In depth · Finance

Near-free at the margin.

The solar-installation subsidy stack defrays the cost of the rainwater layer to the point where the water infrastructure approaches free.

The thesis

The economic insight at the centre of the memorandum

Solar photovoltaic panels installed for energy generation are also the rainwater catchment surface. Tilted, glass-fronted, hydrophobic, self-cleaning. The Spanish IDAE NextGen 30% subsidy and the EU NextGen Climate Fund already absorb a meaningful share of the solar layer CAPEX. The water layer — gutter geometry, first-flush diverter, cistern, and the EU Drinking Water Directive 2020/2184 compliant filtration train — bolts on at incremental cost.

The economic consequence is unusual and material: the solar-installation subsidy stack defrays the cost of the rainwater-catchment layer to the point where the water infrastructure approaches free at the margin. That sentence is the canonical thesis of the memorandum. It is not a marketing claim — it is an accounting outcome of stacking a state-funded solar incentive against an incremental engineering layer that shares the same surface, the same install crew, and the same permitting envelope.

Anchor unit economics

The typical estate, in four numbers

400 m²
Typical roof
~€85 K
Combined system
€6–9 K
Annual saving
3–5 yr
Unfinanced payback

These four numbers describe a typical Ibiza luxury estate at roughly 400 m² of contiguous roof — the realistic median of the addressable book. They scale at a 0.5× ratio from the canonical reference case at 800 m² (Sabina / Pawson-villa scale) where the combined system cost is €167K, the annual saving is €12–18K, and payback lands inside the same 3–5 year window. Larger roofs do not shorten the payback; they widen the absolute saving and the absolute subsidy capture. The geometry of the curve is consistent across the portfolio.

Per-project revenue

What Las Lluvias earns on a single installation

Revenue lines are always itemised separately, never bundled. This is institutional discipline: the family-office reader needs to see which lines are engineering, which are regulatory, which are subsidy-capture, and which are ongoing. The bundle obscures the unit economics. The itemisation is the unit economics.

  • Design and engineering consultancy — €5K–12K per project
  • Registration and compliance — €3K–6K per project
  • Subsidy application (IDAE NextGen, regional and municipal layers) — €3K–8K per project
  • Certification consulting (EU DWD, Passivhaus, BREEAM) — €5K–15K per project

On top of these consultancy lines sit the hardware install margin and the optional ongoing certification subscription — the latter is the recurring layer that converts a one-off install into a relationship. A complete villa-scale installation therefore lands in a €32K–70K envelope per project. Hotel-scale installations sit in a different bracket entirely — €60K–170K per installation — because of larger roof areas, more demanding storage geometry, commercial-grade certification, and more complex regulatory choreography.

Subsidy stack

The layers, named honestly

The subsidy stack is real, layered, and currently favourable. It is also time-bound. Each layer must be named with its scheme of origin and its current state, never aggregated into a single optimistic percentage.

  • Spanish IDAE NextGen — residential solar self-consumption (RD 244/2019 framework, NextGen funding envelope). Currently absorbing ~20–30% of solar CAPEX on qualifying residential installations. Wind-down risk: 2027–2028 as the NextGen allocation depletes; future framework not yet legislated.
  • EU NextGen Climate Fund — variable per project, eligibility dependent on building-performance certification and regional disbursement schedule
  • Regional Balearic incentives — Decreto-Ley 1/2020 drought-emergency framework and successor instruments, typically targeting rainwater capture and water-efficiency upgrades
  • Municipal deductions — IBI and ICIO reductions vary by municipio; Santa Eulàlia, Sant Joan and Sant Josep each operate distinct schedules

Stacked, the total subsidy bandwidth currently sits at ~20–35% of solar CAPEX defrayed. The honest framing: the upper end of that range is what makes the water-layer-near-free thesis work today. If the IDAE NextGen layer winds down in 2027–2028 without a successor, the arithmetic tightens. The Year 1 Ibiza-only pilot programme is sized to land inside the current window.

Financing layer · concept

Savings-based financing — the instrument being developed

One of the revenue layers being explored is a savings-based financing instrument. The design intent is that the household pays for the system from the certified saving it produces — the water and electricity bill that no longer arrives — rather than from new household cash. The system would be capitalised against the verified annual saving, and the household would route what it would otherwise pay the utility into the financing layer until the instrument retires.

A note of honesty: this instrument is at concept stage. The structure has been designed but has not yet been validated with banking counterparties. No term sheet exists. No credit committee has reviewed it. Conversations with banking partners are intended but not yet active. It is described here as the design of the financing layer, not as a product available today.

If the instrument matures, it converts the unit-economics conversation from a CAPEX question into a cash-flow question — which is the question the luxury homeowner is more comfortable answering. Until then, every installation in the Year 1 cohort is sized to clear on the unfinanced 3–5 year payback alone.

Capital structure

The pre-seed round

The current raise is a €400–600K equity round, structured as a SAFE note with a €1.5M valuation cap and a 20% discount. Use of proceeds is concentrated on Year 1 Ibiza-only operations — three installations as the proof cohort, the IP filing programme, EU DWD certification of the treatment chain, and the first hires on the technical side.

Active investor conversations are underway across strategic operators and angel checks, including counterparties with directly adjacent expertise in luxury Ibiza construction, climate-tech infrastructure, and venture engineering. Specific investors are not named on a public surface.

Read the full memorandum