"The gas produced may be used for a number of purposes, but one of the main uses in larger plants is driving engines for production of electricity. To this end it is essential to know the concentration of methane in the gas, allowing the mixture to be adjusted appropriately. The level of carbon dioxide and proportion of methane will give valuable information about the state of the fermentation process as well. Infrared sensors are the best means employed today for this purpose. The need for calibration is minimal or nonexistent and the small size, relatively low cost and minimal power consumption make them ideal for this type of application. Combined heat and power uses are increasingly common."

In the process of formulating and evaluating a project, we give concrete form to what we have proposed. Our recommendations must be the most appropriate solutions that are socially desirable, technically feasible, economically more effective, efficient and cost-effective and environmentally sustainable over time. Indeed, this module responds directly to key questions related to investment projects and accelerates solutions in order to insure financing and long term success for all concerned.

It is best to dispose of a project before you start to realize it is bad to spend financial resources, time etc. and see that the project fails. When the project is from private sources, the losses are borne by an individual, but when resources are public (ie is silver of all the people that administers the national government, regional government or local government) loss affects the entire population. If someone wants to risk their own money and time is free to do so, but who manages public funds can not do so, hence, before starting to do something, you must have a good project. On the other hand, civil society takes every day a more participatory role in public decision, which is permanently with the complexity and specificity of the instruments by which it leads the state.

A particular case is represented by the National Public Investment System that raises unique methodological assumptions and considerations, given the diversity and complexity of the intervention. In a process to strengthen the capacity of NGOs to participate in support of the local or regional management can not neglect the knowledge of the public investment system, including harmonization of the methods used.

Indeed, this module seeks to respond directly to synthetic and some key questions related to investment projects, especially those commit public resources.