Multi-GW renewables need multi-GW storage, or fossil fuelled power stations will be needed to balance for intermittency. For the same reason, such balancing must be able to last for an entire evening peak if renewable...Multi-GW renewables need multi-GW storage, or fossil fuelled power stations will be needed to balance for intermittency. For the same reason, such balancing must be able to last for an entire evening peak if renewables are not generating at the same time. Batteries and DSR （demand side response） make very useful contributions and there is a large market for both, but without large scale and long duration storage, they cannot do the job. Interconnectors also contribute to the solution, and storage will make them more profitable, but （taking a UK perspective） Ofgem identified that all our neighbours have similar generation capacity crunches and similar demand patters, so if we need the electricity when they do, we’ll have to pay through the nose for it. Last winter’s ￡ 1,500/MWh prices proved that―even with only 4 GW interconnection. Following exit from the single market, our neighbours will be able to say “our consumers are more important than yours at any price”. We need UK-based storage at the right scale, to store UK-generated electricity for UK use and for export―otherwise we lose security of supply. CAES （compressed air energy storage） and pumped hydro are the only technologies currently able to deliver this scale and duration of storage. Pumped hydro is cost-effective in the long term but there are few sites, and it is （location dependent） over 3x the cost of CAES. Storelectric has 2 versions of CAES： one is a comparable price to existing CAES, but much more efficient （~70% v 50%） and zero emissions （existing CAES emits 50%-60% of the gas of an equivalent sized power station）. The other is retro-fittable to suitable gas power stations, is more efficient （-60% v 50%）, almost halves their emissions, adds storage-related revenue streams and is much cheaper. Both are new configurations of existing and well proven technologies, supported by engineering majors.展开更多
The temporal behaviour of a flow separation in the hub-suction side comer of a transonic diffuser is studied thanks to unsteady numerical simulations based on the phase-lagged approach. The validity of the numerical r...The temporal behaviour of a flow separation in the hub-suction side comer of a transonic diffuser is studied thanks to unsteady numerical simulations based on the phase-lagged approach. The validity of the numerical re- sults is confn＇med by comparison with experimental unsteady pressure measurements. An analysis of the instan- taneous skin-friction pattern and particles trajectories is presented. It highlights the topology of the separation and its temporal behaviour. The major result is that, despite of a highly time-dependent core flow, the separation is found to be a ＂fixed unsteady separation＂ characterized by a fixed location of the main saddle of the separation but an extent of the stall region modulated by the pressure waves induced by the impeller-diffuser interaction.展开更多
文摘Multi-GW renewables need multi-GW storage, or fossil fuelled power stations will be needed to balance for intermittency. For the same reason, such balancing must be able to last for an entire evening peak if renewables are not generating at the same time. Batteries and DSR （demand side response） make very useful contributions and there is a large market for both, but without large scale and long duration storage, they cannot do the job. Interconnectors also contribute to the solution, and storage will make them more profitable, but （taking a UK perspective） Ofgem identified that all our neighbours have similar generation capacity crunches and similar demand patters, so if we need the electricity when they do, we’ll have to pay through the nose for it. Last winter’s ￡ 1,500/MWh prices proved that―even with only 4 GW interconnection. Following exit from the single market, our neighbours will be able to say “our consumers are more important than yours at any price”. We need UK-based storage at the right scale, to store UK-generated electricity for UK use and for export―otherwise we lose security of supply. CAES （compressed air energy storage） and pumped hydro are the only technologies currently able to deliver this scale and duration of storage. Pumped hydro is cost-effective in the long term but there are few sites, and it is （location dependent） over 3x the cost of CAES. Storelectric has 2 versions of CAES： one is a comparable price to existing CAES, but much more efficient （~70% v 50%） and zero emissions （existing CAES emits 50%-60% of the gas of an equivalent sized power station）. The other is retro-fittable to suitable gas power stations, is more efficient （-60% v 50%）, almost halves their emissions, adds storage-related revenue streams and is much cheaper. Both are new configurations of existing and well proven technologies, supported by engineering majors.
文摘The temporal behaviour of a flow separation in the hub-suction side comer of a transonic diffuser is studied thanks to unsteady numerical simulations based on the phase-lagged approach. The validity of the numerical re- sults is confn＇med by comparison with experimental unsteady pressure measurements. An analysis of the instan- taneous skin-friction pattern and particles trajectories is presented. It highlights the topology of the separation and its temporal behaviour. The major result is that, despite of a highly time-dependent core flow, the separation is found to be a ＂fixed unsteady separation＂ characterized by a fixed location of the main saddle of the separation but an extent of the stall region modulated by the pressure waves induced by the impeller-diffuser interaction.
