Sure. And I'm aware that those terms are used in different ways by equipment manufacturers.
In this context I'm referring to the heat-pump being powered either directly from the grid, or via battery storage. Moreover that battery storage may itself be charged via the grid and/or solar PV.
The present regulations don't entirely cover that situation. The HP is notifiable under the existing LCT Application. But the storage/inverter falls outside the requirement to notify the DNO or obtain consent. If the installation only facilitates the stored charge being supplied to the HP, then the storage battery and the inverter charging it don't require permission.
That being so, there is also no specification which covers safety aspects of the installation.
The final 240v AC connection to the HP only comes within the remit of an approved electrician if it installed within the fabric of the building. Only if an electrical system operates above 50v and is installed as part of the building does it require a qualified electrician. If the HP is connected directly to the inverter using a flexible lead then it doesn't fall within Building Regs Part-P.
Such arrangements are widely used by crofters, outbackers, 'pioneers' and mariners in the UK and elsewhere. They do not get prosecuted. Provided that there is no export to the grid, then it's unregulated.
If a crofter with a wind-turbine and a grid connection both being used to charge a stack of lead-acid batteries which are 'full', decides to hot-wire another couple of empty batteries into the stack then they are free to do so. Common sense might suggest that the arc created by that action shouldn't be in proximity to the hydrogen being vented from the full cells. But there is no enforceable requirement to make that connection using a sealed DC-rated breaker in an adjoining room.
Thank you for the clarification. I had assumed that in this context the terms would relate to a mixture of grid, solar PV and/or battery storage supply.
If my understanding is correct, if there is no grid connection, the output from a solar PV and/or battery storage system is not limited, but if there is a grid connection involved, the DNO has to be informed and defined limits apply?
I am now considering installing battery storage, which wherever possibly will be powered by our solar PV, but during the Winter may need to be charged from the grid. The primary reason is obviously to reduce energy consumption, both electricity and gas, an hence reduce costs, but also to help move demand from the peak periods.
From reading various posts on the website it would appear that export power to the grid is limited to 3.6kW. If a battery storage system with an inverter with a maximum output of 3.6kW or below is installed, is it still necessary to seek approval from the DNO?
This post was modified 2 years ago 2 times by Derek M
@derek-m I don't believe so as you aren't exporting that power to the grid. My battery never exports to the grid, it's home demand only. You'd only need one (in my view) if you were building a battery system for grid stabilisation or demand, which is a bit more industrial.
12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE
If my understanding is correct, if there is no grid connect, the output from a solar PV and/or battery storage system is not limited, but if there is a grid connect involved, the DNO has to be informed and defined limits apply?
As I understand it, that's correct.
From reading various posts on the website it would appear that export power to the grid is limited to 3.6kW. If a battery storage system with an inverter with a maximum output of 3.6kW or below is installed, is it still necessary to seek approval from the DNO?
From the hoops I had to jump through to get an export tariff, my understanding is that the DNO has to be informed irrespective as long as there is a grid connection involved. If the maximum output of the inverter is at or under 3.6kW, or if it has been configured to only output to the grid at a maximum of that level, the DNO approval is basically just a formality. If the maximum output of the inverter is higher, different paperwork would be needed and different hoops might need to be jumped through but it is still potentially possible. The DNO approval, however, would be far from guaranteed. Either way, if you want to export anything to the grid your energy company will need an export MPAN and they can't get that set up with the DNO without the DNO's approval which can't be given without the DNO being notified.
I should point out, however, that my solar installer did the paperwork and the notifying, but I ended up having to chase the DNO after they gave their approval and then rejected Octopus' attempts to set up an export MPAN. I've therefore seen the process as a reluctant participant but not as any kind of authority, and so my understanding could easily be wrong. I should also point out that my inverter is 5kW but with export limited to 3.6kW, and the DNO gave its approval on that point.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and inverter
Raised beds for home-grown veg and chickens for eggs
I don't believe so as you aren't exporting that power to the grid.
I agree. The crunch point is that it must impossible for the inverter to export to the grid. Simply installing an inverter and configuring it not to export is not permitted.
We're now discussing a very important matter which others will find difficult to locate hidden here in this particular topic. I'm anticipating that Moderators will want to intervene and move this to a new topic, or possibly re-create it as a tutorial article.
The regulations are constantly changing, and I too keep learning rules when I discuss this with the DNO engineers who actually write them!
I've actually just requested a new regulation, and this will need to be discussed by the professionals in liaison with the Electrical Networks Association (ENA).
So please don't be surprised if I change my opinion on something over the ensuing months as things get clarified. Many members of this Forum will necessarily be working on the edges of the grid-connection regulations! So let's all keep an open view on this and cultivate an atmosphere of helpful feedback to/fro the ENA specialists.
My battery never exports to the grid, it's home demand only.
Grid export should still be considered by home-owners, especially if they operate as a community group, called an Aggregator.
There are areas of the country where DNOs predict electricity deficits between certain times throughout the year. You can see these for your own area on the Flexible Power website.
These CMZs (Constraint Management Zones) offer financial rewards to balance supply and demand during the specified time-frames. These 'contracts' with the DNO can be the removal of demand (shutting down a number of users) or supply of additional power. Depending on the contract, the supply payment might be for committed generation, or a lesser amount if you are offering 'stand-by' generation.
Here's the CMZ overview for a substation owned by Western Power in Barry, South Wales. The Flexibility Procurement depicted was for four days of the week during May and October 2021.
It's true that offering flexibility services within a CMZ is a strategy more often considered by larger power-users, but Western Power have in the past been willing to take stored energy in bundles as low at 6kWh. "Every little helps!"
Well that's interesting to hear what Granular want to do @jeff
However in the four regions managed by Western Power Distribution, the local Energy Mix has been available in hourly blocks for many years already. Here's one page for today showing me the mix for the area supplied by the Bulk Supply Point transformer at Ernesettle in NW Plymouth.
I can 'zoom in' for further detail on each of the four main categories of electricity generation in the mix, and see the forecast for six days in advance. The last three histogram plots in the above graph are a forecast because I took the snapshot just after 8pm.
The total (height) of each hour-block is always forecast as a maximum demand due to the way in which WPD use the data internally. The mix/proportions of the four categories is usually accurate, however. It gives me a pretty good idea how much power I can expect from my own rooftop solar panels several days in advance.
The BSP transformer is the right level in the Distribution Grid to display these statistics. It would typically output at 33kV (or 66kV in South Wales) and covers an area with a population of around 50k-150k people. Here's the coverage for the Ernesettle BSP I referred to above, shaded in green:
Do others living in Distribution Regions served by other DNOs have similar data available?
Or is Granular proposing something you don't yet have?
Well that's interesting to hear what Granular want to do @jeff
However in the four regions managed by Western Power Distribution, the local Energy Mix has been available in hourly blocks for many years already. Here's one page for today showing me the mix for the area supplied by the Bulk Supply Point transformer at Ernesettle in NW Plymouth.
I can 'zoom in' for further detail on each of the four main categories of electricity generation in the mix, and see the forecast for six days in advance. The last three histogram plots in the above graph are a forecast because I took the snapshot just after 8pm.
The total (height) of each hour-block is always forecast as a maximum demand due to the way in which WPD use the data internally. The mix/proportions of the four categories is usually accurate, however. It gives me a pretty good idea how much power I can expect from my own rooftop solar panels several days in advance.
The BSP transformer is the right level in the Distribution Grid to display these statistics. It would typically output at 33kV (or 66kV in South Wales) and covers an area with a population of around 50k-150k people. Here's the coverage for the Ernesettle BSP I referred to above, shaded in green:
Do others living in Distribution Regions served by other DNOs have similar data available?
Or is Granular proposing something you don't yet have?
As you say the raw data is already available via DNOs, i can see something similar via UK Power Networks portal for my transformer. The local EV and Heat Pump load data i found interesting on the portal.
It is what National Grid, Granular, OVO etc have been trialing with the data and certificates etc that I found interesting reading. I hadn't personally seen that before.
However, I would be more interested to see them offering Time-of-Use tariffs to end users. Apart from Octopus, the billing system software is often not yet robust enough to support that, nor is Ofgem yet requiring all Energy Suppliers to offer one.
Commercial markets tend to arise when there is an opportunity to create money. Altruistic investment to save the planet is rare.
Let me offer the following map to demonstrate what I see is happening:
I've taken the base map for Western Power's SW Region with the circular dots showing the BSP (33kV) and Primary (11kV) transformers. If they're green then there is available capacity to connect further renewable generation. The red dots show transformers which are at, or above, the 'reverse power' rating.
I've added a layer from a different map showing most of the high-capacity cable networks for the West Country. This is aligned crudely because the projections for each map were different. So my apologies for mis-alignments of about 12km at the periphery.
I've then singled out an extremely rural, isolated location in central Devon, called North Tawton. This site, at the end of a 132kV line, has recently been granted planning consent for a 49MWh storage battery. The Application from Balance Power Projects was approved under delegated authority by the head of planning, without discussion at Full Committee by West Devon Borough Council. That's unsurprising; there's probably no greater understanding of the technical documentation by council officers or elected members. 😟
However - I do understand it.
The application stated no storage capacity(!). 49MWh is the maximum permitted under G99 connection protocols, and I found this figure in small print at the foot of an accompanying drawing.
The application provides no indication of hazards or safety precautions when handling chemical substances. This would surely be expected whatever lithium chemistry is to be deployed? After all, there will a long-term programme to replace exhausted cells throughout the lifetime of the plant.
The need for the storage facility is based on a notional requirement to provide frequency balancing for the National Grid.
But my greatest issue with this project is ethical. The West Country is rich in renewable energy resources. There are clear constraints throughout the regional grid which prevent much of this being 'exported' up the line to the rest of the UK. That's what all the red dots on the map tell us!
So the battery storage owners, residing in Merseyside, will be able to accrue a guaranteed long-term income for reselling locally-harvested green energy back to consumers in Devon via their Energy Suppliers.
The proposed Energy-Mix Certificates market is actually a money-go-round hidden in remote locations like rural Devon. And this isn't an isolated incident. I've drawn orange squares on the map for two similar, privately-owned 49MWh storage facilities not far away.
Well - you may suggest that Balance Power Projects has a right to expect a return on its outlay.
It's true that 49MWh of battery storage isn't cheap. But there's also the grid-connection charges to consider. Western Power calculate this at a whopping £6.4m over the next 3-5 years.
But Balance Power won't need to worry much about that. Their contribution to the required grid enforcement works has been assessed at just £225k. The remainder of the costs will need to be found from the 101% rise in standing charge payments recently levied on the very same inhabitants of the SW Region whose riches are being plundered. Aaagh!
It would appear that saving the planet can be extremely lucrative if you know how to get the wider population to fund you for doing it. 😡
This post was modified 2 years ago 6 times by Transparent
the raw data is already available via DNOs, i can see something similar via UK Power Networks portal for my transformer
Can you post a URL to say where you're seeing that data please @jeff ?
I've searched around the UKPN site using a range of different search-expressions and I can't find it!
And if anyone else has a URL for similar Energy-mix data-set with forecasts for another DNO, then I'm keen to have that too please.
Note.... I already know where to find historical energy mix data for the UK. That's on plenty of sites.
It's the live-feeds and projections for the following 24hrs+ that I'm after, and for areas smaller than a typical county. Unsurprisingly, generation from renewable sources is a particularly local affair, and differs considerably when you move from one side of a row of hills to the other!
