Can solar play nicely with coal and natural gas?

Tucson Electric Power (TEP) is working with Areva Solar on a concentrated solar power (CSP) "booster" to the 156-megawatt Unit 4 at TEP’s H. Wilson Sundt Generating Station in Tucson. The Sundt plant is a dual-fueled unit capable of using coal or natural gas.

The Solar Boost Project will use Areva Solar’s Compact Linear Fresnel Reflector (CLFR) solar steam generators to produce up to 5 megawatts of power during peak power demand. Areva acquired the CLFR technology from KPCB-funded Ausra back in February 2010.

If and when fossil fuel prices rise or emission allowances are mandated, solar-augmented steam cycles might be a pragmatic option for energy companies.

A typical system would use steam generated by a solar field coupled to a conventional coal or natural gas-powered steam cycle, offsetting some of the fossil fuel required to generate power. Many energy companies are interested in adding solar power to their generating mix, but most solar technologies are not yet cost-competitive with fossil-fuel power generation.  

Why build a hybrid plant instead of a fossil-fueled plant or a stand alone PV or solar thermal plant?

  • It reduces the amount of fossil fuel being burned
  • A hybrid produces less emissions
  • It potentially "greens" existing assets
  • Hybrids can address regulatory pressures and potentially help meet Renewable Portfolio Standards   
  • The transmission and Balance of Plant (like the power block) are already in place, as well as existing plant staff, along with permits and a water supply

Hybrid solar thermal is gaining popularity. There are more than a dozen projects in development with a total solar component of about 450 megawatts. The largest is the FPL project with 75 megawatts of solar in Florida.

The Sundt Solar Boost Project is part of TEP’s plan to expand its solar generating capacity to more than 200 megawatts by the end of 2014 in an effort to meet the Arizona RPS 15 percent by 2025.

Construction of the Sundt Solar Boost is due to begin in the spring of 2012, and it is expected to be operational by early 2013. 

Areva just broke ground on a 44-megawatt solar booster project for an Australian coal-fired power plant and currently has more than 540 megawatts of CSP projects in operation, under construction, or in development.

Other hybrid CSP-fossil fuel projects expected to start up in 2014 include:

  • NV Energy at the Chuck Lenzie Station in Nevada, an 1100-megawatt natural gas plant with 95 megawatts of proposed solar
  • Tri State G&T in Escalante, New Mexico, a 245-megawatt coal plant with 36 megawatts of proposed solar

Areva's Compact Linear Fresnel Reflector (CLFR) solar steam generators


Correction: This article originally mentioned the Cameo coal-steam hybrid plant in Colorado which has since been retired. Here is a link to a performance report on that project. The report concluded that "[o]verall the performance related to coal and emissions savings were not as good as Abengoa predicted or what Public Service expected."