If the sun certainly attracts media attention, the wind is not, however, remains in California. The state has the third largest installed wind from behind Texas and Iowa in the United States [1]. Indeed for many years California has pursued an aggressive policy with the aim of achieving a rate of 33% of electricity production from renewable sources by 2020. The wind should play a major role in this portfolio with the goal of 20% of production alone [2].

In this context a multitude of projects funded largely by electricity producers are emerging. This is the case of Pacific Wind project: enXco, a subsidiary of EDF Energies Nouvelles and San Diego Gas & Electric (SDG & E) signed an agreement to build a wind farm in Southern California with a capacity of 140 MW. enXco will own and construct the facility, while SDGE agrees to purchase the power generated for 20 years. The project is pending approval by the CPUC is expected to be operational in late 2011 – early 2012 and will be maintained by enXco Service Corporation.

However, the grid 50 years old is not prepared to integrate intermittent generation-related fluctuations and wind-dispersed over the territory. Therefore an update of the infrastructure and the deployment of new technologies is essential for the future.

The storage, key wind

To offset the intermittent nature of wind and compensate for fluctuations in energy, electricity generators rely on storage systems. Last November Obama had announced funding of up to $ 620 million stimulus package, including $ 435 million will be awarded for demonstration projects of the intelligent network. The remaining funding is allocated to 16 projects for experimental storage capacity eventually to greater efficiency and better reliability [3].

In this context Pacific Gas & Electricity (PG & E) has won one of 16 projects and received $ 25 million to initiate work on possible ways of storing energy from the wind during the night. PG & E plans to develop energy storage technology based on compressed air. The idea is to store the air and compress it in underground cellars where the wind can generate a lot of energy and use this compressed air to drive turbines and generate electricity when the wind is fell. If the test proves successful the technology, 300 MW could be produced for an initial investment of $ 365 million. The project must however be approved by the CPUC that will raise the remaining funds needed.

A similar project is being developed at Sandia National Lab’s premises. The Iowa Stored Energy Park [4] is expected to save $ 5 million per year with a capacity of 268 MW of storage compressed air. Indeed, the storage can meet the needs of growing consumption peaks that require the addition of extra power very expensive.

Similarly Beacon Power Corporation has installed a storage system using flywheels inertia connected to a wind farm in Tehachapi, California. The system is part of the demonstration project inertia flywheel driven by the Californian Energy Commission. Tehachapi is an area with high potential. According to a report of the California ISO, up to 4200 MW of wind could be added in the coming years. The main function of these flywheels is to keep current on the network. However during periods of large fluctuations in consumption or production of transmission lines, they can be used to compensate for the lack or excess electricity to the grid.

New transmission lines needed

Another key element of the deployment of wind energy is the transmission network. Large regions with significant wind resources are not those where consumption is most important. The three major areas are Altamont Pass (east of San Francisco), Tehachapi (southeast of Bakersfield) and San Gorgonio (east of Los Angeles) [5]. The problems are posed at the delivery of electricity across the territory. Producer Southern California Edison (SCE) said it had completed the first phase of Southern California Edison’s Tehachapi Renewable Transmission Project [6]. The transmission network will be able to carry forward a capacity of 4500 MW of electricity from renewable energy produced in the Tehachapi Valley and distributed to three million homes across Los Angeles County. The total project cost is $ 2 billion for a network of 173 miles (~ 280 km). The project represents only a portion of the $ 5.5 billion that SCE plans to invest in the transmission network in the next 5 years. The project when completed will help ease the Los Angeles Basin.

The total price for the addition of transmission to meet the objectives of 33% renewable energy production for 2020 was estimated at $ 15.7 billion [7]. Also transport problems of renewable energy is not unique to California. A report [8] recently published by the American Wind Energy Association had highlighted the need for a standard for renewable electricity and an updated infrastructure to connect about 300,000 MW of wind projects still pending connection to the grid.

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