How is the U.S. Attempting to Build a Resilient Grid? Difference Between a Resilient Grid vs Back Up Power
February 26, 2018
After Superstorm Sandy hit the U.S. East Coast in 2012, many stakeholders discussed the need to build a more resilient grid. The concept of a “resilient” grid was not just invented in the aftermath of the hurricane, but as many states looked to rebuild their grids after natural disasters or simply modernize their electricity grids into utility grids of the future, the concept of “resiliency” became increasingly raised.

Resiliency is different from ”back-up” power, a concept utilized throughout the customer segment of the grid. Back-up power refers to customers creating their own generation to create electricity when power is lost. Resiliency is based on building a grid that is more robust and can withstand the impact of natural or manmade disasters and continue to operate and provide power to end-users.

What Technologies Are Key to Building a Resilient Grid?

When engineering new approaches, the concept always seems simpler than the practical designs. This is also the case when examining technologies that are most often utilized when building a more resilient grid. The current efforts to make a grid more resilient focuses on two areas. First, deploying smaller generation technologies throughout the grid, or Distributed Energy Resource (DER) Devices. Second, on deploying a robust communication / control / monitoring system to enable grid operators to “visualize” what is happening at the edge of the grid.

From the generation perspective, distributed energy resources typically comprise of technologies such as renewable solar PV and small wind, clean technologies such as natural gas generators, fuel cells, waste to energy technologies and combined heat & power systems (CHP), or emerging technologies such as electricity storage. If a number of these devices are connected together, you can create a “microgrid” in itself. However, it should be noted that microgrids are used so synonymously with resiliency that it is often thought of as a technology itself. A microgrid is really a group of DER technologies that are controlled, operated as one system, and in cases of outages, “islanded” like a small grid within itself.

The challenges of this approach are represented in the power flows represented in Figure 1 below.

Resilient Grid Fig 1

Figure 1: Representation of Typical Electricity Grid

Traditionally, electricity grids are based on vertical designs with one-way power flows. Power is generated (far left of diagram) at a single, large generation facility. The power is transmitted to areas of population load and then distributed to customers (far right). In fact, this grid is typically segmented in (a) generation, (b) transmission, (c) distribution, and (d) end-use. In examining the figure, it is easy to see how an incident at one point of the system can affect loads downstream of that point.

In the case of DER, generation can also be located at the far right of the diagram. It needs to be smaller in order to be sited in more confined spaces but this distributed generation makes it difficult for a single point of failure to disrupt a particular group of customers.

However, the challenge this creates can also be seen in Figure 1. Electricity grids are designed for power to flow one-way, from generation to customers. However, in the resilient case, power has the potential to flow two-ways.

The second part of building a resilient grid is controls and communications. Again, back to Figure 1, our grid operators would typically need to monitor the large generation plants, transmission, and distribution system to ensure power was flowing to the end-points. Less emphasis was placed on the end-points themselves. In the new case, grid operators are now going to need to see what is occurring on the customer side for reasons of safety, efficiency, and the simple fact that power is now being generated at an end point (customers) and flowing back into the grid. This is represented by the two-way arrow on the “resilient” case of Figure 1 with power flow with DER.

How Are States Implementing Resiliency?

Two States are leading the way in deploying distributed energy and more States are quickly following. New York, through its “Reforming the Energy Vision” is doing this based off lessons learned from Superstorm Sandy. California is doing this because of its desire to create a clean, renewable, more robust grid. For other States, this concept is being incorporated into what are referred to as Grid Modernization plans or for States are also simply taking advantage of the surge in customer interest in deploying technologies such as solar. States are simply taking advantage of those deployments to tap into the new resources.

The challenges rise in both operation and conceptual deployment. Today, States are currently developing plans to allow distributed resource devices to be safely deployed, monitored, and more importantly, compensated for the potential role they can play in operating a more efficient grid. These tasks are not simple as it involves creating new regulatory policies, incentive mechanisms, an overlay of monitoring systems, and design processes to allow the devices to be deployed safely for both the consumers of electricity as well as the operators themselves. These tasks are by no means finalized and work continues today across the U.S. to make a resilient, modern grid a reality across all systems.