Simple net metering vs surplus sale: which fits you (Spain regulation)
Two models to sell solar surplus to the grid in Spain (RD 244/2019). Bill credit or direct sale. Which maximizes your savings (US has different terms).
Spain has two legal models to manage solar surplus: simple compensation (most common) and direct sale. Choice impacts monthly bill up to 30%. (Note: USA uses 'net metering' which works differently state by state.)
Simple compensation (majority)
Your utility credits directly on bill the surplus value. Typical price: €0.05-0.08/kWh exported. Cap: credit can't exceed period bill (no carryover credit). No income tax required.
Direct market sale (self-consumption with sale)
Register as producer. Sell surplus to wholesale market at hourly price (€0-30/MWh = 0.03/kWh). More paperwork (monthly OMIE invoice, quarterly VAT, annual income tax).
Typical numerical comparison
Home with 4000 kWh surplus/year: Simple comp (€0.06) = €240/year credit. Direct sale (avg market €0.05) = €200 gross - €50 admin = €150 net. Compensation wins residential.
When direct sale fits
1) Very high production vs consumption (>60% surplus). 2) Business with recoverable VAT. 3) Want to maximize peak-hour income (with dynamic tariffs). 4) System >25 kWp where 'cap' is reached.
When simple compensation fits
Standard residential (95% of cases). Surplus <60% of production. No paperwork interest. Best effort/savings ratio. Default modality offered by all utilities.
How to switch modality
Request to your utility with CAU (Self-Consumption Code). Effective in 1-2 billing cycles. No cost. Can switch any time but keep 12 months to evaluate.
Compare with what to do with solar surplus.
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