TCEQ’s Power Reliability Requirements: Generator vs. Dual Feed Design
The Texas Commission on Environmental Quality (TCEQ) requires every regulated water and wastewater facility to demonstrate that essential systems will continue to operate during an electrical outage. This requirement is not just a formality; without backup power, a distribution system can lose pressure in a matter of minutes, disinfection can stop, and wastewater lift stations can overflow. Any of these conditions can create a direct public health hazard and, at the same time, put the utility in violation of its permit.
There are two common ways to comply with TCEQ’s power reliability rule. The first is to install a generator system capable of carrying the required load. The second is to design a dual electrical feed so that power can be supplied by two independent sources. Both solutions are recognized by the agency, but the engineering trade-offs are very different.
Why the Standard Exists
TCEQ’s concern is straightforward: when power is lost, core treatment and pumping processes must not stop. For water plants this means the high service pumps, chemical injection, and SCADA system must stay online. For wastewater treatment facilities, aeration blowers, disinfection, and lift station pumps must continue running. If those systems fail, untreated water or sewage could be released. The reliability requirement is meant to ensure that even in severe weather or regional outages, the utility can keep its most important processes functioning.
Generator Systems
Generators have been the most common method of compliance for decades, particularly in rural Texas where electrical redundancy is not available. A diesel or natural gas generator, paired with an automatic transfer switch, can restore power to critical equipment within 10 to 15 seconds of a grid outage. The generator must be sized to handle the facility’s essential loads, which often means pumps, disinfection equipment, and control systems.
The benefit of a generator is that it does not depend on the availability of additional utility infrastructure. A generator can be installed almost anywhere. It is usually the less expensive option in terms of initial cost, and municipalities have long experience with their operation. For many small utilities, it is the only practical option.
The trade-offs are well known. Diesel units require above-ground fuel storage, which brings the need for secondary containment, spill prevention planning, and periodic replacement of aging fuel. Even with natural gas supply, testing under load is still required on a regular schedule. Extended outages raise the question of refueling access, which can be difficult during widespread weather emergencies. Noise and air emissions may also be a concern when facilities are located near homes. The system is reliable but places an ongoing maintenance obligation on the utility.
Dual Feed Systems
Dual feeds are less common but are considered by TCEQ to be a valid method of meeting the reliability requirement. In this approach the facility is connected to two separate utility circuits, often tied to different substations. If one feed is lost, power is supplied from the alternate source. Transfer is essentially instantaneous, and in most cases the process equipment does not even register the loss.
The major advantage of dual feeds is that they remove the need for on-site fuel storage and reduce maintenance requirements. There is no generator to exercise every month, no tank to monitor, and no refueling to plan for during extended events. Runtime is not a concern, since the facility is tied directly into the grid.
The limitation is that not every site has access to two independent utility feeds. In rural areas there is usually only one available line. In some metropolitan service areas, two feeds can be provided, but the utility may require significant infrastructure investment to make it possible. Costs can easily exceed the purchase of a generator. There is also the risk that during a regional outage, both feeds could be affected at the same time, reducing the intended redundancy.
Permitting Requirements
When submitting plans to TCEQ, the permitting expectations differ depending on which option is chosen. For a generator, the submittal must include specifications for the unit, automatic transfer switch, and fuel storage system. The plans must also outline how the generator will be maintained and tested to verify ongoing reliability. For a dual feed, the application must include confirmation from the electric utility that the feeds are truly independent. TCEQ reviewers often require a letter of coordination from the utility along with electrical diagrams showing the separation of the circuits. If either set of documentation is incomplete, the review process can be delayed.
A Central Texas Example
During the design of a wastewater treatment plant expansion in Central Texas, both approaches were evaluated. The serving utility confirmed that a dual feed could be made available, but the extension cost was estimated at more than $500,000. The city determined that the investment was not justified. Instead, a generator system was selected and designed to meet both current and future treatment demands. The plans included a double-wall diesel tank with secondary containment, as well as automatic transfer and refueling provisions. TCEQ approved the project, and the city achieved compliance without the financial burden of utility infrastructure upgrades.
Why Early Evaluation Matters
The decision between a generator and a dual feed should not be left to the end of design. It affects facility layout, budget projections, and permitting strategy. Selecting the wrong option can lead to redesign, resubmittal, and additional cost. Evaluating reliability strategies early allows the engineer to coordinate with the utility, plan for long-term operation, and prepare a permitting package that addresses TCEQ’s concerns before they become review comments.
At Modern Engineering Solutions we guide municipalities, developers, and utilities through this decision process. Our role is to evaluate site conditions, review operational capacity, and prepare documentation that meets TCEQ’s standards. We have designed both generator systems and dual feed systems, and we understand the trade-offs each presents. The right solution depends on infrastructure availability, long-term staffing, and financial priorities.
Conclusion
Power reliability is not an optional feature. It is a core requirement of every TCEQ-regulated facility in Texas. Whether the design uses a generator or a dual feed, the decision must be based on a realistic understanding of the site, the budget, and the long-term operation of the system. With careful planning and proper engineering support, utilities can meet TCEQ’s requirements, protect public health, and operate facilities that remain reliable even under the most challenging conditions.
For assistance in planning or permitting power reliability systems, contact Modern Engineering Solutions at (214) 833-6748 or Sales@mod-eng.com. Our engineers are licensed in Texas and experienced in guiding projects through TCEQ review, from initial evaluation to final approval.