Energy and Economic Balance between Manure Stored and Used as a Substrate for Biogas Production

Jakub Mazurkiewicz

doi:10.3390/en15020413

Abstract

The aim of the study is to draw attention to the fact that reducing methane and nitrous oxide emissions as a result of traditional manure storage for several months in a pile is not only a non-ecological solution, but also unprofitable. A solution that combines both aspects—environmental and financial—is the use of manure as a substrate for a biogas plant, but immediately—directly after its removal from the dairy barn. As part of the case study, the energy and economic balance of a model farm with dairy farming for the scenario without biogas plant and with a biogas plant using manure as the main substrate in methane fermentation processes was also performed. Research data on the average emission of ammonia and nitrous oxide from 1 Mg of stored manure as well as the results of laboratory tests on the yield of biogas from dairy cows manure were obtained on the basis of samples taken from the farm being a case study. The use of a biogas installation would allow the emission of carbon dioxide equivalent to be reduced by up to 100 Mg per year. In addition, it has been shown that the estimated payback period for biogas installations is less than 5 years, and with the current trend of increasing energy prices, it may be even shorter—up to 4 years.

Highlights

Global biomass harvested worldwide mostly ends up in the livestock subsystem as feed or bedding material [1]
The calculations are presented for the current inventory, i.e., Brody farm—600 livestock units (LSU) (Table 4)
Cow manure from the Brody farm is stored in piles on special reinforced concrete slabs

Summary

Introduction

Global biomass harvested worldwide mostly ends up in the livestock subsystem as feed or bedding material (almost 60%) [1]. Reducing greenhouse gas (GHG) emissions is currently one of the biggest challenges for the livestock industry in terms of climate change. Using the life-cycle approach, it has been estimated that livestock accounts for approx. Dairy farms are a major contributor to the total life cycle greenhouse gas emissions of milk and other dairy products. About 70–85% of the GHG emissions occurred in the processes preceding the milk leaving the farm, i.e., cradle-to-farm gate emissions [6,7]. This means that already proper management inside the dairy farm can significantly reduce greenhouse gas emissions

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