Oil prices reversed early losses to extend gains on Tuesday into a fourth day amid a rebound in global demand that is contributing to energy shortages in major economies. Brent crude was up 21 cents or 0.3% at $83.86 a barrel at 0632 GMT, the highest in three years, after rising 1.5% on Monday. U.S. oil gained 13 cents or 0.2% to $80.65 a barrel, a seven-year high, having also gained 1.5% in the previous session. Crude oil is being “swept up in the broader rally across the energy sector,” said James Whistler, global head of energy derivatives at SSY in Singapore. “High gas and coal prices are raising the prospect of more switching to oil for power generation.” Switching […]