Published on January 18th, 2014 | by Zachary Shahan6
Largest Single-Unit Concentrated Solar Power Plant In World — Shams 1 (CT Exclusive)
I got the chance today to visit (for the second time) Abu Dhabi’s Shams 1 concentrating solar power (CSP) plant, the largest single-unit CSP plant in the world. I’ll run through an overview of this CSP plant again, and then will also add some other details I gathered at the site today. I also have video interviews with chief operators of the plant that will be coming shortly.
First of all, the brief overview is as follows:
Parabolic mirrors are used to concentrate heat onto pipes carrying oil. That oil goes on to heat water, which turns into steam and then turns a turbine that creates electricity. A natural gas booster is also used to superheat the water, which can get up to just under 400 degrees. Also, notably, the parabolic mirrors track the sun continuously.
80% of the heat comes from the CSP side of things, while 20% comes from the natural gas used in the booster heater to superheat the water. While the CSP technology accounts for ~80% of the heat, however, it actually just accounts for ~55% of the generated electricity. That ~20% heat from natural gas is used very efficiently to create the other ~45% — that last extra bit of heat is worth a lot!
Regarding the cost per kWh, Shams personnel can’t share that information, since they have a private power purchase agreement with the grid. (But the average cost of CSP plants is currently 20–25 cents per kWh, process engineer and CSP expert Abdulaziz Al Obaidli noted.)
After just about one year of operation, Abdulaziz Al Obaidli reported that Shams 1 was generating 210 GWh annual production, enough electricity for ~20,000 UAE homes (and ~0.5% of UAE electricity demand).
The CSP project is 2.5 km2 in total, and if all the mirrors were lined up, they’d extend about 120 kilometers (~74.5 miles)!
Shams 1 is designed to displace 175,000 tons of CO2 per year, approximately equivalent to planting 1.5 million trees or taking 15,000 cars off the road.
The nameplate capacity of Shams 1 is 100 MW, but it has actually produced up to 125 MW at one point in time a few months ago.
While the plant can use natural gas, it is only allowed to use a maximum of 600,000 btu of it, so the Shams 1 operators have to decide how much of this to use for the booster heater (~80%), for production at night, or for production on cloudy days.
The cost of CSP is still much higher than solar PV, but Abdulaziz Al Obaidli noted that it also comes with some clear advantages. It is:
- dispatchable — you can easily store heat, and heat storage units can have a lifecycle of 25+ years, much longer than batteries;
- less influenced by short-term drops in sunlight, meaning less fluctuation in electricity output, which is easier on grid operators;
- more easily combined with other thermal power plants, or can actually be used to upgrade thermal power plants of other types.
Overall, aside from producing clean electricity, the Shams 1 power station is helping Masdar* and the overall CSP industry to build knowledge, experience, and human capacity. For example, researchers at Masdar Institute and elsewhere work on ways to better optimize the system, while employees operating the plant have been learning how to do so more efficiently and effectively. I asked Abdulaziz Al Obaidli and Shams Power Company General Manager Yousif Al Ali a bit about what they’ve learned in the past year. They discuss those things a bit in this exclusive CleanTechnica video (apologies for the wind and not having a better camera for such a windy location):
I also asked Abdulaziz Al Obaidli a bit about trends he sees in the CSP industry as a whole. I’ll soon publish that section of the interview in a separate article. Stay tuned!
Unfortunately, because the power plant is now in operation, we weren’t able to walk around near the mirrors (they’re hot now!). But if you’d like a closer look, here are a few pictures from last year’s tour:
*Full Disclosure: Masdar is covering my entire visit to Abu Dhabi in order to attend & cover Abu Dhabi Sustainability Week, which includes this and a couple of other exclusive Masdar tours.