2026 The start of Population deline?

I grew up worried that the world's population would grow too much and widespread hunger would result.
But I think 2026 is the year there will be a move to a long term drop in the world's population. 
By this I mean that

1. World fertility will continue to decline at the same rate as it has been recently. So TFR of 2.3 in 2023 going to 2.25 2024, 2.20 2025, 2.15 in 2026.

2. Infant and child mortality will decline at the same rate as it has been recently. It is down to about 3.5% from 9.7% in 1990. Malaria, TB and other vaccines might reduce this considerably but fairly slowly and not much by 2026.

3. Sex selective abortion will continue to decline but not fast enough to keep females being born above replacement level.

Long term it is number of women that are raised per woman that matters. If our life expectancy goes from 40 to 80 to 120 that's really good for us. And it will mean the world's population goes up. But not in the long term.

Long terms it is really women that matter. They are the ones that actually have children. Obviously this men not mattering idea is not true at the extreme end. You do need some men.

Assuming life expectancy and men do not matter. What does matter in particular is number of female children per woman. And particularly how many of those live to an age when they can have children.

And I think these align so that we move below replacement level in 2026. 

The year of peak births seems to have been 2013 and to have moved to below long term replacement that soon afterward is quite surprising. Getting the exact year is hard as in some ways we won't know how many people get to the age they can have children until they get there. At a 1% yearly decline in fertility we will be below replacement birth level soon.

Russian Tank Problem

 If one Russian tank storage base runs out how many tanks are left in the rest? I saw a video today about how the 1295th  tank storage area in Russia is empty.

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There is a famous estimation problem called the german tank problem. If you know tanks have a serial number on them from 1 up as each new one is produced. And you find some broken tanks with serial numbers on them. Can you estimate how many tanks N have been created?

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But I came across a related problem today. If you have some tank storage bases and one of them runs out of tanks what can you guess about the total number of tanks left?

This involves some assumptions. Each tank storage base draws at the same proportional rate. As in if one base has 100 and another has 100 each will have a 50:50 chance of having the next tank removed. And in the case where the second has 1000 tanks it will have a ten times higher chance of the next removal.

Bases should have a similar proportion of fixing up sheds and staff per tank so I think this is a reasonable guess. Unless some base you know to be much more likely to have high repair speeds and rates.

So this tank storage base is empty according to this short video 1295th - Empty of Tanks in 2024 December Satellite Imagery. Looking at the video it does not seem to be high tech refurbishing place. And if it was other tanks to repair would be moved there to also get repaired so it would not be empty first. it does seem small only having 325 tanks 2 years ago. But with the proportional withdrawal assumption that doesn't matter hugely.

This is the code to simulate how many tanks are left in all bases once one runs out. 

Assuming random withdrawals are random.

There is less tanks left than I expected. Once one store is empty less than 10% of the tanks remain. 

And this is with various numbers of bases and initial number of tanks in the base.

Ireland's Electricity Simulation

What will Ireland's Electricity mix look like in 2030 assuming

1. Demand will increase by the amount Eirgrid predict
2. 2030 will be an hour by hour weather copy of 2023.*
3. We will build the wind turbines we say we will.
4. Solar and battery trends keep going as they have for over a decade
5. The grid can handle the new power sources + demands

The code for this projection is here. 
* obviously the weather in any hour of the year won't be the same as that hour in 2023. But by copying a year you get to see how wind and solar peak and lull in an accurate way. Combining more years into an average loses the 'what happens if its dark and calm for a week' accuracy of copying one years weather.

At the moment Ireland gets a lot of wind power. But all the white here under the black line is met by fossil fuels and imports. How much white under the demand line will there be in future?

As wind, solar and battery roll out the amount of fossil fuels and imports needed decreases.

To take one example with these trends continuing in June 2030 Wind and Solar cover a lot of the power needs. With Battery holding enough to smooth out gaps 

On a day view of the year you can see solar has started to cover a lot of low wind times.

and by 2033 continuing trend growth of Solar really would start to cover a lot of demand

 

year	demand_twh	solar_twh	wind_twh	waste_twh	battery_used_twh	unmet_twh
2023	39.7	1.0	13.7	0.0	0.0	24.9
2024	41.2	1.4	16.2	0.0	0.0	23.7
2025	42.9	1.9	19.1	0.2	0.1	22.0
2026	44.6	2.6	22.6	0.7	0.2	20.0
2027	46.4	3.6	26.6	2.0	0.3	17.9
2028	48.2	4.9	31.4	4.3	0.6	15.7
2029	50.2	6.8	37.1	7.9	1.0	13.3
2030	52.2	9.4	43.7	13.3	1.7	10.6
2031	54.3	13.0	51.6	21.1	2.9	7.9
2032	56.4	17.9	60.9	31.8	4.3	5.1
2033	58.7	24.7	71.8	46.1	5.3	3.0
2034	61.1	34.1	84.8	65.1	5.4	1.9
2035	63.5	47.1	100.0	90.0	5.3	1.2
2036	66.0	64.9	118.0	122.6	5.2	0.5
2037	68.7	89.6	139.3	165.1	4.8	0.1

Predictions of ten plus years are really not to be trusted. But the reduction to 10.6Twh in 2030 from 25Twh is something this government we just elected controls. We make planning and other decisions all the time that decide if we meet these trend increases in demand, solar, wind and batteries. We can decarbonise fast enough to prevent billions in fines in 2030 if we follow this path.

How much battery power is there in 2030?

 This post here estimated there would be about 16.5GWh of Grid scale batteries power in ireland in 2030.   an actual expert said 13.5GWh. Eirgrid estimate 3.4GWh and SEAI 1.7GWh.

But apart from Grid scale batteries what other ones will we have?

Grid scale solar and domestic solar are about equal. There might be a similar relationship between Domestic and grid scale batteries. In 2019 in the UK 10,000 homes had domestic storage batteries. And those batteries seemed to be about 5KWh on average. They have gone up since. that would be 50MWh. This is tiny compared to the amount of grid scale energy at the time. I do not think currently domestic batteries make up a big proportion of total batteries. I could be wrong on this but that is what the data I see at the moment says. 

One place we do have a lot of batteries is in Electric cars. 73000 Electric cars registered in Ireland each with an average 40 kWh battery. Which is a total of just under 3GWh of batteries. That is over 3 times the amount in grid storage systems.

'Under the Climate Action Plan, the Government initially set a target of having 175,000 electric passenger cars on the road by the end of 2025 which would increase to 845,000 by the end of 2030.' That would be 34GWh of batteries in cars. And given that EV battery capacity keep going up, Range doubles every 7 years  that could be nearly doubled by then. Even if they do not go from 40KWh to 80KWh, 60KWh is pretty standard and probably will be average by then.

70GWh of electric batteries driving around involves us meeting our agreements and increased capacity trends continuing. It would be a huge amount of power 16.5GWh grid + 70GWh EV is a big chunk of a days worth of current electricity usage.

There is a problems getting that much energy into cars in 5 years time. If you could get the electricity out for the owner when it was needed it that would really help but that is not currently practical. I can imagine houses filling up EV batteries in cheap renewables and running their house off the EV batteries. Though this is not practical yet renewable and EV trends mean it would be cheap so there is incentive to make it work. Cars are used slightly under an hour a day on average. Which means 23 hours a day the battery could be used to help the grid.

The average house uses about 12KWh a day. Say 20KWh to include heating with electricity not gas. If you have a battery of 80KWh that could hold 3 days of that power and do the usual short Irish commute (17km) a few days a week. There is a big incentive to charge the battery on windy or sunny times and then use the car battery for the house at peak expensive electricity times.

In a few years based on current trends and agreements Ireland could have a huge amount of its daily energy needs storable in battery form. 

Batteries in Ireland 2030

I think the same estimates for Battery power storage in Ireland in 2030 are really too low.

I have talked here about how I think SEAI (Sustainable Energy Authority Of Ireland) estimates for Solar underestimates how much solar we will add to the grid by 2030. 

The SEAI estimate here that we will have 1GW of battery storage in 2030 and optimistically 1.8GW (1.7GWh and optimistically 5.94GWh in total) p87 here 

This estimate comes from p100 of Eirgrid's Ten Year Generation Capacity Statement 2023–2032 

We seem to be nearly at that lower level of GWh already 'Cornwall Insight’s SEM Benchmark Power Curve sees “significant battery storage growth”, projecting that short-medium term lithium-ion battery storage capacity, up to 4h duration, will reach 13.5GWh by 2030, up from 2.7GWh in 2025.'

To take one current planned battery system Ballynahone Energy Storage Co. Donegal 'The company expects the project, which would take 12 months to build, would be capable of storing 1 gigawatt hour (GWh) of energy while future projects will be capable of storing up to 8GWh' That one project could by 2030 surpass the current optimistic estimates

There are domestic batteries, including in cars, which at least reduce peak consumption but could also be used to directly help the grid. If my predictions of close to zero wholesale prices at sunny of windy times by 2030 there will be good incentives for batteries that store power then. and the 13.5GWh estimate could be low. Nevermind the 1.7GWh one of SEAI.


In April 2024 there was 731.5 MW of Battery storage. We added at least 150MW since. Let us say the total now is 880MW. The world has had an annual growth rate of 63.6% in battery storage for the last 10 years (p56 Grid-scale battery energy storage systems). 2023 had an increase of 120.8% so the growth rate seems to be increasing. But if the 63% rate kept going for Ireland's battery storage that would be 43GW. Over 30 times Eirgrid's estimates.

Adding Solar to Wind Farms

 
I talked in 2022 about how I expected Wind farms in Ireland to have solar added to them. The short version is a bad piece of land with a big electricity cable leaving it that is already selling electricity seems idea to put solar on. 

Because solar is during summer days and the wind mostly winter nights the chances of maximum wind and solar being at any one time is small. And when those windy and sunny times do happen the whole grid will have so much electricity that extra watts will not be valuable. Some wind farms are forested but many are pretty bare hillsides.

Solar panels keep getting cheaper. At the moment they are €0.06/W. To take one example Raheenleagh Wind Farm has a capacity 35.2MW which would cost now just over €2 million in panels. 
Panels are about half the costs of solar farms (planning permission permits etc make up a lot of the rest. Stands a 10%ish chunk. With the inverter and other electrical stuff a fairly small percentage 15%ish).

Combined solar and wind farms make sense in Ireland. It means some infrastructure can be reused and a lot of the work that has already been done for an area. For example this planned hybrid site has 'Grid connection via the existing Richfield Wind Farm 38kV substation;'

Ireland's Solar Electricity in 2030

 

Sustainable Energy Authority of Ireland have released their National Energy Projections 2024. In this they predict Ireland will have *2.6 more solar electricity generation capacity in 2030. And their optimistic estimate is 3 times more. Ireland has promised to install nearly 4 times more.

It is these peoples jobs to make these projections. and they know far more than I do about electricity generation. But I think they are wrong because of straight line continuing reasons

Below is Ireland's increase in Solar generation since 2017, the first year I can find data for. It increases by more than the 40% annual growth Solar has had world wide for decades

But say we slowed down to this 40% increase rate where would that leave us in 2030? We would have 10 times more solar than now. Not the 3 times SEAI predicts on the optimistic path.

Lots of things could interrupt Ireland's trend but
1. there are lots of planning applications for new solar farms. ' If all were developed, it would add a further 9.5 GW in solar energy to the grid,

surpassing our 2030 target of 8 GW'

2. We have promised to install 8GW of capacity so planning hold ups seem less likely

3. Prices keep dropping, and production keeps increasing. Solar installs in general keep surpassing expectations.

I think the SEAI solar predictions are too low and we are going to have over 10GW of solar installed by 2030. Instead of 2030 to have 5.7GW I think that will be 2 years time, by the end of 2026.