Green, ethical, energy issues in the news

zeupater

70sbudgie said:

Apologies, I didn't crop with the intention of deliberately misleading. I was trying to use the graph to show how much the transmission and distributions network will have to grow if we are going to electrify other energy uses (transport and heating).

And if the total electricity demand hasn't grown since the 1990s, the distribution and transmission networks wouldn't have grown. Increases in capacity are only paid for when they are needed. I think we need a change in mindset to try to anticipate how much they will need to grow and start that process of expansion in advance of immediate need.

I had missed the idea that electricity can be generated from the other fuel sources, so it isn't an accurate illustration.

The graph shows a lot of data and I agree @zeupater that the wider comments and context are needed to get at all that.

In terms of batteries, there is no such thing as "supply side" or "demand side" batteries, supply batteries need to charge at some point and when they do, they are adding to the demand. So each battery installation can import and export; when they do is based on their operation. So batteries can import at any time. Then, how do you automate preventing them from exporting at the wrong time?

And what is the "wrong time?". The right time for the grid in total, could be the wrong time for the local network where the battery is connected. The right time for Carlisle could be the wrong time for Cardiff.

So balancing services need to be able to balance load and generation geographically as well as chronologically and I think that might be the bigger challenge.

Hi

No problem, I didn't think there was any form of deception intended, just that the information could have been misinterpreted in some form or other ... the real issue is that the chart covers all forms of energy, including petrol etc ...

The point on distribution is real, but only as long as we look at the network in historical terms, that being centralised generation facilities feeding demand a significant distance away as opposed to forms of distributed generation closer to demand, which many form of renewables can provide .... think about tidal flow & you can immediately identify the Severn & Thames estuaries as being potential energy sources which are close to significant population centres, so little need for distance transmission line provision/upgrades.

Regarding 'no such thing as "supply side" or "demand side" batteries' .... the idea relates to where generation and/or storage is relative to the grid, especially so when combined. Think of a situation where generation & strategic storage are invested in and operated at grid or local level ... when a demand occurs in a domestic or industrial setting, it's satisfied from direct generation or grid level storage and the customer is billed for the energy received ... now consider a site with both generating and storage, that could be a home with microgeneration (PV-DSG) & storage, or an industrial facility such as Nissan with multi MW installations on site where generation on site is either used on site, stored on site, or exported due to excess ...

.... so, what does the grid see and how do they handle supply to balance demand? ... well, quite simply, they can only see demand on the network & balance supply from their managed resources, so generating capacity is (#1) ramped up/down to supply & balance demand on a near real-time basis, this being achieved though maintaining grid frequency under varying load .... it's really import to note that grid operations cannot see demand that isn't actually affecting the grid, that being demand being satisfied from sources that don't actually flow through the grid (#2) and, unless directly metered and monitored on a near real-time basis, grid operations would be totally unaware of any excess power entering the grid from such sources as it would simply act to reduce apparent demand on a netted basis. These scenarios are widely referenced, including in published academic papers, as supply side generation (#1) and demand side for (#2), therefore, in general, if you have PV connected to the grid but on your side of the home's main electricity supply meter it as acting as a DSG system for your home, so considering that domestic battery storage systems being charged only from DSG sources have no impact on the grid (unless programmed to do so) they should also be considered 'demand side' (ie customer side of electricity supply meter) because the result is exactly the same in that all or some of property side demand is being satisfied by property side supply, whether directly from on-site generation, or on-site stored generation. ...

HTH - Z

zeupater

70sbudgie said:

[ ... ]

So batteries can import at any time. Then, how do you automate preventing them from exporting at the wrong time?

And what is the "wrong time?". The right time for the grid in total, could be the wrong time for the local network where the battery is connected. The right time for Carlisle could be the wrong time for Cardiff.

So balancing services need to be able to balance load and generation geographically as well as chronologically and I think that might be the bigger challenge.

Hi

Sorry, I missed replying to this ...

In essence, it's pretty easy for the grid to directly control this through some pretty simple automation  logic, but it would be for the battery manufacturers and/or grid standards compliance to determine right & wrong times.

Grid load controls the spot frequency of generation ... if there's more generation than demand the reduced load on generators causes them to spin faster (actual or modelled), thus increasing AC frequency above a nominal 50Hz, the opposite being the case when demand exceeds supply, the balancing solution is therefore pretty straightforward ...

.... if the grid frequency as seen by the particular battery system is greater than a %age threshold above the nominal 50Hz (obviously slightly randomised to not introduce supply shock events), don't export  ... this could/should also be used as a trigger a system to automatically support the grid in times of short supply - ie %age below a nominal 50Hz allowing a predetermined limited export of stored energy (again randomised threshold), which, if import/export metered, would be the basis for some form of grid balancing based recompense scheme ...

HTH - Z

Martyn1981

70sbudgie said:

zeupater said:

70sbudgie said:

This is what concerns me most about the discussion around generation / storage.

Less the comparison with 1990 than that only 11% of energy was electricity. If we are going to decarbonise transport (oil?) and heating (gas?) we are going to need considerably more electricity than we currently have. Even when we take into account increased efficiencies of electrical appliances. 

And we haven't done much about increasing the number / size of cables since the 1990s (perhaps even as far back as the late 1960s!). I remember reading an article (possibly as long ago as 2010) that said UK electricity demand at the time, was the same as in 1985 (ish), because of the increased efficiencies of appliances, light bulbs etc.

The cables etc have to be sized to accommodate the peaks. It isn't quite as simple as adding a battery to give more kWhrs away from the peak - there need to be control systems to make sure the batteries aren't adding to the peaks, because there are significant safety issues if they do and cause the equipment to exceed its ratings. 

The pie charts are from the Energy in Brief 2022.

Hi

looking at the report it's likely that there may be a little misunderstanding of what the chart actually conveys ...(Report Link - https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1094025/UK_Energy_in_Brief_2022.pdf )

Firstly, there's the issue of 'Primary Electricity' ... the chart doesn't say that '11% of energy was electricity' it says that 11% was 'Primary Electricity', the definition of which includes nuclear, hydro, wind, solar thermal, PV & geothermal, therefore energy that isn't directly derived from conversion of energy stored in a source fuel.

What the chart does show is the change of source energy for electricity generation within the overall consumption ... ie the move from coal to gas & biomass & the reduction of oil consumption as a proportion of the entire energy budget, much of which will be related to transport efficiency improvements (mpg) over the period in question ... however, the chart in itself is a little misleading without referencing the accompanying table and annotations (page 9), which could have been easily addressed by scaling the pie chart area to represent the total energy budget on a temperature corrected basis, in which case the 2021 pie should reflect a 23% (170.7/221.6) overall reduction in energy since 1990 by having a 23% reduction in it's area.

Taking this a step further, if the chart reflected changes in population there'd be a further energy/head reduction to reflect an increase from 57.2million in 1990 to 67.3million in 2021 (17.7%), so we're really looking at a 23% reduction despite a 17.7% increase in population ... that's ~35% less energy used per head of UK population between 1990 & 2021 at the same time that the change in fuel source mix conveyed in the chart has reduced overall emissions per unit of energy requirements.

In conclusion, the chart cannot be read without the context provided in the report & taking this further, even the context provided within the report can be considered misleading without in some way referencing changes in population, a word that doesn't even appear once in a 52 page report.

HTH - Z

In terms of batteries, there is no such thing as "supply side" or "demand side" batteries, supply batteries need to charge at some point and when they do, they are adding to the demand. So each battery installation can import and export; when they do is based on their operation. So batteries can import at any time. Then, how do you automate preventing them from exporting at the wrong time?

Hi, I think Z has answered in detail, but as I wasn't very clear about batts, I apologise. I really do think there is a massive distinction between supply side and demand side storage, and a third category, distribution (DNO) side storage.

You are pointing out the need for grid expansion, something that's very important, and these 3 forms of storage have differing impacts. Supply side storage will have an impact on the transmission network (NG), and also the distribution network (DNO's). Distribution level storage will only affect the distribution network, and lastly demand side storage doesn't impact either - well, to be correct, as Z points out, it does have an impact, via 'negative demand' on the 'Grid', which lowers the total grid load v's UK consumption.

Hope this doesn't appear to be petty, I really do think it's extremely important, especially within the context of the 'Grid's' capacity and ability to cope, to differentiate between different placement of storage. Taken to the extreme (a practice I've been using for many years since (you've guessed it) Z suggested it), if we had massive V2G storage, of perhaps 1,500GWh from just cars (but 30m of them), then they could, at just 2kW, provide 60GW's of power at peak times, which in this ridiculously extreme example, would wipe out all demand, and be seen by the Grid as zero demand in the UK. [Obviously that's not true, as the cars wouldn't be in the right places, like massive factories, but its just to test the extreme.]

I also don't think batts would charge when demand is high. Taking current practices as a guide, we see folk with storage, who top up off the grid, taking advantage of arbitrage, where they charge when prices are low (demand is low v's supply). Given the round trip losses, there is no advantage to charging batts during normal/high demand periods. So I don't see batts adding to high/peak demand, I see them as helping to maximise the use of the 'Grid' by spreading demand across a wider time period, thus increasing demand when it's low, and reducing demand (as seen by the 'Grid')
during peak times.

Hope I don't seem too trusting of market forces, but as the demand side storage market is developing well, with systems including payments to individuals and VPP's for export at times of need, I see this as a system that will develop well, with little to no problems. One possibility I suppose, is like smart car chargers, there may be some legislative rollout preventing batts from charging at peak times, and the ability to stop/slow down charging when demand is very high.

[Just to say I've been using the term 'Grid' as a general term to refer to the cables from power station to customer.]


Lastly, you've got me wondering what the impact on the 'Grid' will be. If leccy demand does increase by 2 to 2.5x current demand, then how much upgrading is needed. Crucially we need to spread the load more evenly. BEV's are easy, with the bulk of charging moved to lower demand periods. Heating will be much harder, though perhaps HP's operated on more of a 24hr smoothing cycle will reduce their impact, but it will still be big.

We have a current ability to cope with peaks of about 60GW, and an annual average demand of about 38GW*. So a doubling would take us to ~ 80GW if spread evenly, so a 33% increase in 'Grid' capacity. But that would require demand side storage to help smooth out demand/supply, and far, far more important, I'm ignoring the seasonality of space heating, which will presumably have a massive impact on seasonal demand, with almost all of the demand (DHW aside) being weighted towards 7 months of the year, and particularly 3 months (Dec-Feb). That I suspect is going to be a pig to solve? Without demand side winter RE generation, and I see no obvious solution, the 'Grid' is going to strain.

*Don't take these numbers too seriously as every source varies a bit, with differences between UK generation, UK demand (after grid losses), net UK demand after imports/exports, and so on.

Martyn1981

Just a thought/ponder, as I've scared myself a bit with my future winter 'Grid' demand waffle.

Our house was upgraded to a 100A main fuse box, and 80A fuse, when we got a smart charger installed. Now, 80A, with say 30A for BEV charging (if one at a time for most properties), and 22A(?) for a heatpump, still leaves a reasonable 30A(ish) for the house, assuming that power showers are excluded, and run from a water tank, so around 7kW spare, double that during the day if no BEV charging.

For a 100A main fuse, there's a bit more spare. So it looks like most residences would cope, or am I missing something?

But my main question is, just because each residence gets an 80A connection, can the local grid cope with that if all homes are drawing at the same time? Does that make sense, are homes rated at a level where the DNO's expect an average demand, or are they rated at a theoretical max level, that local cables can cope with even if all properties were pulling max?

From that question, it leads to me ponderings of whether demand side or DNO side storage is an issue. If the distribution network can cope with max, then DNO level storage will be fine. If however it needs averaging across properties, then demand side storage will be needed to reduce the load on the local cables.

Hope this makes sense, and maybe somebody knows how this works? My guess would have been some level of averaging, but since DNO's use max theoretical export when considering (RE, V2G etc), then perhaps they can cope with a max load from all properties?


I think I'll be keeping an eye out for any news on Grid changes / upgrades, as this may be the next big point of interest (for me).

zeupater

Martyn1981 said:

Just a thought/ponder, as I've scared myself a bit with my future winter 'Grid' demand waffle.

Our house was upgraded to a 100A main fuse box, and 80A fuse, when we got a smart charger installed. Now, 80A, with say 30A for BEV charging (if one at a time for most properties), and 22A(?) for a heatpump, still leaves a reasonable 30A(ish) for the house, assuming that power showers are excluded, and run from a water tank, so around 7kW spare, double that during the day if no BEV charging.

For a 100A main fuse, there's a bit more spare. So it looks like most residences would cope, or am I missing something?

But my main question is, just because each residence gets an 80A connection, can the local grid cope with that if all homes are drawing at the same time? Does that make sense, are homes rated at a level where the DNO's expect an average demand, or are they rated at a theoretical max level, that local cables can cope with even if all properties were pulling max?

From that question, it leads to me ponderings of whether demand side or DNO side storage is an issue. If the distribution network can cope with max, then DNO level storage will be fine. If however it needs averaging across properties, then demand side storage will be needed to reduce the load on the local cables.

Hope this makes sense, and maybe somebody knows how this works? My guess would have been some level of averaging, but since DNO's use max theoretical export when considering (RE, V2G etc), then perhaps they can cope with a max load from all properties?


I think I'll be keeping an eye out for any news on Grid changes / upgrades, as this may be the next big point of interest (for me).

Hi

As you mentioned it, a little thought experiment involving extremes logic .... as 80A=~20kW and there are ~25million households in the UK, the theoretical total maximised domestic demand would be ~500GW, so we'd be looking at ~10x generating capacity to supply a sector that consumes ~40% of energy demand .... looks like logic tends to support your averaging guess ...    

HTH - Z

Martyn1981

Thanks Z. And yes to the question you didn't have to ask, I do feel like a bit of a prat (the polite version of what I want to write). I had the workings out, but completely failed to spot the answer, plus I used max's rather than averages. Doh!

So .... and I hope this still sits within news and forward looking from a thread perspective, then storage at a DNO level may be the best solution for grid sizing.* I've suggested years ago that demand side batts should receive an element of financial support from all beneficiaries, and that probably applies even better at a DNO level, with support representing Gov, generators, grid transmission, energy companies, customers and the distribution network itself. All of these benefit in one way or another from demand smoothing storage. 


*With storage at RE generation level to help manage peaks and troughs of intermittent generation, rather than demand.

QrizB

Here's a (long and fairly dry) article on biofuels that might interest some readers:

https://knowablemagazine.org/article/food-environment/2022/how-green-are-biofuels

Replacing gasoline with ethanol has changed landscapes across the globe as grasslands and forests give way to cornfields. Researchers are deeply divided over what this means for the planet. Here's the science behind the conflict.

It ties in, after a fashion, with the discussion we were having in the "solar in the news" thread about land use and biofuels vs. PV.

zeupater

Hi

I think that is really based around the same (/similar) set of arguments we saw bouncing around in the press and had numerous discussions around on this forum a few years ago, the substance of which was that biofuels/biomass released more CO2 per kWh of generation or kWh.t of heat than fossil fuels, therefore we might as well consume FF as they're more environmental .... this completely ignoring that fact that the CO2 released by fossil fuels were adding to atmospheric concentrations from (long cycle) carbon stored away millions of years ago, whilst timelines for a full biofuel/biomass CO2 cycle can be measured in a range from a couple of seasons to a few decades depending on source (eg.: crops vs wood/pellets etc) ...

Much of the real issue at hand obviously revolves around allocating prime/good agricultural land to energy crops and destruction of natural environments (from Brazilian rainforest to UK uplands) to provide additional biomass cropping area ... again, as long as it's well managed within a fully diversified energy source strategy, then there should be no problem ... however, if there's too much focus on biomass without appropriate oversight we may all need to be placed on a heavily restricted diet ...       

HTH - Z

Martyn1981

Bit of personal news on the subject of biofuels, specifically biomass. Myself and the animal rescue I help out at, have been hit hard. We use wood pellets for the litter trays. They make cleaning up solids easy, and the urine turns the pellets into sawdust, so a quick sift through some soil sifters I've modified, and your sorted. [At home, all of the sawdust goes into composting, it's brilliant, fine wood material, with all the added goodness of urine, makes for excellent compost.]

At the pet shop a 15kg bag used to cost about £7 for 15kg, and as we use about half a bag a day, I started buying car loads (300-360kg) from a pellet provider up in the S. Wales valleys, for about £4 a bag.

This year the price went up to around £6, and now £8-£10 a bag, depending on what loads come in (or don't). The owner is great and has explained that most pellets for smaller boilers (rather than huge ship fulls of loose material) come from Eastern Europe. the main suppliers being Russia and Ukraine.

Clearly this year has been a horror show. Loss of Russian supplies, reduced Ukrainian production, and other countries holding on to production as they and other countries get desperate. The company is getting the impression that some (UK) companies are starting to stockpile supplies in anticipation of a massive price squeeze as homeowners with pellet boilers buy in for the winter.


Personal thoughts - I'm absolutely torn in two regarding bio-mass. If managed well, which E. Europe, USA, and Canada 'apparently' do, then it's a great source of RE, though international shipping is highly questionable. But wood pellets will impact CO2 levels for 20(ish) years, so it's a fine balance. However, if seasonal crops like hemp work out, and the UK (for example) can get two harvests pa, then the ~6 month carbon cycle is excellent.

Don't want to appear to be sitting on the fence, so I think I lean towards well managed sources of bio-mass, being far better than FF's (as Z mentions), and I hope the built in storage of such products adds additional benefits to wind and solar, as it can demand follow. Maybe as part of the bigger RE package it's acceptable, but time will tell. I do however think that an even better solution, would be GW scale generation in Ukraine, with HVDC transmission to W. Europe. That reduces transportation, and provides an excellent income for the growing country. Eastern Europe bio-mass generation could be another link in an European integrated RE package, bit like the Desertec idea of a decade back.

70sbudgie

Martyn1981 said:

Just a thought/ponder, as I've scared myself a bit with my future winter 'Grid' demand waffle.

Our house was upgraded to a 100A main fuse box, and 80A fuse, when we got a smart charger installed. Now, 80A, with say 30A for BEV charging (if one at a time for most properties), and 22A(?) for a heatpump, still leaves a reasonable 30A(ish) for the house, assuming that power showers are excluded, and run from a water tank, so around 7kW spare, double that during the day if no BEV charging.

For a 100A main fuse, there's a bit more spare. So it looks like most residences would cope, or am I missing something?

But my main question is, just because each residence gets an 80A connection, can the local grid cope with that if all homes are drawing at the same time? Does that make sense, are homes rated at a level where the DNO's expect an average demand, or are they rated at a theoretical max level, that local cables can cope with even if all properties were pulling max?

From that question, it leads to me ponderings of whether demand side or DNO side storage is an issue. If the distribution network can cope with max, then DNO level storage will be fine. If however it needs averaging across properties, then demand side storage will be needed to reduce the load on the local cables.

Hope this makes sense, and maybe somebody knows how this works? My guess would have been some level of averaging, but since DNO's use max theoretical export when considering (RE, V2G etc), then perhaps they can cope with a max load from all properties?


I think I'll be keeping an eye out for any news on Grid changes / upgrades, as this may be the next big point of interest (for me).

This is the news that you will need to look out for - this is the draft determination for the networks' pricing from 1 April 2023 (for the next 5 years). The final determination will be published by OFGEM in December and I would expect there to be lots of commentary on it (from the DNOs, ENA and National Grid). https://www.ofgem.gov.uk/publications/riio-ed2-draft-determinations

Also, what you were referring to about modelling max or average loads is called diversity. You have to model / design based on max capacity, but you know that not every circuit will be at max at the same time, so you apply a diversity figure (a really common one I have seen is 80%). So you design your system based on for example, 80% of the max load. This is used all the way through the electricity network - from how many 13A sockets you can put on a domestic circuit (and therefore the size of the cable and the fuse required in the consumer unit), to how big the house fuse needs to be, to how many houses you can have on a substation, how many substations are needed for a town etc all the way up to "how much capacity is required to transmit wind generated power from Scotland to London.

And this is where the current difficulty lies - in the quality of historical data used to determine accurate diversity factors. How we use electricity has changed so much recently (even over the last 8 year price control period), that the historical data becomes less and less useful. The network owner / operators are currently trying to predict (crystal ball!) how our electricity use will change over the next 5 years, so that they have any new infrastructure in place when it is required.

And this is the real reason why smart meters are so important (there is a discussion about this on the energy board). It is providing more granular data to provide up to date information on how electricity use is changing at a domestic level. I know @Zeupater says it is only 40% of demand (it is actually only 33% https://www.gov.uk/government/statistics/electricity-chapter-5-digest-of-united-kingdom-energy-statistics-dukes) but that third is still important. The industry gathers it own data, but from higher points on the network, so diversity is already being applied. Smart meters also introduce the opportunity to offer incentives for positive behaviour change and therefore an ability to manage actual diversity figures (demand side management). Increasing the opportunity for network operation to increase capacity, instead of just equipment capacity having to be extended with more cables etc.