Infrastructure Estimates for a Highly Renewable Global Electricity Grid

A global electricity grid may offer a number of advantages in a future highly renewable energy system dominated by wind and solar power. In this paper, we provide quantitative estimates for the benefits and costs of an intercontinental HVDC grid connecting a number of highly populated super regions in the Northern Hemisphere. The modeling is based on hourly time series of wind and solar power generation calculated from high-resolution global weather data using the Global Renewable Energy Atlas. Taking a European point of view, we find that the annual need for backup energy can be reduced from 18 to 10 % of the load by connecting to North Africa, the Middle East and Russia. A further reduction to 7 % is found for a grid spanning the whole Northern Hemisphere at the expense of substantial increase in transmission capacities. Comparing the economical benefits to the additional cost of intercontinental transmission lines, we estimate that connecting Europe to its geographically nearest neighbors may reduce the total cost of electricity. Longer distance connections to North America or Asia, on the other hand, would require transmission costs to fall to 15–20 % of current levels.