def get_node_demand(nodes, demand):
    """Get demand injections
    
    Parameters
    ----------
    nodes : pandas DataFrame
        Node information
    
    demand : pandas DataFrame
        NEM region demand
    
    Returns
    -------
    df_node_demand : pandas DataFrame
        Demand at each at each node
    """
    
    def node_demand(row):
        return demand[row['NEM_REGION']] * row['PROP_REG_D']
    
    # Demand at each node
    df_node_demand = nodes.apply(node_demand, axis=1)
    df_node_demand['level'] = 'demand'
    
    return df_node_demand