top ten reasons why we need green buildings

Buildings have a huge role to play in addressing environmental concerns. They contribute around 40% of global greenhouse gas emissions and the same proportion of waste; and since South Africa is in the top 20 list of worst offenders, the building industry in this country has a lot to be accountable for. [Update on 10 Nov 2008: The GBCSA informs me that the correct figures for buildings are 23% of greenhouse gas emissions, 40% of electricity use, 40% of waste production and 15% of water use.] The conference held in Cape Town by the Green Building Council of South Africa earlier this week also demonstrated that changing the environmental impact of buildings is relatively easy compared with some other sectors. Many of the appropriate technologies are proven and available.

Green buildings can influence impacts - positively or negatively - in a number of sectors, not only in the operation of the building itself. The technologies for reducing dependence on water, energy and other resources are ready and waiting; but it's not only about what goes on inside the building. By locating offices where more people can walk to do their errands, transport impacts are reduced. By collecting and using rainwater and greywater, downstream problems are reduced and upstream water is available for others. By designing for healthy indoor air quality, loads on the health care system are reduced.

The point is, there's lots that can be done and lots that already is being done - in isolated islands of change. The challenge lies in turning those islands into vast oceans, but the tide is turning. The business case for building green has already been made, and in countries where green building rating systems have been around for a few years, developers now understand the financial benefits.

Here are ten things (in no particular order) that green buildings are already doing in different parts of the world, as reported by the various speakers at this week's GBCSA conference.

material improvements in design

An interesting website called materia reports on innovations in the development and use of materials, in order to stimulate and inspire architects, designers and producers to apply these materials to their designs. One example is the discovery that concrete in which sand and gravel have been replaced with the mineral olivine, seems capable of absorbing, in the course of its life, ten times more CO2 from the air than the amount of CO2 that is emitted in concrete production. Another example is the construction of structures by reusing materials that are capable of being recycled or reused again at the end of the structures' usefulness.

back to the future

It's important to find better ways to build houses for reduced environmental impact, but most existing housing stock will still be around fifty years from now, and all that time they will continue to add greenhouse gases to the atmosphere. With 25 million houses in the UK alone, that's a real concern.

So E.ON in the UK has built a replica 1930s house, complete with "more than 100 sensors to monitor energy use, temperature and humidity, making it one of the most sophisticated research houses in the world." Even the housing occupants "will wear the latest tracking devices to pinpoint the energy cost and CO2 emissions of their activity as well as helping understand how the living space is used and how it changes as the property is upgraded." All for the sake of finding the best way to upgrade old houses to bring them as close as possible to carbon neutrality. The UK government wants all new homes to be carbon neutral from 2016.

where there's sand, use it

Local South African firm MMA Architects have won $100,000 in an international design competition with their entry of a low-cost house (under R50,000 - they could build 16 houses with the prize money) using eco-build technology: essentially a timber and steel frame holding thousands of sand bags in place. The house has been built in Freedom Park, Mitchell's Plain, where there's enough sand to build an empire. Check out the photos. This has to be the ultimate in using locally-sourced building materials and labour. The award is the Curry Stone Design prize for humanitarian innovation from the University of Kentucky College of Design, awarded during the IdeaFestival last month.

how we get to work makes all the difference

While we try to improve the energy performance of buildings through design, efficient technologies, water re-use and various strategies that are recognised through auditing tools like BREEAM, LEED and Green Star, we can't lose sight of how people get to these buildings. A recent study in the UK starts to put some numbers to the role of transport in the overall performance of office buildings.

As reported on BSRIA, an evaluation of a range of buildings shows that the gains made in making buildings energy-efficient can be completely wiped out: among the case studies, the most efficient building had 80% of employees driving to work, while some less efficient buildings were better located or used by more environmentally-conscious occupants and showed better overall performance if the emissions from transport were considered. Which is why the South African pilot version of the Green Star - Office tool gives credit for locating close to high density residential areas so that there is a greater possibility of office workers living close and walking to work.

killing two birds with one stone

There are all kinds of mechanisms being investigated to reduce carbon in the atmosphere, but there are only two basic approaches: one is to reduce carbon emissions at source, and the other is to capture and store emissions. Right now, most viable strategies involve reduction at source, which can involve eliminating the processes that create emissions (like driving less), changing technologies (switching from coal-powered generation to solar), or improving efficiencies (using machines that make better use of their energy source).

Some carbon capture and storage mechanisms are also being used right now, like scrubbers that take carbon out of gas in smokestacks before it enters the atmosphere - but the holy grail for industries that don't really want to change business as usual is large-scale storage using underground cavities. That is an idea that is being promoted in some quarters, but it's not a thoroughly proven concept.

So here is an approach that stores carbon while also reducing the environmental impact of the building industry. A company called Calera is developing a process that uses the flue gas from power stations that run on natural gas or other fossil fuels, and creates a form of cement that uses the carbon in the gas. They bubble the gas through sea water:

The Calera process essentially mimics marine cement, which is produced by coral when making their shells and reefs, taking the calcium and magnesium in seawater and using it to form carbonates at normal temperatures and pressures. "We are turning CO₂ into carbonic acid and then making carbonate," Constantz says. "All we need is water and pollution."

The company employs spray dryers that utilize the heat in the flue gas to dry the slurry that results from mixing the water and pollution. "A gas-fired power plant is basically like attaching a jet engine to the ground," Constantz notes. "We use the waste heat of the flue gas. They're just shooting it up into the atmosphere anyway."

Normal Portland cement produces a ton of CO₂ emissions for every ton of cement produced, and this new process is efficient enough to sequester half a ton of carbon emissions for every ton of cement. Emissions from power generation would be reduced, and emissions from the creation of cement would also be reduced. Buildings, bridges and other structures made of concrete using this cement would essentially be storing carbon, reducing their environmental impact.

survival strategy for existing buildings

The Property Council of Australia recently developed a toolkit to assist owners of commercial buildings to improve the sustainability of existing buildings, many of which are heavy carbon emitters. The toolkit includes a six-step plan and a list of 200 design initiatives to help plan building upgrades, and demonstrates that significant improvements can often be made with minimal cost. It was presented last month at the Property Council's Existing Buildings Solutions Summit in Sydney.

I was reminded in a recent email from David Latimer of Mesothelioma & Asbestos Awareness Center that environmental issues around old buildings are not limited to energy, resources and carbon emissions. Many buildings pose health risks from materials that have been used in their construction, and this is an ongoing concern, despite identification of health problems years ago. I myself worked for a while in a government building in Ontario that incorporated asbestos, and this was removed while I was there. (Which puzzles me, since my understanding is that asbestos is generally benign as long as it is left undisturbed. Wouldn't it have been better to leave it in place as long as the building was occupied?)

I hope nobody is installing asbestos these days, but there are plenty of other materials with known health impacts still going into new buildings; from pvc containing phthalates, to wood and carpet products using formaldehyde, and paints giving off VOCs. And, as the MAAC points out, the impacts extend way back to the people involved in mining and manufacture of the products - it's not just the end user who is at risk. The new building evaluation tools such as Green Star will help raise awareness of these risks by penalising buildings that use unhealthy products. For now these are entirely voluntary standards not enforced in most building regulations, but as countries tighten up on environmental impacts of buildings, related health issues should also be addressed.

It is interesting to note that there has been comment that the Green Building Council of Australia should not single out pvc in the Green Star tool, since many building materials have some level of toxicity, but rather define key performance criteria guiding how material is used in buildings: "All products should be selected on the basis of their fitness for purpose, life cycle cost and environmental performance for each application, and reputable science and life cycle assessment should be used to assess environmental impacts." The Council's response is sensible:

To minimise risk to human health from buildings, credits focus on irritants/allergens (i.e., VOCs, equipment fumes and mould), carcinogens and mutagens (i.e. formaldehyde, equipment fumes, PVC and asbestos), and teratogens (agents that cause abnormal cell masses during foetal growth causing physical birth defects, i.e. formaldehyde). While the source of mould is humidity and thus can be addressed through the design of the ventilation system, the source of the problems linked to PVC is, understandably, the material itself.

The GBCA is considering expanding this credit to cover toxicity more broadly. The GBCA would welcome industry input with respect to other sources of carcinogens and mutagens within the Australian built environment, with the prospect of potentially addressing additional source control measures within Green Star.

the future of LED lighting

Here's an article reminding us that the uptake of new technology is not just about the technology itself. Some people see LEDs as the future, with CFLs as an intermediate technology that will soon be replaced. Others suggest that even the old incandescent bulb will never completely disappear. We still use candles, don't we? Everything seems to have its place, but whether through market forces or regulation, some things will be discouraged. The question is what? and how?

green star office rating tool

This week the Green Building Council of South Africa (GBCSA) launched the Green Star Office pilot rating tool for public comment. [disclosure: I helped with the conversion of the Australian Green Star tool for the GBCSA] If you are curious about how this will affect building design in South Africa, have a look at GBCSA Green Star fact sheet, available along with the full tool itself on the GBCSA web site. The comment period ends on 1 September 2008, and there will be a GBCSA convention and exhibition to launch the final tool in November at the Cape Town International Convention Centre.

The rating tool awards credits for a wide range of design components that reduce a building's environmental impact, but also considers some aspects of building management that aren't strictly about the physical design. And one new credit that has been added, which is not in the Australian tool, addresses 'local connectivity'. As a transport planner, I am particularly excited about this one because it addresses a building's location in relation to other urban amenities, and provides an incentive to locate close to high density residential developments, in order to encourage walking trips instead of car trips. It's tricky for a building rating tool to deal with things that are beyond the direct control of the developer, but the 'local connectivity' credit provides a gentle nudge towards more efficient urban form.

energy standards for buildings jacked up in SA

The South African Bureau of Standards (SABS) will soon be releasing SANS 204 to set new standards for energy efficiency in buildings. If implemented following the public comment period, this should raise the bar for reduced energy consumption from air conditioning and heating. It's not clear how this would be implemented, given the shortage of energy auditors, but SANS 204 and the forthcoming release of the Green Star building rating system by the Green Building Council of South Africa should create greater impetus for the establishment of an industry of consultants and contractors who understand energy efficiency.