Information to support discussion about the BZE model of Gemasolar

Beyond Zero Emissions (BZE) often runs stalls at community events. They frequently have a model of the Gemasolar plant at these stalls and this draws people to the stall. 

This page is to support BZE volunteers using the Gemasolar model.


  • Gemasolar: Spain
  • Aurora Plant: South Australia
  • BZE proposed building this plant
  • South Australia and renewables
  • BZE Zero Carbon Australia Plans
  • Crescent Dunes concentrating solar thermal plant: Nevada
  • Sundrop tomato farm: Port Augusta
  • Hazelwood coal-fired generator

The Gemasolar power plant

How it works

  • A concentrating solar thermal power plant with storage
  • Mirrors collect sunlight to heat molten salts, boil water and generate electricity.
  • There are 2,650 mirrors that move continually, always focusing the collected sunlight onto the central tower.
  • Each mirror (heliostat) is about 12 x 12 metres, about 4 storeys high. They are in a circle of 1.5 km around the central tower.
  • They each focus the sunlight onto the central tower. This heats molten salts to about 565 C.
  • The hot salts then flow into the hot salt tank for use when needed, daytime or nighttime. 
  • The hot salts retain 99% of their heat over 24 hours.
  • The hot salts flow through a heat exchanger to boil water.
  • The steam drives a turbine to generate electricity.
  • The now-cooled molten salts then flow into the cold tank where the temperature is about 290 C.  The salts are then ready to flow into the tower again.

About Gemasolar

  • In Spain, west of Seville.
  • The first commercial-scale plant using this technology. 
  • Started May 2011.
  • Can produce electricity 24 hours a day
  • Longest recorded continuous operation has been 36 days.
  • Can generate for up to 15 hours without sunlight.
  • Registered electrical power: 17 Megawatt
  • Electricity to the grid: 80 Gigawatt-hours per year
  • Power for 25,000 homes
  • Torresolenergy: Gemasolar

In 2013 Gemasolar had a record-breaking run, producing electricity 24 hours a day for 36 consecutive days.
Solar storage plant sets record: Renew Economy

  • A megawatt is a unit of power: energy per second
  • A megawatt-hour is a measure of energy

Aurora plant

  • In South Australia, we are building a plant like Gemasolar
  • Difficulties have arisen with financing the plant (April 2019)
  • About twice as big as Gemasolar
  • 150 Megawatts
  • Concentrating solar thermal with storage
  • Storage: 1,100 megawatt-hours
  • Built by Solar Reserve
  • Heliostats over 10,000

BZE proposed building this plant

  • In 2012, the BZE research report “Repowering Port Augusta” identified Port Augusta as the place to build a solar thermal power plant.
  • BZE advocated for this. The community supported it.
  • The South Australian government held an inquiry into the BZE proposal.
  • In 2017 the South Australian Government awarded a $650 million contract.

South Australia and Renewables

  • South Australia is one of the leading grids in the world
  • Wind and solar now supply 50% of the state demand
  • Tesla big battery,
  • The world’s biggest solar tower and molten salt storage plant,
  • Battery applications for “island-ing” and creating micro-grids,
  • At least half a dozen different pumped hydro projects,
  • The use of hydrogen for storage and grid balancing

BZE Zero Carbon Australia Plans

Since 2009, BZE has been doing research and constructing plans to move Australia to zero carbon emissions.

The plans are all available for free, bar one, on the BZE website

Three of BZE’s most recent plans

  • Australia can become a renewable energy superpower
  • Electrifying industry
  • Rethinking Cement

The Lauder Institute in USA ranks BZE in the world’s top 100 think tanks

Crescent Dunes Plant: Nevada

  • Concentrating solar thermal plant with storage
  • Power 110 MW
  • Energy output: 500,000 Megawatt hours per year
  • Energy storage 10 hours at full output
  • Molten salt lasts for 40 years with no degradation or replacement
  • Developed by Solar Reserve
  • First commercial plant using this technology in USA
  • Entered commissioning phase in February 2014
  • Long periods down due to leaks in the storage tanks: 2017

Power Technology: Crescent Dunes Solar Energy Project: Nevada

Crescent Dunes (Wikipedia)

Concerns about performance of Crescent Dunes

Sundrop Farms: Solar tower powered tomato farm

  • The greenhouses that grow tomatoes use a concentrating solar plant to provide electricity, heat and desalinated water.
  • Sundrop Farms
  • Completed October 2016

Port Augusta becomes Australian renewable energy hub
ABC October 2018

Hazelwood coal-fired plant, Victoria