26 Apr 2007

Why Sustainable Development may be bad for the environment

Last night, I attended a rather depressing lecture given by
Prof. Susan Owens
at the Engineering Dept of Cambridge University. It formed part of a series of lectures on Sustainable Development given by well known figures in the field. Next week, you can get to see David King, the government’s chief scientific advisor, who closes out this year’s series.

The subject of Owens’ lecture was Why Sustainable Development may be Bad for the Environment. It was a thought-provoking title and it had me curious as to what a geography don would have to say on the matter. She gave an eloquent discourse, without the dreaded PowerPoint, for 50 minutes on the use and abuse of the word sustainability. She was both interesting and persuasive.

Sustainability is not a new idea and many people in the 18th and 19th centuries held it up as an important aim for a civilised society. But, she suggested, that when the environmental movement as we now know it sprang into life, in the late 1960s, it was avowedly anti-development and anti-capitalist. This situation persisted through the 80s and it wasn’t until the Brundtland Commission Report was published, in 1987, that a bridge began to be built between the growth monkeys and the preservationists. Brundtland promised a new brighter future where growth could continue subject to a few common sense constraints. And so was born the concept of sustainable growth. It was about healing wounds as much as anything else.

But Owen’s fundamental point was that sustainable growth was in fact a chimera, an irreconcilable paradox. In the 20 years that have followed, we’ve had lots of growth but very little of it has been sustainable and increasingly the word is being used to window-dress and little more. She was particularly scathing about Labour’s Sustainable Communities Plan, the £22 billion housing scheme which is planned for South East England. The new housing will put stress on the existing infrastructure, transport systems and water supplies and it’s very hard to see ways in which it differs from any other housebuilding schemes we have had in the past. She could have been even more ruthless, has she wanted to, for it looks to me and many other cynics that they are using the word sustainable to duck out of having to provide an adequate level of infrastructure.

Take roads. There has for many years been a very strong anti-road building lobby which argues that it’s pointless building new roads because they just encourage more people to make more journeys by car. Because road building is largely funded from the public purse, the government seems to be more than happy to bend to the will of this lobby and to cut right back on improvements to the road network.

But the same logic is not applied to housebuilding, just possibly because new homes are a generator of new taxes. If you build new homes, they also have a habit of filling up, just like new roads and these new households will then generate more road traffic. But you rarely hear such an environmental argument against new housebuilding because there exists some pretence that, by adding a cocktail of environmental features to housing, you can make new homes sustainable.

With airports, you do hear persuasive environmental arguments against expansion, but the government has so far chosen to ignore them. How can they argue against new roads but for new runways? Could public expenditure v tax revenue be behind this policy as well?

There is a frightening lack of logic in all this. People living around Cambridge are right in the firing line because we have on our doorstep:

• an already stressed-out road network, which the government is reluctant to improve
• Stansted, the epicentre of the low cost flight networks and Europe’s fastest growing airport, which the government is happy to see expand as fast as it likes
• an enormous sustainable housebuilding programme, which the government is forcing through in the face of stiff local opposition.

So we are faced with a future where something like 460,000 extra souls will be coming from all over the world to live in our region. They will be able to fly back to see their relatives every weekend for next to nothing, provided they take Friday and Monday off to get to and from the airport because the road system has collapsed and there aren’t nearly enough trains to cope.

Roll on the personal jet pack. Biofuel version, naturally.

22 Apr 2007

On housing bubbles (again)

You Tube has the answer. Take a look at this.

The Strange Case of Councillor Hipkin

John Hipkin is, or now more accurately was, a well known city councillor in Cambridge. He was part of the Lib Dem group that currently controls the city council. During his many years service, he had served as Mayor of Cambridge. He was also a prominent figure on the planning committee.

However something he said in 2006 caused him to be thrown out of the LibDems. He apparently overstepped the mark and spoke out of turn. As we have learned to say these days, he went off message.

Councillor Hipkin went on record as saying that there wasn’t enough provision for family housing for large households in the city. It sounds like an innocent enough comment, but it seems to have set a cat amongst the pigeons in the ruling LibDem grouping.

“Within a matter of days,” Hipkin told the Cambridge Evening News, “I began to get complaints. I was told I was too bullying and too domineering in the way I chaired the west area committee and that I had deliberately ridiculed members of the public. There were complaints about the way I spoke and the way I expressed myself.”

His comments about the need for more family homes were then picked up by the council’s lesbian, gay, bisexual and transgender group which said that they considered his comments to be heterosexist, which translates as being biased towards heterosexuals.

Like I suspect most local residents, this was the first time I had ever heard of such a group. That they should see fit to raise their profile above the parapet in order to lambast a councillor for commenting on housing provision seems bizarre in the extreme.

So what is going on? Cambridge has some of the most expensive housing in England and there aren’t that many families that can even contemplate living here. So is there now some hidden agenda to give up on the time consuming process of rearing children and to turn the whole place into a playground for singles and gays? Or did Hipkin merely expose the awkward truth that the great bulk of the tens of thousands of new homes being planned for the Cambridge region are starter homes for keyworkers? Are these keyworkers going to have to sign a non-breeding pledge before they can take possession of their hutches? It’s time we were told.

19 Apr 2007

What water shortage?

I live in the driest county in England, Cambridgeshire. It has a rapidly growing population, currently around 750,000, and projected to increase by another 100,000 over the next ten years. My, that’s a lot of baths, showers, washing machines and car washes. We are constantly being implored to save water, and water saving features form an important part of the Code for Sustainable Homes, which will in time become part of the building regulations. Reducing water consumption is seen as an essential part of being green.

But here’s an interesting fact, a perspective maker. We are currently capturing just 3% of the rainfall that falls onto our county. OK, a lot of it evaporates and a lot gets channelled into the rivers. But even so, there is one hell of a lot of untapped potential out there. And it’s not as though we are taking this water out of circulation: every drop we use gets returned sooner or later.

We are not short of water in this country. Merely short of the wherewithal to create infrastructure to use it. How come if the Victorians could manage it, we can’t?

18 Apr 2007

Passive Passive Houses

Spent the day in Nottingham at the School of the Built Environment, talking with its head, Prof Brian Ford, and two of his colleagues, Rosa Schiano-Phan and Mark Gillott. They had contacted me about my PassivHaus musings: it seems I am not the only one who has had a few doubts about whether this standard is all that it is cracked up to be.

In particular, they wanted to talk about low energy performance standards in warm (i.e. Mediterranean) climates. They have been part of a group of institutions, funded by the EU, which have been looking into creating a sort of PassivHaus-lite standard which would be better suited to Spain and Italy and, just possibly, to the UK and Ireland as well. Nottingham has a particular interest in natural ventilation techniques and they are worried that the German PassivHaus standard shuts out all but mechanical ventilation with heat recovery (MVHR) solutions. I share their disquiet. There remain a number of doubts as to whether MVHR is the best solution for all housing. What doubts?

• It’s mechanical: it requires a fan to operate: it therefore uses power.
• As it’s mechanical, it will require servicing. This may or may not get done. And it will of course break down from time to time.
• This raises one or two health issues. As PassivHaus is nearly airtight, indoor air quality is dependent on fans. What happens if the fans stop? Will anyone notice? Could it even be dangerous?
• People have raised concerns over the health implications of drawing input air through long lengths of ducting. In an ideal world, the ducting should be demountable for cleaning purposes but such a requirement doesn’t form part of the PassivHaus standard and seems likely to be ignored.
• In short, there is concern that the PassivHaus standard has got the balance wrong between carbon reduction and personal health.

But the Nottingham crew have further misgivings. They reckon the maximum space heating requirement figure, the famous 15kWh/m2/annum (the very nub of the PassivHaus standard), was actually too generous for warm climates. It seems to have been set with Germany or southern Sweden in mind: in the Mediterranean you simply don’t need that much heating, or to put it another way, you don’t have to build to PassivHaus standards to get such a predicted annual heat load. In fact, the cooling load is far more significant in the Mediterranean climate and they think it’s a much better approach to incorporate natural ventilation techniques, which can keep the air fresh in winter and cool in summer.

How does this relate to the UK? Here we are in mid-April with the daily maximum temperatures well into the 20s, and having just experienced nothing more than a one-week winter. It’s hard not to conclude that the climate we are experiencing has already changed significantly. The question is why are we getting obsessed with a performance standard (i.e.PassivHaus) which is a) not entirely applicable to our climate and b) over-prescriptive about U values, air tightness and ventilation techniques? They are worried that the PassivHaus standard will somehow morph its way into our SAP ratings as the only way to build a zero-carbon house and that other more compelling options will be effectively shut out.

To this end, the Nottingham group are working up an alternative low energy standard, a naturally ventilated version of PassivHaus (maybe that’s a Passive Passive House), which they think is better suited to warm climates and, just possibly, to the UK as well. They are planning a launch event and a very active debate about the pros and cons of PassivHaus in September (18th and 19th).

The other really interesting thing they are up to is building a series of experimental houses on the campus, to be known as the Creative Energy Homes. They already have one experimental house built on site seven years ago; now they will be erecting another six. There will be public access for some time and it’s sure to be a big draw. Pictured here is the Stoneguard C60 steel framed house, as it looked this afternoon in the balmy sunshine.

16 Apr 2007

On Stamp Duty Tax Breaks for Zero Carbon Homes

The intention to offer a stamp duty tax break to zero carbon houses in Britain was announced in Chancellor Gordon Brown’s pre-budget statement back in December but the definition of what exactly would qualify as a zero carbon house has only just appeared in the budget notes. It’s to be found on pages 66-68.

The aim of the relief is to ensure that on average over the course of a year
the homes are zero carbon. In other words, they will not be required to be
zero carbon the whole time, but the import of grid power and export of
renewable power should at least balance over the course of a year.

Seems fair enough. It continues…

It will also be necessary to ensure that the fabric of the building
significantly exceeds the standards currently required by Part L of the
Building Regulations 2000 (as amended). The requirement will be that the “Heat Loss Parameter” (covering the walls, windows, air tightness and other elements of the building design) is no more than 0.8W/m2K. This standard will mean that space heating requirements are no more than 15kWh/m2 per annum.

“Heat Loss Parameter” is a phrase I wasn’t familiar with but it’s embedded in the SAP calculations. It’s defined as the specific heat loss for the whole house divided by the internal floor area. The figure 0.8 is very exacting, equivalent to constructing to PassivHaus standards, which is where the 15kwh/m2 figure comes from. In fact, I have learned from the Treasury that the figure was defined by taking the PassivHaus standard and playing it through the SAP calculations on a notional house. To get down to 0.8, you need to have super insulated walls, floors and roofs, triple glazing, virtually no unplanned air loss and mechanical ventilation with heat recovery.

Heat and power for space heating, hot water and lighting must be generated either in the home or on the development or through other local community arrangements (including district heat and power) and must be renewable (i.e. non-fossil fuel) energy.

Here it departs from PassivHaus standards and starts to require renewable power input. But what exactly does it mean by other local community arrangements? It is a frustratingly vague phrase.

What about power use over and above space heating, hot water and lights? It goes on:

A zero carbon home is also required to have zero carbon emissions from
use of appliances in the homes (on average over a year).

There follows a table which specifies how much additional power you need to generate depending on the overall floor area of the house. Bigger homes, over 150m2 floor area, need to generate 16.54kWh/m2 to cover cooking and appliances. So a 200m2 home, the typical size built by a UK selfbuilder, would need to generate 3308kWh/annum to cover this load.

This additional power must be renewable power produced either within the
area of the building and its grounds, elsewhere in the development, or
elsewhere as long as the developer has entered into arrangements to ensure that the renewable generation is additional to existing plans.

Now there appears to be an important distinction here. Appliance power, it would seem, can be offset by the developer, whereas power for space heating, hot water and lighting must be site generated, or at least community generated. It’s not exactly clear what the distinction is, or what is meant by entering into an arrangement but the fact that it exists is confirmed by Cl 18 which states The amount of such additional power can be reduced by any surplus from the arrangements to meet zero carbon on heating, hot water and lighting.

So how does one square this? In what sense can one type of electricity be subject to less stringent requirements than another? It’s something that appears nonsensical. Perhaps I shouldn’t be surprised, because its followed by the silliest clause of all of them.

20. Qualifying homes will not be permitted to be connected to the gas main. Mains gas is by far and away the most efficient way of burning fossil fuel. So where on earth is the logic in banning it? Especially as there is nothing to stop you using bottled gas for the same purpose? Or of course cooking with grid-delivered electricity, which releases around two and a half times more carbon dioxide than mains gas. In fact, I am pretty certain you could install an electric Aga, just about the most energy hungry household appliance on the planet, and it wouldn’t effect your zero carbon status one jot. I am afraid the Treasury is shooting itself in the foot here.

So how would you go about building a zero carbon house?
First you would need to construct something close to a PassivHaus, a super insulated shell with triple glazing and mechanical ventilation with heat recovery. The PassivHaus rules are quite prescriptive and it’s not clear just how closely you would have to adhere to them.

Then you would have to develop a strategy to provide renewable power to cover your anticipated demand for space heating, hot water, lighting, cooking and electrical appliances. You would need to carry out a heat loss calculation, using the government SAP rating scheme, to work out what this figure would be but you can assume that overall it is likely to be around 50kWh/m2/annum, or 10,000kWh/annum for a 200m2 house, of which perhaps as much as 30% can be offset — although what counts as an acceptable offset isn’t detailed. You could achieve this with:
• a 6kW wind turbine, mounted in an appropriately windy spot, cost around £15,000 after grant deductions or
• around 80m2 of photovoltaic solar panels, cost around £30,000 after grants.

Hot water and space heating demand could be met by a biomass or pellet boiler, cost around £10,000 and/or solar hot water panels, (cost around £4,000 but will only deliver part of the load.) But neither of these options produce electricity so presumably there would have to be additional installations to cover electricity demand as well. It’s not exactly clear. Alternatively, heat pumps could be used to reduce the heating demand, but they don’t generate any power either, so it’s hard to see quite how they fit into the picture. One form of micro generation, the CHP plant, can’t be used at all, despite the fact that they do generate electricity, because the current models use mains gas, which is of course banned! Oh the joys of joined-up thinking!

Presumably you would be able to mix and match these technologies so that you could for instance use a heat pump combined with a solar hot water panel to reduce your demand and then fit a smaller PV array to make up the difference and then offset the appliance load. But what isn’t explained is how each individual scheme will be judged: there is a lot of fairly complex carbon accounting going on here and you only have to vary the assumptions slightly to get very different results. Who is to say House A qualifies as zero carbon whilst house B doesn’t? I have no idea.

Finally, what’s the tax break worth? As I understand it, the zero carbon house will be exempt from stamp duty only on its first sale and only up to a maximum of £15,000. If you sell the house for over £500,000, which is where the top rate of 4% stamp duty starts, then you would subtract the £15,000 from the duty normally payable. The beneficiary of this largesse is therefore not the developer but the first purchaser, who pays the stamp duty in the normal course of events, although the developer may gain by being able to sell the zero carbon house for a little more than the market would normally bear, because of the stamp duty holiday. Tax breaks should never be sniffed at, but the reality is that the cost of uprating a normal house to a zero carbon house will invariably be considerably more than the value of the tax break.

One supplementary point worth noting: Tony Verran of HM Treasury, in commenting on first draft of this piece, has indicated that selfbuilders will not be eligible for the tax break because it will only cover the first use of the home for residential purposes. It doesn’t cover bare land and it won’t cover a sale made to a second user, even if it’s technically a first sale.

14 Apr 2007

What is multi-room audio?

What exactly is multi-room audio? Or more precisely, what is the point of it? Whilst I can’t say that this question has been exactly eating me up for years, yesterday I got the chance to quiz one of the industries’ experts, Adrian Ickeringill, who is runs Systemline’s Modular project which aims to get multi-room audio into houses being built by developers.

Systemline is a small part of the Armour Group. Armour is itself an AIM-listed micro-conglomerate that specialises in car and home audio and electronics. It’s a difficult market to be in because, whilst it’s undoubtedly a growth market, the products keep changing and so you have to be nimble if you are to survive. Armour history reflects this: it was big in in-car entertainment but found itself getting sidelined as car manufacturers started putting the kit in as standard. Armour switched attention to the burgeoning home entertainment market and it started acquiring smaller businesses like Systemline. But now this market has been turned upside down by the arrival of the iPod, which has rendered all manner of products obsolete. When you have a digital jukebox in a slick white case, who needs a media server the size of a video recorder?

Systemline reacted by creating a wall mounting for the iPod, so that you can dock your iPod and play it through their Systemline ceiling speakers. Whilst this is neat, it is hardly earth shattering, and Adrian let on that one of their key markets is now furniture, by which he means building-in speakers and screens. To aid this, in 2005 Armour purchased Alphason, a Lancashire based business specialising in screen support cabinetry. There are, apparently, much juicier margins in the furniture than in the hardware.

Adrian’s job is to sell multi room audio to developers. He does this by first getting them to install Systemline speakers into their show homes and flats and then persuading the developers to offer Systemline’s products as an extra, all just added onto the mortgage. Whilst this is unlikely to be a sale clincher, the developers like it because they get a cut for doing very little work and they get the cachet of selling smart homes, which is seen as being increasingly important, especially in many urban apartments. There are different levels you can opt for. At its simplest, you can get a few built-in ceiling speakers; or you can opt for home theatre and lighting control, in fact the full home automation kit. These systems are now seen as being somehow separate from home data cabling, which is basically about connecting computers to each other and to the internet. I had always lumped them together in my mind but it seems the way the market is going is to differentiate the two. The internet is increasingly being seen as a commodity whereas audio and video remains an aspirational purchase.

We talked briefly about the non-appearance of Part Q, a phantom building regulation that has been mooted for a long time, which would require a structured cabling backbone to be installed into every new home. Apparently, Portugal has become the first (and as yet only) EU state to introduce a Part Q-type requirement. Apparently, high level discussions have been taking place in Britain about whether to follow suit but methinks it’s unlikely to become mandatory any time soon, especially as the dust is still settling over all the many recent building regs changes which have upset the industry. The trouble is that this is an industry still evolving and there would be great danger that you would end up building in technology that would be rendered obsolete within a few years.

9 Apr 2007

CDM: an afterthought

Like many bloggers, I am in the habit of pointing people to Wikipedia if they want more background information on the topic I happen to be blathering about. As some wag recently pointed out, if you can’t trust the good old internet, who can you believe nowadays?

So I thought I could further elucidate readers on the intricacies of the CDM regs by pointing them towards the relevant page. But Wikipedia has no entry for the CDM regs. Type CDM regulations in the search field and it leads you to a disambiguation page (no, I don’t know what that means either). It suggests the following

CDM may stand for:
• Celebrity Deathmatch
• Clean Development Mechanism, a Kyoto Protocol mechanism to assist industrialized countries reducing their greenhouse gas emissions
• Cold dark matter, a scientific theory
• Ceramic discharge metal halide lamp, a light source
• Cinematic Death Mambo, a genre of music
• Code-division multiplexing
• Council of Diaspora Métis, an international non-governmental organization representing Métis People outside of Canada
• Compact Disc Maxi single
• Common Diagnostic Model
• Consumer Demand Management
• Cisco Content Distribution Manager
• Conceptual data model
• CDM (racing team), Formula 3000 racing team competed in 1989
• Course Description Metadata, an XML data format for educational data (program and course descriptions)
• Cross-Differentiate-Multiply, a demodulator

In fact anything but Construction Design and Management Regulations. To be fair, it does acknowledge that they exists but nobody has bothered to put finger to keyboard to explain just what they might be. As Wikipedia is written by enthusiasts on subjects dear to their hearts, this tells us something. CDM is even more boring than I imagined.

Further afterthought. I wonder just how much money the Health & Safety Executive have blown in disseminating information about the new improved CDM regs? Wikipedia is one medium that millions of people refer to and they haven’t had the wit to use it, despite the fact that it’s free. That tells us something else, doesn’t it?

5 Apr 2007

CDM 2007

Tomorrow, a new version of the CDM (Construction Design & Management) regs come into effect. What should we make of them?

I was not a great fan of the old CDM health and safety regs, which came into effect in 1994 and had precisely no effect whatsoever on building site accident levels. Lots of paperwork, lots of money to be paid out and no positive outcomes. How very UK today.

News that the CDM regs were to be overhauled just filled me with excitement. I have turned down the offers of attending free or near-free CPD seminars to help me ‘get up to speed’, partly because I can still recall the terror of having to sit through a CDM awareness event back in 1994. I’d opt for a day in Guantanamo Bay every time. I decided I would do my catching up this time via newsprint.

Trouble is, every time I try and read a This is what CDM 2007 really means article, I find myself nodding off somewhere in the second paragraph. Building magazine today has no less than three explanatory articles and despite trying to read all three I am really not much wiser about just what is changing, as from April 6th.

Following an industry-wide consultation, writes Peter Caplehorn there is a chance for the new regulations to make a real difference. Only a chance? I am confused already. The irrelevant paperwork has been binned and there is a focus on improving health and safety standards by keeping the regulations proportionate to the task and by focussing on outcomes rather than process. What on earth is he talking about?

All projects will now be subject to CDM except domestic works. Correct me if I am wrong but this is no different to how the old CDM worked. Any projects involving more than 500 person days work or lasting longer than 30 days need to be notified to the Health & Safety Executive using the F10 notification form.

Well, there I have learned something. The form you need is called an F10. Remember that, because it’s probably the only really useful thing you will learn from this article.

A construction phase health and safety plan must be drawn up. Hang on, I thought we had dispensed with irrelevant paperwork? Seemingly not. A big bugbear of the old CDM was that you had to produce a risk assessment plus a health and safety file, and that this work was time consuming and no one ever looked at them. But we still seem to have a H&S file. Funny, there’s no mention of that pesky risk assessment. Maybe that’s the result everyone was hoping for?

One thing that has happened is that the key roles have been given a dust-down and in some instances some new names. The client is still the client, but this time they have to take their responsibilities more seriously. Previously they could sub-out their responsibilities to an agent, but from now on there can be no subbing-out. The client is the client. Except where of course there is more than one client, then they have a duty to co-operate with one another. All good stuff this, isn’t it?

The planning supervisor is now the CDM co-ordinator. Got that. The CDM co-ordinator must either generate or ensure the generation of the health and safety file, But there is, I think, just a suggestion that if the project is low risk, then you needn’t bother with risk assessments and all that hullabaloo. At least that’s the drift I get. But in my semi-comatose state, I may have it all wrong.

Now can I summarise it all in a sentence? The form you need to send off to HSE is F10 and the role you need to appoint is the CDM co-ordinator. I think that should just about take care of it.

3 Apr 2007


This week’s Sunday Times has an interview/article about Bill Dunster, rightly described as one of Britain’s foremost green architects and pictured here at his home with wife Sue. He’s still best known as the designer of
, the south London housing scheme that sits at the top of every magazine and newspaper’s stock photo library and gets aired every time they want to illustrate a feature on low energy housing. His more recent work expands upon the reputation he established there and he’s sort of trademarked the Zed-bit so that anything with a Zed in it, like ZEDHomes or ZEDFactory, is likely to have Dunster’s imprint on it. It’s easy to overlook the fact that ZED, in this instance, stands for Zero Energy Development, a critical feature of all his designs.

But Dunster’s not without his foibles. One of the things he’s really into is thermal mass, which requires the use of tonnes and tonnes of concrete to act as a heat store for his houses. This is done to facilitate passive solar design, already discussed on the blog (see Feb 21st 2007 entry). But using masses of readymix concrete upsets a lot of greens because, well, it’s concrete. And it also upsets the MMC set, because you can’t sensibly prefabricate it in a factory.

He also manages to upset the PassivHaus crowd by rejecting mechanical ventilation with heat recovery and instead espousing wind-assisted passive stack ventilation. This is indeed the raison d’etre behind the massive multi-coloured cowls that sit on top of BedZed, which make the place both other-worldly and photogenic. As you can see, Bill Dunster is not everyone’s cup of green tea.

Personally, I don’t have a problem with using lots of concrete or not using any fans. He puts forward credible arguments for both viewpoints and is all for recapturing the carbon used to make the concrete over the lifetime of the buildings.

But there is one aspect of Dunster’s vision that does trouble me. That is his predilection for site-generated renewable power. In the quest to create zero carbon developments, Dunster seems to have gone overboard on installing renewable technologies, and wind turbines in particular, that really don’t make much sense. And the Sunday Times feature has an interesting clue as to why that might be. In discussing Bill and Sue Dunster’s own house in East Molesey, Surrey, it states “Last year, the Dunsters took great pleasure in disconnecting from mains gas.”

Just why should this fact be a cause for celebration chez Dunster? I am going out on a limb here and speculating that it all stems from a peculiarly British strand of green building, which seeks autonomous or self-sufficient development as an end in itself. There were the John Seymour books published in the 1970s which put forward self sufficiency as a desirable goal, and there were also Brenda & Robert Vales’s books, the Self Sufficient House and the Autonomous House. These plotted a vision where each house was a little island which produced its own food, generated its own energy and disposed of its own waste. These self-sufficient stirrings were being mirrored on the TV at the same time by the antics of Tom and Barbara in The Good Life, a sitcom set in Surbiton — very close as it would happen to East Molesey, home of Bill and Sue.

But I didn’t get self-sufficiency back in the 1970s and I still don’t get it. What is the point? We are social creatures, born to trade and barter, and we get ahead by specialising, by getting a skill set that others don’t have and by making ourselves useful to a wide number of people. Aiming to be self-sufficient seems to be running counter to all this: you need to be part gardener, part engineer, part builder and part composter. In fact, you need to be full time peasant. It may well suit some people but methinks not that many. Most people would prefer to live by their wits and get specialists to look after these aspects of their lives, which is why supermarkets, builders and utility companies always do good business, whatever the economic outlook.

Following on from this, the trends towards decentralised power and, in particular, on-site renewables seems to be driven in good part by a Tom & Barbara agenda. We have a country criss-crossed with energy supply lines, and we have professional power supply companies queuing up to deliver renewably generated electricity into the grid, planning problems not withstanding. Yet at the same time we are being encouraged to bake our own electricity on site, as if this in itself was a worthy goal, and despite the fact that common sense says it would be much more efficiently generated off site. There is now a healthy ongoing debate about just what exactly the definition of on site should be, at least from a power generation standpoint. Could it include a neighbourhood wind turbine? Or a combined heat and power plant for an estate? Or, heaven forbid, just buying green electricity from the grid. You might think it’s all a bit academic, but it’s a point that has become central to the definition of what a zero-carbon home may or may not be. And it’s become central to the work of Bill Dunster, because without on site renewables he can’t build a ZEDHome.

But does it really make sense as a model by which to power the carbon-lite economy? Or are on-site renewables just a throwback to 1970s woolly thinking?