Evaluation of Trends of Electricity Production From Biomass

The research part of this thesis explains the term biomass and the principles of obtaining energy from it, i.e. the processes of thermochemical and biochemical conversion, and consequently deals with using such energy for the production of heat and electricity. It briefly introduces the current situation in utilising the biomass for the purposes of power engineering. The term of cogeneration is explained, along with defining its types and assessing their suitability for specific fuels from the point of view of price, efficiency, etc. The chapter on conditions for using the biomass focuses on the problem points of supplying biomass to the place of delivery, such as limitations in transport distance, storage and quality requirements, or, for example, the smell around the biogas stations. The second part of the chapter lists the conditions for power take-off, especially thermal, namely due to the irregularity of such take-off. It also mentions possible solutions, which consist in placing the units along with suitable objects or the trigeneration method of operation. The thesis also mentions some specific properties of biomass significant to power generation, such as low heating value of wood-gas or biogas, or their lower cleanliness. This is connected to another subject, which is also discussed here, namely the conditions for environment-friendly operation of units. Various types of dangerous substances, such as nitrogen oxides, carbon monoxide, dioxins, etc. are mentioned along with the conditions for their removal. The last chapter of the research part introduces the conditions for connecting the units to the power system; particular interest is paid to the necessary protection during failure conditions, power quality (power factor), and further also the impact of the production facility on the voltage conditions in the point of connection and impact on the level of ripple control signal. The practical part deals with the project of a cogeneration unit for a small woodworking manufacture with a locksmith’s workshop, taking into account the operation’s energy demands, purchase price of the equipment and the fuel consumption. Due to the low energy output consumption, the source of energy is a combustion engine with electrical output of 30 kW, operated on wood-gas produced in a gasification generator. The first part includes the calculations of costs and returnability for non-continuous operation, using the waste from the manufacture. Returnability in such case is 62 years, the costs of power generation being CZK 1.73 per kWh. The second part deals with the advantage of continuous operation supplied by purchased wood-pulp; in this case the production costs are CZK 2.19 per kWh with 50 year returnability