In recent years, cogeneration has suffered from unfavourable market conditions in many EU-15 Member States. The problems facing hpP include: rising natural gas prices that have reduced the competitiveness of cogeneration costs (the preferred fuel for new cogeneration plants is natural gas), lower electricity prices due to market liberalization and increased competition (although these have now started to rise again), barriers to access to national power grids to sell excess electricity and relatively high start-up costs. Until the external costs of energy are internalized in their price, cogeneration may require state support, for example. B through investment promotion or tax exemptions (EC, 2005). So far, the uncertain and changing regulatory environment in many Member States, resulting from the liberalisation of the electricity sector, combined with the lack of coordinated support measures for cogeneration, has led to an increased perception of risks and undermined confidence. Therefore, other support mechanisms will be needed in the future to defuse this situation. The Cogeneration Directive on the promotion of high-efficiency cogeneration (2004/8/EC) is expected to enter into force in 2006; It encourages Member States to promote the uptake of cogeneration and to help overcome the current obstacles to progress. It does not set targets, but obliges Member States to carry out analyses of their highly efficient cogeneration potential. The goal of cogeneration is to use more of the chemical energy in the fuel. The reason for the use of cogeneration systems is that large thermal power plants that generate electrical energy by burning fuel generate between 40% and 60% of waste heat at low temperatures due to Carnot`s theorem. [4] The temperature generated by this waste heat (about 80 °C – 150 °C) allows it to be used for space heating purposes, which is why district heating networks have been installed in some urban areas. Heat networks have a limited scope because it is not economical to transport heat over long distances due to heat losses from pipes, and it will not reach sparsely populated areas, otherwise CAPEX revenues will decrease.
When district heating is not possible due to the low density of heat demand or because the local supplier has not invested in expensive heat networks, this thermal energy is usually wasted via cooling towers or discharged into rivers, lakes or the sea. Cogeneration or « cogeneration » means that heat and electricity are produced simultaneously in a single process. The use of cogeneration can help improve the overall efficiency of electricity and heat production, as these plants combine power generation technologies with heat recovery plants. Increasing the conversion efficiency of electricity generation through the use of cogeneration thus contributes to reducing the environmental impact of electricity production. The Sixth Community Environment Action Programme sets the objective of doubling the total share of cogeneration in the EU-15 to 18 % of total gross electricity production. Cogeneration or cogeneration is the use of a heat engine or power plant for the simultaneous production of electricity and useful heat. Cogeneration refers to the simultaneous production of electricity and useful heat and cold from the combustion of a solar fuel or heat collector. A plant that produces electricity, heat and cold is called a combined heat and power plant or a multigenerational plant. Cogeneration is a thermodynamically efficient use of fuels. In the case of separate electricity production, part of the energy must be rejected in the form of waste heat, but in cogeneration this thermal energy is used. All thermal power plants emit heat during the production of electricity, which can be emitted into the natural environment by cooling towers, flue gases or other. In contrast, cogeneration captures some or all of the by-product for heating, either very close to the plant or – especially in Scandinavia and Eastern Europe – in the form of hot water for district heating with temperatures of about 80 to 130 ° C.
This is also called cogeneration. Small cogeneration plants are an example of decentralised energy. Heat from by-products at moderate temperatures can also be used in absorption chillers for cooling. In the longer term, the penetration of the COGENERATION market in the EU-10 is expected to accelerate by 2030. In the EU-15 and the EU-25 as a whole, the share of electricity production from cogeneration is expected to increase slightly less. The PRIMES projections show that electricity production by cogeneration increased from 13.4 % to 16.7 % for the EU-15 between 2000 and 2010 and to around 21.6 % in 2030 and 24.2 % for the EU-25. This is unlikely to be sufficient to achieve the EU-15 indicative target of doubling cogeneration electricity between 1994 and 2010 (even taking into account some uncertainty caused by the evolution of definitions of cogeneration electricity). The share of cogeneration production is not significantly higher according to EEA projections for a low-carbon energy trajectory with a CO2 permit price (EEA, 2005), suggesting that the price of the permit alone is not sufficient to support cogeneration.
The increase in cogeneration production means that most of these plants are fully operational or on their way back. Micro cogeneration plants allow a very efficient combined heat and power production using waste heat, even with a rather low heat load. This allows the use of combined heat and power outside built-up areas or even if there is no district heating network. It is efficient to produce electricity near where the heat can also be used. Small power plants (μCHP) are located in individual buildings where heat can be used to support the heating system and to charge the hot water tank, saving oil or heating gas. Cogeneration plants are able to increase the overall energy consumption of primary energy sources. For example, cogeneration has steadily gained popularity in all sectors of the energy industry due to the rising cost of electricity and fuels, especially fossil fuels, and environmental concerns, especially climate change. [5] The majority of cogeneration systems use natural gas as fuel because natural gas burns easily and cleanly, can be inexpensive, is available in most regions and can be easily transported by pipelines that already exist for more than 60 million households. [21] A micro-cogeneration system typically contains a small combustion engine as a propulsion engine, which is used to run a generator that provides electrical energy, while using waste heat from the propulsion engine to heat a single building space and provide hot service water.
[2] With fuel cells, there are no rotating machines, but the fuel cell and, if necessary, the reformer provide useful heat. The battery generates direct current, which is converted to mains voltage by the DC/AC inverter. Micro-cogeneration is defined by the EU as being less than 50 kW of electrical energy[1], but others have more restrictive definitions of up to <5 kWe. [3] There are many types of fuels and heat sources that can be considered for micro-cogeneration. The characteristics of these sources vary in terms of system costs, heating costs, environmental impact, comfort, ease of transport and storage, system maintenance and system life. Some of the heat sources and fuels considered for use with micro-cogeneration are: natural gas, LPG, biomass, vegetable oil (such as rapeseed oil), wood gas, solar thermal energy and, more recently, hydrogen and multifuel systems. The energy sources with the lowest emissions of particulate matter and net carbon dioxide include solar, hydrogen, biomass (with two-stage biogas gasification) and natural gas. Due to the high efficiency of the cogeneration process, cogeneration still has lower carbon emissions than energy conversion in fossil fuel boilers or thermal power plants.
[19] [20] This can be achieved by hybrid photovoltaic-thermal solar collectors, another option is concentrated photovoltaics and heat (CPVT), sometimes referred to as combined heat and heat (CHAPS), is a combined heat and power technology used in concentrated photovoltaics that generates both electricity and heat in the same module. . . .