# The benefits of exploring a large scenario space for future energy systems

## TL;DR

The paper shows how analyzing over 11,000 energy scenarios improves understanding of future energy systems by considering many uncertainties and method choices.

## Contribution

A novel approach for multi-criterial evaluation of thousands of energy scenarios to improve robust policy advice.

## Key findings

- Over 11,000 scenarios were evaluated for affordability, supply security, and sustainability in the German power system.
- Considering multiple weather years had the most significant impact on scenario results.
- More than 100 scenarios are needed for robust energy system analysis.

## Abstract

Energy scenario analysis with optimization approaches rarely goes beyond a small number of scenarios. Disadvantages include limited coverage of uncertainties and assumptions, and a limited ability to provide robust policy advice. We present an approach that enables the multi-criterial evaluation of more than 11,000 scenarios and demonstrate it for the German power system. We vary both a wide range of input parameters and method choices. The resulting scenarios are assessed through a number of indicators on affordability, supply-security and sustainability. The most significant impacts on the results stem from considering multiple weather years. Furthermore, we estimate the number of runs required for robust energy systems analyses – well over 100 scenarios are needed. Nevertheless, fewer scenarios may be sufficient for limited scopes. Our analysis also underlines a challenge for future energy system design: cost-efficient decarbonization while conserving natural resources.

Seemingly unproblematic method choices can substantially affect the results of energy systems analyses. Frey et al. show robust results for affordability, supply security, and sustainability from 11,000 scenarios while varying these method choices.