act, and Regulations No 99/2004 and No 94/2004 of the Estonian Minister of the Environment.

The calculations show a considerable change in the cost competitiveness of fuels. Fuel related costs of the fossil fuels with high CO2 emission factors and other environmental impacts may be doubled.


In spite of the progressions in heat storage systems for combined heat and power’ (CHP) plants performance, these innovations have not been implemented in CHP-based district heating (DH) systems in some of the countries where DH systems are still being developed. An examination of environmental and economic advantages that can be gained as a result of heat storage installation into the DH system are necessary to effectively popularise heat storage as a DH system-improvement technology. A real large-scale biomass CHP-based DH system is investigated in this case study. Scenarios for two kinds of support policies (feed-in premium for electricity generated by biomass CHP and energy-efficient biomass CHP) were analysed by changing the extent of the heat storage. The goal of this study was to assess the impact of the biomass CHP policy support instruments on the viability of integrating heat storage. Calculations demonstrate that fitting of heat storage combined with biomass CHP is less viable when all power generated by biomass CHP is subsidised.


The purpose of this paper is to offer a methodology for the evaluation of large district heating networks. The methodology includes an analysis of heat generation and distribution based on the models created in the TERMIS and EnergyPro software Data from the large-scale Tallinn district heating system was used for the approbation of the proposed methodology as a basis of the case study. The effective operation of the district heating system, both at the stage of heat generation and heat distribution, can reduce the cost of heat supplied to the consumers. It can become an important factor for increasing the number of district heating consumers and demand for the heat load, which in turn will allow installing new cogeneration plants, using renewable energy sources and heat pump technologies


The aim of this study is to evaluate and compare the impacts of heat recovery ventilation (HRV) and exhaust air heat pump (EAHP)-based solutions used in renovated buildings, which make it possible to reach performance class C in district heating (DH) area CO2 emissions, primary energy consumption and total energy costs for consumers. Evaluation is based on the methodology presented in the previous research paper [1]. Calculation results show that the use of EAHP has a negative impact on DH sustainability (heat losses in the DH network, DH heat price, reduced consumption of DH heat) and CO2 emissions related to energy delivery (heat and electricity) to consumers in the DH area. Positive aspects of the EAHP use include the fact that almost the same primary energy consumption level can be achieved with lesser (up to 7 %) annual costs (annual capital costs, DH heat costs and electricity costs) and lower initial investments (about 10 %). At the same time, every renovated building with EAHP will experience a negative impact on heat prices. In DH areas where almost all buildings are renovated with EAHP, cost savings are not as evident compared to buildings with HRV in DH areas where the use of parallel consumption solutions (EAHP) is minimized. It is reasonable to promote these renovation packages and solutions that benefit the building’s primary energy reduction, and also do not increase electric energy consumption (additional electric power generators are needed) and do not damage DH networks.


The European Union has set an ambitious goal to transform to a carbon neutral economy. The present paper focuses on thermal treatment of oil shale and biomass blends that could be considered as an important pathway for achieving the carbon neutral goal locally in Estonia. The concept of co-pyrolysis and co-gasification of biomass and oil shale offers various advantages such as higher liquid product yield and higher char conversion than if the oil shale and biomass particles were processed individually. In the paper, an overview of the planned actions for merging oil shale industry carbon neutral economy is given. The selected approaches are justified with information found in scientific literature and initial experimental results. Further, the possible future developments for gasification and pyrolysis in Estonia are also highlighted.


District heating (DH) offers the most effective way to enhance the efficiency of primary energy use, increasing the share of renewable energy in energy consumption and decreasing the amount of CO2 emissions. According to Article 9 section 1 of the Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings, the Member states of the European Union are obligated to draw up National Plans for increasing the number of nearly zero-energy buildings [1]. Article 2 section 2 of the same Directive states that the energy used in nearly zero-energy buildings should be created covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby. Thus, the heat distributed by DH systems and produced by manufacturing devices located in close vicinity of the building also have to be taken into account in determining the energy consumption of the building and the share of renewable energy used in the nearly zero-energy buildings.

With regard to the spreading of nearly zero-energy and zero-energy houses, the feasibility of on-site energy (heat and/or electricity) production and consumption in DH areas energy (i.e. parallel consumption, when the consumer, connected to DH system, consumes energy for heat production from other sources besides the DH system as well) needs to be examined. In order to do that, it is necessary to implement a versatile methodological approach based on the principles discussed in this article.