No barrier to large volumes of wind

The International Energy Agency (IEA) says there are no technical barriers to much larger penetrations of variable generation, such as that from wind power, into electricity grids. "The extent to which the intermittency of natural resources will become a barrier to renewables is mainly a question of economics and market organisation," states the IEA after a study into the technical limits of grid integration of renewables, wind power in particular.

Absorbing growing volumes of wind power into grid networks is set to become an increasingly important issue. Wind currently provides 2.6% of Europe's electricity and the share is forecast to rise to 12.1% in 2020. According to the IEA's World Energy Outlook 2004, renewables will account for 19% of world electricity generation by 2030 under its reference scenario and up to 24% in an alternative policy scenario.

The IEA study, "Variability of wind power and other renewables, management options and strategies," finds that transparent, inter-connected and well-functioning markets help minimize grid integration costs. The regulatory regime in some countries is unnecessarily onerous for wind. Some regions still have long "gate-closure" times for bidding generation into the market, which penalise generators who cannot predict their output well in advance. Moreover, the charges on renewable energy in balancing markets do not always reflect the actual costs of deviations from scheduled bids.

A number of measures are needed to integrate wind and other renewables into modern grids, but the technical principles are not new, the IEA says. Solutions include improved wind forecasting, increasing the geographical diversity of wind turbines and diversity of different renewable technologies, greater grid interconnection and fairer market rules. It adds that its estimates show that significantly higher amounts of wind could be cost-effectively integrated. But it urges policy makers to analyse least cost options for integration and look at their incentive structures to encourage market participants to exploit the opportunities. "Ultimately, the question whether there is an upper limit for renewable penetration into the existing grid will be an economic and regulatory one rather than a technical issue," concludes IEA.

Its findings are welcomed by the European Wind Energy Association (EWEA). The paper shows that wind is disadvantaged by faulty market conditions, points out EWEA's Corin Millais. "Wind is variable and so is the entire electricity system. Predictability is one key to variability," he says.

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