Energy from Pig Manure: Potential at a Farm Scale in Portugal

G. Lourinho, P. Brito, L. Rodrigues
C3i (Interdisciplinary Coordination for Research and Innovation), Polytechnic Institute of Portalegre, Campus Politécnico, 10, 7300-555 Portalegre, Portugal
Tel/Fax: +351245301592, +351245300291; E-mail: glourinho@gmail.com

Introduction

Pig farms occupy an important place in the livestock sector in Portugal. As the industry has evolved in the last decades, pig production has become more concentrated and from this intensive farming considerable amounts of manure inevitably arise. Despite presenting many environmental challenges, animal manure can be viewed as an important source of bioenergy; in fact, manure-based energy can be especially interesting for local pig farms in Portugal as it can help reduce environmental externalities of animal production, alleviate financial pressure on farm owners, and provide clean energy. The main methods available for renewable energy extraction from animal manure include thermochemical and biochemical conversion processes Shen 2015.

Objectives

In this study, the energy potential from direct combustion, syngas production via gasification and methane production via anaerobic digestion of pig manure will be assessed on a preliminary basis. The main goal of the paper is to provide a framework for pig manure based-energy under different technological paths at a farm scale in Portugal.

Methodology

To estimate the energy potential of pig manure, we (a)  identified and classified a portuguese pig farm in terms of animal population and husbandry system; and (b) calculated the farm-specific manure production with its related combustion, syngas and biogas potential taking into account its chemical composition. The farm has a capacity for about 50.000 pigs for a total of 4.768 livestock units (LU). It is a closed cycle pig farm in an intensive production system. The annual production of pig manure is estimated to be 250 m3/day and annual energy consumption in 2015 was 483.900 kWh/year of thermal energy and 718.525 kWh/year of electricity.