Archive for the ‘Features’ Category
Posted on May 1st, 2013
Rob Borruso
As the next set of “improvements” to Part L of the Building Regulations gets nearer, some of the counter-productivities that the current rules throw up will, to my mind, move from being ‘just a little strange’ to cynics like me, to become serious problems.
To begin with, what level of CO2 emissions reduction from buildings will these new rules actually deliver? Well with 99% of buildings being immune from these revisions (because they’re already built) the best we’re looking at is a 1% improvement in the short term. The new rules will only be raising an already high bar – “making the best better”. As it is average emissions we’re interested in, shaving a few percent off the best performing properties i.e. new builds, will have almost no effect on total emissions in the short to medium term. Besides, all houses, both old and new, will be zero carbon in 2050 anyway as by then fossil fuels will be too expensive to burn!!
Ignoring the very real questions about value for money (which few believe lies in squeezing out the last 10% of CO2 emissions from the best performing buildings) I want to explore how a narrow focus on new buildings, without wider consideration of external energy issues, could actually push up CO2 emissions. It seems likely the further revisions to Part L will lead to two technologies in particular getting much more common in new build; these are Air Source Heat Pumps (ASHP) and PhotoVoltaics (PVs). I don’t want to talk about the illusory CO2 savings these technologies may or may not deliver, but rather self-evident facts that are not part of manufacturer sponsored ‘independent’ studies.
ASHP’s are a type of electric space heating; efficient maybe, but electric none the less. And, like all heating solutions, are required to work harder the colder it is. Because there is no requirement for ASHP to be combined with underfloor heating, most systems will be installed with radiators or as air to air to heat pumps. Air to air heat pumps are ‘on demand’ heaters, as are air to water heat pumps if combined with radiators (though to a lesser extent). That demand is going to be predominantly winter mornings and evenings. So, as more and more systems are installed, it will have the effect of increasing peak electric demand, compared to the gas heated alternative – I’ll come back to the gas use later.
Fortunately, (according the Government’s calculations) this increased electricity use can be offset by the installation of PV’s – well here’s the rub; it can’t. It is beyond dispute that PV output on winter mornings and evenings is effectively zero and that the electricity they generate during the summer months is used immediately, within 1/50th of a second of its creation. Therefore, this increased winter demand has to satisfied by some other technology. Wind is simply not reliable enough, nuclear is a base load technology so that just leaves our only other clean(ish) grid generator – gas. Here’s where the sums get interesting. A gas power station will turn 100 kWh of gas into about 40kWh of electricity which is then fed into an ASHP that on those cold winter nights will struggle to turn it back into 100 kWh of heat. So… billions of pounds spent on new power stations and heating systems and the amount of gas (and CO2 ) saved? Zero at best.
The fundamental problem is just about everyone concerned in the Part L revision process assumes wrongly that every kWh produced and consumed has a equal CO2 loading. It doesn’t. Furthermore the idea that the grid can be used as a battery only really works when nobody is actually using it as such. Generators are required to hold spare generating capacity above predicted peak levels, to be called upon if there is, say, planned maintenance or a breakdown somewhere. The problem is that as the network gets older, due to a chronic lack of investment since privatisation and more renewables being added, the likelihood and size of these breakdowns grows. Remember, every night PV’s are effectively ‘broken down’, making the grid increasingly vulnerable to outages at time of peak load. Unfortunately, renewables and peak electric heating (ASHP’s) make matters worse by increasing these peak loads. Therefore, over the coming years as peak time vulnerability increases, power company’s will have to build extra generating capacity that will only be running very inefficiently for a couple of hours in the evening. PVs on the roofs of ASHP heated houses will do nothing to alleviate this problem and if the PVs are used to justify the use of electric heating will actually make matters worse. Until these undeniable facts are faced up to we run the risk of wasting billions on technology that only give the illusion of CO2 savings.
Maybe the fact these revisions will not affect the vast majority of the building stock is not such a bad thing after all.
Posted on March 1st, 2013
Cath Hassell, ech2o consultants www.ech2o.co.uk 
We all know the high environmental load of traditional swimming pools; the energy required to heat them; the chlorine required to keep them clean; the large amount of water that is required to fill them in the first place and refill them after they have been drained down for the winter. It’s also common knowledge that a designer can ensure a pool is more sustainable by specifying a pool cover, installing solar thermal panels to heat the pool and considering ozone instead of chlorine as the disinfection method. But all of that does not need to concern us in the environmental building sector because if a client wants a pool, there is a perfect solution available on the market and that is a natural swimming pool. Right? Well wrong actually!
I was recently asked to provide a critical analysis of the water strategy for a large multi-million pound dwelling that, as with many such sustainable properties, had not addressed water beyond rainwater harvesting and dual flush loos. On first reading the one thing we didn’t have to worry about was the swimming pool as it was going to be a natural pool. But when we began to analyse the pool specification in detail some worrying facts emerged.
Natural swimming pools
A natural pool consists of a swimming area and a planted area, (the filtration zone).[1] The plants extract any nutrients that run into the water, thus restricting the growth of algae. A pump is used to circulate the water through a filter to aid cleaning. Natural swimming pools have several environmental advantages; no chemicals are required to clean the pool, thus preventing the formation of hazardous chemicals;[2] they do not require draining down over the winter and refilling in the summer, thus saving water; they use less energy as they are not heated; they provide a habitat for insects and amphibians in the shallow planted zone; and birds use the pool for drinking and bathing.
Natural pools are often designed to be larger than a traditional pool; in this case a surface area of 124m2 (compared to an average traditional pool size of 45m2). You would assume that a natural swimming pool would be quite happy (indeed prefer) to be filled with alternative sources of water to mains water. However, when we asked about filling the pool from the commercial fish ponds on the site we were told the nutrient levels in the water would be too high. So this pool would require 153m3 of mains water to fill – the equivalent of a daily use of 420 litres of water for a whole year! We asked about topping up with rainwater from the green roof and were again told that nutrient levels would be too high even though no fertiliser would be used on the roof.[3]
Evaporation losses
Evaporation, even from an unheated pool, is significant. Calculating evaporation rates is complicated, with many variables. The main factors that affect evaporation rates from domestic outdoor pools are pool surface area, temperature difference between the water and air, humidity levels and wind. Research in Australia has shown that the average daily evaporation rates from an unheated pool are 6.4 mm/day (6.4 litres/m2/day) for the six hottest months in Melbourne. The same research shows that a pool in Perth, in the coldest months, loses 3,000 litres a month over a surface area of 42m2.[4] In the absence of any comparable data for the UK I calculated evaporation rates from the pond using both sets of data (with changes to better reflect UK conditions) and came up with some depressing figures.[5] With a pool surface area of 124m2, and a rate of 2.1mm evaporation a day, 260 litres a day is lost to evaporation (against the average water use in the UK of 150 litres/person/day. Over four months this is 31,200 litres (31m3). Adding evaporation across the remaining eight months of the year (albeit at a lesser rate) total yearly losses are over a third of the pool volume. So far, so bad, and it gets worse… To keep the pool clear the water is continuously pumped through a filter. A pool this size will require a pump drawing 400 Watts. That is 3,504Wh of electricity a year, the average household’s total electricity use!
Alternatives
So am I saying no ponds at all? No, of course not. That would make for very poor garden design. But these highly engineered natural pools are not the solution. On this site, the response by the architects to our findings was swift and decisive. They reduced the size of the pool to 45m2 for the swimming area with a planting zone of 12m2, cutting evaporation rates, original fill water and electrical load by over 50%. And although the natural pool is currently still in the specification, the architects agreed to our suggestion to provide a natural pond as well, filled and topped up with rainwater from the green roof. The level of the pond will rise and fall with the seasons and the available rainfall. Any overflow from the pond will drain naturally into the ground via swales and rain gardens. A natural pond increases the biodiversity on this site as well as providing another focal point, and uses the runoff from the roof in the best possible way.
[1] The size of the planted area depends on the pool type but most have a planting zone of between 15-25% of the surface area of the pool.
[2] Chlorine in pool water reacts with organic compounds in the water such as sweat and urine to produce a host of hazardous chemical compounds that include nitrogen trichloride, aldehydes
[3] Both of the main suppliers of natural pools in the UK stated this.
[5] As Melbourne in the summer is hotter than the UK, I used a figure of one third the evaporation rates (i.e. 2.1mm/day) and over four months rather than six months. Using the Perth data as it stands but for all twelve months, yearly evaporation losses would be 36m3.
Posted on January 31st, 2013
Lucy Pedler Director, The Green R
egister
Last month one of our dear, long time Green Register and Steering Group members, Jim Allen, kindly wrote us a blog about the breathing wall concept and expressed his concerns about this method of construction, some of which I will try and address here.
The first point to make is that the term ‘breathing’ wall (or roof, floor or ceiling for that matter) is a pretty inadequate name for a very useful way of building that attempts to deal with a number of problems, namely: avoiding interstitial condensation, improving standards of work on site and employing the use of low embodied energy building materials. Jim is right in saying that walls don’t breathe – what the term suggests is that the walls ‘breathe’ large amounts of moisture in and out, much like our lungs do, which is not really the case.
Breathing construction is designed primarily to minimise or, better still, avoid interstitial condensation and it does this by using a combination of breathable materials and placing them in the construction build-up where their various values of vapour resistance will assist with moisture movement most effectively. This includes two vapour control layers – one either side of the insulation layer with differing vapour resistance values and I am not sure many people are suggesting throwing away the vapour barrier except perhaps in exceptional cases for some historic buildings.
The ideal situation would be that all external elements of a building would have a continuous, unbroken vapour control layer that remains intact throughout the building process and thereby keeps the moisture that builds up inside the building during use due to human activities (showering, cooking, breathing etc.) from ever entering the fabric of the building and causing interstitial condensation. This requires competent builders who understand why it is so important to maintain the integrity of the vapour control membrane. With the exception of a few (many of whom are, of course, members of The Green Register – searchable under ‘builders’ on our website list of members), this rarely happens. In my experience a building site is a messy place with lots of trades working around each other trying to meet deadlines and the opportunities for inspecting the continuity of the vapour control layer is quite limited. This can lead to breaks in this layer, the subsequent ingress of airborne moisture into the building fabric and resultant deterioration of the construction, sometimes behind the scenes where it can cause potential structural damage.
Jim’s reference to our Canadian cousins may well be to a World in Action programme back in the 1980’s which reported on the demolition of a timber-framed housing estate in Canada that was found to have damaging moisture buildup within the framing. The programme purportedly described how breathing construction principles had not been understood; the walls were wrapped on both sides of the insulation with plastic vapour control layers, site work resulted in holes in these layers, moisture got in through the holes but couldn’t exit because of the impermeable layer of plastic and rotted the timber which compromised the structural integrity of the building so they had to be torn down. Fortunately we now understand what went wrong with this housing scheme and breathing construction can help to avoid these problems in the future.
It is really important to understand that the principle of breathing construction accepts that there will be some airborne moisture entering the fabric – although this is always kept as low as is practically possible – but that, with a combination of breathing materials and intelligent use of vapour control layers, this moisture will be speedily and safely transported to the outside where it does no harm. It does not suggest that it is acceptable to have excessive amounts of airborne moisture entering the building fabric, only that that which does enter can exit even more easily.
Another misunderstanding is that breathing construction does away with the need for ventilation – this is a dangerous concept. Because only very small amounts of moisture are intended to pass through to the structure of the building, most of it needs to be extracted by one of the various ventilation methods we conventionally employ for non-breathing constructions such as natural or passive ventilation, trickle vents, windows, extract fans and so on.
I am completely in agreement with Jim when he expresses his concern for retrofitting insulation to buildings and the risks of interstitial condensation arising. I am writing this on the day that The Green Deal was launched (again) and, whilst being in the minority of people who think that this is a useful Government initiative with lots of potential, I am very worried about layers of insulation being installed in retrofit projects without a comprehensive understanding of what this does for the dew point and moisture movement. Our ‘All in The Detail’ one day seminar addresses this in depth – Jim attended this seminar and it may have spurred him to write his excellent blog.
Unless Green Deal installers have sufficient knowledge about the risks of interstitial condensation, the retrofitting of insulation onto existing building elements may be storing up problems for the future. But this is a surmountable problem. As Jim suggests, more research must be carried out with real life examples; additionally, training installers in this field will help them to understand the risks and the solutions to avoid moisture build-up in retrofit projects…and also avoid lots of court cases in the future.
Posted on December 1st, 2012
Cath Hassell ech2o consultants www.ech2o.co.uk
Team GB delivered during the Olympic Games on their medal target, but what about water use? Does the claim of “the greenest games ever” hold up under scrutiny? The goal was a 40% water saving compared to 2006 industry standards, and although the “industry standards” were not explicitly stated it was an ambitious target that, if achieved, would certainly be impressive. When the Olympic Park Water Strategy report[1] stated that: “…the Park in legacy mode is expected to exceed this target with a total 57% saving in water consumption”, you could almost feel the nation’s chests swell with pride. However, just as the mantra “delivered on time and on budget” falls apart when you realise that the budget for the Games was increased to £9 billion from the original £2.4 billion, predictions of reduced water consumption also need to be analysed more closely.
The 40% target
In 2006, WC flush was 6 litres maximum, urinal controls were mandatory, and taps in public washrooms were already time controlled, so a 40% reduction would require alternative sources of water as well as efficient appliances, and originally it was expected that would be mostly from rainwater harvesting. The preferred specification for appliances was 4.5 litres single flush WC, fan assisted waterless urinals, PIR operated taps at 5 litres/minute and showers at 9 litres/minute. All venues installed low flush toilets, and low flow showers and taps as recommended in the design brief, but the Velodrome and Aquatics Centre opted for flushing urinals. The Velodrome and Handball Arena installed rainwater harvesting and the Aquatics Centre installed backwash recycling. Rainwater harvesting is estimated to reduce the Velodrome’s potable water demand by 20% and predicted to generate a potable water saving of 530m3 a year.[2] (However, with just 25m3 of storage and the fact that the stadium will be used so intermittently after the Games, this figure seems optimistic to me.) Recycling the filter backwash water for WC and urinal flushing is estimated to reduce water consumption in the Aquatics Centre by three per cent.[3]
Where was the water used?
It was estimated that water consumption up to and during the Games would be 361 Mega litres (Ml).[4] Post Games the figure is 5,735 Ml over the remaining 24 years design life.[5] This meant that 6% of total lifetime water use would be during the Games. How that requirement for water was broken down is very interesting. I had assumed the greatest demand would be WC and urinal flushing from the estimated 3.7 million visitors, closely followed by the Aquatics Centre. But in fact, the Olympic Park Water Strategy estimated water consumption to be as follows: the Combined Cooling, Heating and Power Plant at 26.9%, Eton Manor at 15.6%, 7.7% for the Aquatics Centre and 7.5% for establishment irrigation leaving just 14.5% of water requirement for the remaining venues on the site which included the 80,000 capacity Olympic Stadium and the Press Centre.[6]
I hadn’t even considered the process water requirement for the CCHP plant, but it made sense once highlighted. But Eton Manor, what was happening there? And why was so much water required for irrigation when most of the park was planted with wildflower meadows?
Water based hockey pitch
Hockey is played at Eton Manor on a water based pitch. Water-based synthetic turfs enable the ball to be transferred more quickly than sand-based surfaces and are less abrasive so reduce friction burns, but require a lot of water as the pitch is flooded with water before the start of every match to a depth of 3mm. With a playing surface of approximately 6,000 m², and top up required at half time, water use averages 26 m³ per match.[7] Added to this is the fact that the pitch has to be kept wet constantly and, to prevent the growth of algae, hydrogen peroxide is added to the water. As the Intentional Hockey Federation themselves (back in 2006) suggested that hybrid pitches (sand and water based) would be preferable because of the very high water consumption of water based pitches, it is a pity that a hybrid pitch was not specified for the 2012 Games.
Irrigation
I was surprised at such a high requirement for irrigation. The wildlife meadows on the Park require establishment irrigation for two seasons, (which is not the case in other projects I have been involved with) whilst the trees require irrigation for the first three to four years. Initially, consideration was given to constructing swales to store rainwater but this solution was rejected because “they could not hold the volumes of water required”.[8] So, all irrigation uses water from the Old Ford Water Recycling Treatment Works. There are a lot of green walls around the park which require permanent irrigation, and although drip irrigation is the preferred delivery method throughout the Park for all the planting, using an industry standard approach is a missed opportunity. If the irrigation system was combined with soil moisture sensors then at least the unprecedented rains would have reduced the requirement for watering.
And the result is…
There are no figures to back up the 57% claim, so we will disqualify it. For the 40% target, 18% is estimated to be met by water efficient appliances and the remaining 22% by Old Ford using treated sewage from the northern outflow sewer.[9] Old Ford will provide a minimum 46 Ml (46,000m3) of treated water a year, and as the first direct reuse of waste water in the UK, it will be interesting to see how it performs, particularly in regard to the amount of energy it uses per m3 of water supplied. Water consumption on site during the construction phase seems to have been ignored which (if that is the case) is a cop out. So certainly not a gold medal, but as the feel good factor is still in the air I shall go for bronze.
This article was first published in Green Building magazine, Autumn 2012
[4] One Mega litre is 1,000,000 litres or 1,000m3
[5] 5,735Ml over 24 years is an average of 239 Ml a year. I assume that the bulk of it will be for the CCHP plant and the 2,818 new homes that will be built on the site, although no details were given in the report.
[6] The Olympics Village is not classified as being part of the Park.
[9] Though if the CCHP plant and Eaton Manor hockey park are taken out of the equation, the reduction from water efficient appliances increases to 33%.
Posted on October 31st, 2012
by Steven Harris stevenh@steven-harris.co.uk
Trumpets! Fanfares! Fireworks? Well, maybe not, but as the Green Deal is softly-softly launched, most of us will probably not notice it starting, despite the energy companies’ best efforts to blame their price rises on it. And maybe it’s right only to whisper the launch since I read recently that when asked, the British public distrust both the words ‘Green’ (sandals) and ‘Deal’ (double glazing salesmen). So is this just an unfortunate choice of words? Well before Green Deal and the current Government there was of course ‘pay as you save’; less untrustworthy words even if they did have a touch of the oxymoron about them.
Back in 2006 at ZEDfactory when we were toying with the ‘invest in energy saving’ concept, it all seemed so much simpler. Take out a loan to put some PV panels on your roof and the monthly saving/income they would generate could help meet your loan repayments, and then as energy prices increased, you might even start making a profit. These were pre FIT days of course. It even seemed to make sense when you looked at insulation. Take out a loan to pay for some additional insulation and the kWhrs you save by having less W/m2/oK escape from your walls would repay the loan with ease.
So what went wrong? – Well lots really!
First though for the positive. PV – fantastic! Point a panel at the sun and it will harvest a pretty guaranteed average annual income for at least the period of a suitable loan. With FIT this of course hit the nirvana of the ‘bleeding obvious’ and those with the nous and free cash got on with it. But herein comes the first problem, namely ‘free cash’. This was picked up in an EST/money saving expert.com web forum in 2010. The point made was, is taking out a loan to invest in PV a good use of your personal credit limit? Yes, it made return on investment sense, but would it mean you couldn’t then take out another loan to replace your car or have that holiday next year?
Similarly, while working with the Ecology Building Society at ZEDfactory back in 2006 we discovered the problem of ‘first charge’. The lovely people at Ecology supported the ‘invest in energy saving’ concept strongly, but being forthrightly prudent as proper mutuals should be, they would only loan the money if they could have first charge on the property. They also liked a safe loan to value ratio, which was considered very strange pre 2008. This was a realisation that you couldn’t just go on borrowing and borrowing using the ‘leverage’ of the projected income. At some point your lever would snap! (Although we did also meet Lehman’s to discuss the idea!). First charge means that the lender is first in line to be paid back if things go wrong and the property repossessed. Even being second in line is risky. And of course, risk equals higher interest rates, equals more work for the energy saving measure to do to pay its way.
At this point things start to fall apart.
The other show stopper, which seems blindingly obvious now, is comfort take up. We naively thought that if you doubled the insulative value of a home, half as much heat would escape from it. Well no! Following EST studies into the effects of cavity wall insulation, it seems instead that the occupants have their home twice as warm, or to put it another way, keep their home warm enough that they don’t have to get dressed under the bed sheets anymore. Great, but bang goes your ‘loan repaying’ savings income stream!
So could ‘Green Deal’ get over all of this and do it right?
Perhaps getting past the ‘first charge’ issue by fixing the loan to the property address (like a gas or electricity bill) rather than property value or occupants credit limit could be a good move, but maybe the idea needs representing. ‘Don’t think about the green deal as a loan repayment, but instead as a utility bill! But this isn’t a bill for the energy you have used, this is a bill for the energy you haven’t! It pays for the stuff that has been done to your home to stop you needing energy. A ‘negawatts’ bill if you like.’ A ‘negawatts’ bill might also, with the correct spin, get over the comfort take up problem. You could now have a choice. Pay for the energy to keep you house warm enough to not have to get dressed under the bed sheets, or pay the negawatts bill to do the same. Hmm. Sounds like Hobson’s choice, but then remember, once upon a time we were concerned with climate change and saving the planet.
However – sadly – for Green Deal, all now lies in the hands of financial institutions and what interest rates they decide to charge. So for the time being I think I might think about the golden rule, but then stick within my credit limit and stay with my traditional, prudent, first charge, cooperative, low cost funder. (It also means I don’t have to keep checking the Green Deal rules).
Posted on September 3rd, 2012
Alex Stephenson Director, UK Stormwater Division, Hydro International. www.engineeringnaturesway.co.uk
With one voice, a cry for ‘clarity, clarity, clarity’ has gone out to Government in response to the National SuDS Standards consultation. There are strong indications that both local government and industry believe the standards, as they currently stand, are not yet fit for purpose.
The devil is definitely in the detail as far as the new standards are concerned: The problem is – no-one is quite sure what the detail is. Many are worried that a dilution of the original principles has crept in, introducing exemptions in a number of areas which could undermine the whole intent.
What’s more, just when everyone should be gearing up for an October 2012 start, everything seems to have gone quiet at Defra. No doubt, the responses will have given the Government much food for thought.
So here’s my best guess at the top seven big questions on Defra’s ‘to do’ list.
1. What Will the Guidelines Contain?
The Government has promised detailed Guidelines to accompany the National Standards. There’s little doubt that the Standards in their current form are insufficient without them. As the Local Government Association (LGA) attests, the standards are more ‘a set of guiding principles’ than a ‘national standard or specification’. Many agree the guidelines would need to have been written, scrutinised and agreed by industry before the new SuDS approval system begins. To be effective, the guidance needs to be binding, not just advisory.
2. When will the new regulations commence?
Local Authorities have requested at least 6 months’ notice before commencement. This already takes us beyond October. One leading local authority respondent, the Cambridgeshire Flood Risk Management Partnership claims a 1st October start is “unrealistic” and “unlikely to be achievable” for many councils to build skills and capacity. It seems April 2013 is looking ever more likely – a route favoured by myself.
True, some local authorities are well advanced in their preparations and there is nothing to stop them and forward-looking developers from adhering to SuDs principles in the meantime – providing there is clarity on adoption of any SuDS features developed during the interim phases.
3. What will the Transitional arrangements be?
The Government’s suggestion of a phased implementation in which only developments over 10 dwellings will be required to have SuDS approval for the first 3 years has drawn mixed views. Phasing would allow lessons to be learned on larger schemes by developers and local authorities alike, but some feel this could water down and delay the national take-up of SuDS significantly, as many smaller developers are precisely those that require more guidance and support. One option would be for SABs to be able to sub-contract the necessary expertise from industry, where the skills already exist.
4. What does ‘affordable’ mean?
Affordability is the most hotly debated issue of all: The Government’s statement that “Drainage for surface runoff should be sustainable and affordable to build and maintain” may seem easy to agree with at first glance. But how will affordability be tested in practice?
Developers welcome the addition of an affordability test as part of the guidelines. But there are major disagreements on what affordability means: For developers it means that the cost of constructing SuDS should not outweigh the benefits, protecting them from unnecessary costs. But focusing on capital costs alone is not comparing like with like, and some fear affordability will be used as a ‘get out’ clause. Many argue that affordability should consider the holistic, whole-life benefits of a SuDS scheme. The multi-benefits of SuDs, such as amenity and biodiversity, could also be monetised in some way.
Incidentally, there is a strong argument that SuDS are cheaper or comparable to conventional systems, in any case. And what exactly is meant by conventional, by the way?
5. What does Reasonably Practicable Mean?
The term ‘reasonably practicable’ is used 15 times in the proposed standards. In a dispute between a developer and a SAB – who decides what that means exactly? Will the guidance be sufficient, or will it be left to lawyers to argue?
6. Where does the LA’s responsibility to adopt end, and the Water Company’s begin?
There appear to be some significant potential differences of interpretation of the definition of “sustainable drainage system” as “those parts of a drainage system not vested in a sewerage undertaker”. Respondents have demanded more clarity in terms of which parts of the drainage system will be adopted by the SAB and which part by the Water Company. The forthcoming publication of Sewers for Adoption 7th edition may be able to provide more guidance.
7. Why Exempt Single Properties from SuDS Approval?
The proposal that SuDS Approval and subsequent Local Authority adoption should only be required for drainage systems serving more property is a cause of inconsistency, if not confusion. Why should a large commercial scheme, such as a supermarket for example, not go through the SAB process? What about residential buildings in multiple occupation? Unadopted SuDS on these developments would have to be maintained by the tenants or building owners.
Runoff from large single properties could have significant impact on surface water drainage in the area. What recourse would the water company have in such circumstances? Surely a ruling based on minimum area of land would be more reasonable?
I must stress that there is overwhelming support for the Government in implementing the Flood and Water Management Act, and for the principles embodied in Schedule 3, which seeks to implement the National Standards.
Getting things right from the outset is so important, because failure will lead to a patchy and inconsistent implementation of SuDS across England and Wales. It’s been five years since widespread flooding in England set us on the road to radical changes in surface water management. We must neither falter, nor delay any further.
Posted on July 29th, 2012
By Rob Borruso
Having recently wrecked my environmental credentials by having a second child my world is again one of nappies and sleepless nights. Of course we’re told the most sustainable nappy is a reusable one so they’re hanging up everywhere at home, which got me thinking…
Now, I’m not going to use this blog to do a life cycle analysis of nappies but rather to show just how difficult they can be and include things you’d never think of. The case against the disposable nappy revolves around two points; the resources consumed to make them and the space they take up in landfill. The former I’m not going to question but the latter….. I’ve got some issues.
Over 80% of the weight of a used disposable nappy is water which, because the ‘damage’ caused by land-filling domestic waste is still measured quantitatively not qualitatively, appears to be more of a problem than it actually is. I.e. one tonne of water (which is inert) is counted as having the same disposal issues as one tonne of everything else that ends up in wheelie bins. Whereas, from a long term environmental perspective it really isn’t. So the damage caused but putting nappies in a wheelie bin really isn’t the same as putting in plastic coated paper- but is, nevertheless, not desirable.
Especially as there’s an eco alternative, the reusable nappy right? Well maybe. Reusable nappies do consume lots of resources, some obvious, and some not so obvious. Of course there’s the water, energy and chemicals involved in washing the things, but in my opinion these do not outweigh the issues associated with disposables. But then come the less obvious issues, firstly drying (which I’ll return to later) and then there’s washing machine wear. A baby’s worth of reusable nappies will likely generate about 300 additional loads which is pretty close to the scrap life of a modern, (who bothers to get machines repaired?) washing machine. So now in my view we’re pretty close to there being very little difference between disposable and reusable nappies and the argument starts to boil down to which is more precious, landfill space or water and energy.
With the case for reusables now weakened it wouldn’t take much to make the throwaway option better. This is where the huge issues around drying come into play. Nappies are difficult to dry – they absorb a lot of water they wouldn’t work otherwise. Therefore, drying them artificially, either in a tumble dryer (at least 2kg CO2 per load) or over radiators (which consumes just as much energy and can lead to condensation problems) can wipe out their environmental credentials. This is where that most overlooked but massively effective eco-gadget comes into play – the washing line. Even in my west of Scotland home we can get most of our washing ‘out’ on the line. Do architects and especially planners give much thought to this most cost effective energy saving device – no! Much greater effort should be made to encourage their provision and use. I know this is easier said than done. Experiences with communal drying areas (which CfSH does give credit for) that have been less than positive prove that, but really, is designing a washing line facility beyond the skill of humanity?
The point is planning can and should influence behaviour and its behavioural change that is the key to reducing resource consumption not £600m of PV subsidies given to the well off. The system that dictates the houses we should all live in seems, to my mind, to be far too focused on the wrong things; like whether the right shade of grey for the fake slate roof tiles occupies as much time as ensuring dwellings are suitable for a world in which oil is $200 a barrel. The home owners of the future will be much more concerned about their ability to dry clothes (and nappies) or grow some vegetables rather than the exact colour of their brick mortar.
Posted on July 4th, 2012
By Jim Allen | E&M West Ltd | www.eandmwest.co.uk
You see before you a photograph of a piece of domestic crockery, with a difference. It has been the subject of DESIGN. Its basic function is obvious but for the uninitiated in the art of tea making it is to contain high temperature liquid (water) allowing the diffusion and dissolution of various chemicals from a herbal product (tea).
It is dependent on the skill of its operator if the perfect cup of tea is to result, but we will not dwell on the number of tea spoons or bags, pre-heat, the precise water temperature or brew times here. It is the impact of the pot itself that interests me, and the steps taken by its designers to improve performance.
Arguably this is a very sustainable tea pot. In the first place it is reclaimed, having been rescued from a trestle in the Bude car boot sale for the princely sum of £5:00 (near closing, rainy day).
Moving swiftly from procurement I want to consider how design impacts its central function which is the ability to retain heat to enable sufficient brew time to get a strong hot cup of tea (and no, the microwave does not improve the flavour).
Immediately obvious is its cute wooden stopper snugly fitting its spout and preventing hot air rising and convection heat loss. It sits very daintily on four spherical wooden feet. In this context the wood is a relatively good insulator, and as there is only point contact, there is very limited conduction to any cold surfaces you might be foolish enough to sit it on.
This does however present a second design problem, as this encourages air flow around the hot body, with risk of heat loss due to external convection. The designers have thought of that, and engineered (a subject close to my own heart) an insulated stainless steel jacket, limiting surface temperature. The polished surfaces internally also reflect radiant heat energy further enhancing performance.
But wait, I hear you say, stainless steel is a very expensive and scarce resource, and its manufacture will have consumed much of the earth’s limited stock of raw material. Some truth there, but given this pot originates in the late 50’s, that steel was probably recycled from steam engine connecting rods courtesy of British Rail, and anyway, its robustness has allowed the teapot to survive its journey to the trestle and my car boot which means its been able to save energy for over 60 years.
And just think of those savings. In my kitchen it keeps the tea warm for a good 20 minutes or more and I like it strong. No more boiling of kettles to warm the pot for my second cup. I will leave it to others (I am a structural engineer after all) to calculate the energy savings over a lifetime but they must be huge.
Hopefully the analogy with building construction is not lost on you, dear reader. We should all be investing in good design and quality to ensure performance. But beware, and don’t lose sight of pragmatism as we indulge ourselves in detail at an ever diminishing scale.
Remember, you can always consider the tea cosy.
Posted on May 31st, 2012
There was never really any doubt about the subject of this blog for me. It always had to be about “the wettest drought on record”. It is usually easier to get people to sign up to sustainable water during a drought, (although, conversely, it makes it harder as soon as the drought is over.) But this “drought” has proved far harder because of the amount of rainfall. Plus the fact that the south west of England and the Midlands were classified as being in drought even as the unprecedented April rains were falling made it even more of a PR disaster.
Definition of drought
So what exactly were the conditions that lead to the drought being announced? It was well documented that there had been below average winter rainfall over the last two winters leading to exceptionally low ground water levels. In addition, reservoir levels were low at a time when they needed to be full. In England and Walesit is the Environment Agency (EA) that decides when to call a drought, and it defines drought in two different ways. E
nvironmental drought is when a shortage of rainfall has a detrimental impact on the environment and
water company supply drought is when a shortage of rainfall causes concern for the ability of water companies to supply their customers. The EA makes a decision to move to drought status based on a series of factors including meteorological, hydrological, environmental, agricultural, and public supply.
[i] (I would also add political here but that is just my opinion.) The drought designated areas increased rapidly from the 12
th March until, by the 16
th April, over 75% of England was officially in drought; the subsequent sodden April and early May resulted in a lifting of formal drought status from many areas although the south east and east of England still officially remain in drought
How can we prevent further droughts?
This question is often posed, but it is not the question that needs to be asked. As we cannot control how much rain falls, we should be asking: “How do we manage our water supplies so that prolonged periods of below average rainfall do not result in a problem?” Obviously there are many solutions, from collecting rainwater, recycling greywater, reducing leakage (both in the mains and in customer’s branch pipes), retrofitting water efficient appliances and just using less! As these messages were drowned out (excuse the pun) by the call to transfer water from wetter to drier areas let’s look at how possible that would be.
Transferring water from Scotland to South East England
Areas of Scotland (e.g. the Highlands) do get a lot of water (up to 4000mm/year) but the east of Scotland gets no more than the east of England at 600mm/year. And, in 2010, when the east of Scotland experienced a drought, there was no transfer of water from the west to the east because (just as between Scotland and South East England) the infrastructure to provide large scale water transfer doesn’t exist, and the cost to build it is extremely high.
[i] For a pipeline to be built between Scotland or the north of England to the south east there needs to be a guaranteed profit to incentivise the billions of pounds worth of investment that is needed. A guaranteed profit requires a guaranteed demand. But since 2005 there have been just two hosepipe bans in the south east (and one in the north west!). if the pipeline had already been built, in six out of the last eight years there would have been no demand for this extra water. That is poor odds on which to invest so much money and it is unlikely the shareholders of a private water company would support such a decision. Nor, one would imagine, would the people of Scotland. Of course we can argue that climate change will lead to more likelihood of drought and maybe it will, but in fact, in the UK, wetter, rather than drier winters, are indicated on current climate change modelling. The solution is unworkable without major Government backing, and that will not happen however much local politicians in the south east want it to.
A smarter message
At the start of the hosepipe ban Thames Water flooded London with posters that read “
There is a drought. Please save water” splashed across a picture of cracked earth, which in reality, if not on the posters, quickly turned into a sea of mud. Eventually the sodden April weather resulted in a change to the message which now reads “
Yes we know it’s been raining a lot recently but there are still water shortages.” This is a far more useful message, and yet it still implies, that never mind, it will soon be over and then you can go back to using as much water as you want. We need to highlight a far smarter message.
[ii] It should be as follows: the UK requires a 14% reduction in water use down from 150 litres to 130 litres/person/day and that using water sustainably is something we should be doing all the time, across the whole of the UK, not just during a drought and not just in the south east.
This blog is an edited version of an article that will appear in the summer edition of Green Building Magazine
[i]
http://www.environment-agency.gov.uk/homeandleisure/drought/31783.aspx
[i] United Utilities have recently built a 35 mile long supply pipeline to link Liverpool and Manchester. it cost £125 million, £3.6 million per mile. And, as Panorama’s “Drinking our Rivers Dry? (
http://www.bbc.co.uk/programmes/b013pzns ) showed, the Environment Agency and Thames Water are arguing (to the detriment of the River Kennet) over who should pay for a pipeline just a few miles long, precisely because of the cost of such a solution.
Posted on May 1st, 2012
By Robert Borruso, Independant Energy Consultant and Green Register trainer
While the renewables industry, and in particular the PV crowd, are still smarting over the governments’ decision to halve their subsides overnight, back in December, the wider global issues of what to do when Kyoto expires at the end of the year have hardly been talked about. But what that fiasco1 did, to my mind, was to illustrate just how difficult any further agreement will be.
First, let’s look at what paying 1302 times more for something than it is actually worth has achieved. For a start a massive growth in the rate of PV installations; anyone with a roof and/or a good credit record could look forward to a 6-8% return on investment, and 10-12% if they were a higher rate tax payer. It was a no brainer. Those on low incomes or living in flats needs not apply, but I don’t want to talk about the regressive nature of the scheme here. Beyond this there is the legitimate claim that the scheme has brought down installation costs, which was the aim all along, a laudable achievement and some justification to cut the FiT early. But before we all get too carried away with this success and the current ‘cheapness’ of PV’s I would like to take a step back and examine what has actually delivered these price reductions.
As far as I’m aware there was no significant PV manufacturing going on the UK in 2009 and there isn’t now. All the jobs created have been in sales, marketing and installation. Whilst not wishing to denigrate the work of these people (well maybe marketing) these are hardly leading edge technology jobs that are going to lift us out of recession. Because PV cells are imported, the PV FiT has served to worsen our balance of trade deficit unlike wind and hydro where there is home manufacturing. A 50% reduction in the price of a green technology is still good news, but this reduction might not be quite as it seems. For a start, back in the days when PVs were funded by the Low Carbon Buildings Programme prices were inflated. The question ‘How much does a system cost? was often answered by ‘How big is the grant?’. Prices have reduced quite dramatically, but is the 43p kWh subsidy responsible? I think not. Since 2009 global PV production has nearly tripled to 50GWp3 of which the UK accounted for 0.8 GWp4 (of consumption). It is the massive increase in the global production of PVs, and the economies of scale such an expansion delivers, that has brought about the price reductions seen, not the FiT.5
Interestingly, almost all of this expansion has been in the manufacture of crystalline cells. Yet five or so years ago all the interest was in thin film technology with its inherent low energy of manufacture and therefore low costs, so what happened? Well, in a word, China. One of the reasons why PV’s, especially the more efficient crystalline type, have always been so expensive is the large amount of energy (i.e. electric furnace use) required to heat Silicon to 1000ºC and hold it there long enough to grow suitable crystals. But China has cheap energy as well as cheap labour so it’s the ideal place to mass produce PV’s and that’s exactly what has happened. The problem here of course is where China is getting all this cheap energy from – for the most part brown coal or mega dams.
This brings me back to my point that PVs are a good example (not to mention an ironic one) why an inclusive binding Kyoto replacement will be almost impossible to achieve. A product that is championed in the UK as a cornerstone of our carbon reduction strategy is only possible at anything like a sensible cost so long as the Chinese don’t have to account for all the CO2 they emit on our behalf making the products we need to demonstrate our commitment to the environment.
Notes
1. What the government should have done was to remove the index linking and make any income taxable. Over the 25 year term that would have ‘saved’ as much money as the cut to 21p but preserved the easy to sell 43p rate. In fact a better scheme all round would have been a top-up subsidy whereby any electricity price below say 25p was topped up so as the price of electricity rises and the income from that increases the amount given out falls but that’s another story.
2. 43p paid per kWh of electricity generated means about 80p is spent to save each kg of CO2. The current internationally traded price of a kg of CO2 (i.e. under EU ETS is 0.6p). This is the price at which industry considers it is worth spending money to save carbon. True this figure is probably too low but……..
3. http://www.pv-tech.org/news/ims_research_pv_module_manufacturing_capacity_hits_50gw_in_2011
4. http://www.leeds-solar.co.uk/blog/entry/Analysis-of-solar-pv-installation-figures-vs-Feed-In-Tariff-Budget
5. After 30 years of waiting it has to be said.
6. http://www.solarbuzz.com/our-research/recent-findings/world-solar-photovoltaic-market-grew-274-gigawatts-2011-40-yy
