Why Build Green?
In the field of engineering, the concept of sustainability refers to designing and managing to fully contribute to the objectives of society, now and in the future, while maintaining the ecological, environmental, and economic integrity of the system. Most people would agree that structures such as buildings that have a lifespan measured in decades to centuries would have an important impact on sustainability, and as such, these buildings must be looked at as opportunities for building sustainably. When people think about green buildings, what generally comes to mind is solar panels, high efficiency lighting, green roofs, high performance windows, rainwater harvesting, and reduced water use. This is true, but building green can be so much more.
The truth is that the built environment provides countless benefits to society; but it has a considerable impact on the natural environment and human health (EPA 2010). U.S. buildings are responsible for more carbon dioxide emissions annually than those of any other countries except China (USGBC 2011). In 2004, the total emissions from residential and commercial buildings were 2,236 million metric tons of carbon dioxide (CO2), more than any other sector including the transportation and industrial sectors (USGBC 2011). Buildings represent 38.9% of U.S. primary energy use,72% of U.S electricity consumption (and 10% worldwide), 13.6% of all potable water, and 38% of all CO2 emissions (USGBC 2011). Most of these emissions come from the combustion of fossil fuels to provide heating, cooling, lighting, and to power appliances and electrical equipment (USGBC 2011). Since buildings have a lifespan of 50 to 100 years during which they continually consume energy and produce carbon dioxide emissions, if half of the new commercial buildings were built to use only 50 percent less energy, it would save over 6 million metric tons of CO2 annually for the life of the buildings. This is the equivalent of taking more than one million cars off the roads each year (USGBC 2011).
The United States Green Building Council (USGBC) expects that the overall green building market (both non-residential and residential) to exceed $100 billion by 2015 (McGraw Hill Construction 2009). Despite the economic issues post 2008, it is expected that green building will support 7.9 million U.S. jobs and pump over $100 million/year into the American economy (Booz Allen Hamilton, 2009). Local and state governments have taken the lead with respect to green building, although the commercial sector is growing.
Green building or high performance building is the practice of creating structures using processes that are environmentally responsible and resource efficient throughout a building’s life cycle, from site to design, construction, operation, maintenance, renovation, and deconstruction (EPA 2010). High performance building standards expand and complement the conventional building designs to include factors related to: economy, utility, durability, sustainability, and comfort. At the same time, green building practices are designed to reduce the overall impact of the built environment on human health and use natural resources more responsibly by more efficiently using energy, water, and other resources, while protecting occupant health and improving employee productivity.
High Performance Buildings are defined by incorporating all major high performance attributes such as energy efficiency, durability, life-cycle performance, natural lighting, and occupant productivity (EPA 2010). High performance buildings are constructed from green building materials and reduce the carbon footprint that the building leaves on the environment. A LEED-certified green building uses 32% less electricity and saves around 30% of water use annually (USGBC 2011). Building owners know that there is a return on investment of up to 40% by constructing a green building as a result of savings to energy and water (NAU 2012).
The cost per square foot for buildings seeking LEED Certification falls into the existing range of costs for buildings not seeking LEED Certification (Langdon, 2007). An upfront investment of 2% in green building design, on average, results in life cycle savings of 20% of the total construction costs – more than ten times the initial investment (Kats, 2003), while building sale prices for energy efficient buildings are as much as 10% higher per square foot than conventional buildings (Miller et al., 2007). At the same time, the most difficult barrier to green building that must be overcome includes real estate and construction professionals who still overestimate the costs of building green (World Business Council, 2008).
New data indicates that the initial construction cost of LEED Certified buildings can sometimes cost no more than traditional building practices. A case study done by the USGBC showed that the average premium for a LEED certified silver building was around 1.9% per square foot more than a conventional building. The premium for gold is 2.2% and 6.8% for platinum. These numbers are averaged from all LEED-registered projects, so the data is limited, but demonstrates that in some cases it does not cost much extra to deliver a LEED certified project which greatly improves the value of the building and lowers operating costs (Kuban 2010). The authors’ experience with the Dania Beach nanofiltration plant indicated the premium was under 3% to achieve LEED-Gold certification compared to standard construction.
So the question is, why don’t we see more green buildings? We know water plants can be green (Dania Beach Nanofiltration Plant), but that was the first nanofiltration plant in the world to be certified Gold. The SRF programs prioritize green infrastructure – so why do more people not pursue them? It may be an education process. Or maybe the market just has not caught up. CIties and states are leading the way here. Utilities may want to look at this as well.