With two new turbines up and running, Mica has grown with B.C.
An insider view, in words and video, of how new generating units were delivered
Back in 1973, the year B.C.'s Mica Dam was completed to become one of the world's largest earthfill dams, the population of B.C. was 2.36 million (about half what it is today). And Vancouver had two professional hockey teams, including the bright yellow-and-orange Vancouver Blazers of the World Hockey Association.
By 1977, Mica had a working powerhouse and Vancouver was back to one pro team, the Canucks. Literally carved out of a mountain a 90-minute drive north of Revelstoke, the Mica Generating Station debuted with four power-generating units, and room to add two more.
Nearly four decades later, in 2015, Mica units 5 and 6 went into service and immediately added the ability to power an additional 80,000 homes in B.C. during periods of high demand.
"For me the amazing thing is that the infrastructure was already there," says BC Hydro's Will Kirkness, who schedules contractors working at Mica. "We've added 1,000 megawatts to the system without changing anything."
To Kirkness, one of the most amazing moments was seeing two water passages, built from the Kinbasket Reservoir through the mountain that houses the powerhouse, opened up after decades of being blocked by gates.
"We put these gates in close to 40 years ago," he says. "We pull the gates out and the water passages just open up. That's pretty cool. You installed this water passage that sits underwater all that time, and when it comes time to use it, it just works."
The Mica Unit 5 and 6 projects, at $714 million, are part of the average $2.4 billion a year that we're investing in our generation and transmission systems over 10 years. It's in keeping with the plan to ensure our electrical system stays in step with a province that, according to Statistics Canada, will add a million people in the next 15 years.
Investments in older facilities mean affordable power for decades to come
We don't know whether the Canucks will have a Stanley Cup 15 years from now. But one thing we do know is that an electrical system that had largely been built in the 1960s and 1970s will have been updated and upgraded to meet the power needs of a growing province. Investing in existing assets across the system is just one way we're keeping electricity affordable for British Columbians.
In the case of Mica Units 5 & 6, the planning done decades ago allowed us to provide 1,000 additional megawatts of power to meet the peak demands of the populous Lower Mainland and Vancouver Island just when it's needed most, on the coldest of winter nights. And that power has been delivered while still keeping BC Hydro's rates among the most affordable in North America.
See below how Mica's new generating capacity helped meet B.C.'s power needs in 2015. But first, here are some videos that give you an idea of what it took to deliver Mica Units 5 & 6.
Rebar and draft tube: Draft tubes carry water exiting a turbine and, while regulating water velocity and ensuring the efficiency of the turbine, transfer it to the tailrace (passage) that spills into the river below a dam. Large steel liners were installed in the draft tubes below each new generating unit to provide extra reinforcement and handle the extremely high pressure of the water flowing through the turbines. The sections of liner were lowered into place, assembled, and then encased in concrete. For each new generating unit, nearly a million pounds of rebar was used to provide additional strength.
Turbine transport from Germany: Mica's fifth and six turbines were manufactured in Germany and transported over 12,000 kilometres from the factory to the dam. Finding a route that such a large and heavy load could safely travel was a real puzzle. The final route involved transport by truck and river barge to the port of Rotterdam (Netherlands), onto an ocean freighter to Houston (Texas), and another truck trip through Edmonton (Alberta) to Valemount (British Columbia), before finally travelling by barge down Kinbasket Reservoir to Mica dam.
Turbine delivery and install: Each new generating unit at Mica is powered by a huge stainless steel turbine that measures 6.45 metres in diameter and weighs 137.5 tonnes, the equivalent weight of four humpback whales or just over 1,800 people. It's a real challenge to get such a massive piece of equipment into the powerhouse, where it's carried across the powerhouse by crane and lowered into the generating unit bay with great precision – less than a millimetre of space around the hole it sits in.
900 truckloads of concrete: Water flows through Mica's turbines with incredible force, so a generating unit needs to be solidly built. A concrete batch plant built near the dam ran 24 hours a day during the concrete work to supply the 36 million pounds (900 truckloads) of concrete needed for each unit. Once concrete trucks delivered the concrete through Mica dam's portal access tunnel, the concrete was moved down the powerhouse by way of crane and bucket, pumps, and chutes.
Rotor assembly: Of all the pieces of equipment in Mica's generating units, the rotors – a part of the unit that rotates – were heaviest. A total of 6,210 steel plates weighing 90 kilograms each were stacked one by one to form each rotor’s outer ring. With the rotors weighing in at close to 1,000 tonnes, both of Mica's powerhouse cranes had to work in tandem to move the rotor down the powerhouse and carefully lower it into the stator with only millimetres of clearance.
Stator assembly: Electricity is generated when a magnetic rotor is spun by the turbine within a stationary ring called a stator. The stator frame is made up of thousands of plates individually placed into a precise sequence with over 1,200 copper bars soldered together. Windings are lashed together with a special cloth and glue for insulating purposes. Each generating unit contains nearly 250 kilometres of copper wire.
The combination of a mild 2014-2015 winter and summer drought conditions that really hit the U.S. hard last summer added up to a rare opportunity for Mica to step up its game in supplying power to the Lower Mainland and Vancouver Island.
With the Columbia River basin experiencing its third driest year on record in 2015, BC Hydro was forced – under obligations in the Columbia River Treaty with the U.S. – to release additional water through the Columbia River system that runs through a series of dams in Washington and Oregon. And that meant that Mica, newly fortified with generating units 5 and 6, was able to supply a lot more power to British Columbians than usual.
That took pressure off BC Hydro's W.A.C. Bennett and Peace Canyon dams on the Peace River system in the northeast, ensuring there was plenty of stored water in the Peace reservoirs to serve B.C.;s energy demands this winter.
"As you’re moving that water [through the Columbia's Mica and Revelstoke dams] you're producing power, which means that our reservoir levels in the north are at a higher elevation than normal," Mark Poweska, BC Hydro's senior vice-president of generation, told the Vancouver Sun in an interview last month. "It's a complex system, but it's all tied together."
A few facts about the Mica Unit 5 & 6 projects
- Each unit adds 500 megawatts of capacity to the electrical system – enough to power 80,000 homes – bringing the total capacity of Mica Dam to 2,805 MW.
- At its peak, work on installing the two new units employed 400 workers.
- In 2014, Secwepemc Camp and Catering – a joint venture between the Adams Lake, Neskonlith and Splatsin First Nations, and Horizon North Camp and Catering – was awarded a BC Aboriginal Business Award to build and operate the temporary 400-person construction camp known as Chief Kinbasket Lodge.
- BC Hydro provided $120,000 through the Mica 5 and 6 Project to support trades training programs offered in the local of communities of Revelstoke, Golden, Valemount and Nakusp.
- Of Mica's original four turbines installed in the 1970s, two were manufactured by Hitachi in Japan, while the other two were products of the Soviet Union, from the Leningrad Metal Works plant. The fifth and sixth turbines from Andritz Hydro installed in 2015 were shipped in by boat, truck and barge from Germany.
- The 6.45-metre wide stainless steel turbines at Mica each weigh 137 tonnes, as much as four humpback whales.