Technology Quarterly, Economist - Electricity Grids

[TUK020]

The Technology Quarterly in this week's Economist is devoted to Electricity Grids.
Too much material to summarise here, but lots of good stuff - worth getting a copy if you are interested in this topic.

Some key highlights:
* As much money (trillions) needs to be invested in the grid/transmission/conversion/storage as in new forms of renewable generation in order to get to a low carbon economoy.
* Planning, regulations & permits, and system control will be the key delays and gating factors to much of this coming online
* HVDC links will be needed, not just to decouple disparate grids, but also as a means of allowing power balancing between different parts of the grid, and also as a means of generating synthetic inertia for grid restarts etc.

[odysseus2000]

The Technology Quarterly in this week's Economist is devoted to Electricity Grids.
Too much material to summarise here, but lots of good stuff - worth getting a copy if you are interested in this topic.

Some key highlights:
* As much money (trillions) needs to be invested in the grid/transmission/conversion/storage as in new forms of renewable generation in order to get to a low carbon economoy.
* Planning, regulations & permits, and system control will be the key delays and gating factors to much of this coming online
* HVDC links will be needed, not just to decouple disparate grids, but also as a means of allowing power balancing between different parts of the grid, and also as a means of generating synthetic inertia for grid restarts etc.

There are various views on the grid and how storage will change it, but this all depends on storage happening which at the moment it isn't. Many in the storage field argue that grid storage has to be by battery and vehicle to grid, but there are a number of prototypes of compressed gas storage that look to be lower cost, more reliable, to have longer life times and quicker to construct. But at least in the UK there seems to be almost no money going into storage research even though it is essential for renewables.

Another theme is that if storage works then it should simplify the grid and make it annual operational costs much lower. E.g. if there are areas with lots of local storage then building capacity to supply this area can be reduced in scale, knowing that local storage can make up the difference.

The extension of these arguments is that electricity costs for the consumer should head towards zero if there is free fuel generation and lots of storage.

As I look at the UK it appears to be a cosy shop of existing players that need new competitors to shake up the complacency.

Regards,

[tacpot12]

That cosy closed shop needs the regulator to get shaking, but I don't think Ofgem have the leadership to do this.

[TUK020]

Many in the storage field argue that grid storage has to be by battery and vehicle to grid, but there are a number of prototypes of compressed gas storage that look to be lower cost, more reliable, to have longer life times and quicker to construct. But at least in the UK there seems to be almost no money going into storage research even though it is essential for renewables.

There are two different problems to solve with storage - short term (diurnal) which batteries, compressed gas etc can handle, and seasonal to help cope with winter demand. The only realistic ways of doing the latter are either pumped storage reservoirs, or by using excess renewable capacity for fuel generation (green hydrogen)

[Tedx]

Air to Liquid / Liquid to air looks promising, using excess renewable to chill (but not compress) air to a liquid 700 times denser than natural air - it's pretty much the same tech they use in the LNG industry.

When the liquid air is allowed to warm up it expands and drives a turbine.

https://www.theengineer.co.uk/content/n ... age-plant/

[TUK020]

Air to Liquid / Liquid to air looks promising, using excess renewable to chill (but not compress) air to a liquid 700 times denser than natural air - it's pretty much the same tech they use in the LNG industry.

When the liquid air is allowed to warm up it expands and drives a turbine.

https://www.theengineer.co.uk/content/n ... age-plant/

Difficulty here is about balancing demand of two very different things. To get this economical in a big way, you want to be using the refridgeration when you are generating electricity - do you wait for a spike in electricity demand before you freeze the fish fingers in the processing plant....

[Tedx]

Air to Liquid / Liquid to air looks promising, using excess renewable to chill (but not compress) air to a liquid 700 times denser than natural air - it's pretty much the same tech they use in the LNG industry.

When the liquid air is allowed to warm up it expands and drives a turbine.

https://www.theengineer.co.uk/content/n ... age-plant/

Difficulty here is about balancing demand of two very different things. To get this economical in a big way, you want to be using the refridgeration when you are generating electricity - do you wait for a spike in electricity demand before you freeze the fish fingers in the processing plant....

When I say excess, I dont mean at today's renewable capacity, I mean in, say, 10 years time (or even 20 or 30 years time) when we could be generating many times the offshore wind energy we currently are.

Saying that, we're after a mix of storage aren't we? Hydro, chemical batteries, hydrogen plus air to liquid - plus whatever new comes along that we havent thought of yet.....

[scotview]

The big question is not so much the capacity of stored energy but for how long that stored energy can sensibly be used in winter to support the grid, 2 hours, 4 hours, 24 hours, 2 days, a week? Especially if HCs (all types) will be banned for space heating.

[BobbyD]

Many in the storage field argue that grid storage has to be by battery and vehicle to grid, but there are a number of prototypes of compressed gas storage that look to be lower cost, more reliable, to have longer life times and quicker to construct. But at least in the UK there seems to be almost no money going into storage research even though it is essential for renewables.

There are two different problems to solve with storage - short term (diurnal) which batteries, compressed gas etc can handle, and seasonal to help cope with winter demand. The only realistic ways of doing the latter are either pumped storage reservoirs, or by using excess renewable capacity for fuel generation (green hydrogen)

Actually bothering to insulate the majority of housing stock properly would also help...

Two-thirds of homes, or 19 million, need better insulation, according to government data.

- https://www.bbc.co.uk/news/science-environment-60290876

The primary downside of cheap fuel has been that British householders have grown accustomed to a 'one to heat inside my house, one to heat outside my house' method. Then more efficient heating solutions become available, and they are the devil's armpit because they are reliant on you not letting half the heat you generate straight out through rattly leaded lights, single skin walls, doors with a half inch gap underneath them...

[BullDog]

Air to Liquid / Liquid to air looks promising, using excess renewable to chill (but not compress) air to a liquid 700 times denser than natural air - it's pretty much the same tech they use in the LNG industry.

When the liquid air is allowed to warm up it expands and drives a turbine.

https://www.theengineer.co.uk/content/n ... age-plant/

It's actually the front half of a cryogenic air separation plant more than an LNG plant. Apologies for being a bit of a nerd.

[Tedx]

Happy to learn!

Cheers

[BullDog]

The Technology Quarterly in this week's Economist is devoted to Electricity Grids.
Too much material to summarise here, but lots of good stuff - worth getting a copy if you are interested in this topic.

Some key highlights:
* As much money (trillions) needs to be invested in the grid/transmission/conversion/storage as in new forms of renewable generation in order to get to a low carbon economoy.
* Planning, regulations & permits, and system control will be the key delays and gating factors to much of this coming online
* HVDC links will be needed, not just to decouple disparate grids, but also as a means of allowing power balancing between different parts of the grid, and also as a means of generating synthetic inertia for grid restarts etc.

There are various views on the grid and how storage will change it, but this all depends on storage happening which at the moment it isn't. Many in the storage field argue that grid storage has to be by battery and vehicle to grid, but there are a number of prototypes of compressed gas storage that look to be lower cost, more reliable, to have longer life times and quicker to construct. But at least in the UK there seems to be almost no money going into storage research even though it is essential for renewables.

Another theme is that if storage works then it should simplify the grid and make it annual operational costs much lower. E.g. if there are areas with lots of local storage then building capacity to supply this area can be reduced in scale, knowing that local storage can make up the difference.

The extension of these arguments is that electricity costs for the consumer should head towards zero if there is free fuel generation and lots of storage.

As I look at the UK it appears to be a cosy shop of existing players that need new competitors to shake up the complacency.

Regards,

You might be interested in these people -

https://storelectric.com/

I have been aware of them for almost a decade and they have some very interesting technologies. I am actually not entirely sure why they haven't yet managed to build their first compressed air energy storage system. There's nothing in their energy storage system that isn't very well established engineering. For something novel, the engineering risk is very low. For whatever reason, it hasn't happened yet. Despite the UK energy market never having been more favourable it would seem to me.

[Hallucigenia]

Many in the storage field argue that grid storage has to be by battery and vehicle to grid, but there are a number of prototypes of compressed gas storage that look to be lower cost, more reliable, to have longer life times and quicker to construct.

It depends on what scale you're looking at. At the moment compressed air looks the cheapest for durations of a few hours to a couple of days, but current thinking seems to be that by 2030 the size of its niche will be squeezed by batteries on the short side and hydrogen on the long duration. It'll still have a niche, but perhaps rather smaller than its fans think. And it is somewhat geographically constrained like pumped storage - in this case it will be fighting for access to salt caverns against hydrogen storage.

According to a recent RenewableUK EnergyPulse table, UK battery storage is currently :

2.4GW in operation
2.5GW under construction
15.2GW awaiting construction (presumably grid connections are one factor for delay, plus supply chain bottlenecks)
16.7GW in planning
15.1GW pre-planning

So 20.1GW with planning permission or later stage, and 31.8GW at the planning/pre-planning stage - 51.9GW is more than the current UK peak load! But it's all relatively short-term, what we need is batteries with longer duration rather than discharge capacity, stuff like the Form iron-air batteries with 100-hour duration (even if their round-trip efficiency ain't great).

I've often mentioned the Ruhnau & Qvist paper which looked at German weather patterns over 35 years and concluded that for the absolute worst case, once-in-a-generation Dunkelflaute in that time, Germany would need 36 TWh of electricity, which given the round-trip inefficiencies would amount to 56TWh of storage.

They were more interested in the weather side of things so their economic/technology model is relatively simple, they came up with a 100% renewable Germany (they say peak load is 105GW, whereas other sources put it at about 80GW, UK is about 50GW) having 300GW of variable renewable generation of which 284GW was split pretty much equally between solar, offshore and onshore wind. They see 72GW of storage charging capacity and 81GW discharge capacity (ie 77% of peak), of which 77% was hydrogen-fired CCGT and 19GW of other storage. They see hydrogen accounting for 97.8% of the stored energy, with 1,300GWh from pumped hydro and just 59GWh from batteries. As I say, their model is relatively simple, I guess you can substitute "any cheap long-term storage" for "hydrogen" and "any cheap short-term storage" for "batteries".

I've also mentioned the recent report from HMG's advisors, which admittedly only looked at an "average" year but in more detail on the grid side in 2035. In particular I suggest people look at the separate report they received on "flexibility" (ie storage and related issues). Which sees 2% of electricity coming from gas (without capture, essentially legacy CCGTs) in 2035 and :

The provision of short-duration flexibility from ≤4hr grid storage technologies and [demand-side response] demonstrate rapid growth, more than doubling from 17GW in 2025, to 41GW in 2035...Batteries are expected to experience growth in the 1-2 hours duration capacity levels until 2030, and 4-6 hours thereafter... the role of medium- and long-duration grid storage solutions is expected to be limited, with only existing pumped storage and small levels of CAES on the system by 2035. Instead, alternative sources of flexibility such as hydrogen storage and low-carbon dispatchable capacity are considered to be more cost-effective...

The level of demand shifting in 2035, 50GWh per day or 4% of total demand, is significant and demonstrates the impact that demand response programs can have on the energy storage requirements of the grid. However, the emergence of this smart and responsive demand is heavily dependent on the adoption rates of electric vehicles and heat pumps, as well as consumer engagement in these areas.

They talk about grid upgrades from p56.

[scotview]

It's actually the front half of a cryogenic air separation plant more than an LNG plant. Apologies for being a bit of a nerd.

Aye, expanders are easy, till they throw a shroud plate.

For UK wide implementation you will also need very, very, very large capacity storage vessels with double skinned, vacuum pulled shells. The bigger they are the more thermal flex there is, the higher the probability that thermal cracking occurs at off take penetrations.

It's the wee thingy's that creates all the practical problems. The thermodynamics is the easy bit.