Cost-effective flexibilisation of an 80 MWe retrofitted biomass power plants: Improved combustion control dynamics using virtual air flow sensors

J Blondeau,T Museur,O Demaude,P Allard,F Turoni,J Mertens

doi:10.1016/j.csite.2020.100680

Abstract

As they deliver dispatchable renewable energy, biomass power plants are expected to play a key role in the stability of the future electricity grids dominated by intermittent renewables. Large-scale, biomass-fired power plants are often retrofitted from coal-fired plants. Such a fuel modification combined with decreasing pollutant emission limits and higher requirements in terms of load flexibility can lead to a decrease of the maximum power delivered by the unit. The limiting factors are partly related to the control systems of those plants. In this paper, we present the results of the upgrading of an 80 MWe, retrofitted biomass power plant that was achieved by improving the dynamic control of the combustion process. Thanks to the addition of virtual air flow sensors in the control system and the re-design of the combustion control loops, the undesired effects of a recent 10% power increase on NOx emissions were more than compensated. The accurate control of the local NOx production in the furnace resulted in a decrease of these emissions by 15% with an increased stability. This study will help increasing the cost-effectiveness of such conversions, and facilitate the development of dispatchable, renewable power units able to contribute to the grid stability.

Highlights

Hydropower and bioelectricity are the two main dispatchable sources of renewable energy
The power output increased by 4% after the implementation of the virtual sensors, while the NOx emissions decreased by 15%
We showed the results of the cost-effective flexibilisation of an 80 MWe, retrofitted biomass-fired power plants that was achieved by implementing virtual air flow sensors for the accurate control of the combustion process

Summary

Introduction

Hydropower and bioelectricity are the two main dispatchable sources of renewable energy. In 2016, they provided 12% and 6% of the gross electricity generation in Europe, respectively. The two main intermittent renewable sources, sun and wind power, accounted for 9% and 3% of this gross generation, respectively [1,2]. In addition to energy storage and demand side management, the concomitant development of dispatchable and non-dispatchable renewable energy sources is a key factor to ensure the stability of the electricity grids in the future [3]. The further development of bioelectricity can be achieved in a cost-effective manner by taking advantage of the existing assets currently fed with fossil solid fuels [3,4,5,6].

Methods

Results

Conclusion