SPIDER

The European electricity system and grid model SPIDER (Spatial Planning and Investments of Distributed Energy Resources) optimizes investment and dispatch decisions, taking grid restrictions into account by means of Flow-Based Market Coupling (FBMC). The model analyzes price formation, grid utilization, redispatch needs, as well as the effects of flexible loads. SPIDER assesses political frameworks such as bidding zone splits or grid expansion and quantifies their influence on the site selection of plants as well as future levelized cost of electricity.

SPIDER for Consulting and Research

The model makes visible where bottlenecks arise in the grid and what their remediation costs are, and thus provides a central basis for decisions on site selection, investments, and regulation. SPIDER represents the existing grid and the planned expansion. Depending on the research question, different bidding zone configurations can be simulated and further European countries can be added.

SPIDER in Practice:

• Site and investment decisions: identify cost-optimal sites for generation plants as well as flexible loads (e.g. electrolyzers), taking local grid bottlenecks into account
• Regulatory impact assessment: analyze the effects of bidding zone splits on zonal electricity prices, plant dispatch, and the resulting redispatch needs
• Quantification of redispatch needs: simulate the development of redispatch volumes and costs under different scenarios at high resolution
• Assessment of flexibility benefits: examine the system-friendly deployment of flexibility options (e.g. electrolyzers, heat pumps) and their effect on grid bottlenecks, local marginal costs, and system costs
• Assessment of grid expansion projects: analyze grid expansion projects (intra-German and cross-border) and their effect on levelized cost of electricity and system costs

SPIDER in Detail

Compared to an electricity market model without grid restrictions (a so-called copper plate), SPIDER links the market level with the grid level. As a linear optimization model, SPIDER minimizes the system or redispatch costs and simulates the interaction between energy markets and physical grid restrictions. This linkage supports three central applications: the precise identification of local redispatch needs together with the associated costs, the simulation of a nodal pricing regime in which calculated prices reflect the actual scarcity of grid capacities at individual grid nodes, and the assessment of grid expansion measures or storage deployment for congestion relief.

Methodologically, SPIDER simulates this interaction in three steps: First, the model determines the fundamental load flows in the grid on the basis of generation and consumption data. It then simulates the cost-efficient market outcome and determines the optimal power plant dispatch according to marginal costs, initially without fully taking the grid bottlenecks into account. Finally, a detailed load flow analysis of the European transmission grid leads to an optimized redispatch, quantified in a technology-specific and regionally precise way, which ensures grid stability at minimal additional costs.

Schematic Representation of the Model

The model represents the transmission grid of selected European countries, whereby the physical topology is abstracted to around 600 grid nodes (of which around 300 in Germany). This representation comprises both the alternating current grid and high-voltage direct current transmission systems (HVDC). In order to represent the future infrastructural development realistically, grid expansion is stored in accordance with the relevant planning documents, in particular the European Ten-Year Network Development Plan (TYNDP) and the national Grid Development Plan (NEP). The spatial allocation of generation capacities, the availability of renewable energies (RES), and demand is carried out in a specific, EWI-internal processing step that assigns the data to the 600 grid nodes and thus enables a precise simulation of local grid loads. In terms of time, SPIDER is flexibly designed: it allows both the detailed modeling of complete years (dispatch with 8,760 hours) and the examination of long-term development paths by means of typical days (invest), for example in five-year steps.