RSS and Home Assistant: early warning for grid blackouts

2020-08-16 623 words 3 minutes

Contents

California, like most of the West Coast, is currently in the middle of a prolonged and serious heat-wave. Record breaking temperatures results in a distribution grid stressed beyond it’s abilities which guarantees blackouts.

The organization that oversees the electric grid in California publishes RSS feeds for various types of grid related news and events. All the CA ISO RSS feeds are published here, but the two feed that I’m using are:

As energy demand ramps up, flex alerts are issued as a call to reduce energy consumption. If demand continues to rise warnings and, finally, stage3 events are issued. A warning does not guarantee a stage3 event, but a stage3 event mans that blackouts are all but inevitable in the coming hours. The exact meaning of each alert type is outlined in this PDF.

The noticeRSS.xml feed, has early warning notifications that look like this:

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<item>
\n
<title>NOTICE 202002440: CAISO Grid Warning Issued </title>
\n
<link>http://www.caiso.com/awe/noticelog.html#202002440</link>
\n
<description>Effective: 16-Aug-2020 12:00 PM Terminates: 16-Aug-2020 11:59 PM</description>
\n
</item>

Note: there’s nothing wrong w/ your browser, the \n characters are in the actual feed. No matter, the RSS parser in Home Assistant can tolerate them.

I use the alerts/warnings to do a few simple tasks, but there’s so much potential beyond the automation I currently have:

bumps thermostats up by a few degrees to lighten demand*
re-schedule a few routine activities that are usually done in the evening to as soon as possible (cooking, for example)
notify me to immediately go check that the generator has fuel

Currently in ‘unarmed’ mode as I tweak the logic driving the decision

How to do it

Basically, add the two feeds above to the feedreader integration and use the feedreader type of event to trigger your automation.

Somewhere in configuration.yaml, load the feedreader component.

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feedreader: !include feedreader/rss.yaml

and in the feedreader/rss.yaml file, add the URLs:

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urls:
  - http://content.caiso.com/awe/noticeRSS.xml
  - http://content.caiso.com/awe/noticeflexRSS.xml
# Pull down the feed 2x/ hour
scan_interval:
  minutes: 30

Unfortunately, Home Assistant does not support setting the scan_interval per feed, so you’ll have to figure out a happy middle ground if you’ve already got a few RSS feeds you monitor. Likewise, don’t pull the feed down excessively… I don’t see a lot of evidence that the feed is cached well and the CA ISO does occasionally have to put banners on the top of their site saying that the site is under heavy load. Don’t be the reason the site goes down because you wanted instant notification.

If you’re not in a position to do any sophisticated automation based on the notification, it’s still simple to fire off a notification to manually prepare:

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##
- alias: Notify when new Flex or Warning issued
  trigger:
    platform: event
    event_type: feedreader
  action:
    service: persistent_notification.create
    data_template:
      notification_id: "{{ trigger.event.data.title }}"
      title: "FlexAlert"
      message: >
        {% set tokens = trigger.event.data.description.split(' ') %}
        {% set start_str = "{} {} {}".format(tokens[1], tokens[2], tokens[3]) %}
        {% set start = strptime(start_str, '%d-%b-%Y %I:%M %p') %}
        {% set end_str = "{} {} {}".format(tokens[5], tokens[6], tokens[7]) %}
        {% set end = strptime(end_str, '%d-%b-%Y %I:%M %p') %}
        "Heads up, electricity demand is likely to exceed production from {{ start.isoformat() }} to {{ end.isoformat() }}"        

Which should create a simple notification that’ll look something like this:

The strptime function yields start and end objects that can be manipulated further:

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{% set now = now() %}
{% if start.day > now.day -%}
  It looks like demand will be high *tomorrow*
{%- endif %}

Happy automating.