Saturday 11 November 2023

Greta Gets Diverted

As many of you will know,  we have done quite a lot to our house over the past 3 years in order to increase it's energy efficiency, it's eco credentials and most recently it's size with the addition of a new room / extension complete with underfloor heating (my heat pump was already sized for this when we bought it) and the house is now toasty and warm.

So, we now have heat pump heating,  solar panels, solar batteries, improved insulation, so what's next? Well my latest foray has been solar diversion.  What, I hear you say, you want to divert the sun ?  Not really,  what I am talking about here is that, like many of you, we have solar panels.  We generate electricity for the house and any surplus you then sell (well the rate is so poor, you almost give) it to the grid.  The concept of diversion,  is to find mechanisms to self consume as much as possible,  reducing costs in the process and generally avoiding the cheap rates being paid back to you.  

I thought this was a relatively new concept,  however, may I first introduce you to Solar Diverter 1.0. It's over 50 years old, maybe older than solar panels themselves and is in the form of my wife,  or, the Rebel.  I tell you,  when she's around, everything electrical gets used.  If she is home,  she totally destroys any opportunity for other diversion technologies to be used.  She max’s out the solar panels and the grid.

Solar Diverter 1.0

In fact,  when she is home,  I feel that the electricity board has to be a little like the US Electricity Board in Lampoons Christmas Vacation.  All of the wind, solar, nuclear and gas energy generation is likely to be ramped up.

But enough,  what have I really done to our house to reduce electricity being exported to the grid.

Battery Storage - GivEnergy

The first real solar diversion tech we got when we first started our eco journey was a battery.  We then extended it by getting a second battery earlier this year.  We have almost 18 kWh of Electricity storage in terms of batteries.  They get charged by the solar (and in winter we charge them up overnight when electricity is only 7.5p / kWh) and then use it if the solar isn't generated during the day.

When the sun shines,  the house uses the electricity any excess is then stored in the batteries, which power the house overnight,  or when the weather is particularly poor.  We also have an Emergency Power Supply (EPS) which will kick in and run from batteries in the event of a power cut.  Once the batteries are charged we hand over to the next step in the chain.

EDDI - By MyEnergi

So when batteries are fully charged,  EDDI gets to intervene.  Having a heat pump is great,  it's really efficient and saves us a lot in heating and hot water costs.  However,  the heat pump still has a hot water cylinder.  The cylinder also has an immersion heater to get the water to over 60 degrees once a week to prevent salmonella. 

So what EDDI does, is divert any excess electricity into the water tank and heat our hot water.  It's taking away any need for the heat pump to kick in and do it.  It means for maybe 9 months of the year, most of our hot water is heated for free.
MYENERGI Zappi Eco-Smart 2.1 EV Charger 7KW WIFI/Ethernet Tamperproof Tethered (White)

ZAPPI - By MyEnergi

In the same way as EDDI, Zappi also diverts electricity.  But this time,  it charges up the car.  Yes that's right,  we have two electric powered cars now and what we are able to do is place any excess energy into the car.  

There is nothing like feeling so smug, driving somewhere, on free electricity.  Being part of the MyEnergi product set,  these two devices are able to work together to maximise our savings.

Electric cars, generally can't be charged on AC electricity under around 1.4 kWh.  So when our excess is lower, say in the morning, or early evening, Eddi kicks in and heats the water.  Once our excess exceeds 1.4kwh,  Eddi stops and Zappi kicks in and charges the car for free.  It also charges the car overnight when the batteries for the house are being charged and we get our cheap rate. 

HARVI - By MyEnergi

This little device is not a diverter itself,  it allows the connection of up to 3 CT clamps, that are placed on the electric cables (e.g. the cable coming into our electricity meter).  By metering the electricity at various points in the supply, it allows the MyEnergi eco system to make the best decisions on what to do at any point in time.  

In fact the products from GivEnergy and Myenergi work seamlessly together. I can recommend both. 

So what's next ?

Not sure yet,  I am thinking of getting a hot tub and good old Eddi can be configured to put free electric into heating that too.  So that may be next.  But just remember,  if in doubt and not sure your maximising your electric usage.  Give me a shout,  I can loan out the Rebel to get you started on your diverter journey (and give our a home a break so that there is some free electricity available to be diverted).

But one thing is for sure,  this has all had a real positive impact on our finances.  Before we started this journey in 2021,  we were paying 7.5p / kWh for Electricity, 2p / kWh for Gas and around £400 per month in fuel for both our cars.  

We're now purchasing electricity at 7.5p / kwh for 6 hours overnight and 29p / kwh for electricity.  So I hear you say, you must be losing out.  Well,  I am now paying £150 per month to run the house and both cars (and I hope to reduce that further when our share in the wind farm comes on-line in March).  That's a saving of nearly £450 per month.  

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