The grid is the dynamic web of electricity production, transmission, storage, and consumption that 85 percent of the world relies on. It was designed for constant, centralized power production, not for the variability of solar and wind power. For electricity supply to become predominantly or entirely renewable, the grid needs to become more flexible and adaptable than it is today.
Many technologies contribute to grid flexibility:
- Constant renewables, such as geothermal;
- Utility-scale storage, such as pumped hydro and molten salt;
- Small-scale storage, such as batteries; and
- Demand-response tools, such as smart thermostats and smart appliances, to mediate peaks in demand.
Flexibility also depends on strong transmission and distribution networks—the connective tissue between generation and consumption. Where the grid spans larger geographies and more electricity sources, it can essentially even out the total output of renewables, reducing extremes in variability. Weather forecasting and prediction are also important tools to manage wind and solar generation.
While photovoltaic panels and towering turbines may garner most of the attention, flexibility is the means for renewables to become the dominant form of energy on the planet. Together, they will make the global energy transition possible.
We do not model grid flexibility because it is a complicated, dynamic system, and it is nearly impossible to account for all local factors at a global scale. However, to grow beyond a 25 percent share of generation from variable renewable energy sources require increased grid flexibility. The emissions reductions from this solution are counted in the variable renewable solutions that could not reach their full potential without it.