Upgraded Metallurgical Silicon (UMG) has the potential to reduce the cost of Photovoltaic (PV) technology, while at the same time improving the environmental profile of solar-grade silicon in terms of energy payback time and CO2 emissions. In this contribution we report recent work made in the framework of a European SOLAR-ERA.NET project (CHEER-UP) to demonstrate that UMG multicrystalline silicon is a competitive alternative to polysilicon for the production of high efficiency solar cells. Defect engineering techniques based on phosphorus diffusion gettering have been explored to improve the bulk quality of UMG, reaching bulk lifetimes >300 µs, with record values of 1.1 ms. Black silicon has been implemented, designing this texturing process to make it compatible with gettering and surface passivation effects and obtaining reflectivities in the range of 12% after smoothing. Passivated Emitter and Rear Cell (PERC) has been the cell architecture used to assess the efficiency of UMG, conveniently tailoring an industrial manufacturing process to the specificities of the material, and TOPCon solar cell processing key steps have been tested on the material to further evaluate the potential of the material beyond PERC. Degradation mechanisms related to light exposure and operation temperature have been shown not to be significant in UMG PERC solar cells when a regeneration step is implemented. The project has resulted in the achievement of 20,1% UMG multicrystalline PERC solar cells, an efficiency target that is accompanied by a reduction in the environmental impact of silicon technology.