Distributed Generation in the Electric Energy Landscape
This segment will be the first of several on the topic of Distributed Generation in the electric energy landscape.
Distributed Generation is a source of electric energy produced at or near the point of use. It can be connected to the traditional electrical grid, referred to as grid-tied, or can be stand-alone and independent, referred to as off-grid. Grid connected resources have also been coined Distributed Energy Resources (DER) because they can be leveraged by the grid to offer peak load management and other critical functions to provide grid stability and resiliency. Distributed Generation systems utilize a wide variety of renewable energy sources including solar, wind, hydro, and fuel cells, as well as traditional sources such as natural gas, diesel, or propane generators.
The majority of Distributed Generation systems in operation today are grid-tied. The current centralized grid systems are designed for one-way power flow. In such a system, power comes from large remote generation sources through bulk transmission infrastructure and then moves through distribution networks to end users. With the expansion of distributed resources, the grid network must now manage multi-directional power flows from an assortment of energy sources, like solar and wind, with a high degree of intermittency.
As with any major shift in a traditional landscape, conflicting positions and opinions emerge related the value, benefits, winners, losers, etc. as well as the future direction of the industry.
Some of the positive aspects of Distributed Generation include:
- Minimize line losses by producing at the point of use. In the traditional system, 7% to 9% of the electrical energy dissipates from the central power plant to the end user.
- Upgrades or extensions to the transmission and distribution infrastructure can be delayed or avoided altogether.
- Having numerous smaller generation sources makes the systems more resilient, meaning no one disaster event can take down the grid, be it natural or man-made.
On the other hand,
- Economies of scale are lost with smaller systems of different sizes and energy sources, leading to a much higher costs per kilowatt-hour than grid-scale sources.
- Systems are installed primarily for the private benefits of the end user regardless of the impact on the grid and can actually destabilize distribution circuits.
- System operators are not able to fully leverage distributed systems for grid optimization and resiliency because they are not actively integrated with grid operations.
Arguments over the value of these systems are raging throughout the industry and in governments across the country. While the discussions move forward, global Distributed Generation capacity is expected to grow from roughly 132.4 GW in 2017 to 528.4 GW in 2026, according to a Navigant Research report. The genie is out of the bottle and can’t be put back. It is time we seriously consider how this will affect the electric energy landscape we know today.
Future extensions of this discussion will include the drivers for off-grid Distributed Generation, the value of incorporating storage technologies, as well as the benefits of distributed systems.