1. INTRODUCTION

This report is meant to be a brief guide to energy sources and technologies. The goal is to provide basic indications for an analysis of problems connected with the supply of energy (especially renewable sources) to small and medium-sized milk plants (500–2000 1/day).

In preparing this report, the requirements of the following users were taken into consideration:

1. public sector researchers, whose task it is to identify those energy sources best suited for employment by milk plants (and confirm their findings through subsequent studies by experts in the field) and evaluate plant proposals put forward by third parties;
2. extension service trainers, who must be supplied with practical data and information;

3. engineers in general, who are tackling the problem of energy supplied to milk plants for the first time.

The following subjects are discussed:

4. energy consumption in the production of the most important milk and cheese products;
5. renewable energy sources considered to be best suited to the processes under examination;
6. technologies designed for energy savings and employment of the sources mentioned in point e);

7. a method, currently under study at the Institute of Agricultural Engineering at the University of Milan, for the economic analysis of energy plants.

This discussion is followed by an example, which should clarify the concepts explained in the previous sections.

In addition, summaries are provided to simplify presentation of the various sources and technologies. The purpose of these summaries is to supply:

8. basic data for all types of evaluations;
9. the applicative limits of sources and technologies;
10. managerial problems;

11. the technological level of workshops that are suitable for the manufacture of various plants.

Special attention has been paid to problems that may arise as a result of the adoption of renewable energy sources. Indeed, one of the reasons why these sources are rarely employed today is the fact that farmers know little about their practical application.
Finally, the appendix provides information about the terminology used so that linguistic ambiguities are eliminated as much as possible.

It should be stressed that actual construction proposals that are recommendable for specific social and climatic contexts can only provided after further studies, in which the technological level of equipment used in milk processing can also considered with more attention.
It should also be noted that the costs of various technologies are not supplied here because of their extreme variability from one situation to another.
However, the aim has been to provide the reader with the necessary elements for an initial cost evaluation comparing those technologies with which he is familiar.

Thus, our hope is that this report proves to be a sufficiently flexible and valid work tool.