I have been digesting some of BP's annual statistical review on the energy markets. BP has been doing this since 1952 and has got pretty good at it, because it's widely regarded as being both accurate and impartial.
Embedded in this year's review is a look forward till 2035, incorporating BP's best guess of what will be happening then. From a climate alarmist point of view, this is more than just a tad depressing because BP don't foresee any renewables revolution, nor a renaissance in nuclear power, nor indeed any great moves towards a low carbon future. By 2035 we should be about halfway to our goal of decarbonising our energy networks if we are to maintain the climate in our comfort zone.
Unlike many commentators from the right or neo-liberal camps, BP don't appear to argue with the science of climate change. They are fully up to speed on it, and fully cognisant of what lies ahead if we do nothing about it. There's none of this "The world will be happier if it's a bit warmer" rubbish, nor "Global warming stopped 15 years ago". In some ways this makes their forecasts even more depressing because what they seem to be saying is that the threat is real but there's nothing we can do about it because the energy markets are so big and so powerful that human avarice will trump any thoughts of putting the brakes on, however mildly. Nothing appears to stand in the way of economic growth, especially in Asia. The world looks set to be consuming far more energy in 2035 than it is today and just about the only bright spot in all this is that the switch from coal to gas will reduce the carbon intensity of the energy we use.
In fact, they are quick to point out that a 1% shift from coal to gas makes more difference to carbon emissions than a 10% growth in renewables. A-fracking we shall go? Maybe, although it's interesting to note that BP don't think fracking will ever take off in Europe because of the political opposition. They foresee Europe as being the test bed for renewables.
Impartial and objective BP's report may be, but there is something rather disturbing about such a major player in world energy markets taking such a passive role. We are facing a moment in our history when something like a Manhattan Project for energy production is required, a game changer which does for coal, oil and gas what trains did for canals, or what atomic bombs did for conventional explosives. Yet BP seems not to notice. Perhaps BP should start producing a sister report every year, looking ahead to the effects of all this fossil fuel burning will have on the environment and on our economies? Perhaps there might just be some hint at what BP thinks we might be doing about it it, instead of just continuing to sell fossil fuels to all comers?
18 Jun 2014
4 Jun 2014
The Death of Zero Carbon
It shouldn't really come as much of surprise, but it looks as though the zero-carbon target for new housing is about to be abandoned wholesale, with the news that there will now be an exemption for smaller sites from having to even meet allowable solutions.
Instead, the target will be to meet the current building regs. Which isn't a target as such at all - it's what everyone has had to do all along. These building regs may be upgraded a little in 2016, but for now all bets are off. In other words, we might just as well have not bothered with the whole edifice that became the Code for Sustainable Homes and, with it, the 2016 zero-carbon building target.
The rationale for all this is that we are even more desperately short of housing than we were in 2007 when the scheme was launched and that it would somehow be against everyone's interest to insist on higher building standards because they cost more. In other words, the need for cheap new housing trumps our longer-term concerns about rising fuel prices and reducing carbon emissions.
Once again, it's a blatant example of how political the housing standards debate has become. The growth monkeys have won this particular battle. Their battle cry is "More houses, more units, more, more, more." Never mind if they are any good or not, or whether people actually want them, nothing must stand in the way of builders churning out maximum numbers. And zero-carbon targets are, frankly, in the way.
The shrinking violets, the liberals and the greens, have had to take a back seat. Their vision of better quality housing is, for the time being, shredded. On the surface, it appears to be a rout, but it's not quite that simple. For a start, the zero-carbon target was always indefensible. You simply can't build a zero-carbon house and there is no point trying to pretend that you can. For that, Yvette Cooper and friends (who launched the idea) deserve a round of brickbats. Once you go down the road of allowable solutions and offsetting, you might just as well admit you are wasting your time. Which they didn't.
However, many of the design ideas incorporated into the Code were and are very sound and we will have to wave goodbye to them for a while, although some have made it through to the building regs over the course of the past eight years.
The fact is that building better homes does cost more, but the bulk of this cost is met by the landowner who sells the plots in the first place. If the cost of building house X goes up by £15,000, then the purchase price of the plot it stands on falls by a similar amount, so that neither the housebuilder nor the purchaser pays any more that they would have done.
So who really benefits by this shredding of these targets? Not the housebuilders, not the house buyers, but the landowners. It also very doubtful that keeping these targets would have done anything to dampen the rate of new housebuilding. But that's politics for you.
Incidentally, the text of the announcement which is published today is a fantastic example of how political-speak completely turns common sense on its head:
Instead, the target will be to meet the current building regs. Which isn't a target as such at all - it's what everyone has had to do all along. These building regs may be upgraded a little in 2016, but for now all bets are off. In other words, we might just as well have not bothered with the whole edifice that became the Code for Sustainable Homes and, with it, the 2016 zero-carbon building target.
The rationale for all this is that we are even more desperately short of housing than we were in 2007 when the scheme was launched and that it would somehow be against everyone's interest to insist on higher building standards because they cost more. In other words, the need for cheap new housing trumps our longer-term concerns about rising fuel prices and reducing carbon emissions.
Once again, it's a blatant example of how political the housing standards debate has become. The growth monkeys have won this particular battle. Their battle cry is "More houses, more units, more, more, more." Never mind if they are any good or not, or whether people actually want them, nothing must stand in the way of builders churning out maximum numbers. And zero-carbon targets are, frankly, in the way.
The shrinking violets, the liberals and the greens, have had to take a back seat. Their vision of better quality housing is, for the time being, shredded. On the surface, it appears to be a rout, but it's not quite that simple. For a start, the zero-carbon target was always indefensible. You simply can't build a zero-carbon house and there is no point trying to pretend that you can. For that, Yvette Cooper and friends (who launched the idea) deserve a round of brickbats. Once you go down the road of allowable solutions and offsetting, you might just as well admit you are wasting your time. Which they didn't.
However, many of the design ideas incorporated into the Code were and are very sound and we will have to wave goodbye to them for a while, although some have made it through to the building regs over the course of the past eight years.
The fact is that building better homes does cost more, but the bulk of this cost is met by the landowner who sells the plots in the first place. If the cost of building house X goes up by £15,000, then the purchase price of the plot it stands on falls by a similar amount, so that neither the housebuilder nor the purchaser pays any more that they would have done.
So who really benefits by this shredding of these targets? Not the housebuilders, not the house buyers, but the landowners. It also very doubtful that keeping these targets would have done anything to dampen the rate of new housebuilding. But that's politics for you.
Incidentally, the text of the announcement which is published today is a fantastic example of how political-speak completely turns common sense on its head:
The Government is committed to implementing a zero carbon standard for
new homes from 2016. But it is not always technically feasible or cost
effective for house builders to mitigate all emissions on-site.
new homes from 2016. But it is not always technically feasible or cost
effective for house builders to mitigate all emissions on-site.
The Government would set a minimum energy performance standard through
the building regulations. The remainder of the zero carbon target can be met
through cost effective off-site carbon abatement measures – known as
‘allowable solutions’. These provide an optional, cost-effective and flexible
means for house builders to meet the zero carbon homes standard, as an alternative to increased on-site energy efficiency measures or renewable energy (such as solar panels).
the building regulations. The remainder of the zero carbon target can be met
through cost effective off-site carbon abatement measures – known as
‘allowable solutions’. These provide an optional, cost-effective and flexible
means for house builders to meet the zero carbon homes standard, as an alternative to increased on-site energy efficiency measures or renewable energy (such as solar panels).
Small sites, which are most commonly developed by small scale house builders, will be exempt. The definition of a small site will be consulted on shortly, and set out in regulation.
The Zero Carbon Home standard will be set at Level 5 of the Code for
Sustainable Homes, but the legislation will allow developers to build to Level 4
as long as they offset through the allowable solutions scheme to achieve
Code 5.
Sustainable Homes, but the legislation will allow developers to build to Level 4
as long as they offset through the allowable solutions scheme to achieve
Code 5.
Energy efficiency requirements for homes are set in the Building Regulations
2010 and are made under powers in the Building Act 1984. But there are
insufficient powers in the Building Act to introduce off-site allowable solutions,
so the Government will now bring forward enabling powers for this.
2010 and are made under powers in the Building Act 1984. But there are
insufficient powers in the Building Act to introduce off-site allowable solutions,
so the Government will now bring forward enabling powers for this.
23 May 2014
The joy of seats
I saw this in Sydney last week. First I didn't believe what I was seeing when I saw a fellow passenger using it. Then I couldn't wait to have a go myself. Here is my son Guy demonstrating. This way you get to choose whether the seat faces forwards or backwards.
20 Mar 2014
Is sustainability stuck?
Short answer: yes. The whole topic has reached a crossroads and it's not clear which way to go from here.
Many of the existing green policies are proving to be questionable, to say the least, and many of the really big questions are not being addressed, let alone answered.
My own journey through the byways of sustainability has also reached something of a brick wall. Having quietly campaigned for better energy performance in homes, and for tougher and better building regulations, I began to fall out of love with all the red tape involved with projects like the Code for Sustainable Homes and the move the Zero Carbon everything.
Then I got involved with David Mackay's 2050 calculator project and it opened my eyes up to just how big the problem of global carbon emissions actually is and how little difference having tighter building regulations will make in the great scheme of things. I was already convinced that climate change is an existential problem, the like of which we have never faced before, but I have come to question my belief that the world of sustainable building practice is necessarily very relevant to it.
Take deep-retrofit by way of example. Acres of print has been expended on how it should or should not be done. The government has got itself tangled up in knots over the Green Deal which was meant to kickstart radical retrofit but has simply highlighted how difficult it all is. Underlying all this is the plain fact that our existing housing stock is pretty poorly constructed and that it might well be cheaper and simpler just to pull it all down and start again.
Which is also highly unlikely, seeing as how we have 25 million homes in this country. We are having trouble adding more than 0.5% to this total every year, so retrofitting or rebuilding the existing 25 million begins to look like a pie-in-the-sky project.
One of the pointers coming out of David Mackay's work is that there are many ways to skin a cat. Most people — Mackay included — tend to favour a bit of everything, so here a little bit of retrofit, there electric vehicles, plus a bunch of diverse renewables and maybe some nuclear power, not to mention a little behavioural change. But this pot pourri approach tends to ignore the No 1 critical factor which is that within a very short timescale we need to wean ourselves off fossil fuels almost entirely. If we can't do that, everything else becomes irrelevant. However, it doesn't follow from this that low carbon/zero carbon energy will either be in short supply or be ruinously expensive. We could in fact face a low carbon energy glut, if we got our act together.
But this isn't something that conventional sustainability is at all comfortable with. It's as if some form of future deprivation or hardship is built into the model. Much of the sustainability agenda is based on the idea that we must conserve as much energy as possible because a) it uses less fossil fuel (which is a good thing) and b) because energy is going to get progressively more expensive. It may, or it may not, but we currently have little idea how much energy will cost in 2050, anymore than we know what house prices will be or what the FTSE 100 will stand at. But we are having to make policy as if we did.
But it's not quite true to say we know nothing about future energy prices. We are currently going through a process over commissioning the Hinkley C nuclear power station where a strike price has been negotiated. This is a guaranteed minimum price which EDF, the operator, will receive over the first 35 operational years of the plant. That takes us to 2058. Now, in general, press comment has been pretty negative about this strike price negotiation because, at £92.50 per MWh, it's roughly twice the price currently being paid to generate electricity from fossil fuel. The strike price may or may not be a rip off — we really won't know until well into the 2030s or 40s —but if this strike price sticks, and if it becomes a template for other low carbon energy sources such as wind farms and tidal lagoons, then it may well give us some sort of indication about just where we are headed.
Put it another way, it may appear to be expensive now, but it begins to give some certainty about future directions in energy prices. It's like an insurance policy stating that energy won't cost anymore than this in 2050 (give or take the effects of inflation). The only reason it can do this is because the cost of developing nuclear power — in common with most forms of low carbon energy — is mostly to do with upfront capital cost. The running costs tend to be insignificant in comparison.
Here, I don't want to get into the pros and cons of which low carbon energy source we should be building. Just wish to point out that one of the key advantages of having a strike price like this for low carbon energy is that it builds an element of certainty into the process decarbonising everything. It also begins to address the vexed issue of how much retrofitting we should be carrying out because you can at last begin to quantify the potential savings.
The strike price is key to unlocking a sense of direction. Without it, sustainability is all hot air and easy for detractors to shoot down. When you get sound commentators like Robert Wilson praising something written by David Rose in the Daily Mail, we know we have a problem.
Many of the existing green policies are proving to be questionable, to say the least, and many of the really big questions are not being addressed, let alone answered.
My own journey through the byways of sustainability has also reached something of a brick wall. Having quietly campaigned for better energy performance in homes, and for tougher and better building regulations, I began to fall out of love with all the red tape involved with projects like the Code for Sustainable Homes and the move the Zero Carbon everything.
Then I got involved with David Mackay's 2050 calculator project and it opened my eyes up to just how big the problem of global carbon emissions actually is and how little difference having tighter building regulations will make in the great scheme of things. I was already convinced that climate change is an existential problem, the like of which we have never faced before, but I have come to question my belief that the world of sustainable building practice is necessarily very relevant to it.
Take deep-retrofit by way of example. Acres of print has been expended on how it should or should not be done. The government has got itself tangled up in knots over the Green Deal which was meant to kickstart radical retrofit but has simply highlighted how difficult it all is. Underlying all this is the plain fact that our existing housing stock is pretty poorly constructed and that it might well be cheaper and simpler just to pull it all down and start again.
Which is also highly unlikely, seeing as how we have 25 million homes in this country. We are having trouble adding more than 0.5% to this total every year, so retrofitting or rebuilding the existing 25 million begins to look like a pie-in-the-sky project.
One of the pointers coming out of David Mackay's work is that there are many ways to skin a cat. Most people — Mackay included — tend to favour a bit of everything, so here a little bit of retrofit, there electric vehicles, plus a bunch of diverse renewables and maybe some nuclear power, not to mention a little behavioural change. But this pot pourri approach tends to ignore the No 1 critical factor which is that within a very short timescale we need to wean ourselves off fossil fuels almost entirely. If we can't do that, everything else becomes irrelevant. However, it doesn't follow from this that low carbon/zero carbon energy will either be in short supply or be ruinously expensive. We could in fact face a low carbon energy glut, if we got our act together.
But this isn't something that conventional sustainability is at all comfortable with. It's as if some form of future deprivation or hardship is built into the model. Much of the sustainability agenda is based on the idea that we must conserve as much energy as possible because a) it uses less fossil fuel (which is a good thing) and b) because energy is going to get progressively more expensive. It may, or it may not, but we currently have little idea how much energy will cost in 2050, anymore than we know what house prices will be or what the FTSE 100 will stand at. But we are having to make policy as if we did.
But it's not quite true to say we know nothing about future energy prices. We are currently going through a process over commissioning the Hinkley C nuclear power station where a strike price has been negotiated. This is a guaranteed minimum price which EDF, the operator, will receive over the first 35 operational years of the plant. That takes us to 2058. Now, in general, press comment has been pretty negative about this strike price negotiation because, at £92.50 per MWh, it's roughly twice the price currently being paid to generate electricity from fossil fuel. The strike price may or may not be a rip off — we really won't know until well into the 2030s or 40s —but if this strike price sticks, and if it becomes a template for other low carbon energy sources such as wind farms and tidal lagoons, then it may well give us some sort of indication about just where we are headed.
Put it another way, it may appear to be expensive now, but it begins to give some certainty about future directions in energy prices. It's like an insurance policy stating that energy won't cost anymore than this in 2050 (give or take the effects of inflation). The only reason it can do this is because the cost of developing nuclear power — in common with most forms of low carbon energy — is mostly to do with upfront capital cost. The running costs tend to be insignificant in comparison.
Here, I don't want to get into the pros and cons of which low carbon energy source we should be building. Just wish to point out that one of the key advantages of having a strike price like this for low carbon energy is that it builds an element of certainty into the process decarbonising everything. It also begins to address the vexed issue of how much retrofitting we should be carrying out because you can at last begin to quantify the potential savings.
The strike price is key to unlocking a sense of direction. Without it, sustainability is all hot air and easy for detractors to shoot down. When you get sound commentators like Robert Wilson praising something written by David Rose in the Daily Mail, we know we have a problem.
14 Feb 2014
Taplexia
I think I've discovered a new disability and, what's more, I think I suffer from it. I've called it taplexia and it's the inability to tell hot taps from cold, unless they have an 'H' or a 'C' attached to them, or just maybe a red or a blue ring around them.
Now there is a convention here that the hot tap should be situated on the left and the cold on the right. It's even made it into the building regs: where hot and cold taps are provided, the hot tap should be on the left says Part G. What could be clearer than that? But somehow this convention/regulation has passed me by all these 60 years and I still find myself turning on both taps to find out which is which. The more modern the tap, the worse it seems to get.
Mixer taps in particular leave me completely at sea because they are so designery these days that they eschew all that retro-chique details like red or blue bands. The other morning I was in a strange bathroom (don't ask what I was doing there - this isn't a confessional) and I was faced with a Noughties mixer tap set-up. One spout, two handles: enough to induce a mild panic. I wanted hot but like the idiot-taplexic that I am I started on the right hand side. What was weird was that after five seconds or so it started running hot and I congratulated myself on guessing correctly. Only it turned out to be but a short burst of hot, presumably because the cold pipe had been inadvertently heated as it passed by a nearby radiator or something. It then ran cold on me and it dawned on me that I must have guessed wrong. Silly me.
So I then went left and ran that one. But after ten seconds or more it was still running cold. Could it be that the right tap was actually the hot one and that I just hadn't been patient enough to let the real hot water find its way to the spout? Should I try it again and see? So I turned off the still cold hot tap on the left and went back right. Then I stopped myself mid-track. Surely there had to be an easy answer to this? How come I had been turning this pair of mixer taps on and off for more than a minute and still hadn't got a clue which tap was hot and which was cold? This could only be taplexia in its severest form. A complete failure to adapt to the modern world. For some people it's passwords, for others it's TV remotes. For me, it's taps.
There is of course a simple cure for taplexia. Turn them both on and wait till the ensuing water turns lukewarm. Then you can simply turn one off and—hey voila— even I can work out which is which. But my inner greenie tells me that this is incredibly wasteful habit and I just don't like doing it. So I struggle on with my guesswork approach, often wasting as just as much water by guessing wrong.
Maybe writing about it will help. Maybe not. I won't know until I face another strange set of taps. Even if I do work out a cure, I am still faced with hotel shower syndrome.....or HSS as it's infrequently acronymed. This will find me standing naked in an unfamiliar environment fiddling with dials and levers none of which I have any idea about. It's like it's all been designed to make me feel inadequate.
Is it just me? Or is taplexia widespread?
Now there is a convention here that the hot tap should be situated on the left and the cold on the right. It's even made it into the building regs: where hot and cold taps are provided, the hot tap should be on the left says Part G. What could be clearer than that? But somehow this convention/regulation has passed me by all these 60 years and I still find myself turning on both taps to find out which is which. The more modern the tap, the worse it seems to get.
Mixer taps in particular leave me completely at sea because they are so designery these days that they eschew all that retro-chique details like red or blue bands. The other morning I was in a strange bathroom (don't ask what I was doing there - this isn't a confessional) and I was faced with a Noughties mixer tap set-up. One spout, two handles: enough to induce a mild panic. I wanted hot but like the idiot-taplexic that I am I started on the right hand side. What was weird was that after five seconds or so it started running hot and I congratulated myself on guessing correctly. Only it turned out to be but a short burst of hot, presumably because the cold pipe had been inadvertently heated as it passed by a nearby radiator or something. It then ran cold on me and it dawned on me that I must have guessed wrong. Silly me.
So I then went left and ran that one. But after ten seconds or more it was still running cold. Could it be that the right tap was actually the hot one and that I just hadn't been patient enough to let the real hot water find its way to the spout? Should I try it again and see? So I turned off the still cold hot tap on the left and went back right. Then I stopped myself mid-track. Surely there had to be an easy answer to this? How come I had been turning this pair of mixer taps on and off for more than a minute and still hadn't got a clue which tap was hot and which was cold? This could only be taplexia in its severest form. A complete failure to adapt to the modern world. For some people it's passwords, for others it's TV remotes. For me, it's taps.
There is of course a simple cure for taplexia. Turn them both on and wait till the ensuing water turns lukewarm. Then you can simply turn one off and—hey voila— even I can work out which is which. But my inner greenie tells me that this is incredibly wasteful habit and I just don't like doing it. So I struggle on with my guesswork approach, often wasting as just as much water by guessing wrong.
Maybe writing about it will help. Maybe not. I won't know until I face another strange set of taps. Even if I do work out a cure, I am still faced with hotel shower syndrome.....or HSS as it's infrequently acronymed. This will find me standing naked in an unfamiliar environment fiddling with dials and levers none of which I have any idea about. It's like it's all been designed to make me feel inadequate.
Is it just me? Or is taplexia widespread?
12 Dec 2013
Does embodied energy really matter?
We are hearing more and more about embodied energy and the role it plays in the carbon story. But what exactly is embodied energy and should we pay attention to it at all? Good questions both and the answers are not straightforward.
Firstly, what defines embodied energy? Essentially, it's the energy used to manufacture a product or construct a building. Thus building a new house involves assembling a long list of diverse materials and each of these materials had to be made from other materials and all this had to be transported from A to B to C to wherever your building site is. All this manufacturing and transportation involves expending energy and so, long before your house is ever lived in and the heating is turned on, the TV and computers get fired up and the lights switched on, you have used a great deal of energy — embodied energy.
My rule of thumb calculations show that a typical detached new house, built using brick and block and timber windows, uses around 40tonnes of CO2 in its construction. Now what does that represent? Let's have some comparators.
• The UK releases around 10 tonnes of CO2 per head of population per annum
• A car driving 12,000 miles a year uses around 4 tonnes of CO2
• A family of four flying to Spain and back uses around 2.5 tonnes
• A typical uninsulated 1970s house burns as much as 15 tonnes of CO2 per annum
• A building regs standard new house will burn around 4 tonnes of CO2 per annum
• Same house built to Passivhaus standard will burn around 1.5 - 2 tonnes of CO2 per annum
So given all that, how does the 40 tonnes of CO2 used to construct a new house stack up? One interesting observation is that if you replace a 15-tonne 1970s house with a 1.5-tonne Passivhaus, you will have achieve a net saving of CO2 within three years. In such an instance, you might feel you could afford to ignore the embodied energy total of 40 tonnes.
But of course, not many new homes are replacement dwellings, so they are in fact adding to the overall load of CO2 which Britain as a whole emits. And very, very few new homes are being built to Passivhaus standards or similar, so more typically they will be adding something like ten years of operational energy use in the construction phase alone.
This balance between embodied energy and operational energy is critical. And complex. You have to make some heroic assumptions, such as how long will a house last? And what will be the carbon intensity of energy in years to come? Does the embodied energy level go up significantly if you add energy saving features such as triple glazing to the design? What about features that may need replacing in the house — such as triple glazed windows — long before the design life of the house is through? There are no straightforward answers here. Everything rests on the assumptions made.
And what about reducing the embodied energy levels in a new house? Well, it can be done. The bulk of the embodied energy in new UK housing goes into the concrete and masonry elements because they are both energy intensive to manufacture and extremely heavy relative to volume. In the model house in the Housebuilders Bible 10, masonry and concrete materials make up 27 tonnes CO2 out of a total of 36 tonnes (that's 75%).
Interestingly, over half of this 27 tonnes of CO2 is made up of bricks and mortar, rather than concrete products. There are ample opportunities to switch to materials with lower embodied energy, such as timber and natural materials like stone and slate. Plastics and foam insulation have minimal impact overall (partly because they are so light) so that switching over to alternative materials such as natural insulation isn't really going to make any significant difference. Nor will switching to lime-based products.
And, of course, there is the question of cost. There are similar calculations to be made about construction costs versus running costs and maintenance costs and in some ways financial costs are a proxy for energy loadings. As people often point out, if carbon was correctly priced from an environmental point of view (i.e. if there was a carbon tax applied across the board), then there would be no need to carry out embodied energy calculations separate to cost calculations.
Which begs the question, should we be worried about embodied energy at all, or is it just an obscure branch of environmentalism, pursued by geeks and nerds, which is ultimately of no consequence. By the time we get to 2050, we will either have sorted out our power supplies so that they are all low carbon and thus talk of embodied energy will be irrelevant, or we will be all heading to hell in a handcart, in which case embodied energy will also be irrelevant.
I'm not sure there is a clearcut answer to any of this but energy wonks (I count myself as one) find it all rather fascinating. If you want to know more @CraigJonesUK is the man. Craig has created the invaluable (and freely available) ICE database which will tell you more about embodied energy than you are ever likely to want to know.
Firstly, what defines embodied energy? Essentially, it's the energy used to manufacture a product or construct a building. Thus building a new house involves assembling a long list of diverse materials and each of these materials had to be made from other materials and all this had to be transported from A to B to C to wherever your building site is. All this manufacturing and transportation involves expending energy and so, long before your house is ever lived in and the heating is turned on, the TV and computers get fired up and the lights switched on, you have used a great deal of energy — embodied energy.
My rule of thumb calculations show that a typical detached new house, built using brick and block and timber windows, uses around 40tonnes of CO2 in its construction. Now what does that represent? Let's have some comparators.
• The UK releases around 10 tonnes of CO2 per head of population per annum
• A car driving 12,000 miles a year uses around 4 tonnes of CO2
• A family of four flying to Spain and back uses around 2.5 tonnes
• A typical uninsulated 1970s house burns as much as 15 tonnes of CO2 per annum
• A building regs standard new house will burn around 4 tonnes of CO2 per annum
• Same house built to Passivhaus standard will burn around 1.5 - 2 tonnes of CO2 per annum
So given all that, how does the 40 tonnes of CO2 used to construct a new house stack up? One interesting observation is that if you replace a 15-tonne 1970s house with a 1.5-tonne Passivhaus, you will have achieve a net saving of CO2 within three years. In such an instance, you might feel you could afford to ignore the embodied energy total of 40 tonnes.
But of course, not many new homes are replacement dwellings, so they are in fact adding to the overall load of CO2 which Britain as a whole emits. And very, very few new homes are being built to Passivhaus standards or similar, so more typically they will be adding something like ten years of operational energy use in the construction phase alone.
This balance between embodied energy and operational energy is critical. And complex. You have to make some heroic assumptions, such as how long will a house last? And what will be the carbon intensity of energy in years to come? Does the embodied energy level go up significantly if you add energy saving features such as triple glazing to the design? What about features that may need replacing in the house — such as triple glazed windows — long before the design life of the house is through? There are no straightforward answers here. Everything rests on the assumptions made.
And what about reducing the embodied energy levels in a new house? Well, it can be done. The bulk of the embodied energy in new UK housing goes into the concrete and masonry elements because they are both energy intensive to manufacture and extremely heavy relative to volume. In the model house in the Housebuilders Bible 10, masonry and concrete materials make up 27 tonnes CO2 out of a total of 36 tonnes (that's 75%).
Interestingly, over half of this 27 tonnes of CO2 is made up of bricks and mortar, rather than concrete products. There are ample opportunities to switch to materials with lower embodied energy, such as timber and natural materials like stone and slate. Plastics and foam insulation have minimal impact overall (partly because they are so light) so that switching over to alternative materials such as natural insulation isn't really going to make any significant difference. Nor will switching to lime-based products.
And, of course, there is the question of cost. There are similar calculations to be made about construction costs versus running costs and maintenance costs and in some ways financial costs are a proxy for energy loadings. As people often point out, if carbon was correctly priced from an environmental point of view (i.e. if there was a carbon tax applied across the board), then there would be no need to carry out embodied energy calculations separate to cost calculations.
Which begs the question, should we be worried about embodied energy at all, or is it just an obscure branch of environmentalism, pursued by geeks and nerds, which is ultimately of no consequence. By the time we get to 2050, we will either have sorted out our power supplies so that they are all low carbon and thus talk of embodied energy will be irrelevant, or we will be all heading to hell in a handcart, in which case embodied energy will also be irrelevant.
I'm not sure there is a clearcut answer to any of this but energy wonks (I count myself as one) find it all rather fascinating. If you want to know more @CraigJonesUK is the man. Craig has created the invaluable (and freely available) ICE database which will tell you more about embodied energy than you are ever likely to want to know.
Subscribe to:
Posts (Atom)