Will the DOE turn your house into a nanogrid?

February 21, 2018

The DOE just announced a new office focused on cyber and energy security.

Terry Nielsen believes we are finally getting serious about grid resiliency

Rick Perry, the head of the U.S. Department of Energy (DOE), announced the formation of a new office of Cybersecurity, Energy Security, and Emergency Response (CESER) on Valentine’s day. Peeling the onion on what this really means, the new organization is getting $96 million in new infrastructure funding for cyber security and energy security to finally make a substantial impact on grid resiliency.

As an industry and specifically at the distribution level, I believe we have successfully focused on reliability, as we are now at the point where engineers can clearly show that the dollars spent made a measurable impact. That doesn’t mean that overall reliability is actually improving, because we still face challenges in obtaining funds and convincing regulators and the public that spending money on the improvements is worthwhile. An interesting aspect of reliability is that spending zero dollars doesn’t keep reliability at the same level; it naturally deteriorates, so a certain level of reliability investment is needed to just tread water. Many utilities barely get the budget to do this, let alone make measurable improvements.

The term “resilience” refers to the ability to adapt to changing conditions and withstand and rapidly recover from disruption due to emergencies.  Whether it is resilience towards acts of terrorism, cyber-attacks, pandemics and catastrophic natural disasters, our national preparedness is the shared responsibility of all levels of government, the private and nonprofit sectors and individual citizens.

While the two terms are often confused, resiliency and reliability are not the same. In fact, in some cases, especially in those where reliability engineers are trying to maximize the returns of their reliability improvement investments, they can make the system less resilient. This is because the improvements they make are designed to improve the system’s ability to withstand stress, but only up to the point in which it is designed for, and no more. Doing this maximizes the measured reliability improvements they get from their budget. When reliability is the focus, extra dollars are not spent on making one circuit more reliable and turning it into one that is resilient. Instead the incremental dollars are spent on the next circuit, making it also more reliable, to the point of a target worst case/level of stress. This target point is usually less than what would occur in a more infrequent, but very high impact disaster. This is the so-called approach of “value engineering,” and it occurs in almost everything that is designed and engineered today. Value engineering is why so many things seem to fail right when the warranty expires or when new models become available. The same is true in the distribution system serving your house.

California has 5 GW of residential solar and almost 350,000 EVs that would essentially be useless in a major outage/disaster situation. This is because most rooftop solar systems designed today only operate in a grid-connected situation and intentionally disconnect for a variety of valid reasons, including safety. In a typical PV installation today, no investment is made to turn a residence into something that could operate in an islanded mode when the system is disconnected from the grid.

The solution is to turn a single building into its own mini power system, or what has been recently named a nanogrid. Currently, there seems to be more interest and commercial availability of solutions for residential solar-based nanogrids in the state of Florida than in California, where there is a much larger level of solar penetration. These nanogrids operate by combining one or more local energy sources, solar, backup generation and others, with a system controller. The controller can match load with generation by performing demand management so that critical loads, like refrigeration and lighting, can be served, while non-critical loads, like high energy use appliances, are turned off. For instance, a complete nanogrid package for residential customers enables them to have power for an extended period of time after a hurricane takes out the distribution system. Even more interesting are solutions that can do this without adding storage, such as this product called Secure Power Supply from SMA Solar explained here.

My belief and hope is that this new DOE organization, with its larger budget and expanded charter, will focus on resiliency and explore a wider spectrum of resiliency options. Ultimately, this will help make nanogrid solutions like this much more commonplace and a this could lead to a more resilient society in the future.

Terry Nielsen, GridBright EVP of Utility Solutions

2018-03-20T01:17:20+00:00