Urban Mixed Use – Can They Be Anything but Green?
January 30, 2008
One of the fastest growing building markets in our region is the Mixed Use building, which combines residential, retail, and office spaces into one urban environment, where you can live, work, and play without driving a car. It is a wonderful concept, and when done right it is enthusiastically supported by the marketplace. It may be just like American towns were 100 years ago, and most people seem to embrace it. Does this type of environment have a better or worse impact on our environment? The answer is: yes and no.
Our world is heading towards an energy crisis whether we want to admit it or not. The average European uses 12 barrels of oil for our 26 barrels. We have only 5% of the world's population, but we consume 25% of the world's oil. Now that China and India are growing rapidly, we can expect things only to get worse. Within 20 years, it is expected for those two countries alone to add over 80 million cars to the planet. They are helping cause worldwide demand for oil to rise 2 to 3 million barrels more of oil per day!
Can better facilities solve this crisis? No. However, it has been estimated that by the year 2030, over 50% of the buildings in the United States will have been built between now and that time. If we can cut down by half the energy that would have normally been used by those buildings, we will have cut one quarter of the energy being used by buildings in our country! That will not solve the problem, but it will have a huge impact!
It is generally known that over a 40 year life of a building, the construction costs only account for about a third of the total costs, with the operation and maintenance being the other two thirds. Once again, if we can cut maintenance and operations expenses over the life of the building, the savings are tremendous. Both to the owner and to the environment. If it costs 10% more during the initial construction cost, but it saves 20% of the operation and maintenance costs, then the total savings is a fourfold savings over the life of the building. Everyone wins.
The problem with most urban mixed use buildings that are being designed and built in the medium and smaller sized cities around the country is both a metering and a "sell soon" development mentality. By "sell soon", I mean that the developer plans on selling all of the residential components, and also possibly selling the office components, as well as having others finance the hotel and retail portions of the development. The developer's interests are therefore more short termed. If it saves money and energy over 40 years, he is not too concerned; he would rather save the initial construction cost because someone else has to live with and pay the operation and maintenance cost. This mentality has to change in order for the building construction to change.
The metering issue is the other main issue with sustainable design on these types of projects. Since these large projects have multiple users and user types, the utilities have to be metered so that each tenant can pay for their use. However, usually the most efficient systems (especially on the HVAC side) are very large systems. When you can take the diversity of the different user types together, you usually end up with a smaller system than if they are separated. For example, the peak load for most residential units is during non-business hours. The peak load for most businesses is during business hours. By combining these two into the same system, you can take the diversity of the two user types and have a smaller system. Also, by using a larger system, you usually have a lower energy use per ton of air conditioning. Also, many efficient systems are much more economical on a large scale than a small scale. Therefore, all these items lend themselves to a "central plant" type of infrastructure.
However, the "central plant" does not lend itself to a metering system as easily as a normal utility distribution. Most "central plants", whether they be mechanical or power generation systems, actually cost less overall to build and distribute than traditional distribution systems, and they run more efficiently. However, the developer must now either meter and collect payment for these utilities, or include them in lease rates. Either way, it is more time and effort over the long haul. Once again, it is an education process and a paradigm shift in business as usual. But, as this is written, and the price of oil tops $80 per barrel, the staggering cost of energy in this country is going to help shift those business as usual ideals more quickly than in the past. Let's save energy, maintenance, and money for the future with our new buildings. Let's keep up this great country's standard of living for the next generations! Let's think long term instead of short term!
