By Larry Masur, American Superconductor Corp.
Solutions to avoid reoccurring blackouts and energy shortages have typically focused on the need for generating more power. Ironically, with the increase in construction of new power plants over the last decade we now have a surplus of power, yet the energy shortages and blackouts persist. To effectively resolve this issue we need to finally recognize that the main cause of the problem is our inability to get energy where it needs to go.
While we have enough generated capacity to meet our country’s needs, we’re lacking the proper infrastructure and technology to effectively distribute and transmit electricity to users. According to a recent FERC report, energy bottlenecks in the transmissionsystem have cost consumers more than $1 billion in the past couple of summers, and the agency is supporting investments to improve the grid. The Commission believes that the resulting lower energy costs would pay for the cost of improving the transmission and distribution system within a few years. John Rowe, co-CEO of Exelon Corporation, testifying before the US Senate’s Committee on Energy and Natural Resources said that maintaining the adequacy of our transmission grid at current levels would require a $56 billion investment during the present decade.
Because of community and environmental opposition to siting conventional transmission lines, we are unlikely to see the substantial build out of grid facilities that was prevalent in the 1960s to 1980s. Instead, future grid expansion will most likely focus on intensive use of existing rights of way, on leveraging existing assets by adding smart switching and other capabilities to the existing grid, and by improving underground facilities.
New technologies are becoming available that are designed to alleviate transmission and distribution bottlenecks and improve the quality and reliability of our power grids. One such technology is high-temperature superconductor (HTS) cable, which can carry five to ten times more power than conventional copper underground cable. Power-dense HTS cables, which are currently being tested under field conditions, allow large amounts of power to flow into congested metropolitan areas where power loads are concentrated without environmental impact.
Another technology, superconductor magnetic energy storage (SMES), stores large amounts of power in magnetic coils that can be rapidly discharged into industrial operations and power grids. SMES technology avoids sags and momentary power outages by increasing power quality and allowing a more even flow of electricity through the power grid. By distributing these devices on existing grids, utilities can deliver hundreds of additional megawatts at low incremental cost.
One of the key enabling technologies of new power applications is HTS wire. First discovered in 1986, HTS materials today are being used in the manufacture of high performance electrical wire capable of carrying significantly higher amounts of electricity than copper wire. American Superconductor’s wire can carry 140 times the current of a similar sized copper conductor.
From the lab to the field
The HTS cable demonstration project currently underway at Detroit Edison’s Frisbie substation is an example of what’s involved in transferring technology to a real-world environment and serves as a learning ground to further commercialization of the technology.
American Superconductor provided Pirelli Energy Cables and Systems with the HTS wires to be used in the cables for this project in the summer of 2000. Pirelli manufactured the cables and installed them at the DTE sub station in the summer of 2001. During the fall of 2001, Pirelli completed all cable terminations and installed the cryocooling system components. After the connections were made, Pirelli conducted rigorous tests on the installed cables and verified that American Superconductor’s HTS wires successfully met all the performance requirements. As the cables were being cooled down prior to energizing, Pirelli discovered a problem with the thermal insulation system (also known as the cryostat), causing a delay in the project.
Pirelli is now conducting tests to determine the cause of this problem, and how the system needs to be adapted to meet the specific conditions in the field prior to energizing the cables. This type of delay in adapting new technology to real-world conditions is expected in demonstration projects, and the learning process will be invaluable to the success of other HTS cable projects already underway. In parallel, other HTS cables are being tested successfully at other locations in Japan, the U.S. and Europe.
Larry Masur is director of HTS technology commercialization at American Superconductor. For further information, contact Jeff Nestel-Patt at firstname.lastname@example.org