Europe — Germany
HOMER software for energy projects in Germany
Germany's Energiewende creates a distinctive modelling environment: high renewable penetration, §28a Eigenverbrauch regulations shaping C&I economics, Mieterstrom community models, and Innovationsausschreibungen auctions rewarding combined storage-and-generation bids.
Germany's modelling context
The Erneuerbare-Energien-Gesetz 2023 (EEG 2023) governs feed-in tariffs, direct marketing obligations, and the auction framework for renewable capacity. For systems above 100 kW, direct marketing via the spot market is mandatory — HOMER Grid and HOMER Front model dispatch decisions under spot price exposure alongside fixed offtake assumptions.
§28a of the EnWG (Energiewirtschaftsgesetz) governs Gemeinschaftliche Gebäudeversorgung — the collective supply of electricity within or across building boundaries. Combined with §42b (Mieterstrom), these provisions define the legal framework within which shared-generation and community energy models operate. HOMER Grid's multi-load, multi-tariff input structure is suited to modelling these collective consumption arrangements.
The Bundesnetzagentur (BNetzA) regulates network access and sets the framework for balancing group management. Germany's four transmission system operators — 50Hertz, Amprion, TenneT, and TransnetBW — each operate distinct control areas with slightly different ancillary service procurement approaches.
Commercial and industrial — Eigenverbrauch and Mieterstrom
Germany's self-consumption framework is one of the most developed in Europe. Industrial consumers with on-site generation avoid grid fees on the proportion of electricity consumed on site — the Eigenverbrauch reduction. HOMER Grid quantifies this saving alongside the residual grid costs, demand charge exposure, and PV degradation over a 20-year project life.
Mieterstrom (tenant electricity) allows building owners to supply rooftop solar to residential tenants at below-retail rates. The Mieterstrom supplement (up to €3.8/kWh above the feed-in tariff as of 2024) makes these projects viable. HOMER Grid models the load profiles of individual tenants, the shared generation asset, and battery storage under the combined Mieterstrom-plus-Eigenverbrauch economics.
Solarpaket I (2024) significantly expanded the Mieterstrom framework and introduced Energy Sharing provisions that permit shared consumption across a wider geographic radius than the previous building-boundary rule. HOMER Grid's flexibility in defining consumption groups makes it suitable for modelling these expanded arrangements.
Grid-scale storage — Innovationsausschreibungen
Germany's innovation tenders (Innovationsausschreibungen) reserve a portion of annual auction capacity for combined renewable-plus-storage projects. Unlike standard EEG auctions, innovation tenders reward projects that demonstrate dispatchability alongside generation. HOMER Front models the combined dispatch of solar or wind alongside battery storage under the fixed market premium structure, with dispatch optimised against intraday and day-ahead spot prices (EPEX SPOT).
Frequency containment reserve (PRL — Primärregelleistung) and automatic frequency restoration reserve (aFRR — sekundäre Regelreserve) are procured by the four TSOs on a rolling weekly and daily basis respectively. HOMER Front's ancillary service stacking framework models battery assets simultaneously participating in PRL/aFRR alongside energy arbitrage.
German island systems
Germany's North Sea islands — Helgoland, Borkum, Norderney, Sylt, and the East Frisian chain — are connected to the mainland grid by submarine cables but face constraints on cable capacity and aging diesel backup. Helgoland's 100% renewable ambition and Borkum's hydrogen pilot are among the most cited island energy transition projects in Germany. HOMER Pro models these systems with explicit representation of submarine interconnector limits, seasonal tourism load variation, and the role of hydrogen as seasonal storage.
German regulatory context
Bundesnetzagentur (BNetzA)
Federal network regulator for electricity, gas, telecoms, post, and railway. Sets network access charges and auction frameworks.
EEG 2023
Erneuerbare-Energien-Gesetz. Governs feed-in premium levels, direct marketing obligations (above 100 kW), and auction volumes by technology.
TSOs: 50Hertz, Amprion, TenneT, TransnetBW
Four control areas covering eastern, western, northwest/central, and southwest Germany. Ancillary service procurement differs slightly across control areas.
Solarpaket I (2024)
Expanded Mieterstrom geographic scope, simplified grid connection for small systems, and introduced Energy Sharing provisions.