The increasing deployment of variable renewable energy (VRE) in the power sector, such as wind and solar photovoltaic, is expected to reduce emissions. However, VRE poses challenges due to their intermittency and variability. The Future Renewable Energy Performance into the Power System Model (FEPPS) is used to analyse VRE penetration in Great Britain's (GB) power system, resulting in VRE shares of around 65%, far from over 80% forecasted by 2030 and 2040 due to flexibility and stability constraints. The incorporation of new power generation and energy storage technologies is also analysed, including the role of biomass and hydrogen as low-carbon fuel options. Hydrogen is assumed to be produced from the curtailment of VRE and biomass. Between 6.57 and 283 Mt. of biomass would be required to balance bio‑hydrogen requirements by 2040; therefore, hydrogen production would depend on technology prioritisation. Power generation from hydrogen technologies (fuel cells and turbines) has a significant role in power system decarbonisation, with hydrogen turbines meeting up to ∼10% of annual electricity demand. In contrast, generation from batteries, adiabatic compressed air energy storage and natural gas turbines is not significant. Moreover, between 7.7 and 9.7 TWh of hydrogen storage would be needed, and there is substantial potential for salt cavern storage in GB, providing many 100s TWh. Finally, incorporating new generation and storage technologies relies on levelized cost of electricity (LCOE) reductions of 31% and 13% by 2030 and 2040, respectively, to keep the power sector on track towards decarbonisation.