Building a new home is not only knowing how the process to design and build the project is. The way how we can get energy for our needs is very important, too.

If we find some choices we can apply saving money and resources, we would have a better kind of life.

Some people, including myself, are evaluating new alternative energy systems for sustainable living. I would like to talk about Earth Tube (biodigestor in Spanish) which is, in a small scale, an in-vessel composting system for recycling organic waste materials at the site where they are generated, producing methane gas and compost at the same time.

I think this topic could be interesting, specially for people who are living (or planning to live) in a farm, because this is a source of energy that is cheap and clean, and at the same time you are taking advange of your waste materials, recycling them. Well, indeed any person can take advantage of this system, even he/she is not living in a villa or a farm, but the system is really useful for taking advantage of the waste materials there in order to apply again the benefits in the property.

You can see some sophiticated systems online, that should be pretty expensive, but I would like to consider a system promoted by universities like UNA (Universidad Nacional) and EARTH (Escuela de Agricultura de la Región Tropical Húmeda). Those institutions have several descriptions of the system in pdf files and videos online (for instance, ask for the topic in youtube, using the word “biodigestor”, so you will find “construya un biodigestor sencillo”, obviously in Spanish, EARTH videos show a link, at the very beginning, to another website for translation to English.

According to these documents, you can build an earth tube using a combination of a tubular plastic, some plastic pipes, a plastic bottle (as a safety valve), and some hoses to deliver methane gas to the burners for cooking or for transforming the gas into electricity using an engine or dynamo. The space for the instalation would be around 13 meters (43 feet) long and 4 meters (7 feet) diameter; the tube is partially placed into a trench, so it is around 1.5 meter (8 feet) over the ground.

You can build a smaller tubular system (for instance, 8 meters long, 3 meters diameter), investing around 500 USD in total. Once done, as the videos and tutorials explain, you should get around 20 kilograms of dung, if you are in a farm, to feed the system everyday, or in food waste, too, if you have a food business (for example, a small restaurant, a butcher´s shop). It takes around a month and a half for the system to start producing both compost and gas. The gas should be enough for two burners during 6 to 7 hours a day (depending on the local altitude over the sea level, the main factor involved). Once again, if you are running a food business, it is ideal to save money in cooking energy; if you are in a farm, you can use the gas for cooking and other uses in your property. And the compost could be use for the plantations you have there or just for sale or for sharing it.

Have you known about other alternative energy systems and if it is possible to get them using low investments like this one for earth tube ?

I really would appreciate your comments.

2 comentarios:

  1. Rodrigo,

    We constructed to vertical axis windmills in the hills above Uvita De Osa. The electricity is DC but it is enough to illuminate a couple of LED lights and other components. The investment was $220, which includes generators, inverter for AC components, a battery and physical structure of the windmill. All these things were used and the generators came from the USA cause we could not find any locally.
    Of course if there is no wind, there is no power, but there always seems to be a sea breeze.


    1. Thanks Jimmy for checking my blog and for your comments.

      It is a good idea trying these kinds of solutions, in order to improve the low cost systems which are nice to nature as well.

      I have contact with a newcomer from Texas, Glenn Kawamoto, who founded a company here in Costa Rica to sell and install these kinds of products, specially solar panels, and those related, like windmills.

      So, contributions in the field are increasing. That´s great.

      Please, share with us, in the future, about your progress and news, in order to know the advantages and disadvantages of the system.

      Best Regards,


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