STRAW AS A SOURCE OF ENERGY

Straw is a low-emission renewable fuel, widely available throughout Poland, often at low costs. The production and use of straw bring additional environmental and social benefits.

10 reasons to use straw as a sustainable source of energy:
  • Straw can be harvested locally, what guarantees security of supply.
  • Straw is fuel, which can be stored, thus enables stable production of electricity and heat from renewable sources (in contrast to, for example, wind farms, whose yield is subject to considerable fluctuations).
  • Modern straw-fired boilers are characterized by high combustion efficiency and provide the best available flue gas filtering technology.
  • Heat, a by-product of the electricity generation process, can be sold at competitive prices to local residents and enterprises.
  • Polish straw, obtained under long-term and spot contracts, can provide local farmers and enterprises with the opportunity to grow and support the local economy.
  • When managed properly, straw can bring significant reductions in carbon dioxide emissions in the region and the country, replacing energy production based on fossil fuels.
  • Energy produced from straw is not exposed to fluctuations of the purchase prices of carbon dioxide emission allowances
  • Creating local straw production structures and straw use allows to minimize financial and environmental transport costs. Each Polish region can become a producer of straw, although in some regions this potential is larger.
  • Bottom ash from straw burned in power plant can be used as a valuable, natural fertilizer in agriculture, which is beneficial to the environment and society.
  • Harvesting straw biomass does not reduce food production.

The TergoPower Projects are in 100% straw fired.   In the case of possible transient straw deficiencies, the basic fuel may be partially replaced with wood chips (due to the addition of dedicated storage installations and feeding of wood chips to the boiler).

Chain of supply of straw:

  • Straw-fired power plants are usually designed to receive pressed Heston typw cubes with dimensions of c. 2.4×1.2×1.2 m, however, lower cubes may also be used. The straw should not be shredded.
  • During the compaction process, the straw should be dry, which ensures the highest possible calorific value of the fuel.
  • The moisture content of the material during pressing should be below 15%. Most often, however, the straw is already dry enoughs already during harvesting, as it usually takes place in sunny weather.
  • Collecting the formed strwa cubes from the fields and transporting it to the warehouses usually takes place using large tractors with a trailer, equipped with a telescopic extension arm for loading.
  • Compressed straw is harvested from fields and transported to warehouses, from which it is delivered to the power plant.
  • Warehouses and their location are selected in such a way that the total logistics costs are minimised.
  • The last link in the described chain is the transport of compressed straw from warehouses located in the region to the power plant. A truck with a trailer can accommodate 2 or 3 layers of compressed straw, an average of 24 or 36 cubes, depending on their weight and size, as well as the size of the load permissible in the country.
  • The TergoPower power plant will have an automatic system for unloading, storing and feeding the straw, with the possibility of simultaneous unloading one layer of compressed cubes (2×6 pieces) from a truck and trailer.
  • Bottom ash produced in the process of straw combustion after obtaining appropriate permits preceded by tests of certified scientific centers, may become a valuable fertilizer for agriculture.
USING STRAW TO ACHIEVE A ZERO BALANCE OF CARBON DIOXIDE

Carbon dioxide produced during the biomass combustion process is considered neutral for the atmosphere. Coal of plant origin is part of the natural circulation of this element in nature – it has been absorbed as CO2 in the plant growth process. This results in maintaining a stable balance between emitted and absorbed carbon dioxide.

  • As the plants grow, they absorb carbon dioxide from the atmosphere.
  • During the photosynthesis process plants store carbon in cellulose tissue and release oxygen into the atmosphere.
  • Carbon stored in cellulose tissues is combined with oxygen as it burns, creating carbon dioxide that is emitted into the atmosphere in the flue gas.

In modern solid fuel combustion systems, the resulting compounds like sulphur or nitrogen, are in major part isolated in the filtration process.