No, the calculation is done per transaction, not per block. You can calculate the per-block consumption pretty easily based on the stat that there are about 150[1] blocks mined daily and the total TWh used per year for the network is 200[2]. 200 TWh per year / (365 days * 150 blocks) = 3.6MWh per block. The amount of transactions per block is around 2,000[3], so if you divide that number by 2,000 you get around 1,800 kWh per transaction