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FAQ

How can I contribute to STG? Are you currently taking donations?

STG's 501(c)3 Public Charity status was granted by the IRS in November, 2008. While we are excited to get as many people as possible involved in our work, we are currently able to accept donations only from individuals and organizations in the Commonwealth of Massachusetts, the State of New York, and Maryland. We are working to register our organization in additional states around the country, so please contact us at financials@stginternational.org if you live outside of Massachusetts but are interested in contributing. We will update the website as our registrations are approved, so please check back!

For individuals or organizations located in Massachusetts, New York, or Maryland, please send a statement with your name, address, and donation amount along with a check or money order (made out to "Solar Turbine Group" - no cash please) to:
STG
Attn: Amy Mueller, Treasurer
P.O. Box 426152
Cambridge, MA   02142.

How can I get involved with STG?

We are always looking for help with administrative functions, funding acquisitions, engineering design, construction, and testing, and partner outreach. At this time, we are primarily looking for volunteers; information on part- and full-time positions opening up at STG will be posted on the website as soon as it becomes available. If you are interested in getting involved in any capacity, please send us an email at info@stginternational.org.

Can I get a high resolution copy of one of STG's photographs?

High resolution versions are available for many of the images on our website. Send an email to info@stginternational.org letting us know which image you are interested in and what you'd like to use it for. We are happy to share our photographs and simply ask that you acknowledge STG when you use them.

I would like to build one of these systems. Is it possible to get a copy of the plans?

Unfortunately, we are not currently releasing plans for our microgenerator systems. Our deployment strategy is coupled with intensive training of a local manufacturing partner, with the end-goal of handing off rights for local manufacture and sales to this organization. We are not currently able to support training or implementation of single-system installations.

How can I purchase a microgenerator system?

At this time, STG does not manufacture these systems for sales. Our focus is on technology development coupled with training of local manufacturing partners to reach markets in developing countries. For more information on availability in your location, please contact the lead engineers at our local partner organizations, listed on our “Contact” page.

Why aren't you selling these systems in the United States?

Our systems have been designed to be affordable relative to the options available to rural communities with no access to a national electrical grid. The design is economically competitive with other technologies in this area (e.g. diesel generator sets and photovoltaic panels) in these markets, however none of these technologies is as inexpensive as electricity sold through a national grid. This is especially true here in North America, where more than 99% of the population has access to grid electricity. Due to the niche size of the market here in the US, STG has currently chosen to invest our resources in the development of a technology optimized for deployment in rural areas of developing countries, where we believe we can have the greatest impact.

I am part of a group interested in becoming a local manufacturing partner of STG. How do I get more information about starting a partnership?

The focus for this funding cycle is on research and development for the next generation of microgenerator. We will post more information on our website calling for proposals for the subsequent funding cycle, so please keep an eye on the website for more details!

Would it be possible to install a microgenerator system at my home, local school, church, clinic, or other location?

While we at STG would love to see microgenerators installed around the globe, we cannot currently support single-system installations. Our implementation methodology focuses on strong partnerships with local manufacturing partners. An intensive training period results in a hand-off of local technology manufacturing rights, strengthening the local economy while bringing clean energy to the population. If this is something you would be interested in, please keep us in mind and keep an eye on the website for more information about applying to be part of our next round of field trials.

Are there micro investment opportunities in the local operators using STG designs?

STG is currently in the process of helping our first project partner incorporate a for-profit enterprise in Lesotho based on STG's designs. At this time, we are not yet accepting donations or investments for this enterprise. Such opportunities will, however, be available within the next 12-18 months (FY2009). More information about such opportunities will be posted on our website as soon as it becomes available.

I would like to use a solar ORC as an example in curriculum that I am teaching/developing. How can I learn more?

Solar ORC technology is a device for transferring energy from sunlight into heat and then electricity, in our case using a parabolic trough collector and a Rankine engine with an organic working fluid. An appropriate approach to modeling the system would start with the sunlight impinging on the collector, followed by an account of all the energy conversions and energy lost from the system. The two main modes of losses are the thermal efficiency of the receiving tube and the efficiency of the organic Rankine engine, the latter being limited by the Carnot efficiency, but in practice will be close to half of Carnot in a well made system. Numerous parameters affect the performance of the technology, and these can be best understood through a review of the literature.

As a general background to parabolic trough technology, NREL's troughnet is a good resource, as is Duffie's "Solar Engineering of Thermal Processses." For info on the organic Rankine cycle we use, any thermodynamics textbook should have some discussion on it, and an introduction written by our colleague Sylvain Quoilin can be found here.

These are a good place to start for developing a mathematical framework of how the system works.

How can I get a copy of STG's application for tax exempt status or most recent federal filings?

As a 501(c)(3) Public Charity, our application for tax exempt status and yearly federal filings are available to the public. This includes Form 1023, IRS ruling letter, and yearly 990s. Please note that this information is available under the name "Solar Turbine Group" for our work in Lesotho and under the name "Solar Turbine Group International" for work outside of Lesotho. All information is available here for download:

Solar Turbine Group     1023 (pdf)         Ruling (pdf)         FY06-07 (pdf)         FY07-08 (pdf)         FY08-09 (pdf)    
Solar Turbine Group International     1023 (pdf)         Ruling (pdf)         N/A         FY07-08 (pdf)         FY08-09 (pdf)    

If you would prefer to have this information emailed to you or sent in hard copy, please send your name and address, along with a description of the information you are seeking, to financials@stginternational.org and we will be sure to satisfy your request within 3-5 business days.

Does STG have a patent on this technology?

STG has filed for a patent on this technology in the USA and in India (May, 2008). These patent applications are pending review and should be considered by the respective Patent Offices in the next 2-3 years. Currently, it can be found under Patent Application Number 20080289334.

Would a Stirling Engine work with your parabolic collectors?

A Stirling engine is another example of a heat engine which could work in the place of our ORC engine. The choice of engine design is motivated by ease of construction (number of machined parts, tolerances, etc.), cost, and complexity of design. Our organization has chosen to focus on the ORC engine as we feel it provides a simpler design that is easier to teach, construct, and maintain. Initial analysis has also shown that the capital cost of an ORC engine will be competitive or lower than that of a Stirling engine for the system size we are considering.