Amid increased efforts to decarbonize the power industry, hydroelectric plants can offer immediate access to clean energy. Unfortunately, the vast majority of existing plants have far outlived their systems and infrastructure. Rather than retirement, opportunities abound to upgrade these aging facilities with current technology and boost operational efficiencies.

According to a 2017 research study conducted by the U.S. Energy Information Agency (EIA), hydroelectric generators are among the oldest U.S. power plants. With an average age of 64 years, hydroelectric plants account for 99% of all current operating capacity built before 1930. Despite their age, though, these existing facilities hold great potential for continued decarbonized generation without having to build something new.

However, embarking on an upgrade within a facility built in the 1950s or earlier is not without its challenges. Modern electrical equipment is significantly different and requires new accommodations for sizing variances, maintenance requirements, and environmental and safety codes. Updates must adhere to new standards for oil discharge locations, access guidelines from the Occupational Safety and Health Administration (OSHA) and fire containment requirements from the National Fire Protection Association (NFPA). Therefore, upfront and detailed planning and budgeting for these projects needs to include not only the electrical and mechanical equipment replacements but also the surrounding auxiliary modifications.

For example, removing and installing new transformers on an existing turbine may pose access challenges. Overcoming these design constraints may require cutting larger entry points to facilitate installation, adding access platforms, or establishing lockout capabilities for ongoing operation and maintenance. This additional work on an older structure could potentially add the need for remediation of asbestos or lead in outdated materials.

Also, typical hydroelectric facility construction from the early 1900s featured switchgear erected in place inside second-story electrical rooms. Modern switchgear, on the other hand, is preassembled at the factory and is too large to be moved through existing stairways for installation. Therefore, modifications to the existing structure are then needed to accommodate installation but are rarely accounted for early in the project budgeting process.

With the rising industry trend of pairing batteries with existing renewable generation plants, future plans for co-located battery storage should be considered during these structural changes. Incorporating these changes into existing structural upgrades has the potential to save capital expenditures and help prepare for subsequent upgrades.

Upgrading an existing hydroelectric plant is a cost-effective way to maintain a steady supply of green energy in a utility’s portfolio. However, a comprehensive evaluation of the building structure and considerations for the future are needed. Front-end planning for hydroelectric projects can help safeguard against potential issues, reducing costly changes and scheduling delays.


To maintain performance, reduce failure risks and maximize access to plant data, the New York Power Authority is upgrading its Robert Moses Niagara hydropower plant’s control and electrical protection systems. Learn how a phased approach is delivering the enhancements while maintaining the plant’s ongoing service.

Read the project profile

Andrew Roedel, PE, is a structural engineer specializing in electrical, mechanical and control system retrofits and upgrades for hydroelectric power plants.