Drought causes historic disruption at hydropower plant

Low water level threatens stability of water supply & energy grid

On 5 August 2021, the California Department of Water Resources (DWR) took offline the 750-MW Hyatt Powerplant at Lake Oroville. Historically low water level has caused this unprecedented disruption since the generating station began operating in 1967.*

Despite “record-low reservoir levels due to dramatically reduced runoff this spring,” according to DWR director Karla Nemeth, “the fact that hundreds of hydro plants throughout the West have continued to generate (electricity and deliver water) is a testament to the efforts of the owners and managers of reservoirs and generating facilities,” according to the National Hydropower Association.

25 July 2021 aerial photo of Lake Oroville, California reservoir; historic low water level disrupts hydropower generating operations in 54-year history | photo credit Robyn Beck for AFP Getty Images

In July, 2019, California Data Exchange (CDEC) reported that Lake Oroville was essentially full at 900 feet. However, two years of below-normal precipitation seasons has demanded continual planning, coordination and improvement to meet water allocations for domestic water supply and fish, in addition to generate clean, renewable electric power.

The DWR anticipated the dire situation at Lake Oroville. With the possibility of losing the asset of water and grid management, the state’s water management agency informed the California Independent System Operator (CAISO) and the California Energy Commission. The latter organizations are working with the California Public Utilities Commission (CPUC) to procure additional electricity and continue to balance demand and supply.

Similarly, Pacific Gas and Electric (PG&E) planned ahead – implementing aggressive water storage and conservative water release strategies at its reservoirs during the spring.

Like droughts, managing heatwaves and extended periods of extreme temperatures involves a high level of coordination and communication without disruption to hydropower generation. Waterpower continues to provide operational flexibility as robust sources of solar and wind power scale.

In Idaho, Hydro Review has reported that Avista Utilities expects discharge at the Post Falls Hydroelectric plant to drop to the minimum of 500 cfs due to low rainfall and uncharacteristic heat. The reduction is the least amount permissible by 2009 license issued by the Federal Energy Regulatory Commission (FERC). The reduced flow is expected to be compliance, in order to maintain the Coeur d'Alene Lake water level and Spokane River flows.

KISTERS is dedicated to providing customers with accurate and reliable IT innovations to meet multiple demands associated with operating reservoirs and hydro plants. The combination of devices that monitor water flow and snowpack as well as software to visualize past, present and forecast conditions to ensure electric load requirements and flow obligations for fish, recreation, and transportation are met.

aerial photo of Lake Oroville, California dam with damaged spillway and eroded hillside, 11 February 2017 | photo credit Robyn Beck for AFP Getty Images

* Some may recall that heavy rainfall in February, 2017 damaged Oroville Dam’s main and emergency spillways. Rain raised the lake level till water flowed over the emergency spillway, while headward erosion threatened to collapse the weir and send a 30-foot (10m) wall of water downstream.