2 November 2009
Shifting the focus from utility-scale CSP projects, CSP Today talks to Darren Kimura, CEO of Sopogy, about the advantages of micro CSP.
By Rikki Stancich
Micro CSP technologies are leveraging the economics of proven large scale CSP for application in the distributed generation markets. The market potential is vast.
CSP Today talks to Darren Kimura about why CSP technology has the technological and economic edge over its PV competitors in this space.
CSP Today: Sopogy has developed a ‘micro’ CSP system. What are the advantages of going small?
Darren Kimura: We’ve taken the large-scale parabolic trough technology and reduced its size – we’ve changed the position of the receiver and reduced the size of the reflector frame, which in itself reduces manufacturing costs.
So, there is a new frame, tracker, algorithms and a different temperature. And rather than running off a steam turbine, we use an organic ranking cycle, or ORC.
The ORC win is that it doesn’t use steam, it uses the temperature difference between fluids in a closed loop. In other words, we don’t have the high water requirement of the large-scale desert projects that run off steam engines.
And because the ORC can continue to operate at lower temperatures (unlike a steam turbine, which shuts off if the steam temperature drops) there are much lower operating costs and maintenance costs involved.
The ORC could be operating at 10 percent of its operating efficiency and the engine would still continue to operate. In other words, it can operate in cloudier places than the large-scale desert systems.
CSP Today: A system with a lower insolation requirement must be adaptable to a wider market than large-scale CSP. Can you expand on which markets you are targeting?
Darren Kimura: ORCs are smaller, so rather than competing with the likes of Solel or Solar Millennium, we focus on the distributor-generator market. The units can be situated nearer to city grids, on buildings. We are targeting the 2-5 MW market.
While the current competitors are the PV market, the ORC system is 10-15 percent cheaper and it produces more energy. It has a tracker and storage built-in to the system and can be used for steam production or water heating.
The market we are focusing on is the commercial and industrial sector – the big energy users. This market represents some US$750 billion, but the current market penetration is less than 1 percent.
On a global scale, we are looking at the US and international high energy cost markets – and of course, markets where there is sun.
CSP Today: What are the drawbacks of smaller-scale ORC systems compared to steam systems?
Darren Kimura: It is twice the cost of steam (if the steam systems have perfect direct normal irradiation, or DNI). But then again, these systems need to have perfect DNI to run efficiently and there are only a handful of places around the globe that can offer those conditions. The big guys are searching for perfect DNI because turbines only work on or off – if a cloud passes overhead, the system shuts down.
Most cities are not in high DNI environments, which is why large CSP doesn’t get there.
CSP Today: What are the cost benefits of using an ORC system?
Darren Kimura: With large utility-scale projects, the minimum size needed to recoup the project costs is around 100 MW. With the Micro system, the reduced size means there is a fewer number of welds and steel components.
Because the system can operate at lower temperatures, we don’t need to employ highly skilled steam contractors. Instead, we use standard plumbing contractors, which reduces the costs three-fold.
Finally, we combine the energy output from the system. In the desert you create power and heat. Normally the heat gets dumped. We capture the heat and use it for something else. In other words, we provide the client with an added form of energy saving.
So, the lowered cost of the collector; modular technology; and energy streams, combine to equal a competitive solution.