How to allow "limited account" users to change power management plans in Windows XP

Spent a significant amount of time searching for this, so figured I ought to note it down somewhere:

Accreditation: Written by Curtis Clay III (original source here)

1. Log on as Administrator.

2. Click Start , click Run, and then type "Regedt32" (without the
quotation marks).

3. Locate and click the following registry key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\ControlsFol
der\PowerCfg\GlobalPowerPolicy

On the Security menu, click Permissions. Either add the users separately,
or add the users' group and give all the users full control over this
key.

4. Locate and click the following registry key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\ControlsFol
der\PowerCfg\PowerPolicies

On the Security menu, click Permissions.
Either add the users separately, or add the user s' group and give all
the users full control over this key.

5. In addition, users need to be given the right to shut down the system.
To accomplish this, follow these steps:

a. In Control Panel, double-click Administrative Tools, and then
double-click "Local Security Policy".

b. In the left pane, expand Local Policies and click User Rights
Assignment.

c. In the right pane, double-click "Shut down the system", and add each
user individually or add the Users group to this local security policy.
Making these changes will allow normal users to alter power scheme settings
without being added to the Local Administrators group.

Note If users are running Windows 2000 Service Pack 3 (SP3), an
Administrator must also provide the users with the "Create Pagefile"
permission.