Demand-Driven Biogas Production from Anaerobic Digestion of Sewage Sludge: Application in Demonstration Scale

Abstract

The power system needs flexible electricity generators. Whilst electricity generation from anaerobic digestion (AD) of sewage sludge has traditionally been baseload, transforming the generation capacity into a modern flexible operator is an opportunity to further valorise the resource. This work aims to demonstrate that AD of sewage sludge can support flexible generation and be operated dynamically in a relevant operational environment, to promote full scale implementation. A demonstration scale plant (20 m3 conventional AD reactors) was used to test several feeding regimes designed to return a biogas production rate that matches the demand. Two demand profiles are defined, either by common corporate power purchase agreements or by the main balancing mechanism used by the grid operator in UK. Demand-driven biogas production is demonstrated in this relevant operational environment, and the flexibilisation performance is positive in all scenarios. The value of the biogas increases by up to 2%, which outperforms the results obtained at pilot scale. Additionally, an increase in biogas yield is observed. Whilst transitional imbalances are recorded, they last for few hours and the overall stability is not affected. In conclusion, these trials demonstrate demand-driven biogas production is a feasible operational solution and full-scale implementation is possible. Graphical Abstract

Economic and Carbon Costs of Electricity Balancing Services: The Need for Secure Flexible Low-Carbon Generation

“…Similarly, the annual CI of the CM is calculated by multiplying the generation and the CI for each fuel (Equation ( 5)). For the purpose of this work, the total generation of the CM is calculated assuming that the capacity secured is equally used for generation during the peak hours (16:00-20:00) [34,35] of the winter period (November-March), which is the period of higher stress for the grid [67].…”

“…Hydro, and pumped hydro storage (PHS), are largely used for flexible generation. Bioenergy (in solid, liquid or gaseous forms) can be produced, stored and used according to the demand at peak time [29,[32][33][34][35].…”

The Diffusion Rule of Demand-Oriented Biogas Supply in Distributed Renewable Energy System: An Evolutionary Game-Based Approach

“…In recent years, researchers have investigated the application scenarios of DO mechanism from different perspectives, in which most of them focused on its technical improvements, such as how to use mathematical models for biochemical reaction control [6,7], the selection of suitable feeding substrates [8,9], and process optimization [10,11] to better ensure on-demand biogas supply. Several studies have previously focused on the practical application of biogas; however, these studies often employed simplified demand profiles [12,13].…”