You can use Windows UI Automation as explained here: Enumerating notification icons via UI Automation

The difficulty is to find the power icon, whatever the end-user language is. Luckily, some icons have an AutomationId set, so we can search the power one using its id.

There is one issue though: for some reason the UI automation dlls (UIAutomationXXX) shipped with Windows are not up to date (and buggy) so don't use them for this task, and use the UIAComWrapper dll (originally written by a Microsoft guy) instead, for example from here: https://www.nuget.org/packages/UIAComWrapper/

So, here is a sample Console app code (with helper code from the link above):

static void Main(string[] args)
{
    // you can find the value of this guid using SDK's "inspect" tool, hovering over the power icon.
    var SCAID_Power = new Guid("7820ae75-23e3-4229-82c1-e41cb67d5b9c");
    var power = EnumNotificationIcons().FirstOrDefault(i => string.Compare(i.Current.AutomationId, SCAID_Power.ToString("B"), StringComparison.OrdinalIgnoreCase) == 0);
    if (power != null)
    {
        power.InvokeButton();
    }
}

public static IEnumerable<AutomationElement> EnumNotificationIcons()
{
    var userArea = AutomationElement.RootElement.Find("User Promoted Notification Area");
    if (userArea != null)
    {
        foreach (var button in userArea.EnumChildButtons())
        {
            yield return button;
        }

        foreach (var button in userArea.GetTopLevelElement().Find("System Promoted Notification Area").EnumChildButtons())
        {
            yield return button;
        }
    }

    var chevron = AutomationElement.RootElement.Find("Notification Chevron");
    if (chevron != null && chevron.InvokeButton())
    {
        foreach (var button in AutomationElement.RootElement.Find("Overflow Notification Area").EnumChildButtons())
        {
            yield return button;
        }
    }
}

public static class AutomationHelpers
{
    public static AutomationElement Find(this AutomationElement root, string name) => root.FindFirst(TreeScope.Descendants, new PropertyCondition(AutomationElement.NameProperty, name));
    public static IEnumerable<AutomationElement> EnumChildButtons(this AutomationElement parent) => parent == null ? Enumerable.Empty<AutomationElement>() : parent.FindAll(TreeScope.Children, new PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.Button)).Cast<AutomationElement>();

    static public AutomationElement GetTopLevelElement(this AutomationElement element)
    {
        AutomationElement parent;
        while ((parent = TreeWalker.ControlViewWalker.GetParent(element)) != AutomationElement.RootElement)
        {
            element = parent;
        }
        return element;
    }

    public static bool InvokeButton(this AutomationElement button)
    {
        var invokePattern = button.GetCurrentPattern(InvokePattern.Pattern) as InvokePattern;
        invokePattern?.Invoke();
        return invokePattern != null;
    }
}