The wind, sun and ocean represent exciting resources for clean energy backers. But for the bulk power system, the prospect of more than 145 GW of power from these resources in the next decade presents a daunting amount of variability in the power supply. According to the North American Electric Reliability Corporation (NERC) — the international regulatory authority for reliability of the bulk power system in North America — if only half of this estimated capacity comes into service, that will mean more than triple the amount of variable resources will be feeding the grid than were doing so last year — and so far, we still have no reliable way of stockpiling those electrons.
In a new report, NERC explains the challenge of switching from dirty-but-reliable fossil fuels to clean-but-variable energy like so:
“Today, the bulk power system is designed to meet customer demand in real time – meaning that supply and demand must be constantly and precisely balanced. As electricity itself cannot presently be stored on a large scale, changes in customer demand throughout the day and over the seasons are met by controlling conventional generation, using stored fuels to fire generation plants when needed.”
NERC sees upgrading the transmission grid to handle all of these new resources as an essential piece of the climate and security puzzle. In a report issued late last year, it warned that “inadequate attention to the transmission grid will undermine all efforts to address climate change while endangering our electric reliability, and thereby our national security.” In its latest report, the group lays out a different path, proposing six key strategies for maintaining reliability while integrating these new sources.
- Deploy different types of variable resources (e.g. solar and wind) to take advantage of complementary generation patterns, and locate the resources across a large area.
- Craft policies to make transmission development, siting and permitting easier and faster.
- Develop additional flexible resources — such as plug-in electric cars — to help grid operators quickly respond to changes in output without putting excessive strain on the system.
- Invest in R&D for better measurement and forecasting of output, and incorporate forecasting techniques into real-time operating practices in addition to daily operational planning.
- Treat distributed variable generation, such as small scale wind and rooftop solar, similar to transmission-connected power plants for planning purposes.
- Create larger balancing areas, possibly by consolidating current base-load areas to allow for larger pools and more flexibility in matching generation and demand.