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Author Topic: G59, G100, Export limitation, EMMA and Myenergi  (Read 3860 times)
jonc_uk
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« on: March 10, 2018, 01:16:06 PM »

Hello All.

I am in the process of adding an extension to my house and recently submitted a G59 application for ~16kWp PV plus battery storage. The PV is for self-consumption and so I am happy with the limit of 16A per phase export over 3 phases. My submission included an export limitation device with G59 isolation relay and all my research led me to the EMMA being the only suitable equipment for limiting the export.

My application has been confirmed, offer issued and I have accepted, and so I am on to planning and organising the export limitation etc.

I tried to contact Coolpower Products and to cut a long story short, they no longer exist. The EMMA moved to Warik Energy, also in Dublin, and now they have discontinued it.

Searching for 'export limitation' tends to lead you to the newer generation of PV inverters which can limit their output. This makes sense in places where there is plenty of sun to heat your water but less so in the UK. A 'G100' search did produce better results. G100 is the guideline for limitation.

A new company, Myenergi make the Eddi which is a power diversion device and can be configured for export limitation. It is a single phase device and so three are needed in my case. Myenergi founder, Lee Sutton was behind the Immersun device and was part of the G100 drafting process.

I just wanted to post since export limitation info on this and other forums is out of date. I guess the changes in export tarriffs have shaken things up in the industry.

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nowty
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« Reply #1 on: March 10, 2018, 09:12:33 PM »

Looks like the Eddi is just an updated Immersun and cannot do true export limitation but can turn on additional loads based upon export limits with an additional relay & sensor board.

Their website suggests they can do the true G100 export limitation but they are custom systems and you need to contact them about it.

Probably a custom price tag to match too, but this is all promising news as its only a matter of time before a more mainstream device is available, either from them or somebody else.
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10kW of PV installed and 40+ MWh generated.
Usable battery storage of 50+ kWh.
Heat storage of 20+ kWh.
6kW Ground Source Heatpump.
190,000+ litres of water harvested from underground river.
A few cold frames and raised beds.
M
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« Reply #2 on: March 11, 2018, 08:58:37 AM »

Hiya, and welcome. As the export limit is so close to probable sustained peak 11kW v's 12.8kW (80%), and you are having batts, then wouldn't a DC coupled battery system be enough to absorb any potential excess, and allow the inverter to cap AC output at 11kW if and when necessary?

Edit - Just a thought, but is all the PV planned for the same orientation? If there's a mix, and it's not all 30d pitch south facing, then you'll be far less likely to hit and hold sustained PV maxes (again, approx 80% when hot) for long.
« Last Edit: March 11, 2018, 09:01:30 AM by M » Logged

Just call me Mart.     Cardiff: 5.58kWp PV - (3.58kWp SE3500 + 2kWp SE2200 WNW)
jonc_uk
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« Reply #3 on: March 13, 2018, 11:34:24 AM »

The Eddi likely follows the same principals as the Immersun given that it was designed by the same person.

As far as I am aware, it will provide true export limitation.

The first 3kW dump load will be controlled by the variable output. The second 3kW will be switched by the first relay on the optional relay board with an export threshold set via the menus. The second relay on the expansion board will control the G59 isolation relay, with it's threshold set appropriately via the menu. A menu passcode will stop tampering. The CT sensor will be wired directly back to the Eddi. I spoke to Lee Sutton about it's use for limitation and if it doesn't do exactly what we want, there will be a software update. I did also speak to him about the specific G100 solutions. Nowty you are right about the 'custom price tag' for this! I think it is aimed at industrial-scale deployments not domestic.

M, you are probably right about the peak generation by PV since it is on three separate roof sections and and at four different pitches. However, the DNO treat the AC coupled battery system as an export-capable generator and so the limitation has to cover this.

I could have gone DC-coupled, but I wanted to be entirely micro-inverters. They are a combination of Enphase M215 and M250s. My aim is for self-consumption with near zero export and so I would rather heat the 3x thermal stores than limit inverters.

The main point of my post was to save people time in future expecting to put in an EMMA since this is no longer an option.

Jonathan
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dan_b
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« Reply #4 on: March 13, 2018, 11:37:40 AM »

Have you considered SolarEdge vs the EnPhase microinverters?

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3.06kWp SolarEdge system with a split array:
2.18kWp 10x South facing, plus 4x West facing 880W

Mk1 ImmerSUN DHW diverter
4kW PowerVault Battery
jonc_uk
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« Reply #5 on: March 13, 2018, 01:19:27 PM »

Hi dan_b,

Yes, I did consider Solar Edge when first looking at PV a couple of years ago.

I figured that if I am going to mount a box behind the panel, it might as well be the inverter. Also, I am more comfortable with AC up to the roof than big DC strings and with each row having it's own loom and isolator I can balance them across the phases for best use according to the loads.

I installed 17 panels on my house in Portugal last year with M250s and have been very happy with the system. I also have a 3-phase supply there.

My preference is for AC-coupled storage for future modifications or expansion of the energy system. For example, the winter time is when the PV is less likely to meet the needs of the home. If I add some CHP I can't easily charge a DC coupled battery. If the CHP is in my detached garage, I already have an AC power supply to tap into. I appreciate that there are greater round-trip losses with AC-coupled, but I am prepared to pay for that to get the greater flexibility.

The only thing missing from the current range of AC-coupled storage is built-in (and DNO approved) export limitation so the DNO doesn't have to treat it as generating equipment.

Jonathan.



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Ricc
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« Reply #6 on: March 13, 2018, 04:23:00 PM »

    Hi,
       How about the Victron Energy Anti-islanding Relay UFR1001E  it monitors voltage and frequencyand fulfills the requirements of VDE-AR-N 4105 bdew-directive, G59/3, G83/2 and ÖVE/ÖNORM E 8001-4-712:2009 for generators connected to the public grid.

    Also does it matter how you connect extra panels via DC or AC for DNO notification ie if you used lots of panels to charge batterys then fed the output back to your house Huh

    Being a newbie there seem to be lots of little differences in how things connect up and is allowed or not allowed within G83.

         cheers

                Richard
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RIT
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« Reply #7 on: March 13, 2018, 04:53:40 PM »

Have not the standalone solutions been superseded by the more integrated solutions from vendors such as SMA? I've no real idea what they are doing in the 3P market, but for general 1P installations, they offer the option of a monitoring device that varies the output of the inverter depending on the monitored export. Such a configuration would allow the addition of additional AC based generation devices such as an always on CHP device as the inverter(s) output would just be lowered more if there was no internal demand for the excess energy.

At the point storage is added to such a configuration I guess you will be limited to the same vendor (SMA in this example), otherwise you could end up with the different export monitoring solutions causing feedback loops in the devices they control.

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2.4kW PV system, output can be seen at  - https://pvoutput.org/list.jsp?userid=49083

Why bother? - well, there is no planet B
nowty
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« Reply #8 on: March 13, 2018, 05:19:08 PM »

The Eddi likely follows the same principals as the Immersun given that it was designed by the same person.

As far as I am aware, it will provide true export limitation.

The first 3kW dump load will be controlled by the variable output. The second 3kW will be switched by the first relay on the optional relay board with an export threshold set via the menus. The second relay on the expansion board will control the G59 isolation relay, with it's threshold set appropriately via the menu. A menu passcode will stop tampering. The CT sensor will be wired directly back to the Eddi. I spoke to Lee Sutton about it's use for limitation and if it doesn't do exactly what we want, there will be a software update. I did also speak to him about the specific G100 solutions. Nowty you are right about the 'custom price tag' for this! I think it is aimed at industrial-scale deployments not domestic.

I have read the manual for the Eddi and there is no way a DNO would allow this to be used as an export limitation device.

If you read the export limitation info on the MyEnergi ELS G100 controller http://myenergi.uk/export-control/ , you can see that device can simultaneously control several loads via solid state relays and has several failsafe features that a DNO would want, i.e. controller power failure, removing the CT clamp, availability of loads, etc.

The Eddi however, can only control one load at a time, and needs to switch between loads via standard relays when each one is satisfied or unavailable. If you used the second relay to control a G59 isolation relay, then it would be tripping out your inverter(s) every time it switched between loads, assuming there was an excess of PV energy available.
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10kW of PV installed and 40+ MWh generated.
Usable battery storage of 50+ kWh.
Heat storage of 20+ kWh.
6kW Ground Source Heatpump.
190,000+ litres of water harvested from underground river.
A few cold frames and raised beds.
jonc_uk
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« Reply #9 on: March 14, 2018, 11:44:33 AM »

Hi nowty,

The Eddi has a variable output, which will auto-switch between two loads (eg. two tanks, top/bottom etc.) plus two additional relays configured through settings in software.

If the designer tells me it can be made to do the job, I am prepared to accept that. With an electronics/software engineering background myself, I am comfortable with that claim. As the spec stands at the moment, I agree that the CT disconnected fault condition is not handled.

In a 3P setup, it will also work as three independent single phase systems. That doesn't matter to me, and is better for the DNO (than net-zero export).

Jonathan.
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nowty
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« Reply #10 on: March 14, 2018, 12:26:19 PM »


How about the Victron Energy Anti-islanding Relay UFR1001E  it monitors voltage and frequency and fulfills the requirements of VDE-AR-N 4105 bdew-directive, G59/3, G83/2 and ÖVE/ÖNORM E 8001-4-712:2009 for generators connected to the public grid.


That does not do any export limitation, all it does is trip out if you lose the grid which is what mainstream inverters do anyway. Looks like its use is for inverters that don't have the ability to trip out if they lose the grid.
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10kW of PV installed and 40+ MWh generated.
Usable battery storage of 50+ kWh.
Heat storage of 20+ kWh.
6kW Ground Source Heatpump.
190,000+ litres of water harvested from underground river.
A few cold frames and raised beds.
M
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« Reply #11 on: March 14, 2018, 12:26:31 PM »

Hi nowty,

The Eddi has a variable output, which will auto-switch between two loads (eg. two tanks, top/bottom etc.) plus two additional relays configured through settings in software.

If the designer tells me it can be made to do the job, I am prepared to accept that. With an electronics/software engineering background myself, I am comfortable with that claim. As the spec stands at the moment, I agree that the CT disconnected fault condition is not handled.

In a 3P setup, it will also work as three independent single phase systems. That doesn't matter to me, and is better for the DNO (than net-zero export).

Jonathan.

Hiya Jonathan, million dollar question, has this (or any) DNO actually approved this device/set up for export limitation?

Going back a bit, and I have to admit to being a SolarEdge fan with 26 Power optimisers and two inverters of theirs ....... wouldn't SolarEdge be cheaper than Enphase, possibly more efficient, but more importantly opening the issue back up to a DC side battery, meaning that you can simply accept the DNO limitation without having to worry about any loss. Of course, it doesn't ahve to be SolarEdge, any inverter that offers DC side storage.

You'd still be able to heat water, or run a heat pump, but more by your choice, so perhaps leaving PV for an EV, rather than hot water.

Apologies for doing the 'why don't you just ...... instead' annoying thing, but it just seems like you are in a perfect position to make use of DC side storage, and avoid any DNO limitation issues/costs.
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Just call me Mart.     Cardiff: 5.58kWp PV - (3.58kWp SE3500 + 2kWp SE2200 WNW)
jonc_uk
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« Reply #12 on: March 14, 2018, 03:41:20 PM »

Hi M,

DNO actually said "At present the EMMA GVS controller (with proportional export control) is the only approved apparatus for use on our network.. ...nevertheless, Electricity North West will consider alternative proposals."

Lee at Myenergi told me that G100 is not actually an approval document and that no specific protocol currently exists for an approval process. I have a copy of G100 and it is titled "Technical Guidance for Customer Export Limiting Schemes" and so any 'limiting scheme' which meets the requirements would potentially be allowed to be used (subject to appropriate testing as set out in G100).

I am installing around 70 panels, but at four different angles and three different azimuths. I can see how the power optimisers can help here in the same way as micro-inverters. However, it would be multiple strings and so multiple inverters, lets assume one per phase. I am not clear whether it would be multiple separate batteries or whether they could connect to one. I can see the inverters can also be export limited.

Ultimately, with SolarEdge it becomes about as complex a system as I am planning, plus I would install diversion to the solar stores in any case. The only difference is a G100 test approval, but then the SolarEdge system would be *capable* of greater than 11kW and so I would have to do the G100 test approval in any case.

So then it comes down to cost, oh - and not being able to charge the batteries via AC, and not being able to peak-shave the high startup current of the heat pump or pool air handling units.

An interesting discussion, but ultimately I have bought all the kit and have the looms installed on the roofs pending tiling.

I will report back when the G100 tests are completed and system is live!

Jonathan
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M
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« Reply #13 on: March 14, 2018, 04:37:10 PM »

Hi M,

I am installing around 70 panels, but at four different angles and three different azimuths. I can see how the power optimisers can help here in the same way as micro-inverters. However, it would be multiple strings and so multiple inverters, lets assume one per phase. I am not clear whether it would be multiple separate batteries or whether they could connect to one. I can see the inverters can also be export limited.

Jonathan

Hiya, sorry to be pedantic, but last time you just said 4 different pitches. So if you have 3 different azimuths too, then isn't it not just safe to assume that you won't need to exceed export limits, but actually certain that you won't exceed them, certainly not for any significant amount worth worrying about. So no need to worry about meeting rules and regs, just have an inverter / inverters capped at the limit.

[Edit - sorry, you said you already have the kit. I now recall that micro-inverters are treated differently by the DNO's, so that's a PITA. Oh well, hope you get approval. M.]
« Last Edit: March 14, 2018, 04:40:08 PM by M » Logged

Just call me Mart.     Cardiff: 5.58kWp PV - (3.58kWp SE3500 + 2kWp SE2200 WNW)
Ricc
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« Reply #14 on: July 06, 2018, 03:26:29 PM »


     Hi Jonathan,
           How did you get on the DNO...

        I was thinking of doing a similar project and just wondered, as my winter oil cost was £2500 and need to do something about it....

          Plus my elctricity usage was 20kw a day....

        I have just brought a small farm with a stone farm house and it turns out that the previous owner had hard wired the immersion heater so it was on all the time.... and insulation was a little lacking plus the bioler was wired setup to constanley heat hot water.

        There was a heating controller which on the surface looked as if it controlled everything but no just the central heating......

          I have put in some insulation but there are some barriers to put in more...


                      thanks


                    Richard



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