Failed Concentrating Solar Power Plants' Lessons: Haste Makes Waste

published: 2020-07-17 18:30 | editor: | category: News

The cost of concentrating solar power (CSP) plants has rapidly dropped. From 2010 to 2020, the cost has decreased by 47%. How about its quality? Recently, the National Renewable Energy Laboratory (NREL) of the US published a 257-page report for CSP. NREL pointed out that local incentive programs indeed speeded up CSP's development pace. However, the urgent construction schedule indirectly led to reliability problems.

Haste makes waste. Engineering, procurement, and construction (EPC)'s fixed-schedule and fixed-price nature indirectly led the following issues to occur. They didn't train the operators enough to trouble shoot technical difficulties. The designs of power plant might be problematic. In the very remote sites, how to retain the maintenance personals and operators becomes an issue. Perhaps due to the lack of collective experiences as one team, many CSP projects had failed.

There were many types of CSP projects. Most of them use curved mirrors to focus solar heat to heat up salt water or molten salt. Then the mechanism will convert energy into a steam driven generator. Then the motor will generate electricity. There are currently more than a 100 CSP projects in the world. After NREL collected feedback from nearly 80% of the operators and owners, most of the issues and challenges were discovered to be related to non-technical issues. The majority of them were operational issues and maintenance issues. 

Mark Mehos, a manager of NREL, said that operators and maintenance technicians should join each project as early as possible. He hoped that design engineers have enough experiences to provide professional knowledge to operators.

Different CSP technologies encounter different challenges. Let's take a look at another type of CSP. Luz from California used parabolic trough solar energy collector systems (SECS). This kind of CSP technology used curved mirrors to focus solar energy to tubulous collectors that have mineral oil. After this oil is heated, it generates steam. Steam will cause a generator to product electricity. Luz believed this type of power plant can lower electricity prices.

However, it didn't come out as planned. Luz went bankrupt. The then vice president of Luz, Mike Lotker, expressed that it was very difficult to earn tax exemption, get permitted by the authority, and do fund raising. When Luz was constructing the 9th plant, cost-overrun, working-overtime expenses and many operational issues collectively made it difficult for Luz to raise money for the 10th power plant.

Another type of CSP plant is "power towers" that are currently more popular. This system uses mirrors that are arranged in a round shape, and mirrors focus sunlight to the towers where molten salt will absorb the sunlight heat and will raise temperature to above 500 degree Celsius. The molten salt will flow to a reservoir and store the heat energy, and then the heat will be fed to a steam turbine generator that can make electricity.

There are about 10 power towers of CSP in the world. There are various issues in them. For one, steam is hard to generate. According to the report of NREL, in the past, after the CSP power plants had finished construction, the transition duration between the builder and operators and maintenance people was very short. Thus, operators didn't have sufficient time to get familiar to the site and the plant that they take over.

Mehos added that it is more ideal to build a smaller power plant first. After a period of testing, operating, and accumulating experiences, then it is a good time to build a larger CSP plant. Or, another ideal way is to work with well-experienced builders. Insufficient shared experiences easily reduces the performance of the CSP plant. Haste Makes Waste.

Another reason for the lack of shared experiences could be that the early CPS projects kept secrets of their training results and failed experiences. Thus, Mehos hopes that the next-generation developers could learn from the past successes and failures. After all, CSP plants can store sunlight energy and heat energy and can partner with the PV energy industry. CSP technology is still being used and its body of knowledge is learned over time. Thus, the learning curve is constantly improving. Over 12 countries are using CSP technologies, including China and nations in the Middle East. Newly-built CSP plants' operation statuses are improved. The outlook of CSP plants is still optimistic.

 (Photo credit: Amble [CC BY-SA])

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