During the last year or so, the percentage of ‘green zealots’ in M&S research has risen from 3-4% to nearer 8%. Henley also sees a figure of 8% for the two greenest groups ‘principled pioneers’ and ‘vocal activists’. A further 31% (Henley Centre) or 30-35% (M&S) are actively concerned and want to adjust their behaviour. There has also been a big growth in this group in the last year.

In both surveys another third are aware of environmental and ethical issues, but are unlikely to take active steps unless pushed. A final quarter or so don’t care very much. M&S says that they are ‘struggling’. Henley calls them ‘disengaged’.

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Consumers do not generally see climate change as the most important environmental and ethical issue

M&S’s strikingly ambitious Plan A has five sets of targets. Only one of these relates to climate change. M&S emphasises the hierarchy of consumer concerns that drove it towards the wide spectrum of targets in the 100-point Plan.

1. Food and Health: consumers want food to be made from high quality ingredients, with no additives and minimum amounts of salts, saturated fats and other undesirable ingredients.
2. Ethical sourcing: M&S customers generally want to buy goods that are made and sold under what might be called ‘FairTrade’ conditions. Suppliers are paid properly, workers are not exploited and environmental damage is minimised.
3. Better recycling, less packaging
4. Climate change

M&S commented that Food and Health was ‘way out on its own’ as an issue, but other concerns have been creeping up to match it. Respondents to its surveys are now much better informed about environmental issues but ‘there’s still an awful lot of confusion’.

M&S customer segmentation work throws up 4 groups:

• A: Green zealots: people who will actively seek out the most ethically and environmentally responsible products. Climate change is particularly important issue to these people.
• B: Those interested and concerned, but often uncertain how to shop to achieve their ethical objectives.
• C: Aware of the problem, not certain that their actions can have much effect or that they need to shop differently.
• D: Struggling, do not give high priority to issues covered in Plan A.

The company gives some approximate figures for the numbers in each group compared to the numbers of three years ago.

Marks and Spencer consumer segmentation

The key change in the last few years has been the move from group C to group B. The A family has grown substantially but still remains a small percentage. The strugglers have largely remained in the same group. To put it in simple terms, the mainstream M&S customer has shifted from a C to a B. This makes Plan A seem entirely logical, though I think the company may actually be moving somewhat faster than its customers. Plan A almost seems to suggest that M&S thinks that its core shoppers are just about to shift to Group A.

M&S’s numbers have great similarity to those produced by the Henley Centre in mid-summer.

Henley Centre consumer segmentation

Henley makes the point that consumers in group A will already be choosing their goods and services with care. Group B will tend to make the same purchase decisions, though they may be less vocal about their preferences. Group C will not take active measures themselves, but Henley says that they will not object if companies selling to them ‘edit out’ products that do not meet reasonable ethical or environmental standards. This is consistent with M&S’s view that its customers wanted the chain to take positive actions to improve the environmental attributes of the products its stores sold, even at a small increment in the price.

Perhaps the two main features of these research findings are:

• Trusted brands do have some freedom to take less environmentally acceptable goods and services off the shelf. Three quarters of the population accept that issues such as climate change should affect what is selected by retailers for sale.
• The zealots are growing in number, but don’t yet form a mass market for most products and services. Products like British Gas’s Zero Carbon tariff (covered in Carbon Commentary Newsletter #1) will be taken up by this group, but will struggle to penetrate beyond this demographic.

Separately, Henley comments that the most concerned consumers do not strongly congregate in a particular age group, social class or region of the country. This finding is entirely consistent with other surveys. Boden mums in Surrey may not be any more likely to search out ethical brands than middle-aged male teachers in Gateshead. This makes ethical marketing more difficult because target audiences do not correspond well to well-understood existing demographic segments. It will be interesting to research what TV the zealots watch and which web sites attract their regular attention. My guess is that these consumers are disportionately members of ethical pressure groups such as WWF and Greenpeace. The Friends of the Earth mailing list is going to get more valuable.

The Ceres fuel cell (on the left) is incorporated into an ordinary domestic condensing boiler (on the right)

Ceres promises reductions in utility bills of £300 a year and 2.5 tonnes savings in carbon dioxide for the typical UK house. Our short report shows why we think that these savings are unlikely even in the most appropriate UK installation. In fact, the emissions reductions are likely to be minimal and the reductions in the electricity bill will not easily justify the approximately £1,000 extra cost of the CHP cell.

Micro CHP is a difficult proposition. Other companies have found that it is hard to make substantial savings in domestic installations. CHP is not well suited to rapidly fluctuating and unpredictable demand for electricity and hot water.

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What is micro CHP?
The logic behind CHP is that almost all electricity generation methods involve gross inefficiency. A large coal-fired generating station might only convert 35% of the energy in the fuel into electricity. The rest is lost as heat. An average of 7% of all electricity is then lost in the transmission networks, emitted as heat or electromagnetic radiation. A combined heat and power plant captures the lost heat and uses it to warm buildings or heat water. Big CHP plants exist in the UK, and in much greater numbers in northern Europe. Micro CHP devices are attempts to replicate these plants at the scale of a single household. The core financial proposition is that the householder generates valuable electricity using inexpensive gas.

Why is it difficult to make CHP work, either in terms of reduced emissions or lower bills?
Home electricity demand fluctuates every second. All small generation technologies find it difficult to adjust to this. Unless surplus power can be sold to the electricity networks, CHP devices lose money from using gas to make electricity with no value. In the UK, unlike Germany and other countries, the money paid for feeding electricity into the grid is negligible. There is very little prospect of so-called ‘feed-in’ tariffs improving in the UK. Secondly, the household has to have a use for the heat that is produced as a by-product of generation. In most micro-CHP, the heat is dumped into the hot water tank, which may or may not need it. Thirdly, most CHP devices, including Ceres, are slightly less efficient (converting fuel into useful outputs) than a new condensing boiler. There just isn’t much of a gain from installing a tiny CHP plant.

Past experience
Field trials of other micro CHP devices have proved inconclusive. In some cases, fuel bills went up as a result of installing the technology. In the large majority of cases, the savings in carbon emissions were low. Ceres claims its new technology, which is based on a relatively new type of fuel cell, is much better. I accept that its fuel cells may be excellent at delivering efficient generation of electricity, but I think that in domestic homes the savings are likely to be as disappointing as previous technologies.

The ideal Ceres CHP installation
The new Ceres CHP power plant delivers between 300w and 1 kW of electric power, responding to the level of electricity demand in the household. 300 W is equivalent to a two large TVs operating simultaneously. 1 kW is a typical power use for an electric heater.

To have maximum value to the householder, the electricity demand of the home should be a constant 1 kW. This would enable the CHP plant to deliver a high and consistent efficiency and maximise the savings.

When it was generating 1 kW of electricity, the CHP plant would also be delivering approximately 1 kW of heat to the hot water tank. About 0.4 kW would be wasted, partly in the form of unused heat and partly in electricity used to drive the CHP plant itself.

• The input cost of 2.5 kWh gas is about 6.25p.
• The hourly output of the CHP appliance (1 kWh electricity and 1 kWh heat to the water tank) would cost about 13.8p.
• So the hourly saving would be about 7.45p. Grossed up, this is £653 a year.
• The saving in CO2 is about 1.3 tonnes a year.

These are the absolute maximum savings attainable with this boiler. To get these savings the CHP plant needs to be working at 100%, or exactly 1 kW all the time. This means the house has to have an absolutely constant electricity demand. This is, of course, an unreasonable assumption; typical domestic demand fluctuates every second and falls to very low levels at night and when the house is empty. If the CHP plant is working flat out it will deliver 8,760 kWh a year, or over two and a half times the UK average for a domestic property. A large house might well have aggregate demand this high, but not consistently. Secondly, the house also has to need about 8.760 kWh of heating for the hot water tank. This is a very high level for a UK property and unlikely to be used except in houses with a large number of occupants.

What about the benefits of installing the CHP cell in the typical UK property?
The typical UK house is thought to take about 3,300 kWh of electricity a year, far lower than the level discussed in the preceding paragraphs. (This conventional assumption is used in all advertising and in product comparisons. It is out-of-date and 3,700 would be a better figure.) If this demand was exactly constant, it would mean that the CHP plant would need to deliver 377 watts of electricity all the time, and provide a similar amount of hot water heat. I calculate that the annual savings from using the Ceres CHP plant, above and beyond those installing a good condensing boiler are still quite large, though not as great as if the CHP cell worked constantly at 1 kW.

• £249 in reduced electricity charges, net of a smaller increase in gas bills
• 0.55 tonnes of CO2

These figures are much lower than those provided by Ceres, which suggests figures of £300 and 2.5 tonnes of CO2 for a typical installation. I want to stress that the savings that I estimate also assume absolutely constant electricity demand and a perfect match between the amount of heat provided and household needs for hot water. Of course, real households have rapidly and erratically varying electricity needs and more consistent, but still highly unpredictable, hot water needs.

The other reasons why the Ceres forecasts of carbon and cash savings are unlikely to be met
I have suggested so far that the maximum saving from using the CHP stack would be achieved in a very big house with stable electricity demand and very high water needs. In the average UK house, needing 3,300 kWh of electricity a year, stable electricity demand and full use of the hot water heat, the CHP plant would save some carbon dioxide and a reasonable fraction of the home energy bill, though not as much as Ceres suggests.

Now I want to go to show that the rapidly varying electricity demand in an ordinary household, combined with the likely pattern of hot water need, will mean that a Ceres CHP plant will not save the householder significant sums of money or avoid much carbon emission.

There are six principal reasons for my scepticism:

1. The Ceres CHP plant does not react instantaneously to changes in electricity demand. According to a company spokesperson, the stack may take over 5 minutes to adjust its output to the level of demand in the house. This is an extremely important failing. The chart below shows how demand in a typical house might vary over the course of an hour.



The swings in demand are sharp. The ‘baseload’ of the typical house might be 150-200 W or so, depending on the number of appliances on standby and other factors. When major appliances are switched on, the amount of electricity taken by a house will instantaneously rise to 3 kW or more. A kettle, for example, uses 3 kW, and is on for about 3 minutes. A dishwasher has quite low demand for part of its cycle, but uses large amounts of electricity when it is heating water. Refrigerators are using electricity some of the time, but not at other points. To give the most obvious example, if the Ceres CHP plant adjusts its output with a lag of five minutes, it will completely fail to meet any of the extra demand ever created by a kettle or a toaster. These two devices alone might be as much as 7% of electricity demand in some houses.

The output pattern of a CHP stack based on a fuel cell is likely to look very roughly like the dotted green line in the drawing below. The stack is often supplying power when it is not needed, but at other times is failing to meet the household’s demand.



This reduces the household’s savings in electricity consumption, perhaps significantly. (Please note: the relatively small Ceres plant can only ever produce 1 kW, so not only would the output lag demand, but it will not meet the peaks.)

2. The Ceres power-generating stack will generally not generate electricity at a level below 300 W. In many houses, but not all, the baseload electricity demand is well below this minimum level. The Ceres machine can either be programmed to turn itself off when demand is lower than 300 W, or it can simply ‘spill’ the excess production back into the electricity network (for which the householder will generally not get paid). When I questioned Ceres about this, I was told that in most households, for most of the time, background demand is 300 watts or more. Ceres has done substantial work on the profile of household demand, so I defer to their findings. Nevertheless, it is worth pointing out that a household taking 300 watts all the time uses over 2,600 kWh a year on baseload alone, out of a total electricity use of 3,300 or 3,700 kWh.

In my view it is inherently unlikely that baseload demand is such a very high fraction of total demand. (People often mention the high ‘standby’ demand of consumer electronics when discussing baseload, but total use from this source is very unlikely to exceed 50 W in the average house, or perhaps 60 W in houses with a Sky box. The underlying point is this – a household that is careful and economical with its electricity is unlikely to have a base demand as much as 300 watts. For households, buying a Ceres CHP plant means that a lot of electricity is going to be lost to the outside network or the Ceres machine will simply not be working most of the time.

3. And, perhaps more importantly, the Ceres power plant cannot generate more than 1 kW. Most domestic households will frequently exceed this level during the average day. Any domestic appliance that heats water (kettle, dishwasher, tumble dryer, washing machine) uses two or three kilowatts for a substantial part of their operating cycle. At those times, the Ceres CHP will be able to fulfil only a small fraction of total electricity demand. Similarly, any machine with a large motor (a vacuum cleaner) or heating elements (toasters) will generally use much more than 1 kW. The Ceres unit will be unable to cope with these peaks. I don’t have accurate figures but I suspect that electricity consumed in a typical house at times when total demand is over 1 kW may be as much as 30% of total usage. This demand is completely unmet by the Ceres device.
4. The CHP plant responds to electricity demand; the useful heat produced goes to the hot water tank. On days when not much electricity is produced, not enough heat will get to the hot water tank. Households use hot water primarily for washing. This does need does not fluctuate much each day. But electricity use varies greatly. It varies by time of year (winter higher than summer), it varies by the day of the week and by the hour of the day. At times, the heat produced when the CHP plant is generating electricity will not be enough to cover the hot water needs of the house. When I asked about this point, Ceres responded by saying that the central boiler will make up any deficiency. And indeed it can in most circumstances. But imagine the following scenario: water is taken from the tank at 10.30pm for showers. From that point on, electricity generation is very limited, largely because the house is on baseload use, probably less than 300 watts. The CHP plant may not be operating at all until the household gets up again in the morning. Therefore the central heating boiler will heat the water instead of the CHP device, so that the tank is ready for any morning draw of water. This is fine, but then the CHP plant is needed to generate electricity during the day. If the water is already hot, there will be nowhere for the heat to go and it will have to be dumped, or the CHP plant turned off. Once again, this will reduce the cash and carbon savings of the device.
5. An analogous position arises when the house needs a lot of electricity and little hot water. Imagine a big house with only two people in it who only take brief showers. Electricity demand is high, but hot water need is low. In these circumstances, the CHP plant will have to dump the heat or turn itself off. Savings will be small.
6. When the household is not present, the CHP machine will have to be turned off, or waste all its heat. A house has continuing demand for electricity when unoccupied (perhaps when the household is taking a holiday) but not for hot water. The continuing demand may be lower than the 300-watt minimum, in which case the CHP plant may be off anyway, but it will still be wasting heat.

Our conclusions
The Ceres plant is an extraordinarily impressive piece of technology. It has solved major problems in applying fuel cell technology to small-scale installations and at low cost. Unfortunately, I think that the household savings are unlikely to be anywhere near as large as the company hopes. This will severely restrict potential demand.

All these schemes are ‘offsets’; they seek to counter-balance the impact of human activities with schemes to reduce CO2 elsewhere. The technology optimists believe that one or more of these techniques can completely counteract human effects. The cost often seems very reasonable – in the billions rather than the trillions – and the technological challenges seem not insuperable. The pessimists say these schemes will have huge unintended effects, possibly worse than climate change itself, and that toying with ‘geo-engineering’ projects, as they are called, simply delays the day that the world starts to realise it must cut fossil fuel use. Geo-engineering deals with the symptoms, not the causes, of global warming. And none of the proposed schemes deal with the adverse effects of higher CO2 concentrations, such as increased ocean acidity.

This article argues that all the major geo-engineering proposals have substantial pitfalls, but that it makes clear sense to increase the research funding into these schemes. The opponents and proponents of geo-engineering have got locked into an almost theological debate as to the ethics of climate modification but this argument should be secondary to the need to have well-defined back-up plans in the event of increasingly rapid deterioration of the global climate.

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Geo-engineering
The idea of geo-engineering has a long history. John von Neumann thought that climate modification could be used to ensure drought in the Soviet Union during the Cold War. Von Neumann later foresaw ‘forms of climatic warfare as yet unimagined’. More peaceful schemes for climate modification in the 1960s included spreading heat-absorbing soot across the Arctic ice in order to encourage melting and eventually increase temperatures across northern Canada and Siberia. In the 1970s the US military made a failed attempt to increase rainfall over the Ho Chi Minh trail to impede movement by North Vietnamese forces.

By the 1970s scientists were already beginning to propose schemes for future emergency remediation of the atmosphere to counter rapid increases in temperature or other effects of global warming. Contrary to many people’s impressions, scientific papers on the dangers of fossil fuel burning began to be written as long ago as the late 1950s.

The main ideas for geo-engineering to counter global warming have evolved gradually, usually over a period of decades. They can be divided into two main categories: improving ocean take-up of carbon and reflecting more of the sun’s energy.

• Ocean seeding of iron to increase plankton growth and sequester carbon.
• The Lovelock scheme is a variant of this.
• Mirrors in the upper atmosphere to reduce the amount of the sun’s energy reaching the earth.
• Increasing the reflective aerosol content of the upper atmosphere, also to reflect more sunlight.

Seeding the oceans with iron
In some parts of the world the growth of ocean plankton is impeded by a lack of iron in the water. The advocates of ocean seeding say that seeding the ocean with more iron will enhance the growth rate of micro-organisms. Many experiments have confirmed that this is the case. This growth absorbs carbon. Approximately half of all photosynthesis on the planet is carried out by plankton, so this form of carbon capture is potentially extremely useful. It is also true that in many parts of the world’s ocean plankton volumes appear to have fallen substantially, partly as a result of the warming of the oceans. So improved iron availability in the water may restore some part of the missing plankton. Increased plankton availability may also improve the volume of fish and birds up the food chain.

This much is largely agreed; the arguments come over whether the plankton stores carbon for a significant period of time.

The proponents of ocean seeding of nutrients say that when the organisms die they will sink to the ocean bottom and the carbon in their cells will be stored for centuries. The sceptics respond by expressing doubts as to whether the plankton sink, or simply rot near the surface; or, if they do sink, whether the carbon will be stored on the sea floor. So far, the evidence supports the sceptics.

This hasn’t stopped attempts to use carbon sequestration by plankton as a commercial opportunity. Planktos, a US company, is just about to start an experiment by tipping one hundred tonnes of powdered iron into the Pacific, not far from the Galapagos Islands. The company sees the project as an attempt to understand whether seeding the ocean with iron can sequester carbon for long periods. Success would enable the company to start selling commercial offsets. Its critics say the experiments are just another form of pollution.

The dangers from the project are probably quite limited. The increase in oceanic iron will be measured in parts per trillion or less than the impact of Chinese sandstorms on the iron content in the western parts of the Pacific. This year’s experiments by Planktos will probably show significant plankton growth, but are unlikely even to begin to convince the sceptics that the carbon taken up will be stored productively. But if it were to work, it would surely be quite inexpensive per tonne of carbon sequestered.

Plankton blooms off the coast

The Lovelock scheme
James Lovelock – along with Chris Rapley of the Science Musuem – proposes that the world considers placing millions of vertical pipes several hundred metres long in the world’s seas and oceans. Cold water would come to the surface as a result of a one-way valve and the upward and downward moving of the pipe. Cold water from the deep contains more nutrients and the scheme is intended to encourage the growth of tiny sea creatures such as salps. These organisms excrete carbon-rich waste, which then falls to the ocean floor. As with the iron dust idea, the increased growth of sea-level organisms helps to capture carbon. Once again, the key question is how long the carbon is held for before returning to the atmosphere.

The scientists behind the proposal think that the pipes may also have the effect of increasing algae growth. This will add to the ocean’s output of dimethyl sulphide, a chemical known to stimulate cloud formation, possibly helping to block sunlight from reaching the earth.

Lovelock and Rapley don’t propose this scheme because it is the best way of dealing with climate change. They seem to be advancing the idea in despair at the slow pace of political endeavours to check emissions growth. By coincidence, their scheme is in the early stages of commercial development by Atmocean, a US company based in New Mexico. As with Planktos, the immediate commercial applications of this technology seem non-existent. Their entrepreneurial drive must be based on a view that the carbon market will eventually reward businesses like these two for sequestering CO2. It has to be said that this is a brave gamble.

Mirrors in the atmosphere
The global warming impact of increased atmospheric CO2 can be counterbalanced by decreasing the amount of solar energy reaching the earth’s surface. Instead the light energy could be reflected. The percentage of the sun’s energy that needs to be reflected is quite small; perhaps one or two per cent.

This could be done by placing billions of small mirrors in the high portions of the atmosphere reducing the amount of light energy getting to the earth’s surface. Despite this idea resurfacing regularly at scientific conferences, there appears to be no large-scale research trial planned.

Sulphate or other aerosols in the high atmosphere
Fine dusts thrown into the atmosphere reduce the strength of the sun’s rays reaching the earth. We know this works because of the measurable impact of large volcanic eruptions that have spewed small particles into the air. The explosion of Mount Pinatubo in 1991 chilled the world by about 0.5 degrees the following year. Sulphates can be used as a countervailing pollutant to CO2.

Edward Teller, the main proponent of the US ‘Star Wars’ missile defence programme, wrote an article in 1997 suggesting that blasting enough reflective dust to chill the atmosphere would only cost a billion dollars a year.

This idea received powerful support over the last year from Nobel scientist Paul Crutzen who advocated further research into sending light-reflecting particles such as sulphates to the edges of the atmosphere. He and others have stressed that they view such schemes as last resorts but that the world needs to research these ideas further because of the possibility of extremely rapid warming at some stage in the future.

It does seem clear that we need to research this idea, however unattractive it seems. Blocking a portion of the sun’s rays does not reduce the CO2 in the atmosphere so problems such the increasing acidification of the oceans will continue. The eruption of Mount Pinatubo did cool the world, but it also significantly changed rainfall patterns, causing drought in some areas.

In 1971 British meteorologist Hubert Lamb said that before we engaged in geo-engineering it would be ‘an essential precaution to wait until a scientific system for forecasting the behavior of the natural climate…has been devised and operated successfully for, perhaps, a hundred years’. He was right, but we probably don’t have the luxury of waiting.