In this topic, an analysis of the potential application of photovoltaic solar energy systems in the state of Paraíba is presented.

Theoretical potential

Theoretical potential is understood as the available potential for photovoltaic solar generation, assuming that the modules would be installed in ideal conditions for photovoltaic generation, i.e., modules oriented to geographic north with an inclination of 10° relative to the horizontal plane and without shading.

The calculation of the theoretical potential used the Global Irradiation database on the 10° Inclined Plane (GTI₁₀), assuming the use of the entire area of the state of Paraíba for solar generation – with an occupancy rate of 100%. For this analysis, none of spatial restriction was assumed; therefore, protected and flooded areas were not excluded in this calculation.

Optical and electrical losses in energy generation and transmission were also not considered, as technological development and improvement are projected into the future. This premise is equivalent to assuming a Performance Rate of the photovoltaic system equal to 100%.

In addition to the assumptions described above, the calculation assumed:

• the whole area of the State of Paraíba of 56,467.242 km² (IBGE, 2022);
• the average value of Global Irradiation Inclined at 10° (GTI₁₀) in the territory of Paraíba was determined at 5.73 kWh/m².day;
• the use of photovoltaic modules with the most widespread technology currently available on the market – monocrystalline silicon, bifacial with a power of 650 Wp, with an approximate area of 3.1 m² and efficiency of 21%.

Once these assumptions were established, the theoretical potential obtained is approximately 12 TWp, generating around 70 TWh/day or 25,550 TWh/year. To illustrate, an area with only 0.02% of the State of Paraíba would be enough, in theory, to generate an amount of electricity equivalent to the energy consumption of the entire state in 2021, which was 5,881 GWh.

Technical potential

As in determining the theoretical potential, the evaluation of the technical potential of photovoltaic generation assumes the ideal conditions for power generation: modules oriented to the geographical north with an inclination of 10° in relation to the horizontal plane and without shading. In addition, the following assumptions are assumed:

• previously calculated theoretical potential;
• exclusion of areas with environmental and geographic restrictions: water supply pipeline, permanent preservation areas (50 meters margin for watercourses), water bodies (100 meters margin), transposition channels (50 meters margin), urban areas (500 meter margin), slopes greater than 5 degrees, highways (100 meter margin), railways (100 meter margin), indigenous lands, quilombola lands, conservation units;
• optical and electrical losses in the photovoltaic system were considered using a performance ratio equal to 75%;
• occupancy rate with photovoltaic modules equal to 44 MWp/km², typical value observed in centralized photovoltaic plants operating in the Brazilian territory.

Considering these assumptions, the technical potential was determined at approximately 1.54 TWp, capable of generating around 6.88 TWh/day or 2,512 TWh/year.

Economic potential - I

This economic scenario for photovoltaic energy potential assumes, as a starting point, the previously determined technical potential, adding a restriction for the distance between the place of interest for generation and the next point of connection to the National Interconnected System (SIN):

• maximum distance equal to or less than 30 km from the grid connection point (69 kV lines or superior).

Thus, the result obtained for economic potential I is approximately 1.46 TWp, capable of generating around 6.51 TWh/day or 2,375 TWh/year.

Economic potential - II

The second scenario of economic potential has as assumptions those considered in the previous scenarios, plus the following restriction:

• maximum distance from the grid connection point (69 kV lines or superior) equal to or less than 10 km.

Thus, economic potential II results in approximately 907 GWp, generating around 4.05 TWh/day or 1,479 TWh/year. To get an idea of this economic potential, just 0.14% of the state's area would be enough to generate an amount of electricity equal to the consumption recorded in 2021 by Paraíba, about 5,881 GWh.

Economic potential – III

The third scenario adopted for the economic potential of solar resources in the state of Paraíba aims to evaluate the use of solar energy in distributed generation systems installed on the roofs of buildings in urban areas. To this end, the following assumptions were adopted:

• guidelines indicated in Technical Note DEA/EPE 19/14 - Insertion of Distributed Photovoltaic Generation in Brazil – Conditions and Impacts;
• information on the number and type of residences (house or apartment) was obtained from the 2010 IBGE CENSUS for urban areas (source: https://sidra.ibge.gov.br/); when this document was prepared, detailed data from the 2022 Census were not yet available;
• average roof area of 85 m² for houses and 15 m² per apartment was assumed;
• the total number of households in an urban area in the State of Paraíba of 829,761 was adopted based on IBGE data (2022);
• utilization factor of 30% of the final area found for photovoltaic systems connected to the grid;
• database of Global Irradiation in the Inclined Plane at 10° (GTI₁₀);
• generation system based on Mono-PERC photovoltaic modules with an approximate power of 650Wp, an approximate area of 3.1 m², and an efficiency of 21%.

Considering these assumptions, the economic potential III is estimated at approximately 4.16 GWp, capable of generating around 17.87 GWh/day or 6.52 TWh/year, that is, greater than the electricity demand of the state, being possible to export the surplus to the National Interconnected System (SIN).

Figure 5.1 presents the concept of distributed generation.

Figure 5.1 - Photovoltaic installations in homes, industries, buildings, and rural areas.