Can solar panels cover the fixed power fee?

On your electricity bill, there’s a fixed charge you pay every month—whether you use electricity or not: the power capacity charge. In most households, this cost is around €30 per month.

But what if I told you that you could cover that cost with solar energy surpluses? Let’s break it down with real numbers.

How much surplus do you need to cover €30 per month? ⚡

If you sell your solar surplus at an average price of €0.08 per kWh, then to cover those €30 per month:

€30 / €0.08 = 375 kWh per month

That means you need to generate at least 375 kWh of solar surplus each month. Projecting that over a year:

375 kWh × 12 months = 4,500 kWh/year

This is the minimum amount of unused energy—meaning energy that exceeds your household consumption and is fed into the grid—to generate income that offsets the power capacity charge.

How many solar panels do you need to achieve this?

Here’s where a bit of technical analysis comes in. If you have a contracted power capacity of 3.2 kW, you’ll need to generate a specific surplus of 720 kWh per year for each kW of contracted power.

This is calculated based on:

Average energy price:
Peak: €0.12 + Off-peak: €0.04 = €0.16/day

Monthly power capacity charge per kW:
€0.16 × 30 days = €4.80/kW/month

Annual charge:
€4.80 × 12 months = €57.60/kW/year

Energy required to offset this cost with surplus:
€57.60 / €0.08/kWh = 720 kWh per kW per year

So, to cover 3.2 kW of contracted power:

3.2 × 720 kWh = 2,304 kWh of annual surplus

How many panels are needed to generate this surplus?

In sunny areas like southern Spain, a 580 Wp panel generates between 750 and 1,000 kWh per year.

Therefore, to achieve around 2,300 kWh of annual surplus, you need about 3 additional solar panels, on top of the ones already covering your own consumption.

If each panel produces about 850 kWh/year (a realistic average), then:

2,300 kWh / 850 kWh = 2.7 panels, which rounds up to 3 panels of 580 Wp

Hence, for different contracted capacities:

  • 5.5 kW = approximately 5 extra panels

  • 9.9 kW = approximately 8 extra panels

Conclusion

If your solar installation is properly sized and produces enough surplus energy, you can passively cover the power capacity charge. This turns a fixed cost into virtually zero expense, increasing the return on your investment and boosting your energy independence.

Want to know if your roof has the potential to achieve this? Contact us and we’ll carry out a personalized assessment for you!

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