Crescent Dunes Solar (CSP) Energy Plant Background
In September 2011, construction began at the Crescent Dunes Solar Energy Plant, a 110MW concentrated solar power (CSP) plant located near Tonopah, Nevada. SolarReserve, a US-based developer of large-scale solar power plants, is developing the Crescent Dunes Solar Plant utilizing its market-leading solar power technology with integrated energy storage to deliver clean, reliable electricity on-demand, 24-hours a day. The 540 foot solar power tower, which is located in the centre of the overall plant layout, was completed in February 2012.
Crescent Dunes Solar Energy Plant Key Operating Facts
Unlike most solar plants, which are made up of rows of interconnected solar photovoltaic (PV) unit, the CSP technology at the Crescent Dunes Solar Energy Plant uses thousands of mirrors to concentrate the sun’s energy to the 100-foot tall heat exchanger that sits at the top of the central tower and captures the sun’s energy using liquid molten salt, which is heated from 500 to 1050 degrees Fahrenheit.
The Crescent Dunes Solar Energy Plant will use approximately 10,000 mirrors, called “heliostats”, to direct sunlight towards the receiver at the top of the solar tower, each heliostat continually moving to track the sun and maximise the amount of thermal energy that the tower receives. In technology similar to SolarReserve’s, the heat is used to superheat water to generate steam to drive a steam turbine, but this is not the case in SolarReserve’s technology. SolarReserve’s technology uses molten salt to both capture the sun’s energy and then store the energy, which allows the plant to generate steam for a traditional steam turbine whenever electricity is needed, even after dark.
Comparing Traditional Solar PV to SolarReserve Technology
Previously solar energy, such as Solar PV, has largely been considered an intermittent energy source (like wind farms), meaning that the plant can only generate electricity when the sun is shining. Traditional solar plants can’t produce electricity at night, and even cloudy days or other forms of shading impact the total output of the solar plant. However, SolarReserve’s technology has found the solution to intermittency through the use of integrated energy storage. The molten salt solar thermal power technology that will be used at the Crescent Dunes Solar Energy Plant allows the plant to produce electricity 24×7.
At the beginning of the day, the “cold” molten salt, which is held at a temperature of about 500 degrees Fahrenheit, is pumped up from the “cold” storage tank, up the tower, and into miles of piping that run through the walls of the receiver that sits at the top of the solar tower. Here, the molten salt is heated from 500 degrees to 1050 degrees Fahrenheit by the sun’s energy and then pumped back down the tower to the “hot” salt storage tank where the thermal energy is stored. When electricity is needed, the hot molten salt is used to generate superheated steam to drive a standard steam turbine. After the hot salt is used, the cooler molten salt is then pumped back into the cold salt storage tank for the process to be restarted once again.
Crescent Dunes Solar Electricity Potential
As the electricity generated by the Crescent Dunes Solar Energy Plant will provide electricity to Las Vegas, this 24/7 electricity generation potential is perhaps a prudent measure! SolarReserve will sell 100% of the electricity generated to NV Energy, Nevada’s largest utility, under a 25-year Power Purchase Agreement.
It is estimated that Crescent Dunes Solar Energy Plant will generate approximately 500,000MWh of electricity per year, which is double the amount of electricity that would be generated by a similarly-sized PV plant, and is enough electricity to power over 75,000 houses during peak electricity periods.
Crescent Dunes Solar Power Plant Environmental Impact
Despite producing an abundant, clean source of electricity, the CSP plant may impact the environment. Obviously the mirrors are concentrating an incredible amount of heat at a very small area, posing a danger to anything that gets in its way. Any wildlife, such as birds, that come into contact with this sort of heat will be in serious trouble. In addition, the diameter of crescent Dune mirrors is 2 miles, so it is taking up serious acreage to fulfil its role.
On the whole though, the Crescent Dune Solar Energy Plant seems like a great engineering feat, providing clean electricity 24/7, in a much more efficient way than existing solar PV technology.