Who’s next door?

Finding the right neighbours for every shared solar plant

solarneighbours · Norrsken Fixathon · Barcelona · October 2026

Shared solar plants sell what their neighbours don’t use for almost nothing

~3–6 c/kWh*

unused: sold or credited

8 c/kWh*

used by a neighbour

Every kWh a neighbour uses earns the plant 8 c instead of ~3–6 c.[1][2][3]

  1. Benjamín Silva, Zenit Solar, emails, 14 Oct 2026: participants pay the plant owner ~€0.08/kWh; unused energy is exported at wholesale price, “usually well below €0.08/kWh and at times close to zero”
  2. UNEF via pv magazine: solar captured price €29.68/MWh (H1 2026)
  3. Selectra 2026: retailer surplus compensation ~€0.04–0.06/kWh, selectra.es
  4. * Spanish prices: unused solar is either credited on the owner’s bill at ~4–6 c (simplified compensation, capped at the energy part of the bill) or sold at market for ~3 c (€29.68/MWh, H1 2026); 8 c is what participants pay the plant owner (Zenit Solar). France pays 1.1 c for surplus; Italy pays a premium on shared energy instead.

Sharing energy: one plant, many neighbours

  1. Every houreach neighbour gets a share of the plant’s output[1]
  2. Used: 8 c*paid to the plant, instead of 14–24 c to the grid[2][3]
  3. Not used: ~3–6 c*sold or credited to the grid, “at times close to zero”[2][4]
  1. MITECO, FAQ on self-consumption (RD 244/2019: shares sum to one for each hour)
  2. Benjamín Silva, Zenit Solar, emails, 14 Oct 2026
  3. Acciona Energía, 2.0TD prices 2026 incl. network tolls
  4. UNEF via pv magazine: solar captured price €29.68/MWh (H1 2026)
  5. * Spanish prices (see slide 2). Hourly shares follow Spanish rules (RD 244/2019).

Shared solar is booming

2 km5 km

6×

more neighbours per plant in Spain since March 2026[1]

~2.5%

of Barcelona’s rooftop solar potential is used today[5]

  • 22,000 → 45,000+

    shared supplies on Endesa’s grid in a year[2]

  • ~130% a year

    growth in shared operations in France[3]

  • 4,800+

    energy communities in Italy[4]

  1. Energías Renovables, Apr 2026 (RDL 7/2026)
  2. Energías Renovables, Jun 2026
  3. Enedis data via Les Énergies Renouvelables (+129% in 2024, +133% in 2025; 2,276 operations, Jun 2026)
  4. GSE data via edotto, Aug 2026
  5. IDRA, Institut de Recerca Urbana de Barcelona, “Qui té accés a l’energia solar a Barcelona”, Sep 2026: solar covers 1.5% of household electricity vs ~60% possible from rooftops, idrabcn.com

But which neighbour should consume your electricity?

Find the neighbours

Every building within 5 km could join. Today they’re found door to door.[1]

Find the right ones

Who uses power while the sun shines? It depends on the type of building.

Homes: mornings and evenings

Shops, clinics, offices: daytime

solar usedsolar sent to the griddemandSchematic

“What slows us down is finding the right consumers around each plant.” Zenit Solar[2]
  1. Oihan Goenaga, CEO, Zenit Solar, email, 9 Oct 2026: recruitment is “mostly door to door”
  2. Benjamín Silva, Business Development, Zenit Solar, email, 14 Oct 2026

Validated by an operator who fills these plants

What Zenit Solar told us

The pain point“Knowing which consumers to go after and in what order.”[1]
What they want from us“A ranked list… with a clear reason for each one.”[1]

Same job elsewhere

  • SpainElecsum, Som Comunitats, Cercle Solar[2][3]
  • FranceEnogrid · 2,276 operations[4][5]
  • ItalyGSE · 4,800+ communities[6]

One operator confirmed. Next: two or three more.

  1. Benjamín Silva, Business Development, Zenit Solar, email, 14 Oct 2026 (first reply)
  2. Elecsum Share; Som Comunitats
  3. Cercle Solar (Enerbite), Sep 2026, energias-renovables.com
  4. Enedis data via Les Énergies Renouvelables
  5. Enogrid press kit
  6. GSE data and “Vetrina” directory, via edotto, Aug 2026

Drop a pin. Get a call list.

solarneighbours prototype: a 155 kWp plant in Barcelona with its 5 km circle, and the three neighbours to call first with what they save, what the plant earns and CO₂ avoided123
  1. Drop the plantEvery building within 5 km is scored
  2. Rank by fitHow much of their use falls in sun hours
  3. Show the impactWhat they save, what the plant earns, CO₂ avoided

Our prototype, 155 kWp plant in Barcelona, top 3 neighbours selected · figures are model outputs on open data our model[1][2] · Open it

  1. Ranking criteria and request for “a clear reason for each one”: Benjamín Silva, Zenit Solar, emails, 14 Oct 2026
  2. PVGIS · Catastro · Red Eléctrica · OpenStreetMap

Two published levers to use more solar next door

Today

~45%

used as it’s produced when all the neighbours are homes[1]

Lever 1 · add daytime businesses

+37%

shared energy in an Italian energy community[2]

Lever 2 · shares that follow the hour

34%

of the solar that went to the grid is used locally instead, in a Catalan energy community[3]

Each neighbour’s share of the plant changes every hour to follow who is using power, instead of a fixed share all year.[4]

Our call list does the first; hourly shares do the second.

  1. Gallego-Castillo, Heleno & Victoria (2021), Energy Policy 150, Table 5, arxiv.org/abs/2006.06459
  2. Veronese, Lauton, Barchi, Prada & Trovato (2024), Eurac Research / University of Trento, Energies 17(16) 3984
  3. Madrigal Ballestero et al. (2026), Universitat Autònoma de Barcelona, Applied Energy 409, 127469
  4. Spain allows hourly sharing coefficients: MITECO, Orden TED/1247/2021

€10–25m a year left on the table

€5–11m

Spain[1]

€3–6m

France[2]

€2–8m

Italy[3]

+€5–12m with every year of new plants, before Germany and the rest of the EU.[4][5]

Value for plant owners and neighbours, not our revenue · conservative: +6 to +13 points of local use, from the studies’ own self-consumption gains our model · Spain: Endesa’s grid only assumption

  1. Spain: 45,000 supplies (Energías Renovables, Jun 2026) ÷ 12.3 participants per plant (UFD) × 100 kWp (assumption) = 366 MW
  2. France: 380 MW (Enedis via Les Énergies Renouvelables); local ~12 c€ (Énergie Partagée) vs 1.1 c€ feed-in (photovoltaique.info)
  3. Italy: ~400 MW (GSE via edotto); incentive €60–120/MWh (MASE)
  4. Germany: energy sharing since 1 June 2026 (§42c EnWG)
  5. EU: Directive 2024/1711 Art. 15a, deadline 17 Jul 2026 (ieu-monitoring)

The panels are cheap. The rules are ready. We tell operators who to call first, and why.

Next: test the call list on a live plant.

Find your solar neighbours

Appendix

Shared solar plants use only ~45% of their power locally, leaving €10–25m a year on the table

~45%used as it’s produced

~55%sent to the grid

A shared plant whose neighbours are all homes[1]

€10–25m

a year left on the table in Spain, France and Italy[2] our model

  1. Gallego-Castillo, Heleno & Victoria (2021), Energy Policy 150, Table 5: shared plant where all participants are homes, Catalonia, arxiv.org/abs/2006.06459
  2. Conservative estimate on today’s shared capacity (~1.1 GW): see slide 9