Why do my blocks not have a baseFeePerGas property?

Question

I've got a private network that's using the clique consensus protocol and is running using Geth (if that's relevant).

I have been confused about gas and transaction fees, so wrote a script to look at how the fees change given the [gas] size of the previous block. I ran my script on the Rinkeby network to try it out, and what I saw aligns with what I expected. (If the block is >100% of the target size, I expect the baseFeePerGas to increase; if it's <100% I expect baseFeePerGas to decrease.)

However, when I run the same script on my private network, the baseFeePerGas property is missing from every block. Given that my network and Rinkeby use the same protocol, is it unreasonable of me to expect the same properties on blocks?

Currently my network is completely suboptimal in that it only has one miner. Could this be why baseFeePerGas is missing?

UPDATE:

Geth version is 1.10.16-stable-20356e57.

My genesis.json is:

{
  "config": {
    "chainId": 21456,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip150Hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0,
    "clique": {
      "period": 600,
      "epoch": 30000
    }
  },
  "nonce": "0x0",
  "timestamp": "0x5eccf14a",
  "extraData": "0x0000000000000000000000000000000000000000000000000000000000000000f1bfa564d354a59ca9c71e606c8f19eae19d52cb0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  "gasLimit": "1000000000",
  "difficulty": "0x1",
  "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "coinbase": "0x0000000000000000000000000000000000000000",
  "alloc": {
    "0000000000000000000000000000000000000000": {
      "balance": "0x1"
    },
    "0000000000000000000000000000000000000001": {
      "balance": "0x1"
    },
    "0000000000000000000000000000000000000002": {
      "balance": "0x1"
    },
    ...252 others...
    "00000000000000000000000000000000000000ff": {
      "balance": "0x1"
    },
    "000211184408e571bdb4fd96f1815f515e7b2a03": {
      "balance": "0x200000000000000000000000000000000000000000000000000000000000000"
    },
    "1081d21e1e6bcb3e71bcf025305e80f68e45351d": {
      "balance": "0x200000000000000000000000000000000000000000000000000000000000000"
    },
    "702e36767e3c5298c91160c5716ea0d9c807a881": {
      "balance": "0x200000000000000000000000000000000000000000000000000000000000000"
    },
    "793c20626b11a569460186e803a32391bc759ff9": {
      "balance": "0x200000000000000000000000000000000000000000000000000000000000000"
    },
    "f1bfa564d354a59ca9c71e606c8f19eae19d52cb": {
      "balance": "0x200000000000000000000000000000000000000000000000000000000000000"
    }
  },
  "number": "0x0",
  "gasUsed": "0x0",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
}

I've trimmed it to get rid of an excessive number of accounts.

Answer 1

With thanks to @Ismael for the guidance, here's a trimmed version of my genesis.json file:

{
  "config": {
    "chainId": 21456,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip150Hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0,
    "berlinBlock": 0,
    "londonBlock": 0,
    "clique": {
      "period": 150,
      "epoch": 30000
    }
  },
  ...
}

The relevant bits are the inclusion of londonBlock and berlinBlock. (I also changed period from 600 to 150, but that's unrelated.)