TSE1 is the first of 15 CSP DSG parabolic trough plants be built in Thailand

Interview by Rikki Stancich

German concentrated solar power technology provider, Solarlite, set a precedent last month as the world's first direct steam generation parabolic trough plant to supply 5 MW of electrical power to Thailand's public power network.

The development marks a major milestone for the concentrated solar power (CSP) sector. With direct steam generation, the solar radiation heats water directly in an absorber tube, which produces the steam required to power the turbine.

The major advantage is that it enables higher operating temperatures of up to 500°C, in contrast to the limit of 395°C in traditional parabolic trough plants. According to the company, this increases the long-term efficiency and performance of the parabolic trough, the most proven among CSP technologies.

The simplified design also avoids the need for additional components such as heat exchangers, and bypasses the need for costly and polluting thermal oils traditionally used as the heat transfer fluid in parabolic trough systems.

CSP Today speaks exclusively to Solarlite’s CEO, Joachim Krüger, to learn more about how the company will achieve operating temperatures of above 500°C and its strategy for rolling out a further 14 plants throughout Thailand.

CSP Today: TSE1 is the first of 15 projects to be built by Solarlite for its customer Thai Solar Energy Co. Ltd. Can you provide some indication of the scale of the consecutive projects, and what their application will be (i.e. electricity generation for utilities, industrial power and process, co-generation for heat and power)?

Joachim Krüger: The plants will be 9MW each, spread across the country to supplement rural electricity supply in order to support local economic growth in the more remote areas of Thailand.

This electricity supply will really benefit local companies producing local products.

These 9MW plants will produce electricity that will feed directly into the national grid. The off-taker is the Electricity Generating Authority of Thailand, the grid operator is the Provincial Electricity Authority (PEA).

CSP Today: What is the timeline for these projects?

Joachim Krüger: The second plant (TSE2) is currently under construction, and construction will begin on two more plants within coming months. Thereafter, the plants will be built on a rolling basis.

Thailand’s Solar Programme requires that the plants be completed by 2015. The new programme was recently announced, under which 2GW of solar capacity (both solar thermal and PV) must be installed by 2020 as part of Thailand’s commitment to sourcing 25% of it total energy requirement from renewable energy sources.

CSP Today: What is the proven cost advantage of direct steam generation in parabolic troughs?

Joachim Krüger: Direct steam generation has a lower investment requirement than oil systems. It is also more ecological and safe, given that it only uses water. In fact, TSE1 uses rainwater, so does not even require access to municipal or groundwater supplies.

CSP Today: What is the LCOE of Solarlite’s plants?

Joachim Krüger: The LCOE of Solarlite plants is 9c/kwh (for 50MW plants) – 16c/kwh (for 5MW plants).

CSP Today: Solarlite’s current project TSE 2, will achieve higher operating temperatures (400°C with 40 bars) than TSE 1(330°C with a pressure of 30 bars). How have you achieved this? What is the maximum operating temperature you are aiming for?

Joachim Krueger: We have further developed the direct steam generation technology in terms of increasing the operating temperature and pressure, and we aim to achieve operating temperatures of 550 degrees Celsius in future plants.

The next five plants will be designed to operate at 400 degrees Celsius, at 40 bar, with an efficiency of 29%. Thereafter we will increase the operating temperature to 550 degrees Celsius (this will take place in the next 2 – 3 years).

CSP Today: TSE 1 does not have storage. Will any of the future plants include storage? Or is not economical at that size?

Joachim Krueger: Size does influence the cost of storage and it is less economical at a smaller scale. In any case, while storage technology is available the conditions in Thailand (the feed-in tariff), do not allow for that level of investment.

For the next project we are looking at a storage device that can help the plant through the transient periods – periods of, say, 20 minutes of cloud cover.

But it is actually more interesting to combine direct steam generation with a biomass plant.

CSP Today: What is the market outlook for CSP hybrid applications in Southeast Asia?

Joachim Krueger: We are working on getting acceptance of hybrid solutions. Currently, combining solar with fossil fuels is not allowed in Thailand, but we think there is a lot of potential for combining CSP with biogas. We have a biogas-CSP product prepared, but it is not yet commercially available.

We are optimistic that solar-biomass plants really present a solution for rural areas, given the abundant biomass resource that grows quickly and can be harvested often. Because we are talking about small (5-10MW) systems, local farmers could provide the feedstock, which in turn supports the local economy.

CSP Today: Concerns have been raised over whether biomass plants would compromise food security. Is this likely to be the case with plants of this scale?

Joachim Krueger: There is a lot of readily available biomass, and because the plants are small-scale, they would not present a threat to food security. The biomass feedstock could be rice, palm or sugarcane by-products, as well as non-food crops such as Jatropha. There are different ways to maximise the concept to make it a workable solution for everyone.

CSP Today: What have been the main challenges and advantages of operating in Thailand?

Joachim Krüger: One of the biggest challenges was to adapt the technology to the Southeast Asian market. We needed to have local content to meet the price level, given that we faced different conditions to those in Europe.

The FIT in Thailand, for example, is limited to a 10-year period, so the plant had to be adapted to be made more economical.

CSP Today: What is the current feed-in tariff?

Joachim Krüger:  It is comparable with Spain’s, at 11.5 Baht/kwh / 27c/kwh.

CSP Today: How have you managed to work within such a tight framework and remain competitive?

Joachim Krüger: We needed to source as much as possible locally.  In fact, we have managed to source 60-70% of the content locally.

CSP Today: How have you achieved this?

Joachim Krüger: We needed to develop things like the composite structures and the steel support structures locally and so we opted to establish manufacturing facilities in order to produce these components. We now have several installations where we manufacture our main components locally, which is also in line with our stated objective: “To serve the Thai market, from Thailand”.

The main facility is located in Chon Buri, which is where we manufacture the trough elements. The steel works are welded in Suphanburi.

CSP Today: Have Solarlite’s products undergone accelerated weather testing – do they meet current international benchmarks for performance?

Joachim Krüger: We have implemented very high standards, in line with DLR standards. We developed our trough technology 100% in-house and later had the components tested by DLR. DLR also provided constant oversight during the construction of the TSE1 plant. 

CSP Today: Solarlite’s technology is designed for medium-small scale CSP plants (below 50 MW). Is there any scope for large-scale plants to be built in Thailand and is this on your radar for future plants?

Joachim Krüger: No, not really. Thailand’s grid can’t handle large-scale generation. There is very little potential for large-scale systems. Nearer to Bangkok it might be possible, but then you would have issues with haze.

There is large potential for building plants below 25MW, but the biggest market opportunity is for plants smaller than 10MW. Outside of Thailand, this picture looks different. We are actively discussing larger power plants with several potential customers.

CSP Today: Is Solarlite looking to add any other CSP technologies to its portfolio?

Joachim Krüger: We could go into other CSP technologies but for now we are maintaining our focus on the parabolic trough. You will see more and more troughs built in the future and our direct steam generation system provides a solid proof of concept of a CSP technology that adheres strictly to economic and environmental performance.

CSP Today: What challenge do local climate conditions present for operating a CSP plant in the region?

Joachim Krüger: You are operating in elevated temperatures and high humidity, but on the other hand there is less dust.  There are plenty of criteria to consider. Our thinking was: “If we can make it in Thailand, we can make it anywhere!”

To leverage the advantages of producing in SE Asia, it is not just about accessing the resource availability and production capacity; you also really need to know with whom you can work to achieve the right quality.

CSP Today: Will Solarlite use Thailand as a production base from which to export to other Asian markets?

Joachim Krüger: Yes, we will use it as a base to export to other Asian markets. Thailand is a good place to work; with the right team in place, it is easy to be successful.

However, we would appreciate it if the economic framework was more favourable to CSP technologies. The current ten-year feed-in tariff framework is really too short, and the feed-in tariff has already been reduced. This presents a considerable challenge to bringing CSP into the mainstream.

To respond to this article, please write to the Editor:

Rikki Stancich: rstancich@csptoday.com