Stromeus · Tarifrechner

A real-time tariff comparison and calculation engine for German electricity and gas customers, allowing users to discover available plans instantly and view detailed pricing information.

What was built

The core problem: Stromeus customers need to compare hundreds of available tariffs based on their specific consumption profile and location. Building a custom search engine is complex — tariff availability varies by region, pricing is dynamic, and calculation rules are non-standard.

The solution: A web-based tariff calculator backed by enet's APIs (Europe's largest energy data platform) and Google Sheets for calculation logic and data management.

Database & Data Modeling: Structured data model for tariffs, providers, pricing rules, and customer consumption profiles. Google Sheets stores tariff options, provision rates, and calculation parameters. Regular imports from enet APIs update available plans. Custom fields track plan features (spot pricing, bundles, add-ons).

Real-time Tariff Lookup: When a user enters their postal code, consumption (kWh), and service type (SLP = small customer, RLM = large customer), the app queries enet APIs for all available plans in that region. Filters by gas vs. electricity, tariff type (standard, spot, bundle), and provider.

Calculation Engine: Complex pricing logic implemented in Google Sheets and Apps Script. Calculates:

• Total annual cost based on base rate, usage rate (ct/kWh), and consumption
• Provision (Maklergebühr) based on sliding scale — larger deals get better rates
• Filters for minimum/maximum consumption thresholds
• Support for decimal inputs (unusual for historical reasons)
• Multiple tariff scenarios in one calculation

UI/UX Features: Web-based interface with date picker (dd-mm-yyyy format), dropdown filters, search by city (with address autocomplete fallback), dynamic calculation results table. Summary row showing lowest-cost option. Deduplication of results to prevent duplicates in the output.

Admin & Management: Role-based access (different teams can modify tariff lists). Backoffice tools for admins to add/update tariffs, adjust provision rates, and manage provider data. Scenario-based testing to validate changes before going live.

Monitoring & Optimization: Weekly reviews of calculation results, error logging for invalid inputs or API failures, performance monitoring for query response times.