Fusion Held Seattle's Lights Through the Heat; the Old Wires Nearly Didn't

SEATTLE — When the Pacific Northwest's demand spiked during last week's heat corridor, the new power flowed as promised — and the century-old lines carrying it groaned. Fusion now supplies close to 30 percent of the reconnected grid, and Aurora Fusion Works, whose newest baseload reactor came online early last month, ran near capacity without a stumble. The failures, engineers say, were downstream. "We can make the electrons," said Deng Yao, a distribution engineer for the regional operator. "We cannot always find a wire built this century to carry them." Two substations in the Kent valley throttled output to avoid overheating conductors, briefly dimming three neighborhoods. Aurora's Emeka Okonkwo, the firm's chief executive, has argued for months that generation has outrun transmission. The heat week proved his point in miniature: a grid can be modern at its heart and brittle at its edges, and it is the edges — the old poles, the tired copper — that decide whether a family keeps its air conditioning at three in the afternoon.