Mar 12 2010

More renewable energies == new transmission lines

Last Thursday took place the Berkeley Energy Symposium which brought together a large panel of companies representatives, researchers, and policy makers involved in clean technologies. Among them Philip Moeller, one of the five commissioners at the Federal Regulatory Energy Commission (FERC), said during one of the keynotes that the U.S. needs to beef up its transmission grid, and citizens seem to understand this. Unfortunately people also regularly object to new transmission lines, natural gas lines and to other components required to keep the lights on: "There is a recognition that we need more transmission... There is no way to capture more renewable without more transmission, but people don't like to look at it... People hate energy infrastructure." (greentechmedia)

Current situation and why it needs to be improved.

The Californian state already requires its major utilities to deliver 20 percent renewable energy by the end of the year. State lawmakers are now considering boosting that to 33 percent by 2020. A report published in last August from California regulators and utilities put a $15.7 billion price tag on the new transmission lines needed to meet this goal. This would most likely require carrying lots of power from where it's most efficiently generated – by wind turbines in the Midwest or solar-thermal power plants in the Southwest – over long distances to population centers that need it. But that will require a whole new set of transmission lines, marching north and south along the state's Central Valley and east and west across its mountain ranges and deserts, according to a map of proposed routes given in the report.

Long-distance, high-capacity power transmission circuits operating at high power levels will be needed to bring power from remote sources such as large wind farms to urban load centers. “In the future we may see the development of generation facilities, such as large wind farms or nuclear farms capable of producing 5 to 10 GWatts, but located far from urban centers of demand. It will then be necessary to move large amounts of power over long distances” said Arshad Mansoor, vice president of Power Delivery and Utilization for EPRI. This is timely considering the U.S. government focus on upgrading the nation’s outdated electric transmission grids and distribution systems by 2030 with a network of powerful superconducting cables. The move comes in response to increasingly frequent power failures and other power supply-related problems that have plagued the US power systems in recent years.

How to do it

To face the transmission issue, the Renewable Energy Transmission Initiative (RETI) has been created. It is a statewide initiative to help identify the transmission projects needed to accommodate these renewable energy goals, support future energy policy and facilitate transmission corridor designation and transmission. RETI’s goals are to assess all competitive renewable energy zones (CREZ) in California and possibly also in neighboring states that can provide significant electricity to California consumers by the year 2020. Then identify those zones that can be developed in the most cost effective and environmentally benign manner and prepare detailed transmission plans for those zones identified for development. RETI conceptual plan takes for granted that California will also fully achieve its energy efficiency program targets and exceed its currently adopted goals to aggressively expand distributed photovoltaic generation.


To forecast and plan an efficient transmission deployment, policies makers have to rely on simulations as detailed as possible. In response, the Renewable and Appropriate Energy Laboratory (RAEL) based at the University of California in Berkeley (and also present at the Berkeley energy Symposium) has developed a new software. Switch (standing for Solar, Wind, Hydro and Conventional generators and Transmission), can explore development options for the future electricity grid throughout the United States. The model identifies cost-effective investment decisions for meeting future electricity demand, taking into account the existing grid as well as projections of future fuel costs, technological developments, renewable energy potential, and proposed policies. Early results for California indicate the state's Renewable Portfolio Standard can be met with no additional cost to consumers

Lines updating with more efficient technologies

Moving huge quantities of electricity over vast distances could become easier over the next decade if utilities adopt a new type of power transmission system using direct current (DC) rather than alternating (AC) and superconducting cables according to the Electric Power Research Institute. The institute describes the design of a superconducting direct current cable system capable of moving thousands of megawatts of electricity between regions in a recent report (published March 3). Two companion superconducting reports highlight the practical issues of integrating a long-distance high-power superconducting DC link into an existing lower-power AC transmission and distribution systems, and states that the operation and control of this link will be critical to the viability and acceptance of the concept. As designed, the superconducting cable system outlined in the report would provide 10 GW power capacity with a nominal current and voltage of 100 kiloamps and 100 kilovolts. The report also points to the cable system’s potential to enhance the safety, reliability and efficiency of the existing AC power grid.

The report also indicates that builders of superconducting DC transmission lines could rely on commercially available technology and construction methods similar to those used in natural gas pipeline construction. These include factory manufactured, transportable sections of an outer carbon steel pipe containing inner stainless steel piping for the flowing coolant and superconducting cable, and trucking to the site for assembly, welding and burial

Assuming the current trend in cost-performance improvements in superconducting wire continues, EPRI said a superconducting DC transmission line could become an option within a decade, along with the extra high voltage AC lines that are currently being used to move large amounts of power over long distances.

Projects in California

Several projects are underway or completed. Here a list of these projects from the Californian Energy Commission (CEC)
• SB 1059 State Corridor Planning
• Imperial Valley Study Group (Completed)
• Renewable Energy Transmission Initiative (RETI)
• Solar Programmatic Environmental Impact Statement (PEIS)
• West-Wide Federal Energy Corridor Programmatic Environmental Impact Statement (PEIS)
• California ISO Regional Transmission Planning
• California Public Utilities Commission - Transmission Information and Projects
• U.S. Department of Energy National Interest Electric Transmission Corridors (NIETC)
• U.S. Department of Energy Wind Energy Development Programmatic Environmental Impact Statement Information Center

Green Tech Media
A FERC Commissioner’s Top Trends to Watch
California ‘Green’ Transmission Lines Could Cost $15.7B

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