This year's theme for World Tourism Day is "Tourism and Sustainable Energy: Powering Sustainable Development," highlighting the tourism industry's role in creating a more sustainable, energy-efficient global economy. In honor of this year's theme, we're highlighting some of the hotels featured on that are using renewable energy to increase sustainability and decrease some of the negative effects of using fossil fuels.

Solar Panels - Photo by Totoco Eco-Lodge, Nicaragua

Tropical and subtropical regions are known for their sunny climates, making them hotspots for tourism and also very well-suited to use solar panels to meet some of their energy needs.. Depending on a hotel's location, hydroelectric and wind power can also be viable alternatives to conventional sources.

Solar power is most often used for heating water, but some of the hotels on have accomplished the impressive feat of going completely off the grid and only use renewable energy sources:

You've probably heard of solar and wind power, but have you ever heard of biogas? Biogas is made 100% from organic matter and can be used as fuel for cooking, lighting, heating, and refrigeration.

Biodigester diagram

To produce biogas, organic matter (commonly, the excrement of livestock) is put into a machine called a biodigester, where it undergoes anaerobic digestion. The matter breaks down into an odorless gas known as "biogas," which is primarily comprised of methane and carbon dioxide. It can then be piped into the kitchen or wherever else it is needed to be used as fuel. Another useful product of the biodigestion process is a liquid organic fertilizer, which can be used in gardens and on farms.

This brilliant and sustainable method of producing renewable energy is particularly useful for farmers and rural lodges that have easy access to livestock, since quite a large amount of organic matter is needed to produce a reasonable amount of biogas. However, even hotels without access to livestock can feed their wastewater into a biodigester and convert it into biogas.

Learn more about the use of biogas at these Costa Rican lodges: