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Energy demand, supply and flexibility

Energy demand, supply and flexibility
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Last month I needed to calculate Maximum Demand for my house. This is a technical assessment which adds up all the electrical devices, socket outlets and lights to arrive at an MD which truly reflects the possible peak current. This can’t be calculated from a Smart Meter because that shows half-hourly averages.

My 3-storey house with 280m² floor-area, two workshops, 5 power rings and two electric ovens has an MD of just 19.6 Amps.

This illustration of MD shows how the UK electricity demand would be more than doubled if we move along the Government’s Net Zero timescale for phasing out ICE transportation in favour of EVs.

So in my case, adding a 7.5kW EV charge-point to the house last month takes my MD from  19.6A to 51.6A :scream:

There are two separate calculations to be considered:

a: Do our houses have adequately-sized conductors to deliver the current required for houses with EV charge-points fed from the local substation?

b: Is there enough capacity to get that power through the 33kV and 11kV Distribution Grid to those substations?

The answer to both is NO.

 

This is where Kaluza’s Flex Platform could provide the answer, using intelligent load-control to better utilise those times when the infrastructure is lightly loaded.

However, only one of Kaluza’s Trials has addressed the above two calculations thus far. That’s the one in the Woodhall Spa area of Lincolnshire using Sönnen Storage Batteries.

Until OVO/Kaluza start addressing local grid-support, the algorithms which the country urgently needs aren’t being created.

Instead, the dominant supply/demand data being used by Flex is the UK-wide overview provided by National Grid.

 


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Definitely some crossover here with your guide on balancing the grid, @Transparent, found here:

 

 

Can you offer us some more insight into why this is definitely a ‘NO’?:

 

There are two separate calculations to be considered:

a: Do our houses have adequately-sized conductors to deliver the current required for houses with EV charge-points fed from the local substation?

b: Is there enough capacity to get that power through the 33kV and 11kV Distribution Grid to those substations?

The answer to both is NO.

 

Is this property type or region specific? 

 

 

Userlevel 7

 

Last month I needed to calculate Maximum Demand for my house. This is a technical assessment which adds up all the electrical devices, socket outlets and lights to arrive at an MD which truly reflects the possible peak current. This can’t be calculated from a Smart Meter because that shows half-hourly averages.

 

Interesting calculation to consider, @Transparent. Can imagine it would be hard to use all possible electrical appliances you own at exactly the same moment - how much did the Maximum demand figure differ from your average usage figure?

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There has to be some common-sense applied to this calculation @Jess_OVO. The MD is required by the DNO to ensure that its fuses at the substation and at the house are not going to blow. It also allows them to build up a picture of the capacity required from their feeder cables.

There are several methods to assess the MD for a property. Adding up the number of sockets on the power ring is no longer regarded as useful. I have about 20 double-outlets on each ring!

Totalling all the power devices doesn’t generally provide a sensible answer either. Kettles, washing machines and tumble driers are OK. But could I really use all 18 of my mains-powered workshop tools simultaneously?!

Lighting is even more tricky, especially if there are bulb-holders into which could be fitted an old-style incandescent bulb. Aagh!

But most of my lighting is dedicated LED fittings (no replaceable bulbs).

 

The method of calculating MD increasingly favoured by electricians is to fit a temporary logging device and leave it in place for at least a week.

As I already have such data-logging on my PowerVault Storage Battery, this was the obvious starting point. Better still, it’s been operating for six months and therefore has a record of peak winter usage.

Such a data logger gives a fair amount of information on daily household usage… far more than you could obtain from an IHD connected to the Smart Meter:

I then checked to see if this logging recorded the surge-currents from devices with motors. The largest surge in my house is from the well-pump. (Yes, we have no mains water!)

But those transient surges are not as significant as you might suppose. They last just a few hundred milliseconds. They are unlikely to have any affect on the 100A Service Fuse for example. It takes a sustained over-current to actually melt that fuse-wire.

 

I will be adding more evidence to this topic over time… for some of which I need permission to release the data.

It may at first glance appear that this subject overlaps with the description of my Balancing the Grid topic. However that looks at problems, and from the viewpoint of the Distribution Network Operators.

In contrast this topic is about solutions, such as the Flex Platform being developed by Kaluza.

Flex has the potential to handle electricity usage for each house on a country-wide distributed energy network. It’s that sort of innovative technology which is needed to under-pin the UK’s move towards Net Zero carbon emissions and the Government strategy of Demand Side Response.

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Over on the topic about Ground Source Heat Pump installation, @Glaikit wrote:


I’m probably going to install a Ground Source Heat Pump (GSHP)[….]

I’m no electrician but Maximum Demand with diversity is approaching single phase limit with V2G charger and GSHP.

 

In the tutorial on Obtaining permission from your DNO, I reproduced that flow-chart from the Electricity Networks Association (ENA) which enables customers to check whether they must get consent for high-demand devices before or after installation.

Whether or not Glaikit’s plans will exceed the permitted MD for the single-phase supply, there are still two Low Carbon Technology (LCT) devices being installed - a Heat pump and an EV charger.

For that reason the rule in such a case is “Apply to connect”. The application to the DNO must occur before the installation work commences.

That puts the onus on the DNO to then calculate the MD and apply the most appropriate network reinforcement.

In my region (SW England) the policy adopted by Western Power Distribution is to take a 3-phase cable to the house in streets that are being re-cabled or for any new-build property. That’s enabled me to have a nice shiny 3-phase connection, even though the house is still currently fed from just one of those phases.

3-phase connection box fed by Aerial Bundled Cables (ABC)

Since Glaikit lives in Edinburgh, the relevant DNO is SP Networks. Their website has an advisory page about connecting Heat Pumps, within which is the section with a link to download the generic LCT Application Form.

 

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This is a great post, @Transparent - great to see application of the rules for specific examples. One question, would this be better placed here?:

 

 

 

If you see this comment and haven’t read that article above, it’s well worth a look! 

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Hold on @Tim_OVO …. in this topic I’m about to take the discussion a bit further and explain concepts that could operate for local grid support and sharing network infrastructure resources. This is futuristic stuff which may or may not occur. It depends on the development of products such as the Flex Platform.

The topic about Obtaining permissions only considers the regulations as they are and how to comply with them.

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There are two separate calculations to be considered:

a: Do our houses have adequately-sized conductors to deliver the current required for houses with EV charge-points fed from the local substation?

b: Is there enough capacity to get that power through the 33kV and 11kV Distribution Grid to those substations?

The answer to both is NO.

 and @Tim_OVO asked:

Is this property type or region specific? 

 

The problem of adequate supply spans the entire Distribution Grid from the 132kV lines right down to the 440v (3-phase) feed cable in our streets. But the problems are not experienced evenly.

Housing estates built post-1945 may be still using the same feed cables which were laid at the time of construction. They are allowed to heat up during the early evening peak-demand, but rely on cooling again overnight.

Once we start adding EV chargers, the cooling-off period will instead become an extended time of peak-demand.

Local politics can also play a huge part in how the network infrastructure gets prioritised for replacement and enhancement. Consider Bristol, where OVO has its HQ. The City Council are actively pursuing policies for zero-carbon transport - a strategy which is being underpinned by the regional DNO, Western Power Distribution.

 

All regional Distribution Network Operators are required to produce workable plans to meet the UK Government’s target of Net Zero by 2050. The national strategy is called Future Energy Scenarios (FES) and is described more fully on the website of National Grid.

the four Future Energy Scenarios

The Steady Progression scenario isn’t able to reach the Net Zero target by 2050, but is there as a base-marker against which the other three scenarios can be evaluated.

 

Each DNO must file a matching set of plans by December 2021 which are fully deliverable, albeit at different cost. This Distribution Future Energy Scenario (DFES) is currently subject to public consultation.

Western Power has also created an interactive map, enabling the user to see how the roll-out of certain energy devices changes each year up to the 2050 deadline.

Here I’m using that map, zoomed in to show the Bristol area, and divided into the geographical areas served by each Primary sub-station. Those are the transformers that take the incoming 33kV and change it to 11kV which goes to the local substations on our streets.

I’ve further chosen the year 2030 (see top left in each graphic) and selected the map to display the number of ‘on-street’ and ‘off-street’ EV charging points. This allows us to model the effect of Bristol Council’s initiative:

System Transformation scenario; off-street (private) EV charge points
System Transformation scenario; on-street (public) EV charging points

In this pair of maps you can see that Bristol has the highest density of charge-points, led by the Council’s initiative.

In the upper map I’ve singled out Whitchurch to show that it has the highest density of all Primary substation areas (depicted in dark blue).

The areas served by the Whitchurch Primary transformer straddle the southern limit of Bristol City, the Easternmost part of North Somerset and the NW portion of Bath & Northeast Somerset local government districts.

 

Now let’s compare that with the Consumer Transformation scenario for the same year (2030) and the same illustrative pointer of EV charge points.

Consumer Transformation; off-street (private) EV charge points
Consumer Transformation; on-street (public) EV charging points

With less intervention from the local Councils, it has now been left to the individual to ensure that they are able to drive into the zero-emissions zone in the city of Bristol. So they install many more of their own charging points (off-street).

Once again Whitchurch has the highest density of privately-owned chargers.

But the lack of Council investment elsewhere means that the number of on-street (public) charge points is much reduced for the wider area beyond the city itself.

 

I will leave it for the reader to visit the map for themselves and explore the different scenarios for a wider range of dates and against other parameters such as the proportion of homes with Heat pumps or Energy Storage, for example.

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An interesting post here from the Kaluza team, on:

 

The course of net zero never did run smooth: price spikes, electric cars and grid flexibility

 

Of particular interest was their comments on type of use vs time of use tariffs, which I know have been discussed here a lot. @ArundaleP, @Transparent, @EverythingNeedsAUserName @Jequinlan keen to make sure you see this blog as I think you’d find it worth a 5 minute read:

 

Type of Use vs Time of Use

 

Much has been made of the idea of the ‘dynamic time of use’ or ‘tracker’ tariffs, in which an energy supplier passes the changing cost of energy directly on to consumers. By publishing prices in advance, customers can make informed decisions about when to use electricity, for instance, by avoiding peak times. While tariffs of this type may be suitable for some consumers, they have two drawbacks which will come to light if high energy prices continue:

 

Firstly, they require customers to follow prices closely and adapt their behaviour accordingly. As a customer, failure to do so means you are forced to pay a steep penalty price for consuming electricity at the ‘wrong’ time. Take your eye off the ball and you risk a serious shock on your next bill!

 

Secondly, as prices follow the market on a live basis, risks normally borne by a supplier are passed on to the consumer; in this way, customers are perhaps inadvertently speculating on market prices on signing up for such a tariff. Over the course of this September, customers on these tariffs are likely to have seen their bills increase by more than 50%. By contrast, customers on OVO Drive Anytime can be certain that their prices will not fluctuate day to day.

 

This plot shows the kWh rates of a hypothetical dynamic type of use tariff tracking wholesale and network costs in August and September. Customers on such a tariff would have been exposed to a 50% increase in average unit rate in just one month.

 

I’m not coming down in favour of one or the other, but I thought it was worth sharing, and I am keen to hear your thoughts, given your opinions are backed up by more knowledge and context then mine… 

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This is a fair reflection of risk vs reward as, if looking at covid 1st hitting and lockdowns the price of energy tumbled and the customer would have seen the benefit. In reality i see this much like a mortgage; something i need to have and buy, but i can pay a premium and lock myself in to mitigate risk for 2 or 5 years (energy is 1 or 2 years) this just brings the fluctuation down to a smaller time period and possibly larger volatility. All pricing can be made as a "profit" or loss, share trades and capitalism wouldn't be a thing without it.

 

What i Really want is options to pay more to cooperatively buy wind turbines and other green production with other users for a small amount on my bill initially entitling me to a share of that energy production for its life...

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Firstly, they require customers to follow prices closely...

I don’t think such a projection of a Time Of Use tariff is reasonable.

There should be two separate concepts in the way a ToU tariff is presented:

1: The overall daily pattern. This allows customers to avoid higher-price periods if they choose to do so.

2: One-off variations on that pattern. These are notified a day in advance. A variation may be to the customer’s benefit, such as a period of cheaper electricity on a sunny day with a windy afternoon. It could also be to the detriment of the customer, such as raising the cost per kWh when the DNO declares an anticipated energy shortage for a few hours.

(See Point-3 description of CMZs in the topic Balancing the Grid)

 

as prices follow the market on a live basis, risks normally borne by a supplier are passed on to the consumer;

This assumes that a Time Of Use tariff is based solely on price.

If customers wanted that, then it’s already available by switching to Octopus.

The USP of OVO is its ethos of delivering renewable energy and combating Global Warming by its Net Zero strategy.

As such any ToU tariff offered by OVO must reflect these ideals by allowing choices to be made on the energy mix.

This is even more important in areas which experience over-generation of renewables. Unless and until these gluts are reflected in interim incentives for consumers to use or store that excess, then OVO would be failing in its core mission.

Only when demand starts to follow this (over)-supply can we start lifting the constraints on the Distribution Grid and increase the quantity of green electricity being generated.

There is a tacit obligation on Kaluza to ensure that its joint development of the Flex Platform and a ToU tariff is directed to achieve this.

 

Over the course of this September, customers on these tariffs are likely to have seen their bills increase by more than 50%.

That statement is at odds with the official company line that it is able to remain steady during the current gas-crisis because it buys energy sufficiently far in advance.

The advance-purchase strategies employed within OVO aren’t any less important as more customers opt for a Time Of Use tariff. Rather, it is that prudent management which brings greater stability to the overall daily pattern preferences on that tariff and thereby attracts a higher market share.

 

A Time Of Use tariff offers flexibility.

Flexibility is not a chaotic free-for-all. :scream:

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