Hello,
Has anyone conducted (or had conducted) cost-effectiveness calculations for a 10 kWp system compared to a smaller one (e.g., a 5 kWp system) and compared the results? What were the findings?
Here is my calculation:
A 10 kWp system does not cost twice as much as a 5 kWp system, for example €13,300 instead of €7,600 (1340 €/kWp instead of 1530 €/kWp)*. This could be an argument that a larger system is more cost-effective.
On the other hand, with a 10 kWp system, I can only use about 20% of the generated electricity myself, while with a 5 kWp system it is about 30%.* (Self-consumption saves 23.99 cents/kWh, feeding into the grid only brings in 12.2 cents/kWh). This would be an argument that a smaller system is more cost-effective.
The question is which effect predominates.
I am comparing two 5 kWp systems with one 10 kWp system. In both cases, I assume 7000 kWh per year.
Two 5 kWp systems cost €1900 more.
Annually, they generate:
70% * 7000 kWh * 12.12 cents/kWh + 30% * 7000 kWh * 23.99 cents/kWh
=
€597.80 + €503.79
=
€1101.59
The 10 kWp system generates annually:
80% * 7000 kWh * 12.12 cents/kWh + 20% * 7000 kWh * 23.99 cents/kWh
=
€689.74 + €335.86
= €1025.60
So the difference in return is €76. This means the additional cost of the two 5 kWp systems is recovered in 25 years.
This leads me to the conclusion that the cost-effectiveness of both options is quite similar, and it is more a matter of personal preference how much money one wants to invest. Generally, a larger system probably pays off somewhat earlier. If a battery storage system is to be added in x years, the larger 10 kWp option also seems more reasonable to me.
Have you done similar calculations and come to similar results?
Has anyone conducted (or had conducted) cost-effectiveness calculations for a 10 kWp system compared to a smaller one (e.g., a 5 kWp system) and compared the results? What were the findings?
Here is my calculation:
A 10 kWp system does not cost twice as much as a 5 kWp system, for example €13,300 instead of €7,600 (1340 €/kWp instead of 1530 €/kWp)*. This could be an argument that a larger system is more cost-effective.
On the other hand, with a 10 kWp system, I can only use about 20% of the generated electricity myself, while with a 5 kWp system it is about 30%.* (Self-consumption saves 23.99 cents/kWh, feeding into the grid only brings in 12.2 cents/kWh). This would be an argument that a smaller system is more cost-effective.
The question is which effect predominates.
I am comparing two 5 kWp systems with one 10 kWp system. In both cases, I assume 7000 kWh per year.
Two 5 kWp systems cost €1900 more.
Annually, they generate:
70% * 7000 kWh * 12.12 cents/kWh + 30% * 7000 kWh * 23.99 cents/kWh
=
€597.80 + €503.79
=
€1101.59
The 10 kWp system generates annually:
80% * 7000 kWh * 12.12 cents/kWh + 20% * 7000 kWh * 23.99 cents/kWh
=
€689.74 + €335.86
= €1025.60
So the difference in return is €76. This means the additional cost of the two 5 kWp systems is recovered in 25 years.
This leads me to the conclusion that the cost-effectiveness of both options is quite similar, and it is more a matter of personal preference how much money one wants to invest. Generally, a larger system probably pays off somewhat earlier. If a battery storage system is to be added in x years, the larger 10 kWp option also seems more reasonable to me.
Have you done similar calculations and come to similar results?
Both systems are definitely overpriced at the stated purchase prices [emoji4]
Don’t get caught up in these details. Once you factor in taxes, it will drive you crazy.
(By the way, self-consumption doesn’t save you 23.99 cents. It costs 4 cents VAT for the first 5 years, and you forgo the feed-in tariff if you use the kWh yourself.)
10 kWp, if it fits and the money is available.
Don’t get caught up in these details. Once you factor in taxes, it will drive you crazy.
(By the way, self-consumption doesn’t save you 23.99 cents. It costs 4 cents VAT for the first 5 years, and you forgo the feed-in tariff if you use the kWh yourself.)
10 kWp, if it fits and the money is available.
T
toxicmolotof19 Feb 2018 15:07That's right, you seem to be ignoring taxes and depreciation.
In total, I have 5.4 kWp (no more would fit), but I would say that a larger system wouldn’t have caused a significant additional financial burden.
If I had had more space, I would have chosen a bigger one.
In total, I have 5.4 kWp (no more would fit), but I would say that a larger system wouldn’t have caused a significant additional financial burden.
If I had had more space, I would have chosen a bigger one.
Here is an updated calculation.
The average electricity price over the next 20 years was assumed to be 0.36 cents/kWh, corresponding to an increase of 3% per year. The return rate is considered as the key figure:
5 kWp system
============
Cost: 7,600 €
Annual yield:
70% * 3,500 kWh * 12.2 cents/kWh + 30% * 3,500 kWh * 36 cents/kWh
=
€298.90 + €378
= €676.80
Return = €676.80 / €7,600 = 8.9%
10 kWp system
=============
Cost: 13,300 €
Annual yield:
80% * 7,000 kWh * 12.2 cents/kWh + 20% * 7,000 kWh * 36 cents/kWh
=
€683.20 + €504.00
= €1,187.20
Return = €1,187.20 / €13,300 = 8.9%
This leads me to the conclusion that the profitability of both options is quite similar, and it is more a matter of preference how much money one wants to invest. If you consider adding a battery storage system in x years, the larger 10 kWp option seems more reasonable.
Have you performed similar calculations and reached comparable results?
The average electricity price over the next 20 years was assumed to be 0.36 cents/kWh, corresponding to an increase of 3% per year. The return rate is considered as the key figure:
5 kWp system
============
Cost: 7,600 €
Annual yield:
70% * 3,500 kWh * 12.2 cents/kWh + 30% * 3,500 kWh * 36 cents/kWh
=
€298.90 + €378
= €676.80
Return = €676.80 / €7,600 = 8.9%
10 kWp system
=============
Cost: 13,300 €
Annual yield:
80% * 7,000 kWh * 12.2 cents/kWh + 20% * 7,000 kWh * 36 cents/kWh
=
€683.20 + €504.00
= €1,187.20
Return = €1,187.20 / €13,300 = 8.9%
This leads me to the conclusion that the profitability of both options is quite similar, and it is more a matter of preference how much money one wants to invest. If you consider adding a battery storage system in x years, the larger 10 kWp option seems more reasonable.
Have you performed similar calculations and reached comparable results?
What I don’t understand is why you assume 30% self-consumption for the smaller system and 20% for the larger one.
No matter the size of the system, the proportion of self-consumption should be the same, right? Unless the system is so undersized that you inherently end up with a higher percentage.
As many have already mentioned here, the larger the system (up to 10 kWp), the faster it pays off. Especially if you can get costs down to €1100 per kWp or less. You probably won’t achieve this with a "small" 5.7 kWp system.
No matter the size of the system, the proportion of self-consumption should be the same, right? Unless the system is so undersized that you inherently end up with a higher percentage.
As many have already mentioned here, the larger the system (up to 10 kWp), the faster it pays off. Especially if you can get costs down to €1100 per kWp or less. You probably won’t achieve this with a "small" 5.7 kWp system.
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