June 08, 2006
Counting Energy Efficiencies: Wooden Verus Cement Floors
At the recent Timber Communities Australia national conference, prominent federal Labor politician Martin Ferguson called for a rethink of the national energy efficiency standards for residential buildings in Australia. He told conference delegates:
"Whilst we would all support practical measures that increase energy efficiency, it seems to me that the new building standards are underpinned by too many questionable assumptions and too little scientific evidence.So does the Productivity Commission which reported its concerns about the analytical basis for the standards last October.
The key issue is the focus on reducing household energy running costs and the thermal performance of the building shell.
And, at least at the time the Productivity Commission was undertaking its investigations the Australian Greenhouse Office’s (AGO) home design manual noted that true low energy building design will consider embodied energy and take a broader life-cycle approach to energy assessment – merely looking at the energy used to operate the building is not really acceptable.
Because timber framed construction is lightweight in nature, it does not fit the thermal performance philosophy.
The analytical basis used also means that concrete slab-on-ground comes up trumps for efficiency over suspended timber flooring.Consequently, $70 million worth of sales a year have been lost in the Victorian timber flooring market since the Victorian rating system was introduced.
This is despite the fact that a 1999 study undertaken for the AGO found it would take 62 years to get a net greenhouse benefit from a concrete floor over a timber floor.
And recent research indicates a concrete slab produces a net increase in CO2 emissions of 15 tonnes per house compared to a timber floor.
The problem is the standards ignore the fact that cement is highly energy intensive to produce while timber is a renewable resource, grown using direct sunlight and processed using relatively little energy in sawmills.
And sometimes, the energy in sawmills is produced using biomass from wood waste itself.The Productivity Commission has recommended the Australian Building Codes Board commission an independent evaluation of energy efficiency standards to determine how effective they have been in reducing actual – not simulated – energy consumption and whether the financial benefits to individual producers and consumers have outweighed the associated costs.
And the sooner the government ensures this is done, the better because in the meantime the timber industry is suffering and it may well be doing so for no good reason.
I am pleased to see that the industry has successfully lobbied the Victorian government for an amnesty on wooden floors in new homes until April 2007 to allow time to address this issue.
But it is clear that the greens are now much more sophisticated in their attack on the forest industries, directly targeting industry markets to achieve their ends.
The Wilderness Society responded to the Victorian amnesty saying it was a “cynical attempt by the industry to maintain market share” rather than improve energy ratings or environmental sustainability."
My house is cold in winter, it is wooden, with old wooden floors. But its my choice and I can't understand why environmental groups don't support the Australian timber industry so other home owners can appreciate the beauty of wood... wooden floors, wooden furniture, wooden window frames. And as Martin Ferguson said at the conference:
"Australia has 164 million hectares of native forests – 4% of the world’s forests – and 1.7 million hectares of plantations.About 10% of our native forests are managed for wood production with less than 1% being harvested in any one year. That small proportion of forests harvested annually is regenerated so that a perpetual supply of native hardwood and softwood is maintained in this country.
Australia’s rigorous forestry standard, the AFS, has global mutual recognition under the Programme for the Endorsement of Forest Certification, the largest international sustainability recognition framework for forestry in the world.
But the greens are running a duplicitous campaign around the globe to undermine the status of the standard."
Posted by jennifer at 09:58 AM | Comments (29) | TrackBack
January 27, 2006
Which Climate Change Consensus? (Part 3)
There are some interesting questions being posed at the Which Climate Change Consensus? (Part 2) thread. Following are two questions from Graham Young that interests me. They seems to have been lost amongst the more general policy and economic discussion about Kyoto.
David,Your quotation from the MIT piece illustrates the problem that you have with your models. You say "a projected 18 percent increase [in CO2] resulting from fossil fuel combustion to the year 2000 (320 ppm to 379 ppm) might increase the surface temperature of the earth 0.5C". Now CO2 is at 380 ppm and you are claiming a rise in surface temperature of 0.5 degrees.
So far, so good, but as we know that temperature of the earth can and does vary independently of CO2 concentrations, how do you know that the rise was due to CO2 alone? And if it wasn't, then in fact you may have overshot or undershot by more than the 0.5 degrees. If you overshot, your modelling was completely unsuccessful, and if you undershot, then things are a lot worse than you thought.
The IPCC graph at http://www.grida.no/climate/ipcc_tar/wg1/figspm-4.htm is interesting.
It shows general trends between model and observations reaching more or less the same end point, but with significant divergences along the way. You'd probably get a better feel for this by graphing a rolling average.
But you might well be getting this result by massaging the factors that are programmed in until you get a reasonably good fit, but without those factors necessarily being the right ones if you are missing some ingredients.
I've gleaned some of my information from the graphs that Jennifer put up on the site on the 28th November. While you're explaining your models, could you please tell me what the mechanism is that makes temperature dive just after the peaks in CO2 shown in those graphs?
Graham Young
Posted by jennifer at 11:33 AM | Comments (38) | TrackBack
December 04, 2005
Wooden Floors Fail Enery-Efficiency Test
I live in Brisbane in an old Queenslander. These are wooden houses traditionally with high ceilings and on stilts to allow for air circulation and beat the heat of the tropics. They tend to be difficult to insulate and my home is particularly cold during our brief winter. When there is no breeze the house can also be hot in summer.
There was some discussion about energy efficient homes at this web-log on 25th November; that was the day the Australian Building Codes Board meet to discuss implementing a 5-star building standard for new homes across the whole of Australia, click here.
In a comment following the post Steve explained:
This standard relates to a home's thermal design - how much energy is required to keep it cool in summer and warm in winter.Victoria had already implemented a 5-star requirement for new homes, since July 2004.
In addition to the 5-star requirement, the Victorian policy requires the home builder to also install either a solar hot water system OR a raintank.
The Housing industry media release posted by Jen is about the implmenetation of 5-star across the country.
According to the today's The Sunday Mail - a local Brisbane paper - the resulting new energy-efficiency laws could spell the end of the iconic Queenslander home:
Changes to the building code to be adopted next year mean wooden houses and timber floors could be a thing of the past, Federal Industry Minister Ian Macfarlane told The Sunday Mail yesterday.The "five-star" energy-efficiency measures to be introduced from May are also tipped to increase the cost of building an average house by up to $15,000.
Mr Macfarlane called the decision a "terrible mistake" and warned it would be the death of elevated homes built with timber floors on stilts.
"The ordinary house on stumps that is the finish of them because everything will have to be concrete," he said.
"And it is the end of the use of natural timber unless you are prepared to substantially increase the cost of houses."
Under the system, concrete is more energy efficient than timber.
The National Association of Forest Industries also warned the changes could signal the end of timber homes.
Chief executive Catherine Murphy said there had already been a 40 per cent decline in the suspended-timber-flooring industry in Victoria since the introduction of five-star standards three years ago.
Australian Building Codes Board chairman Peter Laver said the states and territories had unanimously supported boosting the four-star requirement up to five-star, in line with Victoria.
He denied it would mean the end of timber floors and wooden homes but conceded it would increase the cost of building a house.
"There are a couple of little problems with how you treat Queenslander-type houses up on stilts," he said.
"That isn't adequately handled in the existing home energy-rating scheme. But there is a new scheme that will be a launched early next year."
Mr Laver said timber homes and floors would require additional insulation to meet the standard.
The Housing Industry Association estimates the change will add up to $15,000 to the cost of building an average $200,000 home.
HIA senior executive director business services Malcolm Roberts said the environmental benefits were not proven with the estimated reductions of greenhouse gas emissions being just 0.8 per cent.
But Mr Laver said three independent studies suggested the cost increase would be closer to $2000.
"Where the cost impost is going to be higher is the million-dollar houses sitting on cliff tops," he said.
Premier Peter Beattie said he would intervene to ensure the legislation did not apply to Queenslanders in their Queenslanders.
"We are not going to give up the very essence of Queensland," said Mr Beattie, who owns a Queenslander in Brisbane's inner-north.
"I am not going to give up my Queenslander for something that suits Sydney or Melbourne."
The Premier is obviously getting a bit ahead of the requirements that will only apply to new homes. But, ofcourse, down the track they could be applied to us all.
Is it useful to have one rating system for the whole of Australia? Is the new code based on a more temperate model that suits Sydney and Melbourne more than Brisbane?
And what about promoting concrete floors over wooden floors? Wood sequests carbon while a lot of energy is used in the production of concrete. There is some information on cement production and carbon emissions here.
Also, the Queensland cement industry has been accused of wiping out bat colonies, click here.
It all seems about as silly as moving to biodiesel to save on carbon emissions when in fact so much carbon dioxide is emitted in forest fires associated with palm oil production in south east Asia, click here.
How often do the advocates of various carbon reduction initiatives do a full lifecylce analysis before mandating a particular course of action?
Posted by jennifer at 07:52 PM | Comments (49) | TrackBack
November 25, 2005
Designed to Be Energy Efficient - or Not?
Through an agreement with the building sector, the Australian Government has resolved to eliminate worst energy performance practices through a national standard approach to minimum performance requirements for buildings, see Greenhouse Office website.
Based on this advice, the Australian Building Codes Board is set to consider the introduction of five-star energy regulations in all new homes when it meets today.
But the Housing Industry Association say it is all a crock. According to their media release:
The regulations will not deliver a significant reduction in greenhouse gas emissions, nor making significant inroads into energy savings. By 2020 they will have imposed a $31.5 billion cost on Australian families for a saving of just 0.8 per cent of greenhouse gas emissions.
Posted by jennifer at 09:12 AM | Comments (35)