The Zero-Carbon House E-Book

Martin Godrey Cook

• Herausgeber: Crowood
• Kategorie: Lebensstil
• Sprache: Englisch

Veröffentlichungsjahr: 2011

Beschreibung

Zero Carbon' is an abstract concept for most people, but we have lived energy-profligate lifestyles for too long on finite fossil-fuel resources. We now face potential environmental catastrophe from climate change and global warming, with a continuing exponentially expanding global population that doubles every four decades. The capacity of the planet to reabsorb carbon dioxide is about two to three tonnes of carbon equivalent per person at current population levels of seven billion and therefore there is a desperate need for us to reduce our carbon footprint. A way of helping to achieve this is to live in a zero-carbon house, and this will become UK legislation for new homes by 2016. This fascinating book covers all aspects of the zero-carbon house, from its evolution to achieving carbon neutrality in old and new homes as well as entire communities. Includes an overview of zero carbon and how to achieve it on a global scale; covers communities of zero-carbon houses and provides inspirational examples of low-carbon lifestyles. Case studies show how principles are put into successful practice to save energy, carbon, money and the environment.

Leseprobe

THE ZERO-CARBON HOUSE

MARTIN GODFREY COOK

Contents

Title Page

Dedication

Acknowledgements

Preface

1 Zero Carbon

2 Evolutionary Houses

3 Old Houses

4 New Houses

5 Earthships

6 Communities

7 Lifestyles

Appendix: Top Twenty Tips

Glossary

Further Information

Copyright

DEDICATION

For Molly and Lucy

ACKNOWLEDGEMENTS

I should like to thank all the members of the RIBA Sustainable Futures Committee for their stimulating company over the years, not to mention the fierce email debates over the definition of ‘zero carbon’ and many other cutting-edge topics. Particular thanks are especially due to Bill Dunster OBE and Mark Elton RIBA for their help with material for the BedZED and Hyde House case studies, respectively. I think we have now reached a consensus on the definition of good architecture as the three ancient canons of Marco Polio Vitruvius plus sustainability. We will resist all attempts to place adjectives such as ‘green’, ‘eco’ and ‘sustainable’ in front of the term ‘architecture’ for as long as we meet!

I should also like to thank the many owners, architects and other agents of case study zero-carbon houses, who were generous with access and material, particularly John Christophers RIBA. John’s refurbished and extended Victorian terraced house in Birmingham, England, gives a glimpse of the carbon-neutral future for the existing housing stock, in the United Kingdom and elsewhere for that matter – possibly even Birmingham, Alabama, USA.

Internationally, I am grateful to Michael Reynolds AIA for access to Earthships in the UK and abroad, and Jaime Lerner, architect and former mayor of Curitiba for his open discussion at the British Film Institute in London, after the screening of the documentary film A Convenient Truth: Urban Solutionsfrom Curitiba, Brazil towards the end of 2009. The scientists and authors, Stewart Brand and Jim Love-lock, deserve particular mention for the insights that their consistently wise and thought-provoking books have provided me with over the years. The many other publications that have influenced me are given due credit at the end of this book.

Closer to home, I should like to offer my sincere thanks to Crowood for their sound advice and infinite patience during the preparation of this manuscript. Finally, infinite thanks are due to my family for their constant support, and I hope that this publication goes some small way to help to secure a sustainable future for the younger members of my wider family.

Preface

The idea of reducing your carbon emissions to zero is a challenging prospect, but far from impossible to do in your house, prospective or existing, old or new. Our domestic energy use and associated carbon dioxide emissions are a good place to start, as at least three-quarters of the houses we live in now will still be with us in 2050 – the year that dramatic carbon-reduction targets are usually set for. So, the impact of new dwellings is limited – maybe they should be less-than-zero carbon.

The imperative to reduce our collective environmental impact was never more important, as global population continues to grow and more people indulge in profligate lifestyles – business as usual is not an option, on an international level. Indulgent lifestyles are so last-century and threaten to deplete diminishing resources – it is churlish to reduce your carbon footprint at home and then splurge your reductions on luxuries such as long-haul air travel – take the train or ship instead!

Our behaviour is clearly an important aspect of our response to environmental warning signs, such as the depletion and extinction of animal species, many of which it is difficult to see how we could survive without, such as the humble bumble bee. This book gives some consideration to these aspects in its first and final chapters. But the main thrust is the zero-carbon house and how it is achievable in old or new building stock.

Chapter 2 gives a brief description of the evolutionary and theoretical attempts at zero-carbon houses, or zero-energy or autonomous houses as they were called in yesteryear. This quest started almost a century ago, just as we were becoming increasing less sustainable, due to cheap electricity and fossil fuels, and was spurred on by the energy crisis of the 1970s. There is much to learn from the history of the quest, and it is sobering to think that global population has doubled to seven million in the four decades since our last earnest attempts at domestic sustainability.

Chapters 3, 4 and 5 deal with existing, new and communities of zero-carbon houses – the latter is clearly an essential aim to release economies of scale in our quest to reduce our impact on the planet: one-planet houses for one-planet living, and survival. Chapter 5 is devoted to Earthships, first pioneered by the New Mexican architect, Michael Reynolds in the 1970s – for which he was in turn vilified and, latterly, praised by the American Institute of Architects. The recently produced documentary film of his quest, Garbage Warrior, is essential viewing.

Treat the earth well: it was not given to you by your parents, it was loaned to you by your children. We do not inherit the earth from our ancestors, we borrow it from our children.

Oglala Sioux proverb

CHAPTER 1

Zero Carbon

To be modern is to find ourselves in an environment that promises us adventure, power, joy, growth, transformation of ourselves and the world – and, at the same time, that threatens to destroy everything we have, everything we know, everything we are.

Marshall Berman (1982)

INTRODUCTION

‘Climate change is the biggest threat that our civilization has ever had to face up to’. These words were uttered recently by Professor Sir David King in a BBC radio interview. The former Chief Scientific Advisor to the UK Government went on to say that he thought climate change was a bigger threat than terrorism – an existential threat, but one that we are not focusing upon – it is too abstract and seems far off into the future. We focus on threats like terrorism and nuclear weapons, as existential threats that are immediate and tangible. They are easier to focus on than the beguilingly abstract threats of global warming and climate change, which are also serious and increasingly immediate existential threats.

King went on to cite recent events that showed the existential threat of climate change, such as the summer of 2003, which was the hottest on record, and in which 32,000 people lost their lives. It was the largest single natural disaster in Central Europe in recent times, but it was not recorded as such because it played out over several weeks, rather than happening in a media-friendly instant. Although there is no doubt that the media plays its part in sensationalizing scientific predictions, not always helpfully, perhaps.

Sir David King was equally controversial in his views on the invasion of Iraq, and regarded oil as the primary driver for what he called the first of the modern ‘resource wars’ – a friendly government is needed in Iraq to ensure continued supplies of cheap oil, in his view. In particular, he cited the United States of America, who use roughly a quarter of the world’s oil production and have an economy that is based on the availability of cheap oil. Iraq is geographically situated on a very large amount of the remaining conventional supplies of oil, a fact that was thrown into sharp relief by the need to drill a mile beneath the sea in the Gulf of Mexico, for closer reserves of oil – a technically challenging endeavour that can easily go badly wrong.

The USA is an easy target in terms of carbon addiction, but we are all mainlining on fossil fuels. The States could have ameliorated their image by signing Kyoto, but even those nations who did, such as Britain, are not meeting their targets. The UK Government recently admitted that they will fail to meet their 2010 carbon dioxide emissions targets. On a more positive note, Sir David does not view the recent conference in Copenhagen as a disaster for action on climate change – quite the contrary, actually. Although a global protocol was not produced, everyone turned up, including 150 heads of states and all the larger nations, and a document that takes us forward was formulated. Developing countries, such as Indonesia, have committed to reduce their carbon emissions by 26 per cent; Brazil said that they will stop all deforestation and start reforestation by 2025 – and a large part of our rising carbon dioxide emissions are from deforestation.

King was of the opinion that long-term infrastructure and the built environment were the most important issues, such as coal-fired power stations that should be replaced with power sources that do not emit carbon dioxide, for the next half-century. Renewable energy sources, such as solar, wind and water power are ways of doing this, but so is nuclear. That the latter may be a necessary evil, in the medium term, to reduce carbon emissions is a view held by an increasing number of eminent scientists, such as Sir David King, himself; James Lovelock, inventor of the Gaia theory; and David Mackay, who is the UK Government’s chief advisor on climate change and global warming. Mackay is completely unconvinced that decarbonization with renewable energy alone can be done, and certainly not quickly enough. On less controversial ground, there is no doubt that we need to build a zero carbon-built environment – and there is no place like starting at home with a zero-carbon house.

Linear versus circular systems – the holistic zero-carbon house.

PROGRESS AND GROWTH

At the beginning of the twenty-first century we find ourselves potentially careering towards ecological and environmental catastrophe on a global scale – which obviously also threatens concomitant social and economic disaster. The triple bottom line of the new mantra of sustainability is environmental, economic and social sustainability. In the case of the latter factor, the extraordinary progress of modernity, science and technology – spurred on by military rivalry at the worst of times and more benign technology races at the best of times – has allowed a rapidly burgeoning global population growth. Our increasing numbers have, until recently, remained a taboo subject in sustainability circles – too sensitive a subject, perhaps, to admit that fecundity might have an impact on our targets to reduce our carbon emissions. This factor is now recognized and UN population growth projections are published that push out to the twenty-third century – mid-range estimates show an optimistic levelling of global population, eventually.

UN mid-range prediction of population growth until 2200.

As it ever was, some would say, and it must have appeared a similar scenario a century or so ago when the previous century had wrought a quadrupling of the UK population, for example, with massively increased urbanization. The success of the industrial revolution’s ability to feed its expanded population, through industrialized agricultural methods, made this possible – inconceivable to Thomas Malthus as he wrote his famous essay in 1798. Those historic times had their own problems of poverty, pollution and economics, but we are still linked to those old notions of progress through growth, fuelled by fossil fuels. Ironic then, that the first industrial mills were sited next to watercourses, as the only viable source of sufficient power before the invention of the steam engine – a renewable energy world that we are now striving hard to reinvent.

The greenhouse effect.

The cooling factors.

We are also still linked to those historic times by our continuing population explosion, to the extent that global population is now doubling every forty years, has reached seven billion, and is set to rise to nearly ten billion by 2100 or earlier. The last two centuries of this extraordinary progress and growth was fuelled by fossil fuels, first mainly in the form of coal, and the last hundred years or so by oil and gas. The planet’s finite fossil fuel resources took million of years to create, and ultimately come from the power of the sun, through photosynthesis in ancient vegetation. These unique reserves are effectively the ancient sunlight of past eons of time, which we are tapping into at a phenomenal and unsustainable rate as our numbers increase and ‘carbonize’. Ironically, some of this carbonized industrialization also provides cooling factors to counter the familiar greenhouse effect diagram.

Fishy Business

We are currently fighting a war against the remaining stocks of fish in our oceans, and we are winning with the use of technology and efficient, but destructive, techniques such as beam-trawling that leave the ocean bed looking like a desert. Our once bountiful oceans are proving less sustainable than we thought, due to our continuous onslaught. In the early 1990s the apparently unlimited supplies of cod off the east coast of Canada were found to be on the point of extinction, and a moratorium on fishing was the only way to try and save them – they are not rebounding quickly. The situation is not much better in European waters, where relentless fishing of bluefin tuna has resulted in catches declining by 80 per cent over the past decade.

Large-scale industrial fishing began in about 1950, with the result that experts estimate that the once relative abundance of large fish is now reduced by about 90 per cent. These are clearly contentious claims and disputed by those with a vested interest – but there is consensus over many species, such as yellowfin and skipjack tuna in the Pacific Ocean. The latter are decimated, and the argument is only over the scale of the destruction – somewhere between 70 and 90 per cent reductions on 1950 baseline estimates. The basic problem is too many high-tech, industrial fishing boats, which are continuously and very effectively hunting down every known edible species of fish – too much demand pursuing an increasingly limited supply. Global fishing fleets could catch the world fish population four times over, and electronic and sonar equipment leaves fish with nowhere to hide.

Bluefin tuna has an ancient lineage and once sustained Roman legions in battle – it is now in the frontline itself, as the species is hunted to extinction. Additionally, spotter planes are being used to find shoals of bluefin, which are then fished out by fleets of boats. The fishing-out of certain species results in an unsustainable imbalance in local ecosystems, as their natural predators or prey species decline. This gives dubious benefits in some cases, such as the burgeoning population of lobsters in Finland, but also leads to phenomena such as jellyfish infestations in other waters. Oceans that were once full of large fish are now filling up with plankton.

Experts predict that, if current trends are allowed to continue, stocks of fish that we now eat could collapse by 2050. However, we understand much more about what is happening to fish populations than we did as little as five years ago, so we can do something about it. Alaska is a good example, where they are restricting their fishing fleets’ capacity to the resource available, and giving fishermen limited seasons to fill their controlled quotas of fish. Consumers can control excesses by demanding to know where their fish comes from, how it was caught and whether it is endangered, to bring about positive changes. For example, pollock is a potential substitute, which should allow cod populations to increase – choices consumers make will have an effect on marine diversity.

Fish farming is an intensive agricultural solution, but it uses smaller, wild fish to feed larger species, such as salmon. Actually eating the smaller fish, such as anchovy and herring, is more sustainable and optimal. Marine reserves are also being established to provide sanctuaries and areas where commercial fishing is completely banned – but they will not completely solve the problem. Political will is necessary to bring about sustainable fishing policies, and the industry has to abide by them – and we must only eat sustainable seafood. Research suggests that fish droppings help oceans to absorb carbon dioxide – linking over-fishing with global warming and climate change.

POPULATION

The word Malthusian conjures up an infamous and unpopular concept, originating as it does from the work of the Reverend Thomas Robert Malthus (1766–1834) and his essay on the principle of population first published in 1798, and then republished several times in successive revised editions until 1826. Malthus thought that the dangers of population growth would preclude endless progress towards a utopian society, summed up in his pronouncement that ‘The power of population is indefinitely greater than the power of the earth to produce subsistence for man’. He thought that the increase of population is necessarily limited by the earth’s means of subsistence; that population invariably increases when the means of subsistence increases; and that population would be kept equal to the means of subsistence, by what he called ‘misery and vice’.

Malthus cited the geometric or exponential progression of population growth, which was already beginning in the early nineteenth century, as industrialization and urbanization burgeoned, contrasted with the arithmetic or straight-line growth of the means of subsistence or food supply. Malthus’s detractors point to the fact that population has grown exponentially since he expanded his theories, and that he could not possibly have conceived of the technological advances that humankind has achieved, not least in the field of agriculture and food supply. However, the technological progress that has allowed human population to grow exponentially is heavily based on a carbon economy and finite fossil fuels. A reverse exponential curve could apply to our rapid depletion of these resources, particularly as population growth continues to explode.

Exponential and linear progressions.

To Bee or Not to Bee

Bees arrived on the earth 20 million years before humanity, but now they appear endangered by our activities. Scientists have discovered that pollination levels have dropped by nearly a half in some plants over the last twenty years – this ‘pollination deficit’ could herald reductions in crop yields. The decline in the bee population is seen as the equivalent of the canary in the mineshaft – an indicator species to which we should pay some attention. They are essential to the reproductive process of most plants (about 80 per cent) as they cross-fertilize pollen from one flower to another. Climate change has probably created a seasonal mismatch between when flowers open and when bees emerge from hibernation.

The honeybee is our oldest friend, as one in every three bites of food depends on them – without them we are left with only rice, corn and wheat. Our livestock also depends on them for their diet. Their increasing and mysterious disappearance carries an important message for us – our activities are unsustainable. Bees in England are disappearing faster than elsewhere in Europe, with more than half of the hives dying out in the last two decades. The UK Government is funding a £10 million research programme to try and find out what the factors are behind the vanishing bees and other insects.

As our agricultural systems became industrialized, so did the industry of the bee hive, with industrial-scale hives being transported across countries and continents – from the almond groves of California to the blueberry fields of Maine, to seasonally pollinate such crops. A few years ago many beekeepers began noticing an alarming disappearance of their bees – many empty hives but with no dead bees in them. Scientists began to name the disastrous phenomenon ‘Colony Collapse Disorder’ (CCD), while attempting to get to the bottom of the malaise. The novelist Leo Tolstoy stated many decades ago that the workings of the honeybee hive were beyond our comprehension, but that didn’t stop us experimenting with it to improve efficiency – splitting hives and artificially inseminating queen bees in our efforts to increase productivity.

The rate of attrition of the honeybee is high, with more than a third of the British bee population estimated to have disappeared. The number of beekeepers has declined to combine with disease, intensive and monocultural agriculture, and modern pesticides to decimate the humble bumble bee. Loss of the bees’ natural environment, such as herb-rich meadows and heather moorland, over the last half-century has also reduced the number of bees. American scientists believe that all these stresses lead to a reduced immune system in bees – this, coupled with further distances to travel to find nutrition, leads to bees dying outside the hive, or possibly even losing their way and being unable to get back to their hives. Scientists at Sussex University are trying to decode the ‘waggle dance’ that bees make when returning to the hive, which is thought to inform worker bees of the location of food sources, giving the direction and distance to the source that the bee has just located.

The problem of environmental pollution was first mooted in the early 1960s by authors such as Rachel Carson, whose book Silent Spring referred to the death of songbirds as a result of pesticide poisoning, and the ensuing lack of birdsong. Pesticide chemicals were described by Carson as coming out of chemical warfare research during the Second World War. Almost accidentally, some of the chemicals were found to be fatal to insects and were then used as pest controls. She concluded that ‘The control of nature is a phrase conceived in arrogance, born of the Neanderthal age of biology and philosophy, when it was supposed that nature exists for the convenience of man…. It is our alarming misfortune that so primitive a science has armed itself with the most modern and terrible weapons, and that in turning against the insects it has also turned against the earth’.

The use of pesticides on crops is thought have compromised bees’ navigational abilities and weakened their immunity. French beekeepers have experienced similar hive collapses and claim to have identified specific pesticides that cause the problem. It takes several hundred worker bees to gather the pollen from around 2 million flowers to produce a 1lb (450g) pot of honey. Honey is one thing, and a nice thing at that, but the danger to our food supply is truly alarming. The question is, are we able to feed the world using holistic and sustainable means? Organic farming methods are now claimed by many to produce similar yields to intensive methods and use a third less energy, less water and no pesticides. Organic farms are also diversified, with many different crops, to avoid huge monocultures.

More people are voting with their feet when shopping in supermarkets by buying organic and free-range produce, others are becoming beekeepers, even in rooftops in cities. Apart from being a fulfilling hobby, beekeeping should also ensure a supply of increasingly precious honey, which could then be sold. We can also ensure that we create suitable habitats in our gardens for bees, by planting suitable flowering plants. By taking care of bees, we take care of ourselves – in fact, our lives could depend on the humble bumble bee.

Most of the world’s carbon-reduction targets are set as percentage reductions of historic levels, such as the year 1990, but as world population is doubling every forty years, it has increased by 50 per cent in the last twenty years – making population size a finally recognized and crucial factor in the battle against climate change and global warming. Many latter-day Malthusians, such as Professor Al Bartlett, argue that the food supply that has ostensibly refuted Malthus’s theories so far, is only made possible by the petrochemical industries and fertilizers, not to mention genetically modified crops. Bartlett points to what he calls the ‘essential exponential’, the geometric progression – if our use of finite resources such as oil and coal increases by even a small percentage, year-on-year, the remaining resources become increasingly diminished very rapidly, due to the power of the ‘essential exponential’.

This inexorable consequence causes Professor Bartlett to question some of the experts’ opinions that we have sufficient oil reserves for a few hundred years or more and coal reserves for thousands of years. These estimates appear optimistic if we consider the steadily increased rate of depletion, due to population growth at the very least – an increase of just a few per cent leads to a reverse geometric progression, such as Malthus was using to analyse population growth. A simple example is the myth of the ancient Persian king who was so delighted with the inventor of the game of chess, that he asked his subject what he wanted as a reward. The subject replied that he would like a single grain of rice on the first square of the chessboard and then the grains of rice to be doubled on each successive square of the board – a trifling amount, thought the king. The amount of rice on each square would be 1, 2, 4, 8, 16, 32, 64 and so on, and as there are sixty-four squares on the board, he would end up with around four times the annual global rice production of today – many, many billions of grains of rice! The depletion of resources works the other way around, obviously.

The United Nations’ population statistics estimate that the world population in 2010 is around seven billion, and they think that it will increase to about nine billion by 2050. As they are making projections so far into the future, they give a wider range a few centuries from now, the mid-range of which is a stabilization of world population at around ten billion by 2300. This is based, possibly somewhat optimistically, on a lowering of the rate of fertility and generally ageing populations. However, they also show high and low scenarios, with the highest scenario continuing at an exponential rate, and an even higher exponential rate at worst.

At some point we reach the biological carrying capacity of the planet or run out of non-renewable resources, if we are not able to find sustainable solutions, almost regardless of climate change and global warming. One of Professor Bartlett’s ‘laws of sustainability’ states that the size of the population that can be sustained (the carrying capacity) and the average standard of living of the population, are inversely related to one another. A circular, rather than linear, approach to resources, which eliminates the concept of waste, seems desirable to say the least. Or those Mad Max movies may turn out as documentaries of the future, after all!

SUSTAINABLE DEVELOPMENT

Ban-Ki-Moon, the United Nations Secretary-General, used the analogy that ‘Our foot is on the gas pedal, and it is time we took it off… we must stop this from happening further’ when describing the loss of Arctic sea ice as happening at a rate that was thirty years ahead of the predicted ‘schedule’ in 2009. He went on to state that ‘Unless we fight climate change, unless we stop this trend, we’ll have devastating consequences for humanity’. The trend has a long history, and it would be remiss of me not to include the famous Brundtland definition of sustainable development that we still aspire to, over two decades after its formulation in 1987: ‘Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs’.

The past may be a foreign country but the future is an unknown continent. The Stern Report was commissioned by the UK Government’s Treasury Department and published in 2005 – surprisingly for a definitive economic analysis of climate change, it contains at least one concession to dark humour amongst its several hundred pages, 650-odd pages in: ‘we apply only a low discounting rate to the future simply because it is the future (we account for the possibility of extinction)’. Less humour is present in the pronouncement that there could be ‘irreversible effects on future generations. It is as though a grandparent is saying to their grandchild, because you will live your life fifty years after mine, I place far less value on your wellbeing than I do on myself and my current neighbours, and therefore I am ready to take decisions with severe and irreversible implications for you.’ A core purpose of the Stern Report was to devise a market in carbon with globally agreed social costs for carbon – the idea is that with an efficient market, carbon use should also be efficient.

In economic terms, the concept of the ‘polluter pays’ and consideration of the so-called ‘externalities’ of economic activities is gaining more mileage – although the idea that economic growth should be reduced by considerations of environment or ecology is probably still a bridge too far. However, interesting shifts in thought, such as those of prominent economist Herman Daly, could provide some solutions. Daly contends that ‘Value added by labour and capital to natural resources is what we want to encourage, so don’t tax it. Depletion and pollution (resource throughput) is basically a cost to be minimized so tax it.’ This would have the effect of making natural resources more expensive at the point of extraction, with the effect that raw materials were more valuable, so that efficiency, maintenance and recycling is encouraged.

Professor Al Bartlett, and many others, including the UN now, put population growth right at the centre of the sustainability debate. Bartlett posits several ‘laws of sustainability’, of which the seventeenth and final one is that ‘extinction is forever!’ Fortunately, he has leavened his canons with some injections of humour, albeit rather dark, such as the sixteenth law, which alludes to the fact that the addition of the word ‘sustainable’ to our vocabulary, reports and institutions and so on is unlikely to guarantee that our existence becomes sustainable. However, his first law is possibly the most telling and is presumably in that position for that reason: ‘Population growth and/or growth in the rates of consumption of resources cannot be sustained’; which does at least focus the mind on quite what it is that we are trying to sustain, when we keep using the word ‘sustainable’, very often gratuitously.

SUSTAINABLE HOUSING

Overview

The housing stock in the UK emits 25 per cent of our total carbon dioxide emissions, extending to 50 per cent if we include the entire built environment. The journey towards a low carbon or zero-carbon housing stock is one that we started some decades ago, during the oil shocks of the 1970s. The ultimate destination was delayed by an era of cheap energy, but now we have added an urgent environmental imperative to encourage us to continue this journey, and reach the right destination quickly. The economic and political circumstances that caused the energy crisis of the 1970s, triggered an almost unprecedented exploration into more efficient ways of living in our houses – resulting in a spate of passive solar dwellings, particularly in the sunnier regions of the world, not to mention the quest for the autonomous house.

Passive solar design principles.

Solar heating principles.

Energy Efficiency

The buzz word back in the 1970s was ‘energy conservation’, which gradually became energy efficiency, now replaced by sustainability. The wide applicability of the latter terms seems to have resulted in some woolly thinking at times, and a great deal of tokenism, which now attracts the disparaging term ‘eco-bling’ – such as small wind turbines mounted on the roofs of suburban houses, sometimes occupied by politicians. There is rarely sufficient wind speed in such sheltered locations to make the investment in a small wind turbine ever pay off. Solar thermal and photo-voltaics are better investments in such locations, if the quest is for expensive ‘eco-bling’ and symbolism alone. Green roofs and walls should also be part of an integrated approach. A far more holistic approach is necessary in our existing and new housing stock, which begins with the basics that reduce energy demand and increase energy efficiency.

Green wall.

Embodied energy of insulation materials.

The basics of reducing energy demand can be very basic, and not nearly as exciting as installing arrays of photo-voltaics on your roof, but the no-cost and low-cost measures are at least precisely that – inexpensive. The average house in the UK emits several tonnes of carbon dioxide each year, and half of that is probably in the heating. Aside from the most mundane of behavioural aspects, such as switching the lights off, installing energy efficient bulbs and turning appliances off at the mains rather than leaving them on stand-by (it is cheaper for the manufacturers to make them guzzle electricity on stand-by and pass the running costs on to you), super-insulating the loft with a benign material is probably your first priority in an existing house.

The Gaia Theory

The Gaia theory is named after the Greek earth goddess, and proposes that the planet’s biosphere is a complex, holistic and interrelated system – like a single living organism. This ecological hypothesis was first mooted by James Lovelock and published as a paper in 1974, coauthored with biologist Lynne Margulis. Their ideas that the planet is a self-regulating system, with physics, chemistry, biology and humanity comprising a homogenous living system, is now an accepted theory, not to mention a branch of earth science. The author William Golding suggested the name, as the ancient Greeks also felt that the earth was a living being, and now modern science has rediscovered this theory.

Gaia theory states that all living things affect the earth’s environment and provide feedback for potential equilibrium, rather like the theory that the flap of a butterfly’s wing can cause untold effects on the other side of the world – the whole is greater than the sum of the parts. Lovelock hopes that the theory provides an appropriate framework for interdisciplinary work. He also cites the first images of the earth from space as the beginning of environmentalism and a more holistic view than objective scientific data. The latter show that Planet Earth is roughly the same size and made of the same elements as Mars and Venus, but they are dead planets. It seems more than random accident that our environment affords us protection against the hostile cold and radiation of outer space, with just the right constituent gases to allow life.

The proportion of oxygen has remained at nearly 20 per cent in the earth’s atmosphere for millions of years. Ocean alkalinity, temperature and other environmental factors are also regulated by life. Temperature has remained within a very narrow range suitable for life on earth, despite the fact that the sun has increased its radiance and its potential to heat the earth by almost a third within the history of life. Such conditions are controlled by complex systems that we do not fully understand – it is more likely that we are a small part of a much larger whole, and as unnecessary for its continued existence as many of the species that we have made extinct. The Gaia theory is a useful device for us to examine our continuing actions.

Three very different planets.

The UK Government has set a target of zero carbon for all new homes by 2016. This is an ambitious target, to say the least, but new homes are only a small percentage of the total housing stock, a few per cent. The vast majority of the housing stock we have now will still be with us in 2050. Ultimately, they must become zero carbon as well, or as close as possible – and it is possible to reduce the energy demand of old houses dramatically. Efficient housing stock is one thing, but how we use our houses is another, and behavioural aspects are equally important. Smart metering with inexpensive devices is a good way to monitor and control your electricity use, and save money with increased energy prices.

Simple energy efficiency measures received a fillip recently by dint of some research undertaken at the Grantham Institute for Climate Change at Imperial College London. Dr Adam Hawkes undertook a study that analysed several years of UK National Grid energy generation, to investigate the suitability of the average carbon dioxide emission factor used by the UK Government for policy purposes (‘Estimating marginal CO2 emissions rates for national electricity systems’ EnergyPolicy, 2010). The factor is 0.43kg of CO2/kWh; gas generation is approximately 0.2kgCO2/kWh, while coal is nearer 0.6kgCO2/kWh – he estimates that this could be some 60 per cent lower than the rate observed between 2002 and 2009 (0.69kgCO2/kWh). This implies that policy studies are underestimating the impact of people reducing their electricity use, and that simple reduction measures have a great deal more impact on CO2 emissions. Conversely, any small increases in the amount of electricity we use could also have a much larger impact than previously estimated. Either way, we need to reduce electricity use.

The fact that simple energy efficiency and reduction measures may have a markedly increased impact on carbon emissions should motivate us to switch lights off when not in use, and install energy-efficient lightbulbs. These may seem like small interventions on an individual scale but it obviously adds up, and if everyone did it we could reduce the UK’s carbon dioxide emissions by a third. Such basic lifestyle changes could remove the demand for about ten large gas-fired power stations. Reductions in energy demand allow only the more efficient power stations to supply electricity, rather than the older coal-fired ones, which are more carbon-intense (electricity has about two-and-a-half times the carbon impact of gas-fired equivalents, such as space heating).

Simple measures in each household, such as turning all appliances off at the mains when going to bed or going on holiday, would save around 100kgCO2/year; installing ten energy-efficient lightbulbs would save up to 350kgCO2/year; and hanging wet washing out to dry rather than using a tumble drier would save about 260kgCO2/year. If all households took such measures we could reduce our carbon dioxide emissions by the equivalent of several million houses – a third of all houses. The UK Government response to Dr Hawke’s report was that Britons need to wean themselves off fossil fuels and that inaction is not an option, as the cheapest way to cut carbon dioxide emission is through energy-saving measures – curbing energy waste and saving money.