Tag Archives: solar-power

More and More and, surprisingly, Less

I was excited to get my hands on Jean-Baptiste Fressoz’s latest book More and More and More – An All-Consuming History of Energy [1]. He offers up a very lively critique of the notion of historic energy transitions – from wood, to coal, to oil and gas. 

His methodology aims to show how material flows are intimately linked to energy production in often surprising ways over time. For example we needed wood as pit props to mine coal, and in surprising quantities. Most of the book is devoted to examples of the symbiosis that has existed between the successive materials required to meet our energy needs. He mocks the idea of energy transitions with numerous well researched anecdotes, awash with surprising numbers. It is an entertaining read I would recommend to anyone.

However, I was expecting the book would close with some prescriptions that would show how the “amputation” the blurb called for could be achieved, but in the end he tells us he offers no solutions, or “green utopias”, as he discussed in an interview [2].

In the finale, he presents the newest energy transition – towards a world powered by renewables – as just the latest incarnation of a delusional concept, but largely abandons his methodology of using numbers to prove his case. I wonder why?

He does not deny the reality of a need to reduce carbon emissions, or the science of climate change, but it is clear he sees humanity’s insatiable appetite for energy as the central issue that must be addressed. He could have written a different book if that was his objective.

There are fundamental flaws in Fressoz’s scepticism of the renewables transition.

Solar abundance

The first of these is that the new source of energy that supplies our energy in a renewables future is our sun. Energy from the sun is a quite different category to that we extract from the ground.

The most pessimistic projection is that humanity, or what we may become, will have hundreds of millions of years left of usable energy from the sun [3]. No digging or extraction required. I’d call it functionally infinite on any meaningful timescale.

Not only that, but the sheer power of the sun’s energy is awesome, which we capture as wind, through photovoltaics, and the ambient energy harvested by heat pumps. As Frank Niele observed 20 years ago [4]:

“The planet’s global intercept of solar radiation amounts to roughly 170,000 TeraWatt [TW] ( 1 TW = 1000 GW). … [man’s] energy flow is about 14 TW, of which fossil fuels constitute approximately 80 percent. Future projects indicate a possible tripling of the total energy demand by 2050, would correspond to an anthropogenic energy flow of around 40 TW. Of course, based on Earth’s solar energy budget such a figure hardly catches the eye …”

It is clearly a category error to compare renewables with fossil fuels.

False equivalence

Ah, but what about the lithium and all those (scare story alert) “rare earths” needed to build the renewables infrastructure. This is the second flaw in the Fressoz thesis. The example of wood consumption for mining staying high even after the ‘transition’ to coal, is an example of an essential material relationship between the kilowatt-hours of energy produced and the kilograms of material consumed. This link does not exist with renewables to any meaningful degree. 

It has nevertheless become a popular belief amongst those questioning the feasibility of renewables. For example, Justin Webb on BBC Radio 4 [5] posed this question:

“Is it also the case of us of us thinking whether we can find some other way of powering ourselves  in the future … [we are] just going from taking one out of the ground – oil – into taking another thing or another set of things just isn’t the answer, isn’t the long-term answer for the planet.”

This is another category error that unfortunately Fressoz seems happy to go along with. The quantities of minerals required is minuscule compared with the huge tonnage of fossil fuels that has powered our carbon economy, as CarbonBrief illustrated as follows, as part of a debunking of 21 myths about Electric Vehicles [6]:

Credit: CarbonBrief

This false equivalence between minerals extraction and fossil fuels extraction is now widely shared by those who prefer memes to numbers.

A detailed published analysis of the demands for minerals required to build out renewables infrastructure by mid century shows we have enough to do this, without assuming high levels of recycling [7]:

“Our estimates of future power sector generation material requirements across a wide range of climate-energy scenarios highlight the need for greatly expanded production of certain commodities. However, we find that geological reserves should suffice to meet anticipated needs, and we also project climate impacts associated with the extraction and processing of these commodities to be marginal.”

Yet many commentators claim we are in danger of running out of ‘rare earths’ (which they conflate with minerals in general).

Beyond that, it is true that for many minerals it is cheaper to mine them rather than recycle them but Fressoz claims (p.218) “recycling will be difficult if not impossible”. There is no scientific basis for that claim. By 2050, one can expect that better design, improved technologies, economic incentives, and global coordination will become widely effective in tilting the balance to recycling rather than fresh extraction (and energy inputs to do this will not be an issue, as noted earlier).

And once you have built a wind farm it will continue to provide energy powered by the wind for a few decades (which is powered by the sun), without the need for material extraction or material inputs, and the faster this is done, the cheaper it gets, saving trillions of dollars [8]. 

A renewables circular economy is perfectly feasible, following the initial build out of the new infrastructure by mid century, with abundant energy from the sun powering the recycling needed to maintain and refresh that infrastructure.

Intermittency and grid stability

It is sad that Fressoz decides to play the it-doesn’t-always-shine card when he writes (p. 212):

“At the 2023 COP, the Chinese envoy explained that it was ‘unrealistic’ to completely eliminate fossil fuels which are used to maintain grid stability”.

… as though that settled the argument. They may have said this for UNFCCC (UN Framework Convention on Climate Change) negotiating reasons, but it is frankly pretty depressing that Fressoz shared this quote as though it reflected current informed opinion on power systems. 

Firstly, even fossil fuelled generation in the early 20th Century needed flywheels to level out energy supply, and in so doing, maintain grid frequency. Such devices can live on in a renewables dominated grid. More likely is the emergence of ‘grid forming inverter’ technology that can replace inertial forms of frequency response such as flywheels and turbines. 

Secondly, there are several other ways in which a grid that is 100% based on renewables can remain stable, including what is called ‘flexibility’ (including demand shifting), and distributed energy storage. 

The UK is rolling out a lot of battery storage, and these have the benefit of being able to be both large and small to support the network at local, regional and national levels. Battery Energy Storage System (BESS) technology is already making an impact in the UK, Australia and elsewhere [9] demonstrating the resilience that can be achieved in a well designed and well managed grid:

“Recently, a major interconnector trip sent the UK’s grid frequency plummeting. At around 8:47am on a morning in early October [2024], the NSL [North Sea Link] interconnector linking the UK and Norway, suddenly and with no warning, halted … with immediate and potentially disastrous impact on the UK’s electricity grid … battery energy storage systems (BESS) answered the call. Across NESO’s network [National Systems Energy Operator], 1.5GW of BESS assets came online to inject power into the system, bringing frequency to strong levels within two minutes.”

Far from renewables infrastructure causing a blackout, it prevented it. Other countries can learn from this (side eye to Spain!). 

A near 100% renewables grid is well within the reach of countries like Australia, and others are not far behind [10]

As the infrastructure scales up, additional storage will be added, to deal with rare extended periods of poor sunlight and low wind. The Royal Society has provided recommendations [11] on how to handle such extreme episodes. 

The Primary Energy Fallacy & Electrification

While Fressoz does talk about the efficiency arising from new forms of production and consumption, he does not really chose to provide any numbers (which is in stark contrast to the slew of numbers he uses when talking about wood, coal, oil, etc.).

He then makes the point (p. 214):

“In any case, electricity production accounts for only 40 per cent of emissions, and 40 per cent of this electricity is already decarbonised thanks to renewables and nuclear power.” 

He channels arguments that readers of Vaclav Smil will be familiar with. Telling us how hard it will be to decarbonise steel, fertiliser production, flying, etc.; no solutions, sorry. 

Even S-curves (that show how old technology is replaced by new) are disallowed in Fressoz’s narrative, because they are too optimistic, apparently, even though there is empirical evidence for their existence [12].

Just a ‘too hard’ message.

What he fails to mention is that the energy losses from using fossil fuels are so large that in electrifying the economy, we will need only about one third of primary energy hitherto needed (using renewables and nuclear). So, in the UK, if we needed 2,400 TWh (Terawatthours) of primary energy from fossil fuels, in an electrified economy powered by renewables, we’d only need 800 TWh to do the same tasks.

The efficiencies come both from power production, but also from end use efficiencies, notably transportation and heating. By moving to electric vehicles (trains, buses, cars) and heat pumps, we require only one third of the energy that has hitherto been used (from extracted coal, oil and gas). This is massive and transformational, not some minor efficiency improvement that can be shrugged off, as Fressoz does,

Green production of steel, cement and fertiliser is possible and in some cases already underway, although currently more expensive. Progress is being made, while flying is more difficult to crack. Together these sectors account for about a quarter of global emissions. Yet, road transport and heating together also represent about quarter of global emissions [13], and are easy to decarbonise, so I guess don’t fit into the book’s narrative. 

The surprise for many, who are effectively in thrall to the primary energy fallacy, is that we can raise up the development of those in need while not necessarily increasing the total energy footprint of humanity. We can do more and more, with less!

Who is deluded?

In his essay The Delusion of “No Energy Transition”: And How Renewables Can End Endless Energy Extraction, Nafeez M Ahmed offers an eloquent critique of Fressoz’s book [14].

A key observation Ahmed makes is that Fressoz’s use of aggregate numbers masks regional variations in a misleading way:

“Because he fails to acknowledge the implications of the fact that this growth is not uniform across the globe at all, but is concentrated in specific regions. The aggregate figures thus mask the real absolute declines in wood fuel use in some regions as compared to the rise in others. Which means that oil and wood fuel growth are not symbiotically entwined at all.”

Ahmed goes on to present the arguments about the different nature of the move to renewables, electrification of end-use and so on, in an eloquent and persuasive way. I strongly recommend it. 

Fressoz is right to claim that many have been seduced by a simplistic story about past transitions. His  book is very entertaining in puncturing these delusions, but he overplays his hand. Ahmed argues convincingly that Fressoz has failed to demonstrate that his methods and arguments apply to the current transition. 

Fressoz’s attempt to conjure up a new wave of symbiosis fails because he misunderstands and misrepresents the fundamentally different nature of renewables.

Is there a case for degrowth?

Of course, we do live in a world of over consumption and massive disparities in wealth (and over consumption does not seem to be a guarantee of happiness).

The famous Oxfam paper on Extreme Carbon Inequality from 2015 [15] showed how the top 10% of the world (in terms of income) were responsible for 50% of emissions, and the bottom 50% were responsible for 10% of emissions. An obscene asymmetry. As Kate Raworth argues in Doughnut Economics, we need to lift up those in need, while reducing the overconsumption of some that threaten planetary boundaries.

Yet we do not help those in poor countries by getting them hooked on fossil fuels. Indeed, renewables offer the opportunity to avoid the path taken by the so called ‘developed world’, and go straight to community-based renewable energy. This can be done – at least initially – without necessarily needing to build out a sophisticated grid: solar, wind, storage and electrified transport, heating and cooking is a transformative combination in any situation. We can increase the energy footprint of the poorest (providing them with the development they need), while reducing their carbon footprint.

Yet many want to play the zero sum game. True, there is a carbon budget (to remain below some notional global target rise in mean surface temperature, we cannot burn more than a quantity of carbon; the budget). We should share it out this dwindling budget fairly, but honestly, will we?

The game is nullified if people simply stop burning the stuff! The sun’s energy is functionally infinite (in any meaningful timeframe), so why not reframe the challenge? How about the poorest not waiting for, or relying on, the ‘haves’ suddenly getting a conscience and meeting their latest COP (Conference Of the Parties) promises? Countries like Kenya are already taking the lead [16].

Energy Independence and Resilience within our grasp

There are of course multiple interlocking crises (climate, nature, migration, water, and more). They are hard enough to deal with without claiming that energy should join them. 

The land use needed for our energy needs is small compared to what is needed for agriculture and nature, so again, renewable energy is not part of another fictitious zero sum game involving land use. 

A paper from the Smith School in Oxford [17] has found that wind and solar power could significantly exceed Britain’s energy needs. They found that even if one almost doubled the standard estimates of the energy needs (to cater for new demands such as circular economy, AI and synthetic meat in 2050), there were no issues with the area of land (or sea) required:

  • Solar PV 4% of British Rooftop
  • Solar PV 1% of British Land*
  • Wind Onshore 2.5% of British Land 
  • Wind Floating Offshore 4% of UK’s exclusive economic zone.

… and bearing in mind that 30% of land is currently used for grazing. 

The scare stories about prime arable land being covered in a sea of solar panels is politically motivated nonsense.

I gave a talk Greening Our Energy: How Soon, on how to understand how the UK has made the remarkable transition from a fossil fuel dominated energy sector to our current increasingly decarbonised grid, and how the journey will look going forward (and in a way that is accessible to lay people) [18].

In a world of petrostates and wars involving petrostates, there has indeed been repeated energy crises, and they will get worse while we remain addicted to fossil fuels.

Transitioning to a green energy future is the way out. It is already under way, we have the solutions. We just need to scale them up, and ignore the shills and naysayers.

Let’s not say or imply that solving the many injustices in the world is a pre-condition to addressing the energy transition.  This is the false dilemma that is often presented in one form or another, often from surprising quarters, including ostensibly green ones. It is a prescription for delay or inaction.

Achieving green energy independence and resilience might actually undermine the roots of many of those power structures that drive injustices, because energy underpins so much of what communities need: education, health, food, and more.

John Lennon seems to says it right in his song “Power to the people”.

© Richard W. Erskine, 25th June 2025

References

  1. More and More and More – An All-Consuming History of Energy, Jean-Baptiste Fressoz, Allen Lane, 3rd October 2024
  2. Historian Jean-Baptiste Fressoz: ‘Forget the energy transition: there never was one and there never will be one’, By Bart Grugeon Plana, Jorrit Smit, originally published by Resilience.org, December 2024, https://www.resilience.org/stories/2024-12-05/historian-jean-baptiste-fressoz-forget-the-energy-transition-there-never-was-one-and-there-never-will-be-one 
  3. Future of Earth, wikipedia, https://en.wikipedia.org/wiki/Future_of_Earth
  4. Energy: Engine of Evolution, Frank Niele, Shell Global Solutions, 2005
  5. The Fallacy of Perfection, Richard Erskine, essaysconcerning.com, 4th April 2024, https://essaysconcerning.com/2024/04/04/the-fallacy-of-perfection/
  6. Factcheck: 21 misleading myths about electric vehicles, Simon Evans CarbonBrief, 24th October 2023, https://www.carbonbrief.org/factcheck-21-misleading-myths-about-electric-vehicles/
  7. Future demand for electricity generation materials under different climate mitigation scenarios, Seaver Wang et al, Joule, Volume 7, Issue 2, 15 February 2023, Pages 309-332. https://www.sciencedirect.com/science/article/pii/S2542435123000016 
  8. Decarbonising the energy system by 2050 could save trillions – Oxford study, https://www.ox.ac.uk/news/2022-09-14-decarbonising-energy-system-2050-could-save-trillions-oxford-study 
  9. The role of BESS in keeping the lights on, Kit Million Ross, Solar Power Portal, 30th October 2024. https://www.solarpowerportal.co.uk/the-role-of-bess-in-keeping-the-lights-on/ 
  10. A near 100 per cent renewables grid is well within reach, and with little storage, David Osmond, Aug 24, 2022, https://reneweconomy.com.au/a-near-100-per-cent-renewables-grid-is-well-within-reach-and-with-little-storage/#google_vignette 
  11. Large-scale electricity storage, Royal Society, September 2023. https://royalsociety.org/-/media/policy/projects/large-scale-electricity-storage/large-scale-electricity-storage-policy-briefing.pdf  
  12. One in three UK car sales may be fully electric by end ‘23 as S-Curve transforms market, Ben Scott and Harry Benham, CarbonTracker, 5th January 2023. https://carbontracker.org/one-in-three-uk-car-sales-may-be-fully-electric-by-end-23-as-s-curve-transforms-market/ 
  13. Cars, planes, trains: where do CO₂ emissions from transport come from?, Our World In Data, https://ourworldindata.org/co2-emissions-from-transport (Our World In Data provides data on other sectors too).
  14. The Delusion of “No Energy Transition”: And How Renewables Can End Endless Energy Extraction, Nafeez M Ahmed, Age of Transformation, 24th April 2025, https://ageoftransformation.org/the-delusion-of-no-energy-transition-and-how-renewables-can-end-endless-energy-extraction/
  15. Extreme Carbon Inequality, OXFAM, 2015 https://www.oxfam.org.au/wp-content/uploads/2015/12/mb-extreme-carbon-inequality-021215-en-UPDATED.pdf 
  16. Doing development differently: How Kenya is rapidly emerging as Africa’s renewable energy superpower, Rapid Transition Alliance, 1 November 2022. https://rapidtransition.org/stories/doing-development-differently-how-kenya-is-rapidly-emerging-as-africas-renewable-energy-superpower/  
  17. Wind and solar power could significantly exceed Britain’s energy needs, Smith School of Enterprise and the Environment, Oxford University, https://www.ox.ac.uk/news/2023-09-26-wind-and-solar-power-could-significantly-exceed-britain-s-energy-needs
  18. Greening Our Energy: How Soon? Looking back and looking forward, to 2030 and beyond – A layperson’s guide, Richard Erskine, essays concerning.com, https://essaysconcerning.com/2024/12/21/greening-our-energy-how-soon-looking-back-and-looking-forward-to-2030-and-beyond-a-laypersons-guide/ 

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How much energy could a community generate itself?

In a talk I addressed the topic ‘Greening Our Energy: How Soon?’, using recent research [1] to show that the UK could be self-sufficient in energy using wind and solar alone, along with significant levels of long-term energy storage to ensure energy security. The talk also discussed  how electrification of much of our energy use reduces the overall energy demand, something that Mackay and others have talked about for years.

A question raised by an audience member was ‘How much energy could a community generate itself?’. This essay aims to answer this question, using my home town of Nailsworth as an example. As I said in the talk, the focus is on wind and solar.

When considering the total carbon emissions we are responsible for (so-called ‘consumption emissions’) studies [2] include literally everything. Including imported goods and produce. However, in terms of future UK generation, it is better to consider just the energy produced and consumed in the UK (the so-called ‘terrestrial emissions’).

We can narrow the scope further by considering those forms of energy consumption that are truly local and therefore best considered as being potentially met in whole or in part by community energy.

The two big ones are: 

  • electrified private cars and public transport (we’ll call these simply ‘transport’).
  • heat pumps used to heat our homes and offices.

In terms of carbon emissions, these two represent 60% of Nailsworth’s terrestrial emissions, and 40% of our consumption emissions, so highly significant, however they are viewed [2].

Credit: IMPACT: Community Carbon Footprint tool, Centre for Sustainable Energy (CSE)

According to Mackay [3], these would require energy consumption of 18 kWh and 12 kWh, respectively, per person per day in this electrified future world. The total including all energy needed would be 68 kWh/p.d and this is the figure used in the Oxford study referred to in my talk. So these two uses of energy would account for 44% of the total consumption of energy used.

The total of 30 kWh per person per day for transport and heating implies an average delivered power supply from community energy of 30/24 = 1.25 kW per person in Winter. In Summer we still need hot water but the great majority of heating is for space heating so we’d need about 12/24 = 0.5 kW per person in Summer for transport.

Nailsworth has a population of around 5,500, so let’s assume a future population of 6,000, which would imply a power supply required (for transport and heating) of 1.25 kW x 6,000 = 7,500 kW = 7.5MW in Winter, and 0.5 kW x 6,000 = 3,000 kW = 3MW in Summer.

Now the capacity factors for wind and solar in England [4]  are on average, respectively, about 40% and 3% in winter and 20% and 20% in summer.

The winter solar generation depends a great deal on the orientation of the panels – much more so than in summer. I have taken a relatively pessimistic figure, assuming on average East/West orientation, which still provides some energy in Winter but I have based estimates assuming wind alone meets the required demand in winter.

So let’s start with winter where we will discount solar [5]. Applying the capacity factor of 40% (in this case, dividing by 0.4) the 7.5 MW delivered energy would require 7.5MW/0.4 = 18.75MW of wind energy capacity to meet it. Let’s round that up to 20MW. 

For onshore wind turbines, we cannot use the largest ones available and are potentially restricted to say 5MW turbines. Only 4 of these would meet the power requirement of 20MW. Currently we have one 500kW wind turbine high above Nailsworth owned by Ecotricity.  Having established this precedent, and given changing public attitudes, and both Stroud District Council and Nailsworth Town Council having declared a climate emergency, one would hope this could be implemented, especially if it is a community energy scheme. 

Now, should we increase the capacity to deal with peaks in demand or lulls in wind? No, in my view. Community energy will be connected to the grid. When Nympsfield above Nailsworth is having a lull, other community sites around the country, and indeed large resources such as North Sea wind farms, will be able to take up the strain. 

A national energy storage strategy would deal with more extreme lulls that cover most of the country, as discussed in the talk.

Moving now to Summer, the four wind turbines proposed would deliver (now multiplying the wind capacity by the summer capacity factor), 20MWx0.2 = 4MW, so we’d need solar to deliver the remaining requirement of 7.5-4 = 3.5MW. Using the capacity factor for solar in Summer (at 20%, twice as good as the average for the year, 10%), that gives us a required solar PV capacity of 3.5MW/0.2 = 17.5MW. 

The average domestic solar PV installation in the UK has been 3.5kW, but with improved panels let’s round this to 4 kW. Assuming that the average home has 3 occupant, we anticipate 2,000 dwellings. They could provide a capacity of 2,000 x 4kW = 8MW, or about 45% of the solar capacity required. Yes, I know many live in flats, but the goal here is to look at broad brush feasibility. 

Ground mounted solar would then need to deliver 9.5MW. It’s been estimated that “Approximately 25 acres of land is required for every 5 megawatts (MW) of installation while 6 to 8 acres will be needed for a 1MW farm” [6]. So lets assume 1MW parcels at average of 7 acres each. We’d need 9.5 x 7 acres or about 70 acres. 

To give a sense of scale, Minchinhamption Common is 182 hectares or 450 acres, so we’d require the equivalent of 15% of it’s land area. This is not a proposal to use this common I should stress, just to give a sense of scale and feasibility. Nevertheless, shade (for our grazers and humans alike) will come at a premium by 2050 [7] so who knows?

This feels like a doable number.

To the extent to which domestic solar cannot be fully deployed, then ground mounted solar could be increased, or solar on commercial or civic buildings could take up the strain. I haven’t included these but they could make a substantial contribution (actually, are already making a contribution), albeit not necessarily being able to be classed as ‘community energy’.

The question naturally arises as to whether Nailsworth could use small hydro power using its streams, or as a mini Dinorwig, for energy storage, harking back to the Mill Ponds used during the 19th and 20th Century, when they provided some energy resilience to the wool mills of the town. It could of course play and role, and even if at a scale which is less significant numerically [8], could help in enabling local energy resilience [9]. There is strength in diversity, as nature teaches us.

Research on renewables offers up some pleasant surprises in how different forms of it can complement and support each other [10]. All of this is detail to explore of course.

My main goal in this essay was to establish if Community-based renewables – and specifically wind and solar – could compete in relevance with the large national assets such as North Sea wind, and thus provide a strong case for Community Energy schemes.

The answer is a definite yes.

Community Energy could provide a significant percentage (over 40%) of the terrestrial energy demand of a town like Nailsworth, throught the year. This would shift the control of energy, to a significant extent, away from large commercial assets, and could have untold benefits for local communities [11]. Nationally, such diversified and highly dispersed resources would enhance energy security for the whole country.

Richard Erskine, 6th March 2024

NOTES

[1] ‘Greening Our Energy: How Soon?’, Richard Erskine, Nailsworth Climate Action Network, https://www.nailsworthcan.org/blog/greening-our-energy-how-soon 

[2] IMPACT: Community Carbon Calculator, Centre for Sustainable Energy and the University of Exeter, https://impact-tool.org.uk/ 

[3] Mackay (2008), Sustainable Energy without the hot air, http://www.withouthotair.com/ 

3.1) Note that 68 kWh/p.d for a 70m population, say, in 2050 would amount to a UK energy demand per year of 68 kWh/p.d x 60m p x 365 d/y = 1,489 TWh/y – the total energy requirement that the Oxford Study shows can be achieved with wind and solar (actually, they show we could do double that quite feasibly with out excessive use of land or sea area).

3.2) Note that the (18+12)/68 = 0.44 or 44%

But be careful not to assume that means 44% of our consumption emissions being eliminated by transport and heating as it depends on the carbon intensity of different processes. It could be more or less. Actually, due to relatively efficiencies, moving to electrification of heating in particular and also transport, make very good contributions to displacing carbon-creating energy usage. As a percentage of our terrestrial emissions, transport and heating amount to about 60%.

[4] Estimating generation from Feed in Tariff installations, James Hemingway, DECC, December 2013, https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/266474/estimating_generation_from_fit_installations.pdf 

[5] For example, see https://leoht.co.uk/pages/how-much-do-solar-panels-generate-in-the-winter-  and also Sam Jeans, How much electricity will solar panels generate?, Federation of Master Builders, 6th November 2023, 

https://www.fmb.org.uk/homepicks/solar-panels/how-much-electricity-will-solar-panels-generate

[6] Everything You Need to Know About Solar Farm Requirements, Richard Burdett-Gardiner, 26th July 2023, The Renewable Energy Hub, https://www.renewableenergyhub.co.uk/blog/everything-you-need-to-know-about-solar-farm-requirements 

For ground mounted solar the area used has to take account of the spacing of tilted panels to allow for shadowing etc.

[7] Heatwaves such as those in 2022 will become much more common by 2050 on our current trajectory https://www.bbc.co.uk/news/science-environment-62207466 

So who know what solutions will be needed to provide shelter from the heat?

[8] I’m emotionally attracted to the gravitational storage / micro hydro idea. After all, the Mill Ponds around Nailsworth kept the mills running when the streams ran slack. It’s part of our history. But then again, Dunkirk Mill needed only about 16kW to run, a thousandth of what we are now considering, and even 20 of these would match the vastly greater energy footprint of modern society. The Centre for Alternative Energy’s Zero Carbon Britain report includes an estimate of 8 TWh of generation from hydro (including large and micro) for UK, so about 1% of the total.

[9] Assuming 20 reservoirs at 100m above their twins on valley floor, each holding 10,000 cubic metres of water, and a round trip efficiency of 75%, one could store about 40 MWh of energy, a not inconsiderable amount. If each reservoir used a 100 kW turbine (not the largest micro turbine but illustrative) then they would generate in total 2 MW, or nearly 30% of the Nailsworth average power demand, although at full power, the reservoirs would be exhausted in 20 hours. If larger turbines were used, the duration at full power would decline in proportion (eg. if 500 kW, then in 4 hours)

For storage, Micro hydro would have to compete with (or maybe, collaborate with!) domestic or small scale batteries. For example, if each household had a battery with 100kWh storage, then 2000 of these would equal 200 MWh, and would be equivalent to 200MWh/7.5MW = 26.7h, so about 1 day’s worth of storage. That again is pretty significant local resilience to augment a national massive (30 day) storage capacity discussed in the essay.

[10] While either micro hydro or batteries may have limited capacity, they could make an extremely significant contribution to balancing the local grid over a day or so, and that could in its turn relieve pinch points in the distribution grid when there are short term mis-matches between supply and demand. Indeed, I wrote a piece – Small Is Beautiful – local renewables and storage can catalyse the greening of grid – based on some modelling in the USA that showed that even small amounts of local solar could have a disproportionately large impact in enabling increasing grid-scale wind resources. Similar modelling of a diverse array of renewable assets could reveal other pleasant surprises.

[11] A Community Energy scheme could, if setup right, ensure that it incorporates energy security for all as a founding principle, using profits to help fund the restrofitting (insulation, solar, heat pumps, etc.) of poorly built or maintained accommodation and social housing, for example.

THE END

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