there are estimates, but almost all of them are flawed and biased because the bitcoin crowd is making them. For example many consider the energy consumed by banks branches to light up the offices or by the air conditioning systems, as if bitcoins were mined in dark caverns self refrigerated.
Or they compare the total amount of energy consumed, but when making their calculations they "forget" to take into account that the total amount of money in circulation is around 80 trillion dollars (some sources say more, some less, I settled on the CIA estimates that are usually very precise ) directly employing million of workers (5 million only in Europe+USA), while bitcoin market cap is only 600 billion (rounded up by me) and employees zero workers.
Money is used everyday by billions in countless transactions (~1 billion transactions a day only counting CC), bitcoins owners are only 5 million and make only 300k transactions per day.
Also consider that bitcoins are designed to burn energy to exist, money works even if suddenly communications shut down or on a desert island in the middle of the ocean with no internet connection, you don't need to keep a copy of a public ledger of all the transactions and can be reused many times and recycled.