Studying about the Ethereum blockchain I realized that it is ideal for my project. I intend to develop a blockchain to exchange electric energy between consumers on a smart grid. The mining nodes of my network would be the smart meters that exist in every house connected to blockchain, but the smart meters do not have storage modules. Because of the knowledge I have about blockchains, they must be decentralized, that is, they must be stored in the mining nodes of the network. Based on this scenario described, my doubts are:
In an application for IoT scenarios, where there are no storage modules, the blokchain should be stored in which location?
Could I use a database to store the blockchain, and use the smart meters for the mining process? But that would make the blockchain centralized, something that escapes the main idea of blockchain, correct?
I suggest you to do an analysis of existing projects (Grid+, PowerLedger) and blockchain, it will help you refine your idea and be clear on points like public vs private blockchain, PoW vs others etc. I could come up with a more precise answer but assuming you want to build a Dapp on Ethereum:
You really don't have to store the blockchain on IoT modules, you can use services Infura or run your node on a cloud service.
If you are going to build a Dapp on a public blockchain, storing IoT related data on blockchain is not a good idea considering each record will cost fee. And IoT modules are definitely not a good choice of mining equipment.