Affordable Solar Thermal Microgenerator Technology is Coming to Rural South Africa
MIT students develop a low cost, sustainable alternative to the common diesel generator.
The National Collegiate Inventors and Innovators Alliance (NCIIA) combined with the support of the Lemelson Foundation provides $1.5 million to student and faculty programs and ventures annually. Today's featured project by STG International, a non-profit organization started by the combined initiative of engineers and students trained at the Massachusetts Institute of Technology (MIT), is a solar thermal microgenerator capable of providing both electricity and heat to the rural areas of South Africa.
There are 1.6 billion people worldwide who lack access to electricity or affordable energy solutions. The problem is that there are few good options for those who live deep within poor, rural locations. There are a number of solutions out there, such as diesel generators and photovoltaic panels, but these fail for the most part due to their high cost and high risk of theft.
To get around these shortcomings, the Solar Turbine Group (STG) has developed a novel solar thermal technology that decreases the necessity of costly fuel, upfront operating expenses, and theft. Their solution is a turbine which uses parabolic concentrating solar collectors and a heat engine constructed from mass-manufactured HVAC and automotive parts.
The turbine is not only an effective means of supplying energy, but it is also affordable due to its simplicity of parts, which can be found in just about any junkyard. As an added bonus, a bi-product of the technology, heat, can also be used for supplemental heating and hot water for various rural institutions, such as schools and health clinics.
We were lucky to speak with a good portion of the team about their project and get the scoop of exactly how these solar thermal microgenerators are the best solution to the residents of rural South Africa. On behalf of MIT and the STG group allow me to introduce you to Ahmed Ghoniem, Professor of Mechanical Engineering, Harold Hemond, Professor of Civil and Environmental Engineering, Amy Mueller and Matt Orosz, both pursuing their doctorates in Environmental Engineering.
The team members who were not able to join us for this interview were Elizabeth Wayman, Bryan Urban, Motlatsi Sekhesa, Tumelo Makhetha, Makoanyane Khakanyo, Nick Brumleve, and Sylvain Quoilin.
Could you give us a brief overview of this project?
Matt Orosz: Since 2004 we have been developing solar thermal power generation that is conceptually based on the large scale solar thermal power plant technology that is featured in the Southwest of the United States, Spain, and some other countries. We are making it capable of operating at a small scale, autonomously appropriate for clinics or schools off the grid in developing countries. We are working on the size of a few kilowatts, as opposed to the megawatt size that this technology is customarily deployed at.
Ahmed Ghoniem: This technology is known as CSP, Concentrated Solar Power and it is normally deployed at very large power plants. The group is miniaturizing this technology, so that it can generate power for hospitals and schools. Another feature of these is that they not only generate power, but they also generate heat. This is a very clever and efficient way of doing things, because the same system gives you the two kinds of energies you need. That is the purpose behind packaging the system the way it is.
Harold Hemond: The other thing I would add, is this is particularly appropriate for communities that are not on the power grid. One of the objectives is to be able to utilize low cost or mass produced components, in many cases available from the automotive or the heating and air-conditioning industries.
How exactly does this microgenerator work?
MO: It is analogous to the typical steam engine. If you can think of a coal burning power plant that runs steam turbines, it generates the heat from burning coal. But instead of burning coal, we are using heat from the sun directly. Another analogy is to look at it as something like an air-conditioner where you plug it into the wall and it uses electricity to get one side hot and the other cold. You put the cold side in your house and the hot side sticks out the window. In our system, we supply heat on one side and something cold on the other and the end result is electricity.
AG: There is a solar collector used to collect the heat and this heat goes down into an engine and the engine produces power. You don't want a power plant or system that is expensive. Photovoltaic is also a good way to convert the energy, but it is very expensive. The system we are developing is much cheaper. The components are cheaper and can be found readily in these rural communities. By adding the solar collector and integrating it with an engine, we can produce power and heat at a much cheaper price. The economics is a big factor. This is not the Cadillac of systems, it is the Volkswagen.
Who is this system being developed for?
Amy Mueller: We are predominantly looking at developing countries, secondarily looking at rural areas. Where we have been working has 85 percent of it population where there will never have an electrical grid extended. We are first aiming to help institutions in these rural areas. Rural clinics, schools, possibly police stations, community centers. These places see 50 to 80 people per day as patients. By bringing the electricity and hot water to these clinics we are helping to improve the quality of life for the staff, so that they will be able to stay at work longer to help people.
How many areas has this system been deployed so far?
MO: We built two prototype systems in Lesotho in 2007. They were mainly beta test units, so they are not continuously operating right now. With the support of the NCIAA we are partnering with some government entities to install a permanent power solution to a clinic. It will produce about 25 kilowatt hours per day.
Will you be transferring the ownership of these systems to the community?
MO: In these countries, there really is no intellectual property protection to begin with. When you talk about ownership, you are really talking about know how. We are working in partnerships with technicians, engineers, faculty and students in Lesotho so that they can understand and produce this technology.
Is there any way our readers could get involved with this project?
MO: Yes, they could make a donation to the non-profit, there is some information on our website about that. If someone has some other kind of contribution in mind, please send us an e-mail through our website.
Is there anything else you'd like to share about the project?
AG: Another interesting anecdote of something we're doing, is looking at ways to use junkyard pieces in creative ways to build the system. That is one way to make it available for those who have no way of fabricating the custom components. Essentially we are going to junkyards and getting pieces from vehicles and testing them for use in our system.
HH: Car components are obviously made in very large quantities and a lot of these sophisticated materials can be reused for other purposes.
What are a few of these components that could be reused?
HH: Air conditioning, compressors, and alternators.
AG: The power steering pump, the engine cooling system, engine cooling pump, and the heating system is very useful. The affordability of these components is key to making these systems useful for whoever they are being designed for.
Thank you very much STG International for sharing your project with us. We hope that your systems can be deployed to many other rural areas around the world in the future, and we thank you for educating bright young students about the importance of green technology and using it responsibly.
