A private cloud is hosted in your datacenter. Therefore, you cannot close your datacenter if you are using a private cloud.
A public cloud is hosted externally, for example, in Microsoft Azure. An organization that hosts its infrastructure in a public cloud can close its data center.
Public cloud is the most common deployment model. In this case, you have no local hardware to manage or keep up-to-date everything runs on your cloud provider's hardware.
Microsoft Azure is an example of a public cloud provider.
In a private cloud, you create a cloud environment in your own datacenter and provide self-service access to compute resources to users in your organization.
This offers a simulation of a public cloud to your users, but you remain completely responsible for the purchase and maintenance of the hardware and software services you provide.
https://docs.microsoft.com/en-gb/learn/modules/principles-cloud-computing/4-cloud-deployment-models

Reference:
https://docs.microsoft.com/en-us/azure/cost-management-billing/manage/create-subscription