Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
topics:storage [2026/03/14 12:34] – ↷ Page moved from storage to topics:storage admintopics:storage [2026/04/13 11:39] (current) – o.sachs
Line 1: Line 1:
-[[energy_logistics|]]+<WRAP catbadge>Technology and Infrastructure</WRAP>
  
-====== Storage ======+====== Energy storage ======
  
 +<WRAP meta>
 +lead-authors:
 +contributors: Klaus Kubeczko
 +reviewers:
 +version: 0.2
 +updated: 26 March 2026
 +sensitivity: public
 +ai-use: Claude Sonnet 4.6 (Anthropic) was used to structure source material; reviewed by Vitaliy Soloviy, 26 March 2026
 +status: draft
 +</WRAP>
  
-===== Capacity of Storage we need? (UK example) [Sir Llewellyn Smith 2023] =====+<WRAP intro> 
 +Energy storage encompasses technologies that capture energy at one point in time for use at another, enabling electricity systems to manage the mismatch between variable generation and demand. Storage operates across timescales from seconds to seasons and at scales from individual households to grid-level installations, and its role in smart grid transitions extends from frequency regulation to long-duration balancing of renewable energy systems. 
 +</WRAP>
  
-"First of all, it depends: there's this trade-off between how much you're prepared to build of wind, and how much storage. We need, with just hydrogen, we need between about 60 and 100 terawatt hours. Now, to put that in context, the UK today is using about 300 terawatt hours a year of electricity. So, the energy that's got to be the capacity has to be **about a third of the annual electricity generation** in this country."+===== Why this matters =====
  
- +Electricity systems built around dispatchable generation can balance supply and demand in real time by adjusting output. Systems with high shares of variable renewables cannot do this without either curtailing generation or storing surplus energy. The quantity of storage required, and its duration, depends on the generation mix and the degree of interconnection available. Analysis of a net-zero UK system suggests total storage requirements in the range of 60 to 100 terawatt-hours — equivalent to roughly a third of annual UK electricity consumption — with the specific figure depending on the ratio of wind and solar to storage capacity.((Llewellyn Smith, C. (2020). The need for energy storage in a net zero world. ERA Technology. https://www.era.ac.uk/write/MediaUploads/Other%20documents/Need_for_Storage_in_a_Net_0_World_Chris_Ll_S_23_3_20.pdf)) In a scenario where wind and solar are sized 33% larger than peak demand, with 15% of supply coming from storage, modelled costs range from approximately £52 to over £90 per megawatt-hour depending on discount rate and storage cost assumptions, with a central estimate around £64 per megawatt-hour including transmission.((Llewellyn Smith, C. (2023). Solving for storage [podcast transcript]. Cleaning Up, Episode 122. https://www.cleaningup.live/ep122-sir-chris-llewellyn-smith-solving-for-storage/))
  
-Transcript from Ep122: Sir Chris Llewellyn-Smith "Solving for Storage" March 2023 [[https://www.cleaningup.live/p/ep122-eh/]]+<WRAP callout> 
 +Storage duration matters as much as storage capacity. Short-duration storage (minutes to hours) addresses daily balancing; medium-duration (days to weeks) covers weather variability; long-duration (months) is needed only in systems with very high renewable penetration or limited interconnection. 
 +</WRAP>
  
-[[https://www.cleaningup.live/ep122-sir-chris-llewellyn-smith-solving-for-storage/]]+===== Shared definitions =====
  
- +Energy storage is the conversion of electrical energy into another form — chemical, mechanical, thermal, or gravitational potential — for later reconversion to electricity or direct use as heat or cooling.
  
-===== Cost of power per megawatt hour? (UK example) [Sir Llewellyn Smith 2023] =====+A storage classification by discharge duration distinguishes the following operational roles:
  
-"CL-S So, if we have wind and solar 33% bigger than demand, assuming that wind and solar costs £35 per megawatt hour, then I've got to pay 1.33 x £35 for the wind and solar. Then there's 15% has to come from storage. Now, the storage that will deliver 15% costs me about - in our middle case - £80 per megawatt hour. So, I've got 1.33 times £35 plus 15% of £80. So, I end up with a cost of about £60 a megawatt hour. Then I add a bit of contingency, I add about £4 for transmission. So, in that simple model, I end up at £64 per megawatt hour. But that’s a central case. We then we had to assume a discount rate, and different costs of storage. So, we got a range, including the contingency and the extra transmission, from **about £52, up to just over £90**. That's with the top storage costs."+<WRAP tablecap> 
 +**Table 1.** Storage duration classes and system function. //Source: adapted from Llewellyn Smith (2020).// 
 +</WRAP>
  
-Transcript from Ep122: Sir Chris Llewellyn-Smith "Solving for Storage" March 2023 [[https://www.cleaningup.live/p/ep122-eh/]]+^ Duration class ^ Typical discharge period ^ Primary system function ^ 
 +| Short-duration | Seconds to hours | Frequency regulation, peak shaving, daily balancing | 
 +| Medium-duration | Hours to days | Weather-driven variability, multi-day balancing | 
 +| Long-duration | Weeks to months | Seasonal balancing, security of supply | 
 +| Very long-duration (VLS) | More than 180 days | Extreme events, annual renewable variability |
  
-[[https://www.cleaningup.live/ep122-sir-chris-llewellyn-smith-solving-for-storage/]]+<WRAP figure> 
 +{{:energy_storage:storage1.png|Very long duration storage requirements}}
  
-===== Very Long Store (VLS>180 days, or 1 year) (UK example) [Sir Llewellyn Smith 2020] =====+**Figure 1.** Very long store (VLS, >180 days) requirements. //Source: Llewellyn Smith (2020).// 
 +</WRAP>
  
-{{ :storage1.png?600 |}}+<WRAP figure> 
 +{{:energy_storage:storage2.png|Candidate storage technologies}}
  
-[[https://www.era.ac.uk/write/MediaUploads/Other%20documents/Need_for_Storage_in_a_Net_0_World_Chris_Ll_S_23_3_20.pdf]]+**Figure 2.** Candidate storage technologies. //Source: Llewellyn Smith (2020).// 
 +</WRAP>
  
-===== Candidate Storage Technologies [Llewellyn Smith 2020] =====+<WRAP figure> 
 +{{:energy_storage:storage3.png|Conclusions on energy storage needs}}
  
-{{ :storage2.png?600 |}}+**Figure 3.** Energy storage conclusions with UK focus. //Source: Llewellyn Smith (2020).// 
 +</WRAP>
  
-Source: The Need for Energy Storage in a Net Zero World [Llewellyn Smith 2020] [[https://www.era.ac.uk/write/MediaUploads/Other%20documents/Need_for_Storage_in_a_Net_0_World_Chris_Ll_S_23_3_20.pdf]]+<WRAP figure> 
 +{{:energy_storage:storage4.png|Questions about candidate storage technologies}}
  
-===== The Need for Energy Storage in a Net Zero World - (Conclusions with UK Focus) [Sir Llewellyn Smith 2020] =====+**Figure 4.** Questions about candidate storage technologies. //Source: Llewellyn Smith (2020).// 
 +</WRAP>
  
-{{ :storage3.png?600 |}} +===== Perspectives =====
  
-[[https://www.era.ac.uk/write/MediaUploads/Other%20documents/Need_for_Storage_in_a_Net_0_World_Chris_Ll_S_23_3_20.pdf]]+<WRAP perspectives> 
 +==== Actors and stakeholders ====
  
-===== Questions about Candidate Storage Technologies [Sir Llewellyn Smith 2020] =====+Storage assets are owned and operated by a range of actors: transmission and distribution system operators deploying grid-scale storage for system services; utilities and independent power producers operating large battery or pumped hydro assets in wholesale markets; commercial and industrial customers using behind-the-meter storage for peak demand management; and households combining rooftop solar with residential batteries. Aggregators can pool dispersed small-scale storage into portfolios capable of market participation.
  
-{{ :storage4.png?600 |}} +==== Technologies and infrastructure ====
  
-[[https://www.era.ac.uk/write/MediaUploads/Other%20documents/Need_for_Storage_in_a_Net_0_World_Chris_Ll_S_23_3_20.pdf]]+Candidate storage technologies span several physical principles, with different characteristics for power capacity, energy capacity, round-trip efficiency, cost, and discharge duration.((Llewellyn Smith, C. (2020). The need for energy storage in a net zero world. ERA Technology. https://www.era.ac.uk/write/MediaUploads/Other%20documents/Need_for_Storage_in_a_Net_0_World_Chris_Ll_S_23_3_20.pdf)) Key questions for each technology include: What is the energy-to-power ratio? What are the self-discharge characteristics? Can it be deployed at grid scale? What are the infrastructure requirements for installation?
  
 +==== Institutional structures ====
  
-~~DISCUSSION|Discussion Section~~+Whether storage assets can participate in electricity markets, and which services they can provide, depends on regulatory classification. In many jurisdictions, storage has historically been classified either as generation or as consumption, but not both — creating a regulatory barrier to its operation as a flexibility resource. Revisions to market rules to accommodate storage as a distinct category are underway in several regulatory frameworks.
  
 +</WRAP>
 +
 +===== Distinctions and overlaps =====
 +
 +<WRAP distinction>
 +**Energy storage vs flexibility**\\
 +Flexibility is the broader capability of the power system to manage variability and uncertainty; storage is one of several resources that provide flexibility alongside demand response, interconnection, and dispatchable generation. Not all storage provides flexibility in a market sense, and not all flexibility comes from storage.
 +</WRAP>
 +
 +<WRAP distinction>
 +**Short-duration vs long-duration storage**\\
 +The distinction matters for system planning and technology choice. Short-duration storage (batteries, flywheels) addresses daily and sub-daily balancing at competitive cost; long-duration storage (hydrogen, pumped hydro, compressed air) is required for seasonal balancing but faces higher capital costs and lower round-trip efficiency. Policy and market design must account for both.
 +</WRAP>
 +
 +<WRAP distinction>
 +**Behind-the-meter storage vs grid-scale storage**\\
 +Behind-the-meter storage is installed at user premises and primarily serves the owner's energy management needs; its contribution to the wider system depends on whether aggregation and market access mechanisms exist. Grid-scale storage is directly connected to transmission or distribution networks and operated explicitly as a system asset.
 +</WRAP>
 +
 +===== Related topics =====
 +
 +[[topics:flexibility|Flexibility]] · [[topics:grid_edge|Grid edge]] · [[topics:energy_logistics|Energy logistics]] · [[topics:resilience|Resilience]] · [[topics:operator|Operator]] · [[topics:sector_coupling|Sector coupling]]
 +
 +~~DISCUSSION|Discussion~~