21.10 The Capital Costs of Firming Solar Farms with Gas Turbines

May 2021 

Purpose: To challenge the view that solar farms firmed with gas turbines are an economic substitute for coal fired power generators.

Background: The NSW Government’s policy reflected in ‘The NSW Electrical Infrastructure Roadmap’ advises that four of its five coal fired power stations will be decommissioned by 2035.  The Roadmap’s strategy is to construct large Renewable Energy Zones (REZ) consisting of wind and solar farms firmed with some combination of gas turbine, batteries and pumped hydro plants.

Critical Issues: 

  1. If solar farms are selected to replace the coal fired power stations, approximately 75, 270 MW solar farms will need to be constructed to replace the energy lost through decommissioning the four coal fired generators.
  2. Solar farms do not operate after sunset.  If Open Cycle Gas Turbines are selected as the firming technology, approximately 16, 549 MW plants will be required to compensate for the 12 hours of darkness.
  3. The solar farms and the gas turbines will need to be constructed before 2035 at a capital cost of approximately AUD 81.9 Billion.
  4. The four decommissioned coal fired plants could be replaced by nine modern HELE USC 1050 MW coal fired plants at a cost of approximately AUD 22.5 Billion.

Recommendation:

The NSW Government should fund and own the replacement HELE USC coal fired generators and contract their operation and maintenance to private industry under a profit-sharing incentive arrangement.
Should that strategy be adopted, the following advantages would accrue:

  1. The capital cost is significantly less, thus better serving the financial interests of the NSW electricity consumers.
  2. NSW would be provided with reliable, affordable and dispatchable electrical energy which is not weather dependent.
  3. The HELE USC coal plants could be constructed in the same location as the existing coal plants, thus providing easy access to fuel, water and transmission facilities.
  4. Absence of insolation ceases to be an issue.
  5. The requirement to construct firming gas turbine assets would be obviated.
  6. The requirement to construct the 11,000 km of transmission lines identified in the Roadmap would be obviated.
  7. The requirement to compensate landowners for the construction of solar farms would be obviated.

The paper supporting this note provides the analysis that demonstrates the disastrous economic and other outcomes of the flawed NSW Electricity Roadmap.

AUTHORS:
Michael Bowden; IEng(Electronics-UK);CPL;CQP
Craig Brooking; MBA; BE(Civil); FAIC, Dip; formerly FIEAust; CPEng

To obtain a copy of the paper, contact  This email address is being protected from spambots. You need JavaScript enabled to view it.

 

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