Why Self-Consumption, Not Export Income, Should Drive Your Solar System Size
If you are planning to install solar panels in Ireland, you may have heard about the Clean Export Guarantee (CEG), the payment you receive for surplus electricity exported back to the grid. At the time of writing September 2026, CEG rates range from €0.18 to €0.20 per kWh for most suppliers.
But here is the reality: export income should be a bonus, not the foundation of your solar economics. Europe is moving away from generous export schemes, Ireland's own CEG rates have already dropped, and the homes getting the best returns are the ones designed for self-consumption, not export.
This guide explains why sizing your solar system to match your home's electricity consumption, rather than oversizing it to chase export payments, is the smartest long-term strategy.
The European Trend: Export Payments Are Becoming Less Generous
Ireland is not alone in rethinking export payments. Across Europe, governments that once incentivised oversized solar systems are now scaling back:
Netherlands: Net Metering Ending in 2027
The Netherlands is scrapping its net metering scheme (salderingsregeling) in 2027. For years, Dutch homeowners could offset every kWh of export against future consumption at the full retail rate. From 2027, they will receive a lower feed-in tariff instead, dramatically reducing the financial case for oversized systems.
According to PV Magazine, the Dutch parliament approved the phase-out in November 2024, giving the solar sector clarity but fundamentally changing the economics for homeowners.
Ireland: CEG Rates Already Dropped
Ireland's CEG rates have been falling since 2023. Pinergy, which offered €0.25 per kWh in 2025, dropped to €0.185 per kWh (ex-VAT) from 1 August 2026. Other suppliers now range from €0.185 to €0.20 per kWh, down from peaks of €0.24 per kWh in 2023.
While Ireland's system is more stable than the Netherlands' complete phase-out, the direction is clear: export payments are a variable, not a guarantee.
Why Self-Consumption Beats Export Income
Here is the fundamental economics: using your solar electricity directly is worth more than exporting it.
At the time of writing September 2026:
- Import electricity cost: €0.42 to €0.45 per kWh (what you pay to buy from the grid)
- Export payment (CEG): €0.185 to €0.20 per kWh (what you get paid for selling back)
Every kWh you use directly saves you €0.42 to €0.45. Every kWh you export earns you €0.185 to €0.20.
That is a 2:1 value difference. Self-consumption is worth more than double what export is worth.
| Scenario | Value per kWh | Annual Value (1,000 kWh) |
|---|---|---|
| Self-consumption (import avoided) | €0.42–€0.45 | €420–€450 |
| Export to grid (CEG payment) | €0.185–€0.20 | €185–€200 |
| Difference | €0.22–€0.25 | €220–€250 |
*Figures correct as of September 2026.
How to Maximise Self-Consumption
1. Size Your System to Your Annual Consumption
The golden rule: your solar system's annual generation should roughly match your annual electricity consumption.
Use this simple formula:
Annual kWh usage ÷ 1,000 = Ideal kWp
For example:
- 4,200 kWh annual usage → 4 to 5 kWp system (8 to 10 panels)
- 6,000 kWh annual usage → 6 to 7 kWp system (12 to 14 panels)
This ensures you are generating enough solar to meet your needs without oversizing to chase volatile export income.
Read our guide: How Many Solar Panels Do You Really Need in Ireland?
2. Add Battery Storage to Boost Self-Consumption
Without a battery, typical Irish homes use 30 to 40 per cent of their solar generation directly. The rest is exported because it is generated during the day when you are at work or school.
With a battery, you can store that daytime surplus and use it in the evening, increasing self-consumption to 70 to 80 per cent.
Battery storage costs (September 2026):
| Battery Size | Cost (Installed) | Best For |
|---|---|---|
| 4–5 kWh | €2,500–€4,000 | Small homes, low evening usage |
| 7–8 kWh | €4,500–€6,000 | Average 3-bed homes |
| 10–13 kWh | €6,000–€8,000 | Large homes, EV charging, heat pumps |
*Figures correct as of September 2026.
A properly sized battery can save you €400 to €700 per year by reducing your evening grid imports. Over a 10-year lifespan, that is €4,000 to €7,000 in savings, covering the battery's cost.
Read our guide: How Much Battery Storage Do You Need in Ireland?
3. Shift Usage to Daytime When Possible
Even without a battery, you can boost self-consumption by:
- Running dishwashers and washing machines during the day
- Charging EVs during solar generation hours
- Using immersion heaters with a solar diverter (like the Eddi) to heat water with surplus solar
Small changes in behaviour can increase self-consumption from 30 per cent to 50 per cent without any extra equipment.
The Risks of Oversizing for Export Income
Some installers may recommend oversized systems (10 to 12 kWp for a 4,000 kWh household) to "maximise export income." Here is why that is risky:
1. CEG Rates Are Variable and Falling
CEG rates are not fixed. They have already dropped from €0.24 to €0.185 per kWh in the past three years. Suppliers can change rates at any time, and there is no government guarantee they will stay high.
If you size your system based on today's CEG rate and it drops further, your payback period stretches significantly.
2. Export Income Is Taxed Above €400
The first €400 of CEG income per year is tax-free under the Finance Act 2025 (extended to end of 2028). Above that threshold, export income is subject to income tax, USC and PRSI.
If you export 2,500 kWh at €0.20 per kWh, you earn €500, but only €400 is tax-free. The remaining €100 is taxable, reducing your effective return.
An oversized system designed to export 4,000 kWh per year would earn €800 at €0.20 per kWh, but €400 of that is taxable, significantly eroding the financial case.
3. Longer Payback Periods
A properly sized 5 kWp system designed for self-consumption typically pays back in 5 to 7 years. An oversized 10 kWp system designed for export can take 8 to 12 years to pay back, because:
- The extra panels cost €3,000 to €4,000 more
- Export income is worth half what self-consumption is worth
- CEG rates may fall further over the system's 25-year life
Real-World Example: Properly Sized vs Oversized
Let us compare two homes with 4,200 kWh annual consumption:
| Scenario | System Size | Cost After Grant | Annual Savings | Payback |
|---|---|---|---|---|
| Properly Sized (5 kWp, 70% self-consumption with battery) | 5 kWp + 5 kWh battery | €9,000–€10,000 | €1,200–€1,400 | 6–7 years |
| Oversized for Export (10 kWp, 40% self-consumption, no battery) | 10 kWp | €11,000–€13,000 | €1,000–€1,200 | 9–11 years |
*Figures correct as of September 2026. Assumes €0.43/kWh import rate, €0.19/kWh CEG rate.
The properly sized system with battery delivers:
- Higher annual savings (more self-consumption)
- Faster payback (lower upfront cost)
- Future-proofed economics (not reliant on CEG rates)
Future-Proofing: EVs and Heat Pumps
If you plan to add an EV or heat pump in the next 5 to 10 years, your electricity consumption will increase significantly:
- EV charging: +2,000 to 3,500 kWh per year
- Heat pump: +3,000 to 5,000 kWh per year
A system sized to your current consumption may become undersized, but oversizing now to chase export income is still the wrong approach. Instead:
- Size your system to your current consumption
- Add battery storage to maximise self-consumption
- Upgrade your system when you add the EV or heat pump
This avoids locking yourself into an oversized system based on today's uncertain CEG rates.
Read our guide: Should You Oversize Your Solar System? Pros and Cons
What About Existing Solar Owners?
If you already have solar panels and are worried about CEG rates dropping, the best strategy is to increase self-consumption:
- Add battery storage to capture daytime surplus and use it in the evening
- Shift usage to daytime where possible (dishwashers, washing machines, EV charging)
- Install a solar diverter (like Eddi) to use surplus solar for hot water
These steps reduce your reliance on CEG payments and lock in the higher value of self-consumption.
Frequently Asked Questions
Will the Clean Export Guarantee be phased out in Ireland?
There is no official announcement that the CEG will be phased out, but rates have already dropped from €0.24 to €0.185 per kWh (2023 to 2026). Europe is moving away from generous export schemes, so it is prudent to design your system for self-consumption resilience rather than relying on export income.
How much can I earn from exporting solar electricity in Ireland?
At the time of writing September 2026, CEG rates range from €0.185 to €0.20 per kWh. A typical home exporting 2,000 kWh per year would earn €370 to €400. However, self-consumption is worth more than double (€0.42 to €0.45 per kWh), so prioritise using electricity directly over exporting it.
Should I oversize my solar system to maximise export income?
No. Oversizing for export income is risky because CEG rates are variable, export income above €400 per year is taxable, and self-consumption is worth more than double what export is worth. Size your system to match your annual electricity consumption and add battery storage to boost self-consumption to 70 to 80 per cent.
Is battery storage worth it if CEG rates are good?
Yes. Even with good CEG rates, battery storage increases self-consumption from 30 to 40 per cent (solar-only) to 70 to 80 per cent (solar plus battery). Because self-consumption is worth €0.42 to €0.45 per kWh (versus €0.185 to €0.20 for export), a battery typically saves €400 to €700 per year and pays back in 6 to 10 years.
Final Thoughts
Europe is moving away from generous solar export schemes. The Netherlands is ending net metering in 2027, and Ireland's CEG rates have already dropped from €0.24 to €0.185 per kWh in the past three years. Export payments are a bonus, not a guarantee.
The homes getting the best returns from solar in 2026 are the ones designed for self-consumption, not export. By sizing your system to match your annual electricity consumption, adding battery storage to capture daytime surplus, and shifting usage to solar hours, you protect your savings against future CEG rate changes.
Self-consumption is worth more than double what export is worth. Design your system accordingly.
Ready to Get a Properly Sized Solar System?
WattCharger designs every solar system to match your home's electricity consumption, not to chase volatile export income. We include a full usage analysis, battery storage sizing and self-consumption modelling in every free consultation. Get your free quote today.
Blog Author: Rowan Egan