GF Blog 23 – Week 21

24th June

Our beaches – are they as beautiful as they look? Corrections & news in correspondence; Eden’s embarrassing moment; and an introduction to the magical plant, Inga.

I apologise for this. It wasn’t a deliberate plan to make you feel like escaping to the seaside from your desk, or sofa (or wherever you might be working today)! Just that I thought you would love the images, and even more that you would also love the sounds of skylarks from here on the hill.

I swam on Thursday evening from the little beach to the right as you look out at the bay. It is called Spit and lies just around the corner from Par Harbour. But also just around the corner from a sewage outfall and therefore I was really thinking how clean is this water? Officially ‘Good’ they say. But I am not reassured, having read recent info on the current performance of all water companies. Then I got home, to see a feature on TV and it tied in with correspondence received from Lin. She commented by email   A topic for your pipeline given the recent discovery of sea grass meadows in St Austell Bay and followed with a link about the Marine Heatwave and the combination of rising temperatures with pollution in the water.

This article addresses 2 different problems that seagrass beds are facing, first rising temperatures of sea water and secondly the proliferation of algae, due to high nitrogen and phosphate run-off from farmland and sewage releases.

We are told ‘At the time of writing, some areas off the coast of England are up to 5°C warmer than usual. ( This is a challenge because), unlike humans, plants cannot control their body heat. So higher seawater temperatures lead to increased respiration rates … and a greater need for food.

A higher respiration rate is not necessarily a problem for seagrass, if it has lots of light to photosynthesise effectively. The problem is that light is often limited in polluted waters.

Read on to understand how farm and sewage nutrients get taken up by algae, more swiftly and easily than by seagrass.

Algae populations continue to increase and form extensive blooms. The proliferation turns the water green, covers the seagrass leaves and smothers the habitat. This overload of algae prevents seagrass from photosynthesising at the rapid rate they need.  When the water becomes overwhelmed by excessive algae growth, seagrass struggles to keep pace and eventually deteriorates.

The conclusion, to no one’s surprise, is that we need to succeed immediately in reducing run-off from agriculture and sewage releases by water companies. I do not have a clue how ordinary folks can force this change to happen swiftly enough. Keep on reading about our water companies, making comments via all routes, and support Surfers against Sewage, are the only ideas I can think of.

Within the same report, there was a potentially more positive section too (below).  I would give you these as hyperlinks but have not been able to identify them online, sorry.

Other correspondence

I really hate to find out I have misled readers. Last week I failed in my accuracy, but it certainly was not intentional and I am ever so grateful that Bridget emailed to put me straight about The Slurry management challenge – which last week said the following:-

I met one of these tarmac trucks only a few weeks after I wrote up the Bennaman’s methane story.                      It was totally untrue that most of them were powered by Cornish farm methane. They had diesel generators and in actual fact, they came from Sunderland!!! … a whole crew & kit, imported to deal with all of our potholes.

2 years later & I can now share that Bennamans went on to hit a road-block (not literally) when they failed to get a major grant. They now cannot supply a system to the farms who want to participate in the project.

Let’s begin at the top, with ref to pothole repairs. I cannot change my main point; it really has been true that many of our smaller potholes get mended by teams imported from Sunderland. However, I have also been told, by a different source working for the council, another reason why the methane powered trucks faded away was the fire-risk they posed. This probably explains why Bennamanns are pursuing other uses, such as for a methane powered tractor. After 2 years I thought perhaps we would be further along than just seeing tests of one prototype, but apparently not yet.  Here is a little report

My real failure was in the lower section. This is what Bridget told me:-


 Your comment that they can’t supply due to failure of the grant is not really true.  They can supply, it’s just that at our farm we are not quite so willing to pay the higher price!  Lots of systems are being put in and they are properly scaling up, but didn’t get the chance to do a study with diverse farms to work through requirements as they’d have liked.  And they have never claimed all the road vehicles are powered by methane – not nearly enough methane yet – just that some are.

She continues re EV charging

Interesting about how words are used to make an argument.  You quote the green car people saying that the ratio of cars to points is greater than fossil fuels to their fuel points.  May be true but with a lot less EVs, then there can be a lot less charge points to claim that statistic, still making it difficult to find a charge point yet they still can say there are more when there are less!  And more cars on sale that are fast charging doesn’t mean there are more on the road, as many have already been sold. My Dad misunderstood and found his car takes a longer time to charge than he expected so now won’t be using it as extensively as he thought he would.  In the winter the electric is sucked up by heating and he therefore needs several more charge points for a car trip than he needs for his diesel car trip – therefore the proportion needs to be significantly higher for EVs than there are diesel pumps to service the same number of cars. 

Thank you again Bridget.

Whilst with the EV thread, an event for helping to discover more about solar, batteries and EVs is the upcoming Chacewater Nature Recovery, Local Food, Green Energy ~ Retrofitting, and Electric Vehicle Day Saturday 15th July 2023, Chacewater Village Hall TR4 8PZ.  This is a wonderful hall, supported by an enthusiastic community, so seems like a great date for the diary.

Eden Project’s Embarrassing Moment

Our local BBC News on Monday evening took me right back to the date of the Space Launch at Cornwall Airport. This is the danger, if you blow the trumpet with such a level of ‘noise’ and a little glitch occurs. No wonder the founder of Eden Project, Sir Tim Smit, looks glum there!

Still, the overall trend is in the right direction. A replacement fuse is being swiftly couriered down from Aberdeen apparently, and in equal haste Smit tries to reassure that geothermal provides a much more reliable source of power compared to other renewables!

The main headline of their press release intrigued me – A landmark moment for renewable energy took place at the Eden Project in Cornwall today, Monday June 19, 2023, as the UK’s first operating deep geothermal heating plant since 1986 was switched on and is now generating heat.

Who started off in 1986? And what has happened to their scheme. Well governments in the 80s were actually fairly switched on. I was amazed to read of the foresight at Southampton City Council, which is put into wider context by Wikipedia here

Southampton District Heating Scheme

In the 1980s, the United Kingdom Department of Energy undertook a research and development programme to examine the potential of geothermal aquifers in the UK. However, after some initial success drilling a well in the Wessex Basin in 1981, it was deemed too small to be commercially viable. The project was abandoned by the Department of Energy, but Southampton City Council refused to let the project fall and took the decision to create the UK’s first geothermal power scheme. This was undertaken as part of a plan to become a ‘self sustaining city’ in  promoted by then leader of the city council, Alan Whitehead

The scheme was eventually developed in conjunction with French-owned company COFELY District Energy and the Southampton Geothermal Heating Company was then established. Construction started in 1987 on a well to draw water from the Wessex Basin aquifer at a depth of 1,800 m (5,900 ft) and a temperature of 76 °C (169 °F).[6]

The scheme now heats a number of buildings in the city centre, including the Southampton Civic Centre, the West Quay shopping centre, Royal South Hants Hospital, Solent University and the Carnival offices; and is part of an enlarged city centre district heating system that includes other combined heating, cooling and power sources. As of 2011 the district heating and cooling scheme provides annually 26 °CGWh of electricity and over 40 °CGWh of heat  Brine from the geothermal well provided 18% of the total district heating mix, with fuel oil (10%) and natural gas (70%) making up the rest. The electricity generated from the scheme is used by Associated British Ports via a private electrical connection to the Port of Southampton, with any surplus electricity sold back to the grid.

What did I do next? Of course I phoned Southampton and a really helpful man answered. AJAY directed me to this page and so I was feeling confident this particular snippet of CLIMATE HOPE is real. Congratulations to Alan Whitehead.,and%20connect%20to%20each%20other

Back to Eden

Just a little later in the day this came back from Eden team. Glad to receive my corrections in time!

Hello Caroline     Great question about 1986 and thanks for getting back in touch.

We are the first and, currently, the only. This is the first deep geothermal project to actually produce anything since Southampton opened in 1986, which is currently offline.

For reference, Jubilee Pool is at 400m and augmented by heat pumps, so not strictly deep geothermal. United Downs finished drilling its geothermal wells in 2019 and their electricity plant is due to be coming on line in 2024.   Hope that helps!  

The use of underground heat is expected to save Eden Project around a third of its current energy costs and Smit believes this is the way forward to grow food anywhere in the UK. “It’s far better to use our great skills to grow more than we need. I don’t think we have seen such an exciting time (for food production) like this since probably just before the First World War,” he said. Being Dutch by birth, I was not surprised that Smit mentions, in the press release, that Holland has always operated geothermal for greenhouses, and they are predicting an ability to meet 20% of all their heating needs this way, by 2050. Expanding on the theme, Philip Kent, Director at Gravis Capital Management, said “In other countries, like the Netherlands and France, geothermal is making a serious contribution to achieving net zero and energy security targets. With the right policy support, the UK has a huge opportunity to benefit from a resource that can meaningfully contribute to the de-carbonisation and improved security of our electricity and heat systems.”

Dr Joerg Baumgaertner, technical delivery partner for the project and CEO of Bestec (UK) Ltd said: “The deep single well coaxial heat exchanger which we start today is in itself an exciting experiment, which will provide insight and valuable data of this specific technology which we expect to become an important addition to the wide spectrum of geothermal clean energy applications.”

If I interpret this correctly, it means they are aiming to generate KW too.

Smit waxes lyrical about the potential for future UK geothermal and is echoed by the local MP – “I have been talking to ministers for several years and the Government is looking seriously at how that can happen and what support it may need from Government to ensure it plays its part.”

However, the engineers working on the Eden Geothermal project say Government is currently too slow at supporting their work with plans to connect to the National Grid being set to happen at the earliest in 2036.

Gus Grand CEO of the Eden Geothermal scheme says 13 years is a “hugely long time to wait” and if the Government wants to be hitting its net zero goals “it’s got to be faster”. (NB Same old arguments, inevitably …)

Introducing Inga, as described in Science Direct:-           

Inga is a type of legume, with at least 300 different varieties. Several species produce pods with seeds surrounded by a woolly, slightly juicy edible pulp. The most widespread and most cultivated species is Inga edulis, which is now so dispersed that its exact area of origin is uncertain. Inga capitata has a much thicker and woody pod and is a native of the Guianas and Eastern Amazonia. The fruits of many other species of Inga are used locally throughout tropical America. The pulp is eaten raw, and the seeds are spat out.


Anyone who followed the Ceremony 4 Climate Hope in March should recall the students learning about ways to restore soil quality in tropical rainforest areas. It was a revelation then, to find the founder of Inga Foundation living in our parish of Lanlivery. It was perhaps ten times more of a revelation to visit Mike Hands last Wednesday and hear his life story, a journey of such dedication and determination, which is beginning to pay-off at last.

Mike started out on a career as a surveyor but around the age of 40 he felt driven to change direction and that would really mean some new, intense advanced study. He was welcomed by Cambridge Uni (my old place) and took about 4 years or thereabouts to pursue a part time research MSc. His theme was to address the damage caused by repeated cycles of ‘Slash and Burn’ (S&B), finding new ways to farm more sustainably for the planet and for the 300m or more indigenous people, engaged in such practices.

His research work is summarised in this article

Hands 1988 The ecology of shifting cultivation. MSc thesis, University of Cambridge, concentrated on the role of soil phosphorus and attempted to resolve (issues) … The Cambridge Alley-cropping Projects (1988–2002) continued this theme and threw light on the question of sustainable food production in rain forest environments.

Honduras, Slash & Burn plus image of maize crop produced through Alley Cropping

The key to success in regenerating depleted soils proved to be a cocktail of minerals, of which the most significant is phosphorus. But it was not simply a case of applying it as a chemical fertiliser; it is needed either in a Rock form (Rock Phosphate) or as a result of absorption into the leaves of a unique plant, as described by a charity called Rory’s Well, which works in Sierra Leonne. I have adapted their text, adding a few points that I learned from Mike:-

The Inga Alley Cropping System

Large quantities of tough Inga leaves absorb Phosphorus from atmospheric dust and (when pruned and allowed to decompose)return the Phosphorus to the ground between plants. By creating 4m wide gaps between rows of trees on a hillside or plain (Alley ways, or Alley Cropping) the cut-off leaves build up in the alleys, producing a rain resistant mulch containing other key nutrients,            reducing the effects of heavy rain and retaining large amounts of moisture. The mulch prevents invasive grasses and other weeds developing and – as the Inga is also nitrogen fixing – this reduces the need for chemical fertilisers. The result will be at least 4 different types of organic crops, some for food (maize, beans etc), some as cash crops (black pepper, turmeric for example), some companion fruit trees (cacao, avocado, rambutan, citrus) and finally some re-forestation of valuable tropical hardwoods.

These outcomes are life-changing so you might expect that to be putting the biggest smiles on people’s faces, but in actual fact any local farming family will tell you the thing they love best of all is the great firewood, gathered when the cut branches have been stripped of leaves for the mulch.

Rory’s Well again

After pruning, all leaves are deposited in the alleys to build up a bed of biomass, recycling key nutrients and retaining large amounts of water. Crops are planted in the biomass and receive benefit      from the mulch and nitrogen stored on the Inga roots.
Wood harvested from pruning the Inga trees provides excellent firewood for cook stoves, less time is spent collecting and carrying firewood, less deforestation occurs and clean burning Inga is less     smoky/harmful than other sources of fuel.

The Extra Magic Ingredient known by the team as ‘La Mezcla Magica’

Originally, at the San Juan site in Costa Rica, after 4 years, micro-plots were well established. The soil was tested for responses to N (as ammonium nitrate) and, separately, to a mix of cations comprised of dolomitic lime (Ca, Mg and trace elements) and ‘K-Mag’ (MgSO4 + K2SO4), but no significant improvements were found. Then (much later) in the Cambridge/Honduras project, it was found that the Inga plants would become far more healthy and lush if they did receive these extra nutrients. Why?  Because there had been as many as 20 cycles of Slash and Burn here, quite different from the Costa Rican scenario (secondary rain forest for at least 25 years prior to the Inga planting operation).


We need more people to know about these 2 charities and to support them. It is ground-breaking CLIMATE HOPE work they do, (both literally and figuratively!) and – thinking ahead – maybe we should nominate them together, for the Earthshott Prize in 2024? 

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