High penetrations of non-synchronous renewable energy generation can decrease overall grid stability because these units do not provide rotational inertia in the same way as traditional synchronously-connected generators. Many recent studies have investigated 100% renewable energy generation scenarios, but few have explored the trade-offs associated with an electricity grid dominated by non-synchronous generation (i.e. wind and solar). Fast frequency response from grid-forming inverters—along with other technology changes—could help mitigate low system inertia levels, but the impact of this response is unknown. An inertia-constrained unit commitment and dispatch model was used to study the stability of future grid scenarios with high penetrations of non-synchronous renewable energy generation under a variety of technology scenarios. The Texas grid (the Electric Reliability Council of Texas – ERCOT) was used as a test case and instances when the system inertia fell below 100 GW$·$s (the grid’s current minimum level) were recorded. When the modeled critical inertia limit was reduced to 80 GW$·$s to represent changes in grid operation, no critical inertia hours occurred for renewable energy penetrations up to 93% of annual energy. The critical inertia limit could drop to 60 GW$·$s if the largest generators in ERCOT (two co-located nuclear plants) were retired, but emissions increased by $~$25% in these scenarios. If the critical inertia limit was kept the same (100 GW$·$s), adding 525 MW of fast frequency response from wind, solar, and energy storage could reduce the number of critical inertia hours by up to 95%. These results show that changes to grid operating practices and generator retirements reduced critical inertia hours more than fast frequency response from inverter-connected resources. Each of these mitigation pathways has associated trade-offs, so the transition to a grid dominated by non-synchronous energy generation should be handled with care, but high renewable energy penetrations (i.e. >80%) might be feasible in Texas.

非同步可再生能源发电的高渗透率可能会降低总体电网稳定性，因为这些单元无法提供与传统同步连接发电机相同的旋转惯性。最近的许多研究调查了100％可再生能源发电的情况，但是很少探讨与非同步发电（即风能和太阳能）占主导地位的电网相关的取舍。电网形成的逆变器的快速频率响应以及其他技术变化可以帮助减轻系统惯性水平，但这种响应的影响尚不清楚。使用惯性约束的机组承诺和调度模型来研究在各种技术方案下具有高渗透率的非同步可再生能源发电的未来电网方案的稳定性。$·$s（网格当前的最低水平）被记录下来。当建模的临界惯性极限降至80 GW时$·$代表电网运行的变化，可再生能源普及率高达93％的年均无临界惯性小时发生。临界惯性极限可能会降至60 GW$·$s如果ERCOT中最大的发电机（两个位于同一地点的核电厂）已经淘汰，但排放量增加了 $〜$在这些情况下为25％。如果临界惯性极限保持不变（100 GW$·$s），增加525兆瓦的风能，太阳能和能量存储的快速频率响应，可以将关键惯性小时数减少多达95％。这些结果表明，电网运行方式的改变和发电机报废的减少，比与逆变器相连的资源的快速频率响应更能减少临界惯性小时。这些缓解途径中的每一个都有相关的权衡取舍，因此应谨慎处理向以非同步能源发电为主的电网过渡，但是在德克萨斯州，高可再生能源渗透率（即> 80％）可能是可行的。