In areas of poor power condition, where it's difficult to get an alternative power to supply class 1 load, an emergency power is required.

在供电条件比较差的地区，取得第二个电源供给一级负荷有困难时，也需要增设应急备用电源。

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In the first-level load shoulders specially importantly, besides the above two power sources, but must additionally build the emergency power supply.

一级负荷中的特别重要负荷，除上述两个电源外，还必须增设应急电源。

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Only as a last resort (Power Emergency) to avoid the risk of a complete blackout does ERCOT ask utilities to reduce demand by dropping load through rotating outages.

FORBES: Lights Dimming in Texas; Rolling Blackouts Likely