The City of Bloomington, Indiana, supplies essential services, such as water, to its residents. Over the course of a few years, the City installed backup power generators at critical facilities to ensure continued operations during power outages.
| Action | Applicable Resources |
|---|---|
Determined system need
|
|
Hired a contractor to design each system
|
|
Installed systems and conducted maintenance
|
|
One of the purposes of local governments is to ensure residents have access to essential services, like water. As these services are essential, they need to be supplied without disruption. Bloomington installed backup power generators at their water and wastewater plants to ensure continued operations even during grid disruptions.
Over the past 20 years, Bloomington has gone through the process of installing eight backup power systems and seven generators at their water and wastewater facilities. As the City has expanded its facilities, it has included backup power systems in new and existing facilities.
During each installation and upgrade, Bloomington accounted for climate change projections and expected changes in demand at least 10 years into the future. As the population and the local climate are changing, planning based on historical trends and current data is not always sufficient to meet future needs.
When installing its backup systems, the first step was to establish the system capacity and minimum need during an outage. If the grid is down, it would be difficult and costly to provide the amount of power needed to operate at full capacity, so the City of Bloomington needed to determine the appropriate level of backup power capacity. For instance, Bloomington’s water plant during normal operations can distribute 30 million gallons of water per day. The maximum amount the City regularly distributes is around 19 million gallons per day. Using standard engineering calculations, Bloomington determined its critical need at the time for that plant to be 12 million gallons per day.
After determining its critical need, Bloomington hired a contractor to design the backup systems, a task that requires a specialist.
Bloomington made sure to avoid building the backup systems in a floodplain. The consultant, working in partnership with City staff, designed the structures with an open top or in a cool, shaded location, when possible, to prevent the systems from overheating when ambient air temperatures are high. In cases where the cooling options were not feasible, Bloomington installed climate controls.
Currently, all of Bloomington’s backup power systems are fueled by diesel generators. Not enough space was available on-site at any location to host 100 percent alternative fuel sources like wind or solar. However, Bloomington has been adding solar power for some of its backup systems. While there is not enough solar to fully power any one system, the renewable energy source reduces the amount of diesel needed.
When power is lost, Bloomington’s systems turn on the generators immediately to ensure there are no gaps in service. The automatic switches also send alarms to staff to respond as soon as possible to monitor the situation as it unfolds.
For system maintenance, plant operators start the generators around once a month and do a full system test at least annually to make sure the systems are working properly.
The cost for a backup power system varies depending on its size and how much power it needs to generate. Bloomington’s individual systems have ranged from $200,000 to $3 million.
Bloomington has been adding backup power for the past 20+ years in various capacities. Each upgrade takes around a year from the design phase to a finished product, but this can vary depending on the size of the system.
Equity and justice were not directly considered in this project. However, access to drinking water and wastewater services is already insecure for communities with lower incomes and other vulnerable populations. This insecurity is further compounded during a power outage when municipal water services are disrupted. By having uninterrupted facilities, communities can better ensure access to water supplies for vulnerable populations.
Over the past 20+ years, Bloomington has installed three backup power systems on existing systems and built an additional five systems in conjunction with new plant upgrades. They have also added seven generators at their wastewater lift stations. The backup power systems automatically switch on when power is lost, which has occurred several times throughout the years. Coupled with redundant water lines, Bloomington has not seen any disruptions in water to critical infrastructure, such as the local hospital.
Bloomington is continuing to improve upon and upgrade its backup power systems. Recently, the City determined that the 12 million gallons per day they originally planned for is not enough. Bloomington is in the process of designing an upgrade to increase capacity to 24 million gallons per day. Bloomington is also installing solar where possible to reduce the amount of diesel fuel used.
At the wastewater treatment plant, the backup power system only has enough power to pump water through the plant. Bloomington wants to add capacity so that the facility can also treat water during a power outage. Since this requires much more power, a permanent generator would be cost-prohibitive. Instead, Bloomington is installing a connection for a drive-up plug-in generator. Bloomington plans to establish a contract with a supplier that will guarantee to hook up a generator within a set amount of time.
The biggest challenge for installing the backup power systems is the cost of installation and the costs of running them during an outage. The City of Bloomington has found the topic of resilience to be useful for showing how crucial the systems are for the community.
Brad Schroder, an engineer with the City of Bloomington, gave the following advice:
“What has helped us in getting these systems online is talking about resiliency and really explaining how the backup power can help us achieve it for our community. With resilience, we need to look ahead to what our needs are going to be down the road and make sure we are planning for them.”
These questions are designed to inspire readers—especially those wanting to learn broadly about climate change solutions—to think critically about the case study on this page and encourage deeper, more meaningful conversations. A list of ERIT case studies that include discussion questions can be found on the Resilient Communities Case Studies page.
Brad Schroder
Engineer
City of Bloomington
schroedb@bloomington.in.gov
