By Capt. Garrett D. Anderson, U.S. Army Corps of Engineers, Tulsa DistrictJune 22, 2018
Editor's note: The following piece is a firsthand account from Capt. Garrett D. Anderson on the utility of microgrids following his experience as the Power Task Force Chief of Operations and Microgrid Project Manager in Puerto Rico. Capt. Anderson is now a project manager for VA Programs in Tulsa, Okla. The views expressed herein are Capt. Anderson's own and do not necessarily reflect the opinions of the U.S. Army or Department of Defense.
SAN JUAN, Puerto Rico -- In a matter of hours, an entire island's infrastructure was destroyed as high water and sustained winds wreaked havoc on Puerto Rico. Key facilities such as hospitals, water treatment plants, and power grid substations were flooded, while destruction of electrical transmission, sub transmission, and distribution lines severely degraded the power supply.
Hurricane Maria, a category five hurricane, made landfall on Sept. 20, 2017. The resulting damage was so extensive that the Puerto Rico Electric Power Authority, Federal Emergency Management Association, and United States Army Corps of Engineers were still working in April 2018, to restore power to residents living in remote areas.
However, Puerto Rico is not the only place at risk of losing power on a large scale. The damage to Puerto Rico serves as an alarming reminder of the increasing threat of natural and manmade disasters capable incapacitating our power grid in Puerto Rico and across the Nation. With that in mind, USACE officials are exploring the use of microgrids to restore power in areas impacted by the 2017 hurricanes, as well as looking at ways to utilize microgrid systems to reduce the risk of regional, state or nation-wide power outages.
While serving as the Power Task Force Chief of Operations and Microgrid Project Manager, I was asked by members throughout the Task Force Power effort if microgrids are the solution for Puerto Rico and a more sustainable and reliable power grid in general. I want to share what I learned about microgrids from the unprecedented response to Hurricane Maria in Puerto Rico, including lessons learned and recommendations for the U.S. and other nations, as we will certainly face future disasters.
A microgrid is a local energy grid with control capability, which means it can disconnect from the traditional grid and operate autonomously. In layman's terms, it is a power source that can operate independent of the overall grid. In the event of a disaster, attack, or fire, such as the one that caused the blackout in San Francisco over a year ago, a microgrid could have produced power for areas without the entire grid experiencing an outage.
Microgrid generators are plugged into existing lines and use the power produced by the generators. These autonomous grids are capable of producing the amount of power desired depending on the size of the available generators. There are also multiple ways to fuel these units. Although solar power is a popular source of alternative energy, it does not produce sufficient power to meet power needs at peak times throughout the day, which are typically during morning and evening hours. Other sources of energy include natural gas, fossil fuels, wind, and hydro power.
Hydro-powered microgrids could very well be the most reliable form of power, according to research conducted by Alternative Energy News, which says that this source of energy provides "efficient, reliable, energy that doesn't require huge reservoir energy reducing the amount of cost associated with the operations." Unlike solar, wind, and fuel-based power that is unreliable for a variety of reasons, including the consistency of wind and solar or the availability of fuel and varied cost, water at locks and dams is highly controllable. Even in drought-stricken regions, the amount of water to run these grids would be minimal and could be ran with grey water from the treatment plants.
Just as the lock and dam operators control levels of water to ensure the depths are safe for passage, the same concepts to surge water levels to meet power load requirements apply. Controlled releases of water efficiently ensure that only the load necessary for power generation is consumed, thus eliminating unnecessary electricity generation. The sun and wind cannot be controlled, and fuel consumption is expensive and not a renewable source to make fuel a viable option for long term use.
If one thing can be taken away from the efforts in Puerto Rico, it would be that microgrids are an effective way to quickly get power restored if the infrastructure has not been damaged. Areas that experienced the most damage to the distribution lines would not benefit from the use of a microgrid, and spot generation would need to be used instead. The areas with non-structural damage to power grid infrastructure benefited greatly from the use of microgrids. These units are usually able to be installed in less than a day and begin producing energy as soon as the generators are running.
Another benefit of micro grids is they are generally mobile in a disaster area. This is important, because as power lines are restored, the microgrid unit can be moved and used to produce power elsewhere. Several military installations are experimenting with microgrid technology for this very reason. Imagine having liberated grids capable of operating independently without a central point of failure. In the military we often say, "One is none, two is one." Why not treat power the same?
Overall, the microgrid option is in its infancy for large scale plans. The microgrid concept is an effective solution for smaller scale and disaster relief efforts. The goal is to increase efficiency while maintaining cost effectiveness. They may be the solution to concerns about the U.S. power grid, and islands such as Puerto Rico and the U.S. Virgin Islands that have a much higher risk potential of disaster damage.
With that in mind, what can be done now to improve the use of microgrids in the future? One way such a method of improvement can be found is with the Power Task Force in Puerto Rico, where we documented how we used microgrids by first conducting an in-depth analysis with help from the Department of Energy, 249th Prime Power, FEMA, and electrical engineers from USACE. Prior to each commissioning of the microgrid, a drawing of the microgrid was sketched out and a stringent flow chart checklist was followed. The checklist ensured we followed the same steps each time for uniformity.
Despite the fact that each microgrid was slightly different, the safety and functionality of the microgrid was checked and verified prior to handing it over to the host utility company. An analysis determined the max load and meters the grid would re-energize in the relief efforts in addition to technical data points. Photo documentation throughout the process helped to ensure continuity so future operations would have a solid starting point should they need to respond in such a way in the future.
As the U.S. and other countries continue to move forward and explore alternative solutions to power, the microgrid will certainly be a viable option. Renewable energy is the way of the future. The U.S alone has invested almost $40 billion a year in this sector. As technology improves, so will our ability to have more reliable and independent sources of energy. Engineers need to take a closer look into the use of microgrids. Whether it's a natural disaster or a planned attack, we must be ready to respond to the Nation's toughest challenges and provide solutions to the people of Puerto Rico, the United States and around the globe.