I just got my Lenovo Thinkpad 121e.

After installing Arch Linux I've worked on its power consumption.
Therefore I've installed powertop2 (which is now in my repo).
After some analyzing I got a pretty good amount of commands I've added to /etc/rc.local:

rc.local

#!/bin/bash
#
# /etc/rc.local: Local multi-user startup script.
#
# remap caps-lock to escape
echo "keycode 58 = Escape" | loadkeys -q -
 
# powersaving according to powertop2
echo 0 > /proc/sys/kernel/nmi_watchdog
echo 1 > /sys/module/snd_hda_intel/parameters/power_save
echo 1 > /sys/devices/system/cpu/sched_mc_power_savings
echo 1500 > /proc/sys/vm/dirty_writeback_centisecs
echo min_power > /sys/class/scsi_host/host0/link_power_management_policy
 
# enable powermanagement for usb devices
for f in $(find /sys/ -path */power/level)
do
  echo auto > "${f}"
done
unset f
 
# enable powermanagement for supported pci-devices
for f in /sys/devices/pci0000:00/0000:00:00.0/power /sys/devices/pci0000:00/0000:00:02.0/power /sys/devices/pci0000:00/0000:00:16.0/power /sys/devices/pci0000:00/0000:00:1a.0/power /sys/devices/pci0000:00/0000:00:1b.0/power /sys/devices/pci0000:00/0000:00:1c.0/power /sys/devices/pci0000:00/0000:00:1c.1/power /sys/devices/pci0000:00/0000:00:1c.1/0000:02:00.0/power /sys/devices/pci0000:00/0000:00:1c.2/power /sys/devices/pci0000:00/0000:00:1c.2/0000:03:00.0/power /sys/devices/pci0000:00/0000:00:1c.5/power /sys/devices/pci0000:00/0000:00:1c.5/0000:08:00.0/power /sys/devices/pci0000:00/0000:00:1d.0/power /sys/devices/pci0000:00/0000:00:1f.2/power
do
  echo auto > "${f}/control"
done
unset f
 
# enable powermanagement for wlan
iwconfig wlan0 power on

These commands decrease the discharge rate by 2-3 Watt which increases runtime by 0.5h-1h.

In addition I'm running cpufreq with 'ondemand' governour.
Therefore I had to add acpi-cpufreq to 'MODULES'-array of /etc/rc.conf.

Update: Today I tried the module parameters for i915 mentioned on Arch Linux Wiki. These parameters again decreased discharge rate by 2 Watt (ca. 8 W needed on idle).

/etc/modprobe.d/i915.conf

options i915  i915_enable_rc6=1 i915_enable_fbc=1 lvds_downclock=1 semaphores=1