Speaking on the power devices builtin statistics reporting capabilities level, not all devices support providing statistics ... Use the upower command of UPower to list power devices with the option -e like so(this is a demonstration on a test system):

$ upower -e
/org/freedesktop/UPower/devices/line_power_ADP0
/org/freedesktop/UPower/devices/battery_BAT0
/org/freedesktop/UPower/devices/DisplayDevice

Then check the information of the device you want with the option -i ... Names are pretty descriptive, so the direct power line:

$ upower -i /org/freedesktop/UPower/devices/line_power_ADP0
  native-path:          ADP0
  power supply:         yes
  updated:              Fri 11 Aug 2023 03:45:32 PM +03 (68 seconds ago)
  has history:          no
  has statistics:       no
  line-power
    warning-level:       none
    online:              yes
    icon-name:          'ac-adapter-symbolic'

and as you can see, it doesn't have statistics ... So, information about current power consumption (among other information) can't be pulled from that device.

While the battery:

$ upower -i /org/freedesktop/UPower/devices/battery_BAT0
  native-path:          BAT0
  vendor:               LGC
  model:                L16L2PB2
  serial:               5545
  power supply:         yes
  updated:              Fri 11 Aug 2023 03:47:33 PM +03 (2 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               charging
    warning-level:       none
    energy:              5.06 Wh
    energy-empty:        0 Wh
    energy-full:         17.99 Wh
    energy-full-design:  30 Wh
    energy-rate:         9.238 W
    voltage:             7.744 V
    charge-cycles:       N/A
    time to full:        1.4 hours
    percentage:          28%
    capacity:            59.9667%
    technology:          lithium-polymer
    icon-name:          'battery-low-charging-symbolic'
  History (charge):
    1691758053  28.000  charging
  History (rate):
    1691758053  9.238   charging

does have statistics and among those is energy-rate: which you can isolate and format for printing with something like this:

$ upower --show-info /org/freedesktop/UPower/devices/battery_BAT0 |
awk '/energy-rate:/{print $2}'
10.828 # <--- output

However, the statistics update interval might vary and updated: shows the time the statistics were last updated, but you can force statistics refresh of a certain device with for example:

busctl call org.freedesktop.UPower \
/org/freedesktop/UPower/devices/battery_BAT0 \
org.freedesktop.UPower.Device Refresh

and you can pull for e.g. energy-rate every for example three seconds with something like this:

while sleep 3
do
# Refresh device statistics
busctl call org.freedesktop.UPower \
/org/freedesktop/UPower/devices/battery_BAT0 \
org.freedesktop.UPower.Device Refresh
# Query the device statistics
upower -i /org/freedesktop/UPower/devices/battery_BAT0 |
awk '/energy-rate:/{print $2}'
done

On my system I can obtain the power drawn from the battery from

cat /sys/class/power_supply/BAT0/power_now
9616000

On Thinkpads if the tp_smapi module is loaded, the file is

cat /sys/devices/platform/smapi/BAT0/power_now

The value seems to be in µW, though. You can convert it with any tool you're comfortable with, e.g. awk:

awk '{print $1*10^-6 " W"}' /sys/class/power_supply/BAT0/power_now
9.616 W

In case you cannot find the location within the sysfs file system, you can search for it:

find /sys -type f -name power_now 2>/dev/null

Additionally, the package lm-sensors may be used to determine the system power usage on some machines:

# sensors power_meter-acpi-0
power_meter-acpi-0
Adapter: ACPI interface
power1:      339.00 W  (interval =   1.00 s)

We have created a terminal tool to monitor CPU frequency/utilization/Temperature. It now also supports monitoring power on Intel CPUs newer than Sandy-Bridge.
You can see the power graph in watts on the bottom as well as on the side bar.
This only reads total CPU power, not per process and not including other components.