Constant van Aerschot is director of construction trends at Lafarge, a co-chair of the WBCSD Energy Efficiency in Buildings project.
To read a shortened version of this interview, please click here.
The World Business Council for Sustainable Development (WBCSD) will today (27 April) publish the final report of its Energy Performance in Buildings project. What kind of developments have you noticed in this sector?
Since the first report - a summary of new facts and trends on energy use in buildings - came out, we have done a scenario analysis and developed a modelling tool based on those scenarios that can quantify the public policies targeting energy performance of buildings. This gives us a rough idea of how much energy savings and CO2 emissions can be achieved and at what cost by the regulations that governments put in place. These include building regulations, but also tax and financial incentives, energy prices, etc.
We have done this work for four different sectors: single-family homes, multi-family buildings, office buildings and retail. For each of those sectors, we have issued a series of recommendations, around eight to ten each.
The reason for this is that each of those sectors has a different decision-making process. If you're a home-owner, you will be affected differently than a tenant in a multi-family home. Similarly, if you are a property developer for offices, you will have another decision-making process than somebody who is developing supermarkets.
What kind of savings potential do you think energy efficiency in buildings actually has?
It has a huge potential. Our modelling shows that energy use in buildings can be cut by 60% by 2050. And this needs to be achieved in order to meet the IPCC targets.
But the question is of course at what cost. This is what you see very often with the top-down studies. They say that if every building was insulated, if every light system was efficient, this is how much you could save.
We took a top-down scenario approach, but the decision-making process in the model is bottom-up. We start from the decision-making of one person.
If you own your home, which may not be very efficient, then you say, 'How much am I going to spend to make it more energy-efficient?' So you decide to replace the windows, insulate, change the boiler, put shading, etc., and it will cost 20,000 euros. Then you ask what your return is, how much energy you are going to save. You will see that the payback is going to be very long, 10 to 30 years.
The model takes into account this decision-making process of people who own a house, who manage a property, in order to see what the adoption rate of energy-efficiency measures is. The key conclusion is that if you just let the market do it, it's not going to be sufficient, because the payback is just too long and people's decision-making processes, based on financial criteria, will not lead to the market transition that is required.
How can the different actors best improve the energy performance of their buildings, then?
Each of the actors can influence positively or negatively the energy performance of their building. I could give you an example of what a property developer and designers and engineers could do.
Typically, choosing the right energy efficient shape for the building is something that you can do at no cost, but this automatically leads to an improvement in energy efficiency.
If you have a very long or tall and thin building, you have a lot of façades per square metre of lateral space. This ratio between the façade and the square metre of lateral space is going to define energy efficiency, because the heat you produce inside if you're in a cold climate goes through the façade. So you have to minimise their amount for the maximum of square metres inside.
If you choose something that is equivalent to a cube instead of a rectangle, you divide the façades by a great amount. Just by doing this, you reduce the energy consumption.
So developers, designers and engineers should promote compact buildings.
What role should government policy play?
Government has a role in regulating, by setting standards, and by making sure that those standards are enforced. There is in many countries a lack of enforcement. It is not a lack of policies in place but of enforcement.
Those requirements need to be tightened over time. If you see the evolution of the regulation, you can see that there is still room for improvement.
Today, in many countries, you don't need to check on-site whether your building performs according to norms. Building inspectors go on-site to check the safety of the building. They see whether the columns, the slabs and so on are safe for people to live in the building. But they don't look whether the building performs according to what is required.
So this is one regulation that can be added, to actually look at the performance level of existing buildings and new buildings when they are being built.
What kind of balance should we strike between building new self-sustainable buildings and retrofitting existing buildings?
It depends on the region. Our study looked at Brazil, China, India, Europe, Japan and the United States. The dynamics in those regions are very different.
In Europe, Japan and United States, the problem is typically the existing building stock. In those regions, there is no regulation that addresses those buildings. So you have around 1% of new buildings in developed countries that are being added, and the building codes normally only address this 1%. So 99% of the problem is not addressed.
In developing countries, new buildings make up a bigger proportion of the total stock. There, it's maybe between two and 5%, especially in the booming period of China. The replacement rate is much higher there. This is true in Japan to a certain extent as well because of a cultural dimension. In Japan they demolish much more than we do in Europe or in the US.
What measures then are most cost-effective to move to energy-efficient building?
There is no one policy that can do it. You need a package of policies.
Generally, building energy codes are the most cost-effective, but they are not sufficient. Appliance standards are good when you have a computer and a washing machine that is more efficient, but nothing stops you from having three washing machines or 35 TV screens in your home.
The European Parliament last Thursday (23 April) voted on the proposal for the EU's Energy Performance of Buildings Directive, attaching conditions for zero-energy buildings. Do you think the legislation is ambitious enough?
It is good that there is this directive, but it is by far not ambitious enough. It is only addressing the one percent of new buildings. 99% of buildings are not touched by the legislation.
There are some conditions for exiting stock, but when you retrofit your building, you need to bring the building to a certain level of performance. But if they have to do this, people will not do it because then they will have to invest more.
How could Europe then make the most of the savings potential in buildings?
This calls for a change of mindset, not only of the governments but everyone.
Governments should use much more ambitious targets for new buildings and also for the existing ones. New buildings are the easy part. So they should subsidise heavily new buildings that are class A or B, the best performing buildings, and phase out the lowest class G buildings.
We are saying this because the cost of retrofitting G class buildings in some cases is just incredibly high and much higher than building new. If you want to achieve energy savings in an existing, very poorly performing building, you will have to spend a lot of money. If it is public money, it is maybe wiser to launch a new programme of A and B buildings rather than trying to retrofit inefficient existing buildings.
Another reason is that it is Mr and Mrs Jones who will retrofit the inefficient building and they don't necessarily have the knowledge and the capacity to understand what is really required.
There is also a big knowledge gap by professionals. We did a worldwide survey and found out that architects are not the best persons to ask what to do because they don't necessarily have the right level of training. Contractors are not the right people either, and the same goes for some engineers.
Then again, they are quite expensive. Mr and Mrs Jones will not necessarily invest in their advice, so what they're going to do is to look at what the distributor tells them or they do it themselves.
They will invest a lot of money without having a holistic approach to the building. And they will invest in measures that won't bring the necessary performance improvements. They may just change the windows, but if you do this without insulating the roof and the walls, you will not save a lot of energy, because the heat going through the windows will continue to go through the walls and roof.
That's why it is a very important to have a holistic approach to problem-solving. Public money should not be spent on single measures. You cannot say, 'I will give money to replace windows, but I will give money if you have a plan to retrofit the house according to a certain performance level. And I will actually tune the rate of interest according to the actual performance'.
So you can have zero percent interest if you prove that your house went from 250 kilowatt hours to half of that. If you go down to 200 only, then you pay your 2% interest rate on the loan.
There's always a need to make sure that whatever public money is being spent, it is based on actual performance improvement.
Is investment in the energy performance of building really going to be cost-effective?
Buildings are the most cost-effective way to reduce energy use and CO2 emissions. It is going to cost society, but if you address the building sector, it is going to cost less than addressing other sectors. Also, it will cost less if we do it now than if we do it later.
And it will cost several hundred billion euros per year.
People invest already a lot, but they don't do it wisely. They invest in repainting, in new kitchens, in additional appliances, lots of things. A lot of money is being spent, but a lot of money is not directed towards energy efficiency.
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