In an era of climate change, water facilities face multiple energy-related challenges as they strive to both avoid power outages and decarbonize their operations. As a result, some are exploring microgrids, a form of on-site generation.
Reliable power appears to be less assured as North America faces greater demand for electricity from a grid that is both aging and being pummeled by extreme weather.
During Winter Storm Uri in 2021, the water utility for Fort Worth, Texas, experienced emergency rolling blackouts that left three of the district’s four plants inoperable. Some suffered multiple blackouts over subsequent days and extended boil notices for hundreds of thousands of residents.
During Hurricane Ian this fall, almost one-third of pumping stations lost power in Polk County, Florida, resulting in tens of millions of gallons of wastewater and reclaimed water being spilled. This released hazardous materials into the environment and yet to recede flood waters, further endangering public health during recovery from the storm.
Recovery from these types of outages is not as simple as turning the water facilities back on and opening the faucet. Even temporary system outages can result in unsafe water, requiring boil notices and other emergency measures to ensure public safety.
Remote wastewater treatment services are particularly vulnerable. If pump stations lose power, sewage can back up, overflow and endanger public health, especially when raw sewage seeps into basements or contaminates water supply.
A grid not green enough
While facing these challenges, water and wastewater treatment utilities also are striving to decarbonize.
Water facilities account for almost 2% of greenhouse gas emissions worldwide – similar to the impact of the global shipping industry. That figure is set to double by 2040 as demand for the ever-scarce resource continues to grow and more energy-intensive solutions like desalination become necessary to ensure fresh water supplies for more than 8 billion people.
Unfortunately, grid power is not always “green” enough to further sustainability goals. More power still comes from coal than renewable energy on the US grid, according to the US Energy Information Administration.
A microgrid is a resilient energy system that serves a discrete geographic footprint, such as water facilities, campuses, medical complexes, business centers or neighborhoods.
In many ways, it is a mini version of the main electric grid. But because of a key piece of technology – a microgrid controller – it can connect or disconnect its power generation sources from the grid as needed. When there is a power outage, the controller islands the on-site generators from the grid and instructs them to provide power to the facility. This allows the water facility to continue operating without interruption.
But a microgrid's benefits go beyond providing power during outages. They also can be programmed so that the water facility receives an optimal energy mix at any time – whether from the grid or from the microgrid’s generators. The optimal mix will depend on the facility’s goals. If the goal is to decrease costs, the microgrid will be programmed based on the changing price of energy. If the goal is to decrease carbon output, it can be instructed to run the cleanest energy resources available at any given time.
How to procure a microgrid
Typically, a water facility partners with a microgrid company to design, build, operate and maintain the microgrid through four basic steps.
Step 1: Power assessment
Water and wastewater facilities will need to conduct a power assessment as one of the first steps toward installing a microgrid. This will not only help size the microgrid, but also determine likely points of failure and the operations that are critical to the facility.
Step 2: Financing a microgrid
With a scope of the project in hand, the next step will likely be determining how to finance a microgrid system.
There are several financing options, including federal or state grants and loans, bond issuance or even rate increases.
Perhaps the most notable funding source is the Water Infrastructure Finance and Innovation Act (WIFIA) of 2014, which established the WIFIA program administered by the Environmental Protection Agency. WIFIA accelerates investment in water infrastructure by providing long-term, low-cost supplemental loans for regionally and nationally significant water and wastewater infrastructure projects.
Another option growing in popularity is the energy-as-a-service contract. In this instance, little or no upfront capital is required for the microgrid. It is owned and operated by a third party, and the recipients of its benefits pay only for the services they receive. Microgrid companies strive to keep the cost of microgrid electricity at or below the rates charged by the local utility.
Step 3: Building a microgrid and interconnection
The preparation and building of a microgrid can take weeks, months or years, depending on the technologies being deployed, lead times for large components and the complexities of the interconnected systems. Additionally, connecting a new microgrid system to an electric utility can be a very prescriptive process, which can extend completion time further.
One critical step in building a microgrid is a testing process once all the hardware and software is installed. This involves running a worst case scenario simulation – a critical power failure – and ensuring that all systems perform as expected.
Step 4: Operations and maintenance
Once up and running – and testing confirms resilient operations – a microgrid requires very little in ongoing operations and maintenance. Unless designed to perform daily tasks, a microgrid operates in “standby” mode, monitoring system health and performance while prepared to take over in case of emergency.
Ongoing maintenance of the system itself is limited to routine system health diagnostics and occasional cycling of the generators or batteries to ensure operability. There can also be additional maintenance benefits for other integrated systems beyond the microgrid itself, as recurring power anomalies in any piece of equipment can signal a poor state of health and a need for repairs.
Overall, once installed, a microgrid can be invisible day to day or a core component of facility operations, depending on what is most cost-effective to meet the needs of the utility, facility managers and its customers.
The risk to public health and safety from critical infrastructure losing power is an ever-increasing challenge. As storms intensify, infrastructure ages and new cyberthreats emerge, the benefits of resilience are clear.
For more information on microgrids for water and wastewater facilities, we invite you to download the white paper The Case for Microgrids at Water and Wastewater Facilities. If you missed the webinar we did on this topic it is now available on demand.