Intensive livestock farming cannot be uncoupled from the massive production of manure, requiring adequate management to avoid environmental damage. The high carbon, nitrogen and phosphorus content of pig manure enables targeted resource recovery. Here, fifteen integrated scenarios for recovery of water, nutrients and energy are compared in terms of technical feasibility and economic viability. The recovery of refined nutrients with a higher market value and quality, i.e., (NH4)2SO4 for N and struvite for P, coincided with higher net costs, compared to basic composting. The inclusion of anaerobic digestion promoted nutrient recovery efficiency, and enabled energy recovery through electricity production. Co-digestion of the manure with carbon-rich waste streams increased electricity production, but did not result in lower process costs. Overall, key drivers for the selection of the optimal manure treatment scenario will include the market demand for more refined (vs. separated or concentrated) products, and the need for renewable electricity production.
In view of the current nuclear power debate in Belgium, we analyze how uncertainty about a nuclear phase-out, coupled with the implementation of renewable energy subsidies and nuclear taxes, affects investment capacity and productivity decisions by Belgian electricity suppliers. To achieve this goal, considering the key characteristics of the Belgian market, we build a Stackelberg closed-loop (two-stage) equilibrium model in which investment decisions are made in a first stage under uncertainty regarding a nuclear phase-out, and productivity decisions are subsequently made in a second stage in a certainty environment. Our analysis indicates that, regardless of subsidies, an increase in the probability of nuclear license extension results in lower levels of investment-primarily in renewable energy-, lower total production and a higher electricity price. We also show that the implementation of renewable energy subsidies reduces the effect of an increase in probability of nuclear license extension on producer's decisions regarding expanded capacity and on total profits in the market.
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