3. DESCRIPTIVE ANALYSIS RESULTS OF KAUSTINEN FUR FARMS
3.2. Fur Farm 1
3.1.1. Farm 1 Current Electricity Use
The current electricity consumption of this farm is about 24.92 MWh/year. To deploy the use of solar PV in generating parts of the current electricity consumption, there is a need to
dimension the solar PV system size based on the defined criteria in order to achieve a system size that is viable enough to meet the electricity consumption.
Dimensioning System Size Based on Annual Zero Energy Production
The exact system size required to meet the present electricity consumption is about 27 kWp based on an annual zero energy production level. The total production output of 27 kWp is about 24.91 MWh/year. Figure 4 depicts the effect of the production output of 1 kWp on the current consumption and of 27 kWp needed to cover the current electricity consumption. From Figure 4, it can be noticed that the farm has the highest production during the summer months (May, June and July) and this is due to solar resource availability and low electricity consumption. The other months with high electricity consumption and low PV production are winter months, due low solar resource availability and the cold weather condition which requires more electricity for lighting and heating of the buildings.
(a) (b)
Figure 4. Effect of solar production output in Farm 1 current electricity consumption. (a) Effect of a 1 kWp system in current electricity consumption. (b) Effect of a 27 kWp system in current electricity consumption.
As a result of excess PV production and low electricity consumption during the summer, and low PV production and high electricity consumption during the winter. Further analysis is carried out to determine electricity purchased from the grid during low PV production and grid sales during high PV production as shown in Figure 5.
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(a) (b)
Figure 5. Distribution of the 27 kWp production output. (a) Self-use and grid sales production.
(b) Grid purchase and grid sales production.
Dimensioning System Size without Battery
The system size is further dimensioned by carrying out a sensitivity analysis. To determine the system sizes lower than the annual zero energy dimensioning of 27 kWp that is needed to cover the current electricity consumption, so as to derive a system size viable without any sales to the grid. In addition, system sizes higher than the capacity of 27 kWp is also analyzed so as to determine the income saving profitability due to the recipient requirement of selling excessive production to the grid. The result of the sensitivity analysis carried out is presented in Table 6.
The exact system sizes required in all scenarios will be highlighted with in green color to distinguish.
From Table 6 it can be observed that the higher the system size the more the electricity consumption is covered, while grid purchase reduces, grid sales increases while the self-use is reduced. In addition, it can also be noticed from Table 6 that increasing the system size above 27 kWp has no impact on the grid purchase as the percentage of the electricity consumption covered remains the same for 27 kWp to 30 kWp and 35 kWp to 40 kWp, while the grid purchase also remain the same for these system capacities. Also, increasing the system size above 27 kWp for the purpose of selling to the grid may not be feasible and viable for investment as the percentage difference of 1 % is observed for the following installed capacities 27 kWp, 30 kWp, 35 kWp and 40 kWp, while it increased by 2 % for 30 kWp to 35 kWp. The percentage
sensitivity analysis presented in Table 6 is further detailed in Table 7 to show the production distribution in energy unit for each system size.
Table 6. Farm 1 current sensitivity analysis result without battery.
System sizes (kWp)
PV in consumption
covered
Grid purchase
Self-use production
Grid sales
1 3% 97% 79% 21%
2 5% 95% 63% 37%
3 6% 94% 55% 45%
4 7% 93% 49% 51%
5 8% 92% 44% 56%
6 9% 91% 41% 59%
7 10% 90% 38% 62%
8 10% 90% 35% 65%
9 11% 89% 33% 67%
10 11% 89% 30% 70%
11 12% 88% 29% 71%
12 12% 88% 27% 73%
13 12% 88% 25% 75%
14 13% 87% 24% 76%
15 13% 87% 23% 77%
20 14% 86% 19% 81%
27 15% 85% 15% 85%
30 15% 85% 14% 86%
35 16% 84% 12% 88%
40 16% 84% 11% 89%
Table 7. Farm 1 current energy production distribution without battery.
Graphical illustration of the results, particularly for the lower capacities is shown in Figure 6 to give more insightful understanding of the result obtained. The plausible reason for illustrating the graphical result of the capacity of 10 kWp 40 kWp as shown in Figure 6 and 7, is to show the behavior of higher capacity in response to the four analytical factors that is; the grid purchase, grid sales, self-use and consumption covered by PV, to show how self-use is lower than grid sales compared to the lower of 1 kWp to 3kWp which makes these not affordable due to more sales than self-use.
(a) (b)
(c) (d)
Figure 6. Farm 1 current sensitivity analysis result without battery. (a) Excessive production sold to the grid. (b) Production taken in for self-use. (c) Current electricity consumption purchased from the grid. (d) PV production in current electricity consumption.
Dimensioning System Size with Battery
The battery storage potential analysis is integrated into the calculation model to curtail part of the excess PV production for self-use while the remaining part is sold to the grid. However, it is worth mentioning that self-use is the main determinant for estimating the battery potential.
This analysis is applied for the various system sizes presented in Table 6 of subsection 3.1.1.
The output result of the analysis is shown in Table 8, and the graphical illustration of the capacities of 10 kWp to 40 kWp is shown in Figure 7. Table 8 presents the annual sensitivity analysis result and energy production distribution with the battery use. It is observed that the lower capacities ranging from 1 kWp to 8 kWp has a good battery potential that is, the energy
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that could be store in it, is still within the same range as the higher capacities of 9 kWp to 20 kWp. However, due to the cost of battery storage the system size of 1 kWp would be the viable system for this farm as there is no grid sale and all production output is fully utilized with battery use.
Table 8. Farm 1 current sensitivity analysis result with battery.
System sizes (kWp)
Grid sales (MWh/year)
Grid sales
Battery potential (MWh/year)
Battery potential
1 0.0 0% 0.19 21%
2 0.02 1% 0.66 36%
3 0.36 13% 0.89 32%
4 0.86 23% 1.02 28%
5 1.36 30% 1.19 26%
6 1.98 36% 1.30 23%
7 2.64 41% 1.39 21%
8 3.29 44% 1.52 21%
9 3.94 47% 1.67 20%
10 4.60 50% 1.83 20%
11 5.25 52% 2.00 19%
12 5.90 53% 2.19 20%
13 6.56 55% 2.38 20%
14 7.21 56% 2.57 20%
15 7.87 57% 2.77 20%
20 11.14 60% 3.85 21%
27 15.71 63% 5.46 22%
30 17.98 65% 5.87 21%
35 22.10 68% 6.24 19%
40 26.44 72% 6.40 17%
(a) (b)
Figure 7. Farm 1 current sensitivity analysis results with battery. (a) % Battery potential. (b) % Solar grid sales.
To estimate the battery size, 1 kWp which is observed to be the viable system size due to low grid sales without battery and zero grid sales with the use of battery for Farm 1 current consumption, and the exact system size of 27 kWp needed to meet the farm annual current electricity consumption is use to estimate the battery size of this farm on a daily basis and the results obtained is illustrated in Figure 8 (a and b). In Figure 8a the need of battery storage is not required for 264 days out of the 365 days of the year, but after this days subsequent need for battery begins to surface with the use of 1 kWp. The number of days in which battery storage is require is about 101 days in total and the battery size ranges from 0.5 kWh to 4.5 kWh. With battery storage the annual grid sales that occurs from 1 kWp system reduces from 193 kWh/year to 186 kWh/year. Although, in the real sense it is not realistic to induce battery storage due to its high cost since the difference is only 7 kWh/year. However, this solely depends on the recipients need and decision. Also, for 27 kWp there is no need of battery use for 268 days while the remaining days that postulates battery need requires a battery size that ranges from 5 kWh to 125 kWh. With battery use the annual grid sales incurred from 27 kWp reduces from 21177 kWh/year to 17133 kWh/year with battery use on a daily basis.
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20%
40%
60%
80%
10 15 20 25 30 35 40
System size(kWp)
% Grid sales
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5%
10%
15%
20%
25%
10 15 20 25 30 35 40
System size(kWp)
% Battery
(a)
(b)
Figure 8. Farm 1current battery sizing analysis (a) Battery size for 1 kWp. (b) Battery for 27 kWp.
After carrying out these dimensioning analyses there is need to know the impacts of these capacities on the current electricity consumption on a daily basis for two different months. This led to a further analysis, which was carried out for the months of July and September. These two months were chosen because they occur in two different seasons of the year. The former is a summer month when sunlight is available and the latter is an autumn month when sunlight availability is limited or not available. Also, this analysis will be carried out with system sizes of 1 kWp which has no grid sales and 2 kWp which has a grid sale of 1 % with battery potential according to Table 5 above. Furthermore, the result obtained was integrated to determine the impacts of these systems on the consumption on an average day hour of these months. This is to determine how much of the consumption is covered and available for grid sales on an hourly
basis. Figure 9 demonstrates the output results of these systems on the current electricity consumption.
(a) (b)
(c) (d)
Figure 9. Farm 1 current average hour analysis results. (a) Daily analysis result for July. (b) Daily analysis result for September. (c) Result of average day hour for July. (d) Result of average day hour for September.