So let us get started, it's great to see such a crowded room here, I hope you're not all
here just for the next talk to grab a seat.
So my name is Kai, I'm a software architect and a project lead and founder of the project
OpenHUB.
I'm not going to talk about OpenHUB for smart home today here in that talk, if you're interested
in that project, come to see me at our booth directly here in that building at the entrance.
But I'm going to talk about more or less my personal story as a consumer, as an end user
in terms of energy management, my experiences there over the years and the story actually
goes much further back than four years, so it all started already 15 years when we built
the house and I more or less electrified everything possible in there.
So starting from the lights, not that many people use candles nowadays anymore, sure,
but also heating is all electric, warm water through a heat pump, photovoltaic system on
the roof, so everything was nicely connected to a K-next system, so controllable, I could
get all measurements, but what was missing at that time was to really have some software
that really helps me to visualize things, to control things and so on, and that's why
I started the OpenHUB project in year 2010, directly as an open source project with the
intention to have a system that allows me to create overarching rules and overarching user
interfaces over all things I have at home that have somehow an API that I can somehow
connect to and to have such a system in place.
The focus and contrast to all the commercial solutions out there was on local control,
I said, well, it's my home, I have all the devices at home there, they should talk locally
with each other, I want to have all my data locally and I don't want to have any dependency
on the internet for that system.
By now OpenHUB grew quite a community and we have more than 400 different so-called
bindings which are more or less drivers for certain radio protocols, other systems, technologies
to reach out and to really combine into one single system and so you can more or less
get everything what is available at home into that solution.
Now, in terms of energy, what I did is that I hooked up such electric meters with an S0
interface in my electrical cabinet which simply provide impulses as an output and I hooked
them up to a KNEX binary input which then simply provide those on the KNEX bus and created
simple rules in OpenHUB that count the number of ticks for a certain period of time to calculate
the current power out of that.
As you can see here from the graph, I have several of these meters, one for heating and
blue here which usually really turns on and off load, simply the green that was now one
day last week here so winter and not that sunny as the photovoltaic power produced and
then yellow the household energy that we use for more or less all the rest at home.
Now having that in the browser as a visualization is quite nice but how to engage my family
members to actually also get a feeling about the consumed energy where we put up a fairly
simple device here, an energy light which is basically an IKEA lamp with a Philips
U bulb inside and a fairly simple rule in OpenHUB that you can see here which simply
says whenever our household power changes then if it's not night because then we want
all lights off, calculate a U value ranging from green over yellow to red and simply post
that as a new color to that light bulb.
And interestingly that this device that somehow goes a bit to your unconsciousness over time
so we're passing that many times a day in the house and you suddenly feel after a while
that something doesn't seem to be normal, I didn't turn the dishwasher on or the washing
machine and still it's showing red so let's think what I might have forgotten then.
So it really gives a sense of and a feeling about the energy usage at home are not just
for me but also for other family members which is a nice effect on that one.
Now for monitoring heating energy here, this is quite a nice visualization which shows a
calendar here.
This one shows last December where you might remember here in central Europe we had a very
cold phase in the middle and it was fairly mild over Christmas and towards the end.
And so the background color here on each single day shows the minimal temperature of that
day ranging from minus 10 degrees that we had at home to I think on New Year's Eve
it was around 11 degrees minimum temperature that day and the diamonds here show then the
used energy for heating that day and you see a very nice correlation here between those
two figures so that this can be also used to see whether everything works nicely or
if you should actually check if something's not right.
For monitoring photovoltaic system if you set up a bit more complex graph that uses
InfluxDB and Grafana dashboard which both nicely integrate with Open Hub as a system
to really get the data out here.
So you can see in blue the elevation of the sun for that day, in red the luminance in
south direction, in yellow then the power of the photovoltaic system, the gray bars show
when it was raining that day and so you really have a very nice visualization and you can
check that everything's working alright and also a very good correlation here between
really the light intensity and the photovoltaic power so whenever something's off here you
could create alarms on your Grafana dashboard to actually say hey check your system please.
Luckily so far after 15 years with that system everything was smooth and I never needed
a single alarm on that.
Another nice event happened in spring 2015 when we had a partial solar eclipse at home
and it was on a bright sunny day without any clouds and that really resulted in a very
nice curve here and interesting thing is that with a partial solar eclipse when you look
outside you hardly notice it because it's not going dark, it's still daylight but here
see that the power of the sun really went down by factor 3 to 4 roughly and it was almost
as if it's dark so it was quite a nice effect.
So all the monitoring is nice and good but in the end when you're talking about energy
management you really want to do some load shifting, optimizing your consumption and
all of those things.
Now unfortunately at the time that our photovoltaic system went live or at that time there was
no incentive at all for the end customer to self-consume that energy that is produced
but everything goes to the grid and it's paid there and that's it so there's no benefit
for me to actually shuffle around some loads and do things so my only option was to say
well okay our utility should provide different price levels over the day and I can maybe
shift things for that and thinking 10 years back the standard example for shifting load
was hey you can do your washing at night that was what everybody came up with more or less
and so I said well okay sounds interesting let's see such a washing machine that was
smart grid ready usually cost around 300 euros more than the same model without such a feature
okay you could say well one time investment let's go for that fine and at the time also
in Germany the utilities were legally obliged to offer you at least one smart tariff that
had to have two different price levels at least so I said okay let's check that out
and my local utility said okay we have a field trial here and in order to participate in
that you actually have to book our smart tariff which was an additional 100 euros a year I
have no clue why because we already had a smart meter so there was no hardware investment
or anything involved in that but they provided an API then which said for the next day for
that hour of the day it will cost you that much money and the price difference between
high and low was exactly 3 cents per kilowatt hour so I quickly checked okay washing machine
what does that mean actually as a yearly consumption it's roughly 150 kilowatt hours
that you assume here so I did some quick arithmetic and came to the conclusion that hey you can
save four euro fifty a year by doing all your washing at night and yeah so that doesn't sound
that much but you might now argue okay you can also use your tumble dryer at night you
could maybe wash your dishes at night as well and maybe even move your warm meals to the
night when everybody else is asleep but even then you're not coming anywhere close to actually
have any benefit from all of that okay so that that wasn't too interesting for me unfortunately
and somehow my local utility also noticed after a while hey that doesn't seem to be too attractive
nobody really wants that and actually they came by and told me that hey those smart meters
that you have at home they break so often and then they can't read the LC display anymore
and so they can't get the number out of the meter and they have no clue to no clue what
to do about that so they said well in 2016 they ripped that out and replaced it by an
old school Ferraris meter and said hey that one is really lasting 10 years we don't have
to come by everything fine so here you go so that was it more or less with all my attempts
at being really in the front there doing energy management and trying to be cool with all the
smart home stuff and automation here and that stayed like that until more or less four years
ago when we bought this nice little blue Tesla here which had a huge battery and I thought
okay so much battery to store energy I have to do something with that now as I said photovoltaic
system wasn't really helping me here because there was no incentive for self consumption
so I had to put up a second photovoltaic system this time on the garage roof and in 2019 was
now the case that for this one giving power to the grid hardly gave you any money so you
had a big incentive in using all that energy yourself and optimizing that really and so
yeah big parts of the household energy during the day is automatically covered then by such
a photovoltaic system but then with the combination of the car surely surplus charging becomes
very attractive here to say that everything that exceeds what you need in the household
should be used for charging your car quite luckily then for more or less the pandemic
times was that well everybody did at home office so did I so the car was at home during
the day when it was sunny so that worked out really well and this year shows now another
open hub rule that was simply says or that whenever the photovoltaic system power changes
or the household power changes then please check if the car is connected to wall box
and adjust the current that the wall box is delivering to the car and I have a keba wall
box that accepts UDP packets here to control it down to a milli amp granularity which is
really nice because you can steer it very precisely here you have to at least go with
six amps though which is more or less the minimal power to start charging of the car
but with that rule I can do all of that and so on the next slide you see more less than
the outcome on a very nice sunny day so in blue you have here the overall power that
goes to the grid or comes from the grid and the idea is to really level that out on the
zero line ideally so in the morning when there was no sun we had to draw power from the grid
then the sun came up or we gave some power to the grid until the car started to charge
then up a certain level and then you can see that it's really fairly flat at zero so that
works pretty well then came lunchtime when the household power consumption was a bit
more bumpy going up and down so it's a bit more tricky to level that all out but it worked
also quite well then I think at the end the dishwasher went on which used so much energy
already that the charging had to stop completely and it turned actually out that there was some
bug in the car firmware that didn't resume the charging afterwards anymore so at that
time I had to manually then always go there and have to restart it luckily by now this
bug is fixed by Tesla and yeah so the rest of the day the charging rate was a bit reduced
and it works quite well and overall you can see that on the next slide that's the yield
of the photovoltaic system over all of last year and in average that was between 10 and
11 kilowatt hours per day and if you consider that half of that so five kilowatt hours is
then used for the surplus charging that corresponds to roughly 10,000 kilometers a year of driving
the car obviously a bit more in summertime and not that much in wintertime but it corresponds
to a saving of roughly two tons carbon dioxide which is quite a nice effect here and yeah
that's my experience so far I'm looking in the future to also integrate with other solutions
like EVCC for example which specifically looks into car wallbox monitoring and also going
or like OpenStep which is sounded quite nice into looking into the future predicting and
getting more machine learning stuff in there which might be a topic for next year then
and with that I thank you very much for your attention are there any questions
yeah okay the question is if I can imagine whether I more or less give control more to
the grid operator than controlling it myself in theory I can imagine that but from all
that I've seen out there is that that's still a far far future that really the utilities
would be in a position to really make use of that data and problem that I see is also
you know how do you actually make sure that the data is real that I'm not just giving
anything there for maybe benefiting in some way of a better tariff or whatever and sorry
it's measured by the meter okay if that's all just the pure meter values that's I think
anyhow already possible with the smart meters that are installed not in my case now at the
moment anymore yeah for having the utility allow to decide when to charge and discharge
the car I still want to be in the position to say well I actually needed at that charging
state at that moment and so on if that can be fulfilled that works there washing machine
is also something that really goes into your own personal comfort a lot so if they decide
when to do it and so it's all a bit tricky I think it's better here in the households
to really decide what to do and give incentives to do the right stuff
yeah yeah no from utility and the grid side it's obviously very important
to not see a single household but to see more or less a whole city part of the city and
so on and to be able to control things there to more or less get a decent level that's
for sure but I think it's helpful to provide incentives to the single people by having
an API to interact with and then that might work okay I see my time's up thank you very
much if you want to discuss further I'm at the booth