Hydroelectricity is a cornerstone of energy era in the USA. For the reason that 1880s, engineers have harnessed the ability of dashing water to generate electrical energy, from the long-lasting Hoover Dam to a lot smaller hydroelectric tasks.
However in the previous couple of many years, the similar individuals who take pleasure in hydroelectric energy have discovered the environmental affect of dams – particularly on native fish populations.
Species, akin to salmon and herring, migrate from the sea and into rivers to their spawning grounds. As soon as hatched, juvenile fish migrate backtrack rivers to reside within the ocean. Conventional dams have disrupted this existence cycle by means of blocking off the unfastened go with the flow of rivers to the ocean.
Federal and state regulators have taken steps to revive those populations by means of requiring utilities to seek out leading edge techniques to lend a hand fish circumnavigate dams. Tacoma Energy in Washington state is such a utilities. Owned by means of the town of Tacoma, the software supplies electrical energy to over 50 p.c of town citizens. 90 p.c of that power is generated by means of hydroelectric powerhouses on rivers in western Washington.
When Tacoma Energy’s license to supply energy for the town used to be up for renewal, the town had to create a fish passage round two of its dams to lend a hand maintain the native inhabitants of endangered steelhead, sockeye and salmon with a purpose to renew its license.
On the time, Tacoma Energy’s Cushman No. 2 Dam upstream of the North Fork Skokomish River used to be now not provided with hydroelectric era features at the North Fork of the river. The dam have been in position since 1929 as a part of the machine preserving water inside Lake Cushman, a synthetic reservoir.
The facility corporate added two river outlet valves to the bottom of the dam in 1992, permitting water to go with the flow from the lake into the riverbed. On the other hand, the go with the flow of water during the valves used to be too sturdy for fish migration. To supply a gentler passage for the fish, Tacoma Energy had to construct a fish-collection facility for each the grownup fish headed upstream and the juvenile fish swimming towards the sea.
The software had to diffuse the water present and noticed a chance to seize the drive of the go with the flow and switch it into hydroelectric energy by means of construction a brand new powerhouse on the base of the dam.
The powerhouse would want to simulate the herbal go with the flow of the river to stay the encompassing house secure from flooding and make fish migration manageable. Very similar to different powerhouses Tacoma Energy owns and operates, the brand new Cushman Northfork Powerhouse had to be totally computerized to do away with the will for on-site group of workers. Body of workers would remotely get entry to the dam from the operations heart on the Tacoma administrative center.
Shoppers would additionally receive advantages, for the reason that powerhouse would generate sufficient renewable power for 1,700 properties.
Tacoma Energy have been the usage of Allen-Bradley® ControlLogix® programmable automation controllers (PACs) to automate its different seven powerhouses.
“Our enjoy with Allen-Bradley controls satisfied us to make use of the similar resolution for this new undertaking,” mentioned Ozan Ferrin, era automation manager for Tacoma Energy.
Ferrin and different Tacoma Energy controls engineers designed a fully computerized machine the usage of 4 ControlLogix PACs. Two PACs every regulate one in all two 1.eight MW generator gadgets, a 3rd controls the steadiness of the plant together with operation of an current river outlet valve for go with the flow continuation within the match of a unit commute, and a fourth controls the fish sequence apparatus and fish hoist machine on the base of the dam situated simply out of doors of the powerhouse.
With the brand new machine, the operator controls the powerhouse the usage of a unmarried go with the flow regulate setpoint for the plant. The steadiness of plant PAC receives the regulate set level and mechanically problems go with the flow directions to every of the generator gadgets and the river outlet valve to ramp go with the flow at a regulated price, mimicking seasonal river flows. DNP playing cards and Modbus® playing cards from ProSoft Era, a Rockwell Automation Surround™ Product Spouse and a member of the Rockwell Automation PartnerNetwork™ program, interface with sensors, apparatus and different methods on the Northfork Powerhouse. They supply seamless Ethernet communication throughout more than one platforms.
If one or either one of the turbines is going offline, the steadiness of plant controller will in an instant open the river outlet valve to make up for the misplaced go with the flow, preserving water flowing at a uniform price.
For the fish sequence facility, the Tacoma Energy engineering group had to design a hoist that might transfer grownup fish over the dam and smolt down the aspect of the dam easily. This required drives with actual regulate.
That regulate starts on the base of the dam. As fish swim towards the dam, absolutely grown fish are captured in a hopper on the fish sequence facility and mechanically hoisted up the aspect of the dam on a tram operated by means of an Allen-Bradley PowerFlex® 700 AC pressure. The pressure’s Allen-Bradley TorqProve™ capability is helping set up regulate of the hopper when shifting regulate between the pressure and the tram’s mechanical brake. The hopper lifts the fish to the highest of the dam, the place they’re separated, counted and transported by the use of vans to Lake Cushman. PowerFlex 70 drives and aggregate starters are used to function the fish sequence apparatus.
At the different finish of the fish lifecycle, juvenile fish swimming towards the sea are positioned into the hopper on the most sensible of the dam and are carried down onto a smolt free up cart to free up the fish downstream towards the sea.
Tacoma Energy regulate engineers programmed the PowerFlex drives with Allen-Bradley DriveTools™ SP tool and Rockwell Instrument® Studio 5000 Logix Clothier™ programming tool. The engineers have been in a position so as to add the drives without delay to the Studio 5000 Logix Clothier program as an add-on profile, which helped save programming time by means of mechanically integrating pressure parameters into the Studio 5000 Logix Clothier software – the similar tool used to program the ControlLogix controllers.
“We’ve attempted different regulate tool, and none that met all our controls wishes have been as simple to make use of because the Studio 5000 Logix Clothier tool,” Ferrin mentioned. “And because we will be able to use the similar tool that we used to program our controllers to additionally program and retailer our pressure parameters, we save on commissioning time and are in a position to retailer our pressure parameters and controller program in one report location.”
The Tacoma Energy group additionally makes use of I/O playing cards from Rockwell Automation to remotely track temperature, apparatus standing and to regulate apparatus from the Tacoma administrative center.
The gathering facility has restored the fish migration course, and the corporate is now authorized to generate electrical energy for the town of Tacoma till 2048.
Tacoma Energy additionally met its operation objective for the brand new powerhouse – producing three.6 further megawatts of hydropower.
Since the powerhouse is totally computerized, the corporate have shyed away from incurring further operator prices. “With one push of a button from our regulate heart, we will be able to ramp go with the flow up or down – which is extra correct than doing it manually and saves us the prices of on-site staffing,” Ferrin mentioned.
The machine additionally reduces the chance of violating go with the flow necessities set by means of the Federal Power Regulatory Fee (FERC). The facility to mechanically open the backup river outlet valve in case a unit journeys is helping the software corporate meet the ones compliance requirements extra successfully.
Every other plus: Since the corporate added extra renewable power to its portfolio, it now receives renewable power credit from the state.
To additional spice up the fish inhabitants, Tacoma Energy is construction two new hatcheries on the Cushman River Mission. The primary will carry 2 million sockeye every yr, and a 2d will carry 425,000 younger salmon and steelheads. All can be launched into Lake Cushman.
The consequences discussed above are particular to Tacoma Energy’s use of Rockwell Automation services and products along side different merchandise. Explicit effects would possibly range for different consumers.