Heating demand from households and small businesses in many central and eastern European countries may step up in the coming days on falling temperatures.
Average temperatures in many countries in the region were forecast on Tuesday to fall near to 12-13°C in the coming days, which could prompt an earlier start of heating season in line with national law or general practices than a year earlier.
In some central and eastern European countries the supply of heat through district heating systems officially starts based on outside temperatures.
Such rules are particularly important in countries with a high share of district heating systems. While individual households or businesses can turn on their heating according to their preferences, district heat supply is not available across the whole year.
If average temperatures fall below 13°C on two consecutive days in the period between 1 September to 31 May in the Czech Republic, and there is low probability the temperature will exceed the threshold the following day, "the supply of thermal energy will begin", according to national law.
At times, heating can be regulated at a local level, especially when district heating is used mainly in large cities in a country. The Toplofikatsia Sofia firm supplies heat to Bulgaria's capital. It has to ensure heat supply on 1 October-30 April in line with regulations, the firm has said. But the official supply of heat starts if average daily temperatures are below 12°C on three consecutive days.
And a Hungarian government decree sets the heating season on 15 September-15 May, during which heating must be "continuously available."
By comparison, Poland does not have any rules regarding the timing or activation of heating season set in law. But "it is usually assumed that "the" heating period begins when average daily temperatures fall below 10-12°C for several days in a row," according to Polish manufacturer of central heating boilers Stalmark.
Heating season to start sooner in Bulgaria
Average temperatures in Sofia suggest the heating season could start about two weeks earlier than last year, while the supply of heat could start in Prague and Warsaw before the end of the month.
Average temperatures in Prague were forecast on Tuesday to be low in the coming days, but increasing to 13.5°C on 26-27 September (see graph). That said, temperatures are projected to hold well below 13°C from 28 September onwards, suggesting that the supply of heat could start around that time, in line with national law.
And CEZ Teplarenska, which supplies heat in the north of the country to roughly 86,000 households, began to do so on Monday because of a "significant decline of temperatures," it said on Tuesday.
Daily temperatures in Warsaw were forecast on Tuesday to hold below 12°C on 24 September-4 October, averaging 10.8°C on 24-26 September, suggesting the heating season could start soon.
But the heating season in Sofia will not begin until the start of next month, according to forecasts. Average temperatures will fall below 12°C for three consecutive days only from 1 October onwards.
Consumption in many central and eastern European countries has been lower so far in September than a year earlier, but falling temperatures will support consumption in the coming days.
Some heat providers already turned on district heating in the Czech Republic in mid-September last year because of a cold spell on 12-16 September. Total Czech consumption rose to 141 GWh/d on 16-19 September, from 112 GWh/d on 1-15 September and 128 GWh/d on 20-30 September that year. Consumption has been much lower so far this month at 102 GWh/d on 1-20 September.
That said, the heating season could start earlier in Poland and especially in the capital of Bulgaria compared with last year.
Weather was mild in September 2024 in Warsaw, falling below 12°C on 29-30 September in the month, suggesting that the heating season may have started in early October. Polish demand on distribution networks averaged 261 GWh/d in September last year, rising significantly only on 30 September to 322GWh. It has averaged 258 GWh/d so far this month.
And Toplofikatsia Sofia started supplying heat on 21 October 2024, the company has said, which would be later than this year judging by the latest weather forecast. Implied Bulgarian consumption averaged 69 GWh/d on 1 September-20 October last year, rising then to 95 GWh/d on 21-31 October. It was 65 GWh/d on 1-22 September this year.
