Energy 2 July, 2019 10:00 am   
Editorial staff

Gacki: Small heat – big changes

While talking about energy, we usually mean large electric power industry or mining industry. Meanwhile, we often omit a very important sector, without which it is difficult to imagine life in the city at this time. This is a heat sector. The Warsaw heating system is one of the largest in Europe, and heat and power plant Siekierki is a unique phenomenon on a global scale – writes Maciej Gacki, a journalist of, and cooperator of SKN Energetyki of Warsaw School of Economics.

Energy objects of this size are rare in the middle of the city. This time, however, we will look at smaller units. In small and medium-sized cities, heat plants play an equally important role, and they do not have any easier. They have much smaller budgets, and the tariff does not provide adequate funds for modernization. However, small entities may use various types of support, e.g. from National Fund for Environmental Protection and Water Management
for projects related to high-efficiency cogeneration sources or effective heat distribution. Today, we will look at a small municipal heating plant in Zambrów, which has been modernized since last year.

At the beginning, let’s talk a bit about the parameters of the system itself. Power installed in the heat is currently 35.9 MWt. On average, the heating plant sends approximately 200,000 GJ of energy to residents per year so there are 4 water boilers working there, the youngest from the 90s. At the moment, it is difficult to estimate how many connected households are, but in nearly 20,000 the city of Zambrów, almost all multi-family buildings (blocks) are already connected, eliminating small local boiler houses. It is also worth adding that the heating plant operates a municipal swimming pool and several industrial halls. The peak demand is estimated at around 24 MW. In the summer season, which is important in the light of the modernization carried out, the demand is about 1.5 MWt.

Using the support of high-efficiency cogeneration sources, the heat plant decided to invest in two identical reciprocating engines, becoming a combined heat and power plant. The electric and thermal power of each engine is 1.2 MWe and 1.6 MWt, respectively. With the design parameters, the efficiency of both units is 96.2%, which proves the very good technology of the Siemens engines. By combining the thermal power of even one cogeneration engine with summer demand, it is very well seen that it ideally covers the basic heat demand in the city.

In addition, the sale of electricity can significantly improve the financial performance of the unit, because electricity prices on the market are growing. Unfortunately, not every heating plant can afford to diversify the types of fuel it uses. Taking a closer look at the Podlaskie Voivodeship, only a few municipalities are connected to the gas network. Theoretically, the solution may be LNG re-gasification stations, but with such gas volumes as the described engines require, this may be a logistical problem. Deliveries would have to arrive almost every day. The plant under consideration plans further investments. Analyzes are in progress related to the introduction of heat generation technology based on biomass fuel – wood chips. Two of the oldest coal grate boilers are to be replaced with new, meeting the emission standards set out in the EU directive, colloquially referred to as MCP. After a few years of tarnish, which occurred in the biomass industry, at the moment you can see a recovery through this type of investments. So you can say that no one will build a second Połaniec. Biomass is becoming bolder to small units, helping them in this way to meet EU requirements regarding emission standards and energy efficiency.