Hitachi Energy will spearhead the modernization of a key high-voltage direct current (HVDC) system in Canada to support the transmission of 1,500 MW of renewable power between Quebec and New York state’s electrical networks.
Hydro-Québec, Canada’s largest power utility, on Dec. 15, picked the global technology firm to supply a “back-to-back” converter station at Châteauguay, located southwest of Montreal, Quebec. Back-to-back HVDC converter stations are typically used to create an asynchronous interconnection between two alternating current (AC) networks.
|Read more about recent advances in HVDC technology in “The Vital Link: How HVDC Is Modernizing the Grid” from POWER’s June 2022 issue.|
Raising the Power Conversion Capacity by 50%
Hitachi Energy, a global technology firm that evolved from a 2020 acquisition of ABB’s Power Grids business, commissioned the original HVDC converter station at Châteauguay in 1984. The facility owned by Hydro-Québec is already the largest back-to-back HVDC converter station in North America.
According to Hitachi Energy, the substation comprises two independent 500-MW back-to-back converter units that are slated to reach the end of their useful lives in 2024. “It is supplied from a 315 kV source on the Hydro-Québec side and a 120 kV source on the New York Power Authority (NYPA) side. Generation is supplied by the Beauharnois power station, constructed in 1984, and has a maximum power transfer capacity of 1,000 MW at a DC voltage of 140 kV,” the company noted.
As part of the modernization effort unveiled on Thursday, Hitachi Energy will replace the existing Châteauguay system’s existing equipment to increase its efficiency and controllability. The company said the upgrade would also raise the power conversion capacity of the Châteauguay HVDC system by 50%.
“Hitachi Energy is supplying a ‘back-to-back’ converter station, which converts AC power to DC then reconverts it to AC from DC, enabling the interconnection of the 735 kV Canadian and 765 kV New York grids which are ‘out of phase’ and cannot be connected directly via traditional AC systems,” it explained.
Boosting Asynchronous Interconnection Capacity
Hitachi Energy says that 70% of the world’s 200-GW HVDC base is installed with its technology. The company retains a 70-year-old heritage in HVDC expertise, which began in 1954, when ASEA, ABB’s predecessor, pioneered the world’s first commercial HVDC link in Sweden.
Earlier this year, Roger Rosenqvist, vice president of business development for Hitachi Energy’s HVDC division in North America, told POWER that HVDC is well-suited to rapid changes on the grid owing to its many advantages over classical AC solutions. These include active power control, higher transfer capacities, no reactive power, longer possible transmission lengths, and lower active power losses.
HVDC’s ability to interconnect networks that operate asynchronously is also gaining traction, Rosenqvist noted. He said that feature might be especially beneficial in North America, where many asynchronous interconnections exist, such as projects linking Canada to the U.S.
“There are several back-to-back stations in operation in the world,” Hitachi Energy noted. “In these installations, both the rectifier and the inverter are located in the same station and are normally used in order to create an asynchronous interconnection between two AC networks, which could have the same or different frequencies. Another benefit is using a back-to-back for splitting up a too strong network to reduce short circuit current,” it said. “The direct voltage level can be selected without consideration of the optimum values for an overhead line and a cable and is therefore normally quite low, 150 kV or lower. The only major equipment on the DC side is a smoothing reactor.”
HVDC Projects Making an Impact
The Châteauguay order marks another boost for HVDC development in North America, where demand has historically lagged. According to the Department of Energy (DOE), HVDC’s uptake has suffered because large transmission projects require collaboration from multiple regional transmission organizations (RTOs). Another factor is that the cost-recovery aspect of an HVDC “needs a new customer base—similar to a tollway project business model—that is hard to forecast due to competition with existing, lower cost transmission systems,” it said. The DOE suggests that enhancing collaboration between RTOs and developing government policies to stimulate demand could boost HVDC demand as well as HVDC domestic manufacturing.
But the HVDC modernization project is also notable given a spate of newly announced HVDC projects that, bolstered with government support, are being developed to enable the large-scale transfer of renewable power. For example, the state of New York has been pivotal in championing connections to enable the delivery of solar, wind, and hydroelectric power from upstate New York and Canada to New York City. These efforts will accelerate progress to achieve New York’s Climate Leadership and Community Protection Act goal to obtain 70% of electricity statewide from renewable sources by 2030 and put it on a path to a zero-emission grid, the state has said.
New York, notably, has rolled out a first-of-its-kind “renewable energy and transmission program” known as Tier 4. Gov. Kathy Hochul announced two recommended contract awards in September 2021: the Champlain Hudson Power Express project (CHPE) and the Clean Path NY project.
Stemming from a contract finalized in November 2021, construction of the 339-mile CHPE transmission line kicked off on Nov. 30. The HVDC line, which Transmission Developers Inc. is developing, will run from the U.S.-Canadian border, south through Lake Champlain, under the Hudson River, and eventually end at a converter station that will be built in Astoria, Queens. It will deliver up to 1,250 MW of power from Hydro-Québec directly to New York City when completed in 2025. Hitachi Energy said it will supply an HVDC Light converter station to the project, “which will convert the DC power from Canada to AC power and make it available for the AC grid in New York.”
Meanwhile, Clean Path NY’s 1,300-MW HVDC line will be built entirely underground. The full project will be located within New York State, comprising more than 20 renewable energy generation projects (a combined 3.8 GW) and an approximate 175-mile transmission line. The $11 billion project is slated to begin construction in 2024 and operation in 2027.
In related news, Hitachi Energy in October handed over the North Sea Link power interconnector to Statnett, Norway’s national power grid operator, and National Grid, which owns and manages gas and electricity infrastructure in the UK and the northeastern U.S. That link is now the world’s longest subsea power interconnector.
Enabled by HVDC Light, the North Sea Link connects power grids in Norway and the UK, which the North Sea separates. It has the capacity to transmit 1.4 GW of renewable power via a 447-mile HVDC underwater cable. “The link increases power supply reliability and security in both countries, accelerates progress toward their sustainability targets, and facilitates power trading and economic growth,” said Niklas Persson, managing director of Hitachi Energy’s Grid Integration business.
Also in October, Hitachi Energy announced it signed a long-term agreement with Société Nationale d’Electricité (SNEL), a power company owned by the Democratic Republic of Congo, to service the country’s 1-GW Inga-Kolwezi HVDC link. The link supplies power from the massive Inga Falls hydropower plant far west of the country to the Kolwezi mining region in the south. “With a length of 1,700 kilometers, it is the longest HVDC link in Africa. It also enables the Democratic Republic of Congo to export surplus power to the member countries of the Southern African Power Pool,” Hitachi Energy said.