In turnaround, Ivanpah plant gets on track to meet projections

Source: Anne C. Mulkern, E&E reporter • Posted: Friday, April 8, 2016

The Ivanpah solar tower plant in California’s Mojave Desert has doubled the amount of power it’s making versus a year ago, putting it on track to hit the total it promised the state, operator NRG Energy Inc. said yesterday.

The largest power tower project in the world, the Ivanpah Solar Electric Generating System last month received a six-month extension to reach the electricity total in a power purchase agreement (PPA) with utility Pacific Gas and Electric Co.

Ivanpah uses 173,000 heliostat mirrors to concentrate solar power. When it opened, the 377-megawatt plant was touted as able to make enough power for 140,000 homes. It’s fallen short of that total, triggering the need for the forbearance agreement approved by the California Public Utilities Commission.

The total is calculated as a two-year running average, and there were problems in 2014 that pulled down the number. Power generation now is rising rapidly, said David Knox, spokesman for NRG Energy.

“Generation at Ivanpah has been steadily increasing as we have improved the technology and the ability to operate it,” Knox said. “This is the first ‘at scale’ usage of CSP tower technology and by far the largest. We had always planned on a four-year ramp-up to get to mature performance.”

February generation this year exceeded February 2015’s by 122 percent, Knox said. Last year in turn exceeded February 2014 generation by 214 percent, he added.

Knox would not reveal the required level of power, saying it’s a confidential part of the PPA.

There are three units at Ivanpah. Each tower has a separate PPA. The output of Units 1 and 3 goes to PG&E; Unit 2’s power is purchased by Southern California Edison Co.

Total plant output for February was 67,260 MW, up from 30,273 MW a year earlier, Knox said.

“The doubling in generation from February 2015 to February 2016 and the overall increase in generation over the first two years since going online is mainly a result of improved operations,” Knox said. “As an example, by improving the insulation of the turbines overnight, we have decreased morning startup time from three-plus hours to less than 30 minutes.”

Ivanpah has drawn unwanted attention for its side effect of incinerating birds that fly into the “flux field” between the mirrors and the towers. An estimated 3,500 birds died as a side effect of those mirrors during the site’s first year of operation, a consultant report said (Greenwire, April 24, 2015).

Along with NRG, Google and BrightSource Energy Inc. are investors in the plant.