Headline: Thermo-hydraulic and economic aspects of long-length high-power MgB2 superconducting cables

The rising share of renewable energy in the European grid creates a demand for long-length, high-power transmission lines. Superconducting cables represent an attractive option for such connections, offering considerable savings in energy and space for installation. Due to its low cost, the MgB2 superconductor might be an interesting choice, but it requires to be operated at very low temperature. In this paper, a simple thermo-hydraulic model is developed, which allows for a fast assessment of the main dimensions of a four-wall cryogenic envelope around a high-power MgB2 cable as well as the achievable distance between two cooling stations. This model is then expanded to provide the budgetary cost of such a link including the components of the cryostat and the necessary cooling stations. A significant cost reduction as compared to a resistive link can be found for a transmitted power of 6.4 GW. Different optimizations are investigated, which result in further savings.