Tres Amigas SuperStation on Track for 2014

CH2M Hill lands contract for managing construction on the project. Will one grid rule them all?

A 22.5-sq.-mile site in the small town of Clovis, New Mexico is the only place in the United States where the three grids that service the western states, some eastern states, and the entire state of Texas all meet.

Sort of. The three grids come close to each other, but they aren't connected. This prevents electricity from being transferred between the Eastern Interconnection (which services states like New York), the Western Interconnection (which services states like California), and the Texas Interconnection (well, this one is obvious). In that sense, it's like the nation's fragmented roads in the 1950s, before the Interstate Highway System linked the country.

With Tres Amigas, California conceivably will be able to siphon off excess wind capacity from Texas. At the current juncture, that is physically impossible. The transmission structure doesn't exist and energy storage technologies -- flow batteries, compressed air, sodium batteries -- aren't yet economical enough to start planting them en masse in the desert.

CH2M Hill is overseeing the construction of Tres Amigas SuperStation, a project that will change all that. The project will connect the entire power grid across America for the first time. The initial phase of the project will cost $600 million, but the hub is expected to make money by buying and selling electricity to utilities (and could make some $4 billion in revenue every year).

In the last 20 years, blackouts have increased to 124 percent in the United States. Smart grids could predict a potential outage and send electricity to the places where it is needed.

"The three grids are like three giant ocean liners that you are attempting to tie together," said Randy Connett, T&D services head at CH2M Hill.

The SuperStation will transform the way Americans consume electricity, make the grid more reliable, allow different forms of renewable energy to enter the grid, and open up the market for energy producers to unlock their renewable energy assets.

"Renewable resources seem to be a long way from where the load centers are," said Connett. The power grids currently in place are only designed to deliver power locally and can't distribute renewable energy over long distances.

"There are regulatory challenges. It's not a generator, but it acts like a generator. It's not a transmission line, but it is a kind of transmission line," said Connett. "It's a converter station. Because it's a new type of facility, regulators are working on how to classify it. They have rules on how to connect transmission lines and generators, but there are no rules to connect this type."

The SuperStation converts the AC power in the power lines to DC while it is in the station and then reconverts to back to AC (your cell phone and laptop run on DC). The conversion allows the power to be easily transferred from one grid to another. It's worth doing it over long distances so less energy is wasted, and it ensures the power arrives at its desired destination.

Construction on the station will begin in 2012 and should be completed by 2014. It will be built with underground direct current superconductor cables, voltage source converters, and energy storage systems.

The station will have initial power transfer capacity of about 5 gigawatts (GW), which can power 5 million homes. This will soon increase to 30 GW as the market grows, Tres Amigas representatives anticipate. The energy will be distributed more efficiently, so it will save hundreds of millions of dollars.

The nation needs a grid makeover -- and the Tres Amigas project is a good start.

Alan Champagne, vice president at CH2M Hill, said, "We are seeing the whole market change. There's a shift to [offering] more services. We want more plasma TVs [and other household items]. The peak market is growing."

The SuperStation will connect the utilities to other sources of energy. This will reduce the spinning reserve. Each utility is expected to have extra power. "If you are not able to draw from somebody else, you build more and more power plants. But if you can share between locations, you don't need as much spinning reserve," said Champagne.

So if a power plant goes down in Texas and you have spinning reserve in California, you can send the power needed over to Texas. Projects of this scale give the power grids the ability to share power where it is most in demand.

"The SuperStation is an additional source of supply and an additional market to deliver goods to," said Connett. "It's an exciting project that promotes sustainability and creates jobs in the Southwest. Those are both things we are delighted to be apart of."

The move to integrate more renewable sources of energy into the grid isn't all that American -- Europe and China have definitely taken the lead in rolling out converters to upgrade their aging power grids.

"In Europe, HVDC can connect countries using sub-sea cables that are only possible using HVDC cables because of the distances. Also, offshore wind generation can be connected to the grid using sub-sea cables," said Gary Rackliffe, ABB's VP of North America.

In Europe, the North Sea supergrid has opened up markets for solar and wind energy trade. For instance, the European Union's synchronous grid allows Britain to access France's nuclear power through undersea cables.

China is using HVDC for above-ground transmission over long distances in order to connect generation in western China with the load centers in cities in eastern China.

"For Tres Amigas, HVDC is being used because Texas, the Western Interconnect, and the Eastern Interconnect all are 60-Hz operating regions, but they are not synchronized," said Rackliffe. "HVDC is used for the interconnection with 'back-to-back' systems that convert from AC to DC, connect between regions, and then invert from DC to AC. The Texas, Eastern, and Western operating regions can be interconnected at Tres Amigas," he said.

The deal, naturally, is attracting other big name partners. American Superconductor Corp. will supply superconducting wire. Superconducting cables can carry far more electricity than their traditional transmission cable counterparts, though they need to be cooled with liquid nitrogen to do so. Despite their high cost, superconducting DC cables are seen as a viable alternative for certain high-voltage transmission applications (see Superconductors For the Grid).

American Superconductor is already making superconducting wire for Korea's LS Cable to install in that nation's electricity grid (see this Green Light post).

Xtreme Power announced today that it has been selected as the energy storage provider for Tres Amigas. The company's Dynamic Power Resource (DPR) energy management system will deliver consistent power across the three grids and respond to fluctuations. The DPR will also provide back-up power to each grid.

The storage system has been used in locations with extreme climactic conditions, such as the South Pole, and in wind farms in Hawaii. In the Tres Amigas project, Xtreme Power's system will integrate renewable energy sources smoothly into the mega-transmission hub so the power can get to the customers who need it most.