1. Introduction of the target region

Sadki Commune is situated in middle-western part of kujawsko-pomorskie voivodeship. It borders from the west with Wyrzysk and Łobżenica communes (wielskopolskie voivodeship), from the north with Mrocza commune, from the east with Nakło commune; however, southern border with Kcynia commune constitutes Noteć river. The Commune Office is located in the central part of Sadki village. Sadki is located 42 km away from Bydgoszcz, a seat for central administration, and 88 km away from Toruń, a seat for regional administration.

Map 1: Administrative division of kujawsko-pomorskie voivodship.

Main data of Sadki Commune (status on 31^st December 2009):

• Commune area – 15 396 hectares
• Number of inhabitants – 7 345 people
• Number of village districts – 14
• Number of villages – 23
• Population density – 47 people/km²
• Arable Land – 73,97 %
• Forest area – 15,20 %
• Green area – 15,26 %

Sadki commune is the only commune in the nakielski administrative district with dominating agriculture. That guarantees availability of biomass.

Agricultural production comprises mainly cereals (summer and winter), cereal mixtures (summer and winter), maize, leguminous fodder plants, beetroots, potatoes and oil plants.

2. Characteristic of energy demand

Sadki municipality possesses 19 building complexes which are heated with fossil fuels. The main fuel used in the commune is culm with an annual consumption of 333,4 tons, the majority of which is used by a primary school in Sadki. For the heating purposes the school consumes 124 tons of coal
annually what constitutes 37% of the total fuel consumption in the municipality. In addition to culm there are other types of fuel used, namely eco-peas coal (19 t/year), chestnut coal (28 t/year), heating oil (2500 m³) and stone coal (1,9 t/year). The above mentioned fuels comprise basic heating source in the public utility buildings. Supplying boilers with poor quality of culm one will not save money, as it is mistakenly thought, because more of such fuel is required. The existing boilers require modernization, what causes additional costs. New technologies using fossil fuels are relatively expensive and emit harmful gases having a disastrous effect on the environment.

Table 1: Balance of the heat energy demand (19 building complexes and farms in Sadki commune) and supply of potentially available energy in solid biomass.

As it is presented in the table above the energy potential in biomass from Sadki commune can 11 times cover energy demand for heating purposes (8365,6 GJ/year) of the 19 municipality buildings. However, it is not enough to cover energy demand of farms (105000 GJ/year). Energy potential covers only 83,2% energy demand of both the farms and municipality buildings.

Taking into assumption that annual demand for coal per household is at the level of 7 tons and that fuel value of straw is 35%, quantity of straw required to satisfy heating needs of a household should be 10 tons/year. Farms in Sadki commune vary in terms of area and production (most of them have cereal production). Therefore, most of them can use straw as the basic fuel for heating purposes. If 25% of straw was used for heating purposes a farm should have at least 20 ha of cereal production.

3. Available sources of energy

Table 2: Possibility to obtain substrates for biogas and solid biomass production in Sadki commune in relation to total production (%)

The above table presents substrates for biogas and solid biomass production. Liquid manure and silage are the main substrates for biogasification plant and will constitute 30% each of the total input. The other substrates also play a significant role in the biogas production. Meanwhile forest and orchard wood plays a significant role in biomass production. Taking into consideration characteristics of the commune rape and cereal straw are significant as well and they may be a basic material for briquette production.

4. Proposed actions

Thanks to agricultural character of Sadki commune substrates for biogasification plant are widely available. However, currently it is difficult to indicate an exact localization of the biogasification plant. Nevertheless, inhabitants of the commune show a great deal of interest in Renewable Energies, which may lead to starting this kind of investments.

Map 2: Map of Sadki commune.

Taking into account availability of such substrates as silage (maize and silage produced from organic production,) and liquid manure it could be possible to build 0,98 MW biogasification plant including 0,35 MW electricity power and 0,63 MW heat power. These assumptions do not take into consideration losses which may occur in the result of silage storage or during production process.

Another action proposed in the Strategy is modernization of the heating system in the Primary School in Sadki.

For the heating purposes of the school it is used 124 tons of culm annually, the amount varies due to weather conditions in the heating season. As it was mentioned earlier local potential of straw and hey from meadows of the Noteć river may be the basic material for production of heat energy in the school building. The suggested boiler is equipped with automatic fuel dosage device. It is suitable for combustion of sawdust, wood chips, straw
briquette, sawdust briquette. Steering automation allows setting parameters such as:

• water temperature,
• quantity of fuel,
• time of combustion,
• quantity of air needed for combustion.

The automation allows to generate boiler efficiency at the level of 86%. The steering system allows to connect some other devices, for instance, a room thermostat, weather steering system.

Table 3: Comparison of costs and fuel demand for coal boiler and biomass boiler

Calculation presented in table 3 includes only costs of purchase of biomass boiler with service. However, it is important to take into consideration costs of building insulation, costs of new windows, radiators with piping system and costs of building a storage for biomass, what was not included in the analyses. The cost calculation is based on the data from 2009 when price of culm was 510 zł/Mg and the quantity of coal used was 124 tones. At that time annual cost of heating was 63 240 zł. The same heating energy can be produced by a new biomass boiler with the efficiency of 86% when combusting of 139,97 Mg of straw briquette.

Thanks to the biomass boiler investment one can generate 10 053 zł savings per year. These savings will allow to reimburse investment costs after 9 years, what is presented in the chart of accumulated cash flow (Chart 1). The calculation includes prices rises of fuel at the level of 3 percentage points.

Chart 1: Accumulated cash flow (zł/year) for biomass boiler investment

Biomass boiler investment will allow to decrease emission of greenhouse gases. Thanks to that the boiler will limit negative impact upon the environment. Biomass boiler will allow to reduce CO₂ emission by 223 Mg within one heating season. Such low emission of CO₂ is connected with a closed circulation of CO₂, which is produced in the process of biomass combustion.

This investment will also have a social impact. It may trigger local inhabitants to start similar investments in their households and on their farms. In order to guarantee this a wide educational and promotional action is required. Additionally, all proposed investments create new job opportunities for the local society.

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