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Upgrading houses to be cooler in summer, 3 ⁰C warmer in winter using half the CO2 – for free

By Tim Martel

A third of our greenhouse gas emissions are from heating. We need solutions that save more than 50% of the CO2 given that our country’s target is to reduce CO2 by 80% by 2050.  The UK has a very old building stock, Victorian houses are common and about 80% of the housing stock that will be around in 2050 is already built today so solutions are needed for our current buildings.  Over the last 4 years I’ve been working with the AECB, the Association for Environmentally Conscious Builders and have been finding low energy retrofits are surprisingly cost effective when accurate calculations are done which include co-benefits. I’m a Chartered Architectural Technologist, Passivhaus Designer and a tutor for the AECB’s Carbonlite Retrofit course.
So firstly what co-benefits are we talking about? When an eco-renovation or retrofit is done, the owner gets much more than energy savings. They’ll have a smarter, more comfortable and possibly more stylish house which they are likely to heat warmer than before and the comfort is likely to be a main reason. Heating savings would pay for a large part of the work, but you wouldn’t expect heating savings to pay for improvements in style or an increase in living temperature. The typical average temperature in UK houses during the heating season is 17⁰C so we assumed they’d want 20⁰C after the retrofit and they would be willing to pay a little bit extra for that.
Not all energy calculations are the same. There is usually quite a large difference between the energy performance of the design of a building and the actual performance in use, called the ‘performance gap’. The Green Construction board say that typical performance can be double the EPC, the energy figure produced by SAP calculations.  The AECB’s REALcosting software was used for this study eliminates this performance gap by using the much more accurate Passivhaus Planning Package for energy calculations and it also gives indicative costs for the work.  Energy costs were compared over the next 30 years in today’s money.
The graph below left shows that all the retrofit options are cheaper than the existing house. What has become clear is that money to pay for the project is not a problem; over the life of the building there are more than enough energy savings to pay for a high standard of deep retrofit, including heat recovery and triple glazing.

Heating, maintenance and capital costs over 30 years for a semi-detached house using External Wall Insulation (EWI)

The same data plotted over time. Owners will change but the building life after retrofit is expected to be in the range of 60-100 years based on replacement rates of current buildings.

The issue is more how to spread this cost out so that the occupants who pay for it get the benefit.  Even houses 100 or more years old are likely to have at least another 60 -100 years of life because existing houses that are structurally sound are not usually replaced that often. That timescale is usually much longer than the interest of one owner, who is unlikely to be concerned beyond 30 years.  The Passivhaus Institute have a solution for this, they call it ‘Incremental Retrofit’ where the house is retrofitted in stages over many years according to a plan. At the end of the planned time the owner (not necessarily the original one) will have a Passivhaus, and this spreads the cost over a long timescale while starting to add benefits immediately. Owners would start to have a building easier and less costly to heat; and the same insulation that keeps houses warmer in the winter can also protect them from overheating in the summer.

Low Carbon Policies

A personal view from Fred Miller,  Nov 2016


There is an urgent need for national policies to achieve goals that are essential to tackling climate change. We need to be aiming for a per capita emissions rate of greenhouse gases of two tonnes of CO2e 1 per person per year.  This is a rate of per capita emissions that is quoted by the economist Nicholas Stern 2 and others, taking into account the equitable budget of carbon that we have available in order to avoid dangerous warming.

Although, it is hard to effect change on an individual level, it is useful to have this figure in mind, to have some idea of what we are aiming at. If you scale up that figure, you can get an idea of what the population of  Gloucestershire should be aiming for, in the entirety of its emissions, including what we buy from elsewhere.3 This is truly challenging.

But I was inspired by a recent talk by Prof. Kevin Anderson 4, Professor of Energy and Climate Change at the University of Manchester, who itemises relatively simple and achievable objectives to rapidly bring our emissions down. The question is how can we in Gloucestershire help to achieve such policies ?

These first two points are lifted directly from the talk given by Prof. Kevin Anderson in 2016 5 .  The next two draw from other sources.

1. Reduce the need/demand for energy: ‘POWERING DOWN’        ……….and thereby reduce energy demand by 40 – 70 % :     

Housing:  We could retrofit housing at a cost of £40,000 per house so that they are low-energy and low-CO2 emitting, and are better adapted to the changing climate, as well as solving fuel poverty. (10 – 20 % of all households are in fuel poverty). This will cost 2% of GDP but would create a lot of jobs and training, and is regarded as an effective and quick way for £££’s to be spent on emission reductions.

Put in progressive metering tariffs, so that the more you use, the more you pay per unit (above a threshold of basic needs). At the moment, people who are on low incomes in rented housing (using less energy) have to pay more per unit of electricity with pre-pay cards etc. This is grossly unfair.

Fuel efficiency of cars:    Create a maximal standard of fuel efficiency for all new cars (i.e. less than 100 g CO2 per km) . The average in the UK is 185 g of CO2 per km, but 85 g-per-km-cars are now available. As two thirds of vehicles in the UK are less than 5 years old, this would create very rapid change. And if we bring in vehicle electrification we would transfer the energy supply for transport to renewables (which generate electricity).  We also need to invest in and improve emission-free buses.

Electrical goods:    Create highest efficiency standards (A+++) for all electrical equipment. An ‘A+++’ fridge uses 80% less energy than an ‘A’ rated one. These are standard in Japan. A saving of energy ‘at the plug’ scales up to at least five times that back at the power station, because of the losses of energy in generation and transmission.

Individuals’ energy consumption: Support major behavioural change focusing on the 10% of the world’s population who are the highest emitters. The Oxfam report (Extreme Carbon Inequality 6 ) highlights the fact that the richest 10% of the world’s people are responsible for 50% of carbon emissions, and if they merely lowered their level to the average European, it would reduce carbon emissions overall by 33%!

A moratorium on airport expansion

2. Maximise renewables: ‘POWERING UP’

  • Sustainably exploit the huge renewable potentials, e.g. by putting solar panels on all south-west facing roofs, which would generate a third of all UK electricity. (and, I would add, continue with building wind generation capacity)
  • Rapid re-tooling of the oil industry into a renewables industry
  • Electrify household heating and transport which are two of the biggest users of fossil fuel. Electrification helps the transfer to a renewable supply (which generate electricity rather than make fuels)
  • Roll out smart grids, intelligent metering and community energy which enable better tracking and monitoring of energy use.
  • A moratorium on new fossil fuel developments


 3. ABSORB CARBON….in soil and rocks

  • Increase soil organic content through the grazing and arable practices of agro-ecology and ‘restorative farming’, habitat restoration, and tree planting. Carbon can be sequestered at rates of 1 – 10 tonne per hectare per year, as well as improving local resilience to floods and increasing food supply. This is a known technology by which to sequester billions of tons of carbon 7  and increase local production of food to reduce food miles.
  • Absorb carbon in the rocks:    Explore Carbon Capture and Storage in geological deposits, linked to industries such as the steel industry and solar panel manufacture, perhaps using oil wells in the north sea.



  •  Food imports such as soya feed for livestock, and palm oil for food products, are causing deforestation of the Amazon and the burning of Indonesian rain forests and peat lands. These represent huge carbon emissions, and while it is right to change land use in the UK, it is meaningless if we ignore these off-shore land-use related emissions.
  • Cease the global transportation of plain simple food products that can be produced more locally.

Notes and references

  1. CO2e stands for CO2 equivalent.  Different gases have different strengths in their greenhouse effect. A unit volume of methane has much more effect  than the same amount of CO2. It is a more powerful greenhouse gas. The gases – methane, NO2, and HCHC (and some others) –   are given a rating of how much CO2 they are equivalent to. With this common unit of measurement these greenhouse gases are comparable in their forcing effect and they can then be added in to the mass of CO2 to give the CO2 equivalent – CO2e
  1. Nicholas Stern, Blueprint for a Safer Planet, 2009
  2. Population of Glocs. is about 850,000 . So the emissions we should be heading down towards is 850,000 multiplied by 2 tons, equals 1,900,000 tons per year. But I have not yet been able to find an estimate of the Glocs. total actual emissions.


  1. Kevin Anderson is Professor of Energy and Climate Change at the University of Manchester and Deputy Director of the Tyndall Centre for Climate Change Research
  2. See this 45 Minute lecture by Kevin Anderson, given in 2016 touching on carbon budgets, the Paris Agreement and some suggestions for ways forwards.
  3. Oxfam: Extreme Carbon Inequality
  4. See for example:

– Graham Harvey, ‘The Carbon Fields’, and ‘Grass fed nation’, 2016, icon books. Methods of concentrated grazing followed by periods of rest, are said to build soil carbon at astonishing rates, alongside the planting of herb leys, and crop rotation (largely abandoned by modern farming).


Posts on these blog pages are the personal views of the authors only and are not intended to represent any agreed or general view on the part of

Carbon Capture and Storage (CCS): vital technology or greenwash fable?

A personal view from Hugh Richards

In May 2016, Shell produced a publication [1] containing the following:

. . . the ambition contained within the Paris Agreement offers little room for flexibility. It implies dramatic and simultaneous shifts in both the composition of energy supplies (with extraordinary growth of lower- and zero-carbon energy sources, including renewables, nuclear and fossil fuels with CCS) and the way whole sectors and individuals use energy . . . All this needs to be achieved over the course of this century, although a mid-century date will loom large as policymakers consider the 1.5 °C ambition coming from Paris. And it assumes CCS is actually deployed. If it isn’t, then we are left to deal with a clear message from IPCC Assessment Report 5: “Many models could not limit likely warming to below 2 °C if bioenergy, CCS and their combination (BECCS) are limited.”

It goes on to say:

To limit the temperature rise to 1.5 °C would require [global] net-zero emissions around 2050, followed thereafter by net-negative emissions. Most pathways for 2 °C require [global] emissions reductions beginning by 2020. Every year society delays action to substantially and steadily reduce global emissions brings forward by at least a year the point at which emissions of CO2 must reach net zero.”

It is hard to take issue with much of this, with the possible exception (for some) of the underlying assumptions about growth in global population and energy demand, or the projected increase in nuclear power and/or the use of fossil fuels with carbon capture and (geological) storage (CCS) – perhaps particularly “BECCS”.

Shell point out that, as well as being an option for decarbonising electricity generation, CCS is the only plausible option for decarbonising large industrial processes, steel-making and cement manufacture. CCS does not yet exist at scale, yet Shell use a projection in which energy from fossil fuels with CCS outstrips nuclear by the mid- to late 2030s. Is this credible for a technology that adds major costs and reduces the useful energy obtained, compared with unabated fossil fuel use?

Shell’s response is that CCS faces “a number of non-technical challenges, especially in relation to permitting and financing. To get CCS off the ground at scale, favourable geology must be combined with socio-political support and financing mechanisms.”

After interviewing David Hone (Chief Climate Change Adviser at Shell), the writer and activist George Marshall wrote in 2014: [2] “Maybe CCS can work. I hope it does . . . My fear, though, is that CCS is less of a real solution than a much-needed narrative ploy [of the fossil fuel industry] . . . For narrative purposes, CCS does not need to work on a large scale . . . It scarcely needs to work at all. All that is required is . . . a few demonstration sites, some chunky reports. And then lots of creative storytelling about human ingenuity.”

In November 2016, the Oil and Gas Climate Initiative (OGCI), which includes BP, Shell, Saudi Aramco and Total, announced a 10-year $1bn fund, some of which will contribute to CCS development. Compare this with the £1bn “saved” by the UK Government in cancelling a large-scale CCS demonstration project, and it’s not hard to understand the accusation from some quarters that the OGCI money is just “greenwash”, costing very little in comparison to the contributors’ annual expenditures.

So how should people concerned about climate change regard CCS? Should we advocate for it, as we do for renewable energy, or oppose it as a “smokescreen” by the fossil fuel industry to allow it to carry on extracting as if climate change were not a threat? Should we praise companies like Shell that publicly accept the challenge that climate change presents, or regard their output on climate change (including CCS) as “greenwash”?

Despite being more informed than most people about CCS (but not an expert), I am genuinely unsure how to answer these questions. I would like to see more informed public dialogue on the subject, and especially a reasoned response by CCS proponents to the “greenwash” accusation (if they can muster one).

As a geologist, I tend to agree with Shell that the main barriers to up-scaling CCS are not technical but political and financial. In my ideal world, we would be moving swiftly towards a position where extraction of fossil fuels is only permitted if the extracting organisation undertakes or funds equivalent CCS to make the operation carbon-neutral. Perhaps this approach could be pioneered in the UK as a way of negating the climate change impacts of starting to exploit shale gas (or making it uneconomic to do it at all). If Government funding is needed to get CCS started, perhaps it should be first directed towards industries that command wide public support, such as steel-making, rather than giving a life-line to coal-fired power generation, or supporting dubious bio-energy schemes.

With its favourable offshore geology, increasing stock of depleted offshore oil and gas reservoirs and associated infrastructure and expertise, the UK may be well-placed to become a leader in CCS, with all the socio-economic benefits associated with a major infrastructure initiative, provided a politically acceptable way can be found to pay for it. In September 2016, a UK Parliamentary Advisory Group (containing members with backgrounds ranging from Shell to Friends of the Earth) published a remarkably positive report [3] on why and how CCS should and could start to be implemented in the UK, without delay. Perhaps as the political narratives in the UK and elsewhere start to favour investment in infrastructure, opportunities to make CCS a reality may start to open up.

Coincidentally, there is even a Gloucestershire dimension to all of this. The International Energy Agency’s body for managing CCS R&D ( is based in Cheltenham.


[1] Shell: A Better Life with a Healthy Planet: Pathways to Net-Zero Emissions, May 2016 (available online).

[2] George Marshall: Don’t Even Think About It: Why Our Brains are Wired to Ignore Climate Change, Bloomsbury, 2014.

3] Oxburgh: Lowest Cost Decarbonisation for the UK: The Critical Role of CCS. Report to the Secretary of State for BEIS from the Parliamentary Advisory Group on CCS. September 2016 (available online).

Posts on these blog pages are the personal views of the authors only and are not intended to represent any agreed or general view on the part of

The Beloved Beech

by Fred Miller

This morning I decided to  take a closer look at some beech woodland near me. It is a familiar part of the surroundings here in Gloucestershire, which I have taken for granted, but it is apparently threatened by climate change.

Recently published research in the journal ‘Global Change Biology’, shows that beech trees are vulnerable to drought. Lead researcher, Professor Alistair Jump of Stirling University is quoted as saying:
“As our climate continues to warm, droughts will become more frequent and more extreme. Beech forests across Europe will be hit increasingly hard, with a high risk of widespread mortality when the next big dry spell hits – particularly in southern parts of the UK.”

I wandered into Penn Wood from Selsley Common, overlooking Stroud. It was sheltered from the cool wind, and was quite dark. I saw illuminated patches where sunlight came through gaps in the canopy and small scenes were lit up as if by a spot light. One such scene comprised a hazel tree with bright hoverflies resting on its leaves. One hoverfly had been caught in a spider’s web, and was motionless. The spider came over to investigate it, but went back to its waiting station. Perhaps the fly was too big for it to tackle. A speckled wood butterfly landed on another spot-lit leaf.

The huge great trunks rise upwards to dizzying heights, grey and smooth. The bark does not have fissures like other trees do, but it does have ripples like liquid on it sometimes, formed perhaps by the stresses and strains of swaying in the wind, and it has wrinkles around the ‘eyes’ of the old side shoot scars, where former branches have died away in the shade to give us the smooth tall bole. The life story of the tree is etched in its scars and lumps, some of which form hollows, and are made into nest holes by woodpeckers, and offering great places for beetles to live.

I sat on the damp dark-brown soil and listened for a while. The wind made the trees sigh and whisper above, whilst here at ground level it was calm and still. Bird calls came through from above: the ‘kyak kyak’ sound of a nuthatch, the whimsical flutings of a robin, the squeaky yelping of jackdaws, and the rough ‘cor’ of crows from out in the wind.

Looking out horizontally between the trees, I could see glimpses of the view out over the vale below. The great flattish layers of leaves formed windows through to blue sky and the distant horizon. Perched here I felt high up, level with the middle of a giant tree not so far away rising from ground further downhill. On the crest of this slope, looking out, I felt ready to soar out like a bird on the wing, perhaps a croaking raven !

On walking back, my feet crunch on some of the trees’ seeds, known as ‘beech mast’. The path is covered in them. Inside the nut is a tasty kernel, and I feel like a mouse as I nibble one. There must be plenty of voles and mice, scurrying and hidden in the ivy on the forest floor. Peering out of their cover, they see the huge trees silhouetted overhead; the beech makes their world, anchoring and nurturing it. It clothes these steep stony slopes and holds it with its roots.

For the  sake of the beloved beech and all that rely on it , let’s take climate change seriously.