BP has decided to merge all its offshore wind business into a new joint venture with Japan’s energy firm JERA, to which the companies will provide up to $5.8 billion for investments by 2030, the UK-based supermajor said on Monday as it shifts its focus back on oil and gas. BP has been seeking for months to offload spending on project developments in the offshore wind sector, including by studying ideas to sell a small stake in the business. Now BP and JERA have agreed to combine their offshore wind businesses to form a new standalone, equally-owned…