3.5.3. PV on Roads

The total length of public roads with hard surfaces in the Pomerania Voivodeship is 14,547 km [96]. It has been assumed that it is technically possible to place 10-m-wide photovoltaic panels on 10% of the road length. We calculated how much electricity can be obtained with PV panels with an efficiency of 15%, using the following formula:

$$E\_{\rm T} = 0.10 \cdot 0.15 \cdot D\_{\rm T} \cdot \mathbf{U} \cdot \mathbf{N}\_{\prime} \tag{16}$$

where: Er—electricity that can be obtained annually from PV (J/year), Da—length of roads with hard surface (m), U—insolation (h/year), converted to (s/year), N—insolation (W/m2).

The calculated amount of obtainable electricity is 8112 TJ, i.e., 2254 TWh. The electricity produced can be used to power traffic lights, roadside bars, restaurants, etc. The estimated total amount of energy that can be obtained from PV in the Pomerania Voivodeship is 3625 TWh. Of course, this potential can be increased by making greater use of, for example, roofs or closed landfills.

### *3.6. Geothermal and Heat Pumps in the Pomerania Voivodeship*

Figure 9 shows geological wells with a depth of at least 500 m in the Pomerania Voivodeship. Some of them could be used in the future to build heating plants and/or geothermal thermal springs [97]. In general, the Pomerania Voivodeship does not have sufficient conditions for the development of "deep" geothermal energy. However, heat pumps can be used on a large scale in this region.

**Figure 9.** Geological drilling with a depth of at least 500 m in the Pomerania Voivodeship (own study from [97]).

It was assumed that heat pumps will be installed in schools, kindergartens, accommodation, and cultural facilities. It was assumed that every fifth facility with a building area of 1500 m<sup>2</sup> will be heated on average, and the heat pump's heating power will be 70 W/m2. The power of the heat pump P is the product of the area and the unit power of 70 W/m<sup>2</sup> [55]. Assuming an operating time of 2000 h a year and a heat pump's coefficient of performance (COP) = 3.8, the annual amount of heat produced can be calculated as follows:

$$\mathbf{E} = \mathbf{P} \cdot \mathbf{C} \mathbf{O} \mathbf{P} \cdot \mathbf{t},\tag{17}$$

where: E—heat production (MJ/year), P—power of heat pumps (MW), COP—coefficient of performance, t—annual operation time of the heat pump.

The calculated amount of energy for heat pumps in schools in the Voivodeship is 1708 PJ.

In 2020, there were 1555 tourist accommodation establishments in the Pomerania Voivodeship (as a result of the COVID-19 pandemic, this figure has decreased by 103 less compared to 2019), including hotels, motels, and gues<sup>t</sup> houses [92]. It was assumed that 20% of such facilities will have a heat pump, the average area of a single facility is 1000 m2, and the heat pump's heating power is also 70 W/m<sup>2</sup> [53]. Assuming the operation of heat pumps for 2000 h a year, on the basis of formula (16), it was calculated that the annual heat production in the Voivodeship will be 0.614 PJ.

In 2019, a total of 330 cultural facilities operated in the voivodship [98]. It was assumed that 20% of such facilities will have a heat pump, the average area of a single facility is 500 m2, and the heat pump's heating power is also 70 W/m<sup>2</sup> [53]. Assuming the operation of heat pumps for 1500 h a year, based on formula 17 it was calculated that the annual heat production in cultural facilities would amount to 0.052 PJ.
