7 Dec 2012

My RHI response (don't get too excited)

The Renewable Heat Incentive Consultation closes today. Thanks to Kate de Selincourt who alerted me to this. I spent 40 minutes replying to some of the many questions and thought I would share my responses with blog readers. If you want to put your five pence worth in, be quick. It's here: RHI Consultation


1. What are your views about the proposed approach of a universally available tariff scheme? Is a tariff scheme the most efficient way to drive down technology costs, increase innovation and value for money, together with developing a homegrown supply chain? Please include reasoning for your response.

No, I think a tariff scheme, especially a deemed tariff scheme is not the way to go here. It seems to be modelled on FITs which have themselves been copied from Germany. FITs have been successful because they have been generous, but an installation-based subsidy has the potential to be just as successful and would be easier to comprehend from the consumer's standpoint and to administer for government agencies.

2. Do you think that there would be advantages in phasing or piloting roll out of the scheme? On what basis do you think it might make sense to phase or pilot the scheme?

Not really. FITS have been around long enough for us to know what is likely to happen. RHI has already been delayed. "Phasing" sounds like a polite way of adding further delay.

3. Do you think that there may be alternative or additional approaches to incentivising renewable heat deployment that we should pursue? What approaches do you think might add most value?

Yes. If there is to be any subsidy, it should be towards the installation costs. As with almost all non-fossil fuelled power sources, the running costs are generally much lower. It's the capital costs which are the barrier to uptake. Consequently, it makes little sense to incentivise the running costs, which is what the RHI is planning to do. The entry barriers remain just as large as ever, and only the rich or well connected will be able to take advantage of the RHI. This makes it regressive.

10. Do you agree with the proposed eligible technologies set out above? Are there others that should be considered for inclusion?

No, I don't. I am critical of the inclusion of biomass for reasons already made known to DECC. It is quite wrong-headed of us to be subsidising the burning of carbon-intensive fuels, and biomass is carbon-intensive. The inclusion of biomass in the RHI seems to be all about meeting 2020 EU targets for renewable usage, but that doesn't stop it being bad science.

If we must subsidise here, let's encourage the use of timber and other biomass materials in construction, where the carbon will be locked up for the critical years ahead when we have to reduce CO2 emissions.

11. Do you agree that an approved suppliers scheme is the best option for domestic biomass heat installations to demonstrate their use of sustainable fuel? Please provide reasoning with your response.

Hard to answer as I don't agree that biomass is a sustainable fuel. I guess some sort of auditing on the supply side is preferable to none at all, but I fear if biomass really takes off as a fuel source, that it will be sourced from further and further afield and that the auditing is likely to be compromised.

12. Do you agree that as part of the approved biomass supplier list we should assume a level of boiler efficiency?

Yes, if biomass is to be burnt, then at least control the boiler efficiencies. Insist on condensing biomass boilers at the very least.

23. What is the risk of switchback after the period over which tariff payments are made? Do you think this applies solely to biomass?

If you provide a mechanism for people to harvest a subsidy for their fuel bills, then of course there is a risk they will find another way of providing heating after the subsidy is withdrawn. That is yet another reason why capital cost subsidy is preferable.

39. Do you agree that deeming, as opposed to metering, is the most appropriate approach on which to base the calculation of RHI payments? If not, why not?

I can see why deeming is the preferred method, but I don't like it. It seems to highlight yet another problem with subsidising running costs, and not installation costs.

27 Nov 2012

The Gas Saver

Condensing boilers are no longer news. They first appeared in the 1980s and for years were known as energy-saving boilers. They work by having a secondary heat exchanger which is used to take a load of heat out of the flue gases from the main boiler. This makes them more expensive to build and a little more expensive to install. Hence, they were seen as something of a green curio, an expensive option for those who cared about the planet, or the size of their gas bills. By 2004, they had achieved a market penetration of just 3%. Although a condensing boiler could be shown to have a very short payback (less than 5 years), people didn't want to spend an extra £250 for a condenser.

But then the building regs changed. In April 2005, Part L (England & Wales) was amended to make condensing boilers all but compulsory. Today, condensing boilers have over 95% of the new boiler market. That, ladies and gentlemen, is a prime example of government intervention raising the bar. What is more, you can source an A-rated Baxi Solo condensing boiler for just £450 (plus VAT). We were paying that much for ordinary boilers back in the 1990s. So competition and economies of scale have eroded the price differential (though some cynics will argue that quality has also been engineered out).

All in all, it makes a powerful argument in favour of legislation as the best way of increasing energy efficiency. If condensers hadn't been made compulsory, I bet that they would still cost £250 more and that market penetration would be sticky at around 3%.

Which brings me on to Zenex's Gas Saver. This is a new(ish) device which you attach to a condensing gas boiler and it draws even more heat from the flue gases and uses it to pre-heat the water going into the boiler. It is, if you like, a tertiary heat exchanger. The generic name for this is Passive Flue Gas Heat Recovery Devices (PFGHRDs) and the inventor, Chris Farrell, started Zenex to develop and market it.

In some ways, it's been a splendid success. Fitting a PFGHRD to a boiler has been demonstrated to bring about gas savings of up to 40% for hot water generation and consequently PFGHRDs are a ground-breaking British technology, recognised in Building Regulations, recommended by the Energy Saving Trust and recognised in the Green Deal.

Better still, two of our major boiler manufacturers, Baxi and Alpha, now market Zenex's Gas Saver with their own offerings. Indeed Alpha have a built-in version (The In Tec GS) so that you can install the boiler and the Gas saver in just one box.

But the Gas Saver costs. On it's own, it's over £600 to buy. Coupled with an Alpha boiler, it doubles the price of the boiler. And just like the condensing boiler pre 2005, it has a tiny market penetration. There are around 1.5million new boilers fitted in the UK each year (about 90% of these are replacements) and only a tiny fraction have Gas Savers fitted to them.

How best to change this situation? Though the savings appear to be real enough, and the payback period is again probably less than five years, the uplift in price between a condensing boiler and a condensing boiler plus Gas Saver is enough to put most casual buyers off — that's if they ever get to hear about it in the first place. Maybe the Green Deal will come into its own here, as PFGHRDs appear to meet the Golden Rule. But I can't help feeling that the answer lies in building regs enforcement.

14 Nov 2012

At last: a Passiv Wood Stove

In the rarified world of Passivhaus design there has been a small problem gnawing away at many enthusiasts, especially the selfbuilders. Wood stoves. They may not need them, but they want them. Focal point fires. Comfort. Neolithic TV. Call it what you will, but fires have a certain pull. And a pellet boiler just won't do.

There are — or have been — a couple of problems. One is that you need so little heat in a Passivhaus that the smallest wood stove is still too big. It's hard to make a wood stove that doesn't emit at least 4kW of heat, because that's what a log gives off when it's burning well and it seems a bit pointless to start burning kindling. That's not too big an issue — after all, as Passivhaus devotees keep saying, you can always open a window to make the room a bit cooler if you get too hot. Or you can start using the stove to heat hot water — but maybe not, as here things start to get a little bit more complex.

The next issue is the fresh air supply. Opening that same window is not really an acceptable failsafe option. And you can't fall back on the traditional, permanently open, ventilation grill — not when you've gone to so much trouble to make the place so airtight in the first place. In a draughty old pile, it's not really a problem because there is plenty of fresh air coming at you from all corners, but in a Passivhaus that's not the case. The supply air problem is usually addressed via an air duct piped directly into the stove. It's still not ideal, as it creates a cold bridge with the outside and another potential air leakage path — remember, all penetrations are bad news. But it's sort of on the right lines. It makes the stove room-sealed.

But another niggly little issue concerns spillage, the term given to the cloud of smoke emitted from the stove every time you open the door to re-load. In a draughty old pile, it quickly gets lost in the background, but in a Passivhaus the smoke will hang around until it's drawn away into the MVHR system, where it will end up clogging up the filter.

Well, as it happens, Chesney's, the wood stove manufacturers based in London, have just come up with a spillage-free stove design. Nigel True, their stove wizard, (pictured)

has been beavering away in his Whitstable workshop and has hit on a spillage-free design. "Until now, the best solution on the market has been a stove with a hinged door with an automatic closer," he told me. "We've come up with a design which diverts the air intake when the door opens so that the supply flow is redirected from an opening under the door into the stove, and away up the flue. It doesn't smoke at all"

The idea for a Passiv stove came about when they were contacted by CenterParcs with a view to supplying stoves in all their Passivhaus-standard chalets at their yet-to-be constructed Woburn site. The contract itself came to nothing, as CenterParcs later lowered their spec on cost grounds, but Chesney's carried on with the project and have now launched the resultant stove commercially. Its been through rigorous testing at Gastec in Cheltenham (the place where all UK good wood stoves get tested for smoke emissions) and has emerged with distinction. Both carbon monoxide and carbon dioxide emissions were rated as "negligible" even when subjected to worse case scenarios — i.e. forgetting to close the door.

At present, the new design has been fitted into a fairly basic 4.6kW Milan stove. It's being marketed under the name of Milan Passiv and the retail cost will be around £1150 plus VAT, which is around 25% more than the regular Milan stove. This puts it down at the lower end of what people pay for new wood burners.

As it happens, Passivhaus stove enthusiasts may have another promising development on the horizon. Poujoulat, the French chimney and flue manufacturers, are about to launch a triple-walled stainless steel flue which will work in conjunction with Chesneys new stove range. The advantage of a triple-walled flue is that the external cavity becomes the the stove intake air supply, in a the way a balanced flue works on a gas boiler. Not only does the intake air get pre-heated as it's drawn down the flue (thus increasing combustion efficiency), but the extra vent hole for supply air is eliminated. Instead of two penetrations, you have one: music to the ears of Passivhaus builders.

As of now, I don't think this product is yet on the market, but according to James Parkin, their UK technical manager, it's coming soon and anyone interested should contact him at j.parkin@poujoulat.co.uk

9 Nov 2012

Passivhaus Conference 2012

I have just returned from the UK Passivhaus Conference 2012, held in Nottingham. Two days of lectures, networking, eating, drinking and schmoozing in East Midlands Conference Centre and a night sleeping in the brand new Orchard Hotel next door, so new that it wasn't actually finished.

As is so often the case with events like this, you come back down slowly to earth with a huge swathe of unnoticed feelings and unformed opinions, and only gradually do you assimilate the drift of what was going on there.

Some obvious things stand out: Passivhaus is a success if measured by the number of projects underway in this country (75 underway or completed, up from very little last year), and the spread of people taking an interest has widened to include lots of businesses I had never heard of before. There is a surprising amount of interest from RSLs who are more concerned with whole-life costings than up front capital costs, and see a genuine payback in using Passivhaus principles if measuring over a 25 year period. Many of these 75 schemes involve several units: they are not all one-offs.

And there is also great interest from the schools sector and one or two offices. I also talked to a man who was sussing out whether Passivhaus would be suitable for a fire station.

If there was a theme this year, it was summed up by the number of presentations, especially on Day Two, on Post Occupancy Testing. Lots of figures, lots of graphs and lots of tables, all rather hard to take in slide shows if truth be told, but with one over-arching theme — Passivhaus delivers what it says on the tin. Whereas the building world has been bedevilled by many so-called green projects which turned out to be anything but, Passivhaus standards, if properly instigated, seem to hit their targets unerringly.

But, you might argue, we knew that already. Well, yes it's true: there have been lots of testing carried out in Germany and Austria and the reason that Passivhaus is catching on elsewhere is that it has been proven to be effective. Post Completion Testing is construction's equivalent of the Double Blind Trial — a little bit of scientific rigour brought to bear.

What's interesting about this is that it puts Passivhaus firmly into the enlightenment camp of people who believe in logic and science and physics in particular. Not all green construction resides here and there were many people there uneasy about some of the reductive nature of Passivhaus. If Passivhaus works, does it follow that we should be building compact, rectangular boxes, all clad in white render in a vaguely international style? Does engineering have to trump aesthetics every time? And what about if you want to build using more cuddly materials like straw bale, or turf roofs? Do they have a place?

Well of course they do, because there are already examples of straw-bale Passiv and very traditional, vernacular-style buildings as well. Passivhaus boxes clever here because it says it's not prescriptive, it's just a standard and that you are free to interpret it in any way you see fit. But that ignores the fact that it's an engineering standard more than an architectural one, a standard whose primary design tool is a spreadsheet (PHPP) not a drawing board. Elegance, in the world of Passivhaus, is simplicity not ornamentation, and whilst there is nothing to stop you indulging in architecture with a capital A, in doing so you veer away from the essential message.

That's not to say that, for all its scientific rigour, Passivhaus has all the answers. No, there are still questions to be resolved, primarily to do with resilience. The three corner stones of Passivhaus are insulation (lots of it), airtightness (v. tight) and ventilation (MVHR please). It works in models and it works in practice. But how will it work over the lifetime of a building? Will the airtightness be compromised by inhabitants putting in cables for their TV sets or cat flaps for their pets? Or just knocking houses about for the fun of it? And what about these ventilation units? Will they get adequately serviced? Will they continue to work as planned? Indeed, will a new certified Passivhaus circa 2012 still be a Passivhaus in 2022, or 2052? If a Passivhaus is difficult to design and build (it is) then it will surely be difficult to maintain?

This was brought out a couple of times by speakers relating what had happened to some of the social housing Passivhaus projects. Some of the tenants had tinkered (i.e. messed up) the MVHR settings, many of them had installed huge plasma TVs (Lord, help us), one kept a window open all winter long so that he could run an extension lead into the garden to power up the jacuzzi. And you could tell the ones that smoked dope from the state of their ventilation filters.

It all sounded just a tad Victorian as these well-meaning philanthropists bestowed heaven-on-earth (aka Passivhaus) on these poor saps, only to find that they are a bunch of undeserving ner-do-wells, intent on a lifestyle of drink, drugs, fatty foods and general sloth. I'm sure that's a total exaggeration, but as always, it's the anecdotes that you remember, not the graphs.

Retrofit
There was lots on retrofit. Cost and test data is still coming in from the RetroFit for the Future schemes which are now complete. It's a much more problematic area than new build because, whilst there is undoubted elegance in creating a genuinely low-energy structure, almost nothing about retrofit could be described as elegant. It's an almighty kerfuffle and it's also incredibly expensive if done to Passivhaus standards, often considerably more than starting again from scratch. This poses problem for enlightened builders because logic would seem to dictate that we would be better to demolish every inefficient house and rebuild our entire housing stock on Passivhaus principles. But of course that ain't going to happen. Not only is there extreme opposition to it from the population at large, but it's also such a vast task that no way would we be able to complete it in a sensible timescale.

What we don't know — cannot know — is what the future holds in terms of energy supply. Will we have got to grips with the supply problem by 2050? Will we have lots of low-carbon energy to burn, or will it be a precious commodity to be husbanded carefully. And how much will it cost? Without this information, we can do no more than guess at how much effort we should make to "RetroFit" our existing building stock.




1 Nov 2012

Green Deal: Reading the Runes

I spent Tuesday at the NEC in Birmingham, visiting an exhibition entitled RetroExpo. Running inside it was a Green Deal Summit which featured a number of Green Deal(GD) notables working through their PowerPoints. That's not to be disparaging about them, there were lots of very distinguished speakers, and the exhibition is to be congratulated for assembling them all together in one place. Surely, now was the chance to learn something significant about GD?

Well maybe, maybe not. I've yet to write anything enthusiastic about GD and my feelings haven't changed much as a result of Tuesday's deliberations. For a start, it's damned complicated, so complicated that presenters kept flashing up organisation charts only to quickly withdraw them because they were too difficult to explain. Not encouraging.

It seems to get a GD going, you have to start with an assessor coming to visit your property and carrying out a survey. How much will this cost? Various answers from £130 down to nothing. If it's nothing, that tends to suggest that the assessor will be a tied agent. Would you trust such a person to carry out an independent survey? I wouldn't.

Anyway, stage two is to put the survey results into effect. There is much talk of the Golden Rule which means that the works to be undertaken have to payback in 10 years. Or is it 25? Or something else? I'm afraid I still don't know. And do you have to take the GD Finance Deal (at somewhere between 6% and 8% APR — again no one can say for sure)? What if you decide to arrange your own finance, or just pay for it from savings, is it still a green deal, and will you get the guarantee? No one could answer these either.

How much will it all cost? It was here that I did learn something new although it still didn't fill me with confidence. The government has announced some kick start money to get the GD off the ground. I though this was just window dressing, but it turns out this may just be the start and that the energy companies will soon start to subsidise GD works in the way they have been doing cavity wall and loft insulation. They are required by law to undertake carbon saving measures, expressed in tonnes of carbon per annum (it's different for each company, depending on their size). Some of this carbon-saving cash is probably going to filter through to GD providers and it may end up subsidising works such as external wall insulation (EWI), which on their own are very unlikely to ever meet the Golden Rule.

So, for instance, if EWI is estimated to cost £10,000, and the expected saving is, say, £300/annum, then the householder might only have to pay £3,000 (which gets roughly a 10 year payback), with the other £7,000 being paid for via an energy company subsidy - or ECO as it's getting called. Or at least I think that's what ECO is — once again the slippery nature of the GD makes it hard to know what is what. Was ECO a fund or a mechanism? Or both?

If I am right, then you really need someone else acting as a broker, who could fit your job together with the appropriate energy company, the one who is offering the best subsidy for this kind of work.

At least, I think that may be how it will work. I could also be completely wrong. But then, if I am, I will not be alone.

I came away surprised by:
a) how much I already knew about the Green Deal — I kept thinking "I know that" — but
b) how much I didn't understand — like how is it all going to work.

I wish it well, but I don't think the runes are looking too helpful.

27 Oct 2012

Bonfire of the Building Regs?

Building regs front page news. Here. That's twice in one year, after the Conservatory Tax fiasco back in April. What's going on?

It's hard not to conclude that it's the work of the headline-grabbing tea party tendency which seems to have taken over the Treasury, the rip-up red tape at any cost brigade.

In principle, there is nothing wrong with turning the building regs into a political football. In fact, I welcome it as it's actually a fascinating area. The regs are constantly under review in any event, and that doesn't always mean they get stricter and more expensive. I have sat in on a dozen or so government-sponsored meetings in the past five years which were seeking input from the selfbuild/DIY sectors, with a view to simplifying the building regs. What struck me after all this is how slowly the wheels turn and how good intentions very quickly get watered down. If there really is to be a bonfire, it will probably take an age to catch fire and we won't see its effects for about five years. Long after the next general election.

On the other hand, there's no doubt that the heavy hand of state intervention is writ large across our building activities and, thanks to this, we now have building standards that are far in advance of what we were required to meet even in my building lifetime (which began in 1980). Sometimes the regs are intrusive and seem petty, but mostly everyone is happy to accept them as they do make for better, safer homes. And if everybody has to comply, then there is no feeling of being cheated.

But in practice, any change in the building regs causes problems and upheavals. They are not easy to implement and they take years to bed in. If the government chooses to turn back the clock and make our building standards less exacting — and cheaper — that's its prerogative. But the way to do it is to bring it in as a fait accompli, not to announce to the world at large that it's undertaking a review. That's just political posturing which is likely to cause a good deal of confusion. The one thing it won't do is to "Get Britain Building" or some such silly nostrum. If anything, it's likely to make people pull projects they might otherwise have been considering on the grounds that they might just save a few quid.