The Denver Post Utilities in wide swaths of the heartland struggling with electricity shortages and in some cases, outages, after several days of abnormally cold temperatures, urged customers to curtail power usage where they can. Texas has suffered widespread outages and the Southwest Power Pool, which manages the power grid across the Plains states, saw demand outstrip supply for the first time ever, forcing it to order rolling blackouts Monday morning. Colorado has largely been spared, although some customers in the northeast corner of the state fell under the SPP order. Westminster-based ...