With the “sustainable” spotlight shining on the built industry, the design and construction process has evolved to incorporate energy-conscious strategies at every turn. Much of this movement can be attributed to advancements in technology, such as LED lighting, occupancy sensors and renewable energy resources.
However, renewable resources such as solar and wind are expensive. When embarking upon a building project, there is a balance to uphold between sustainable initiatives, the project budget and the lifecycle of the building. In other words: responsible sustainable design.
With current tax-incentive and rebate opportunities, the expense of achieving a net-zero energy use building through renewable resources is more obtainable. But is it an ethical practice if that building’s renewable energy systems have a usable life of 30 years and a payback of over 50 years? The answer is simple, but easy to ignore when funded out of another’s pocket.
Reducing energy use benefits the environment and the building owner’s operating cost, but it’s just as important to deliver a building whose lifespan is equal to those of its systems.
Aligning a project’s sustainable outcome with the lifecycle of the building is achieved by an iterative process that requires extensive evaluation of building-system factors. They work together to create a multiplier effect on energy and cost savings. Manipulating one building factor, such as insulation, creates a domino effect on all subsequent factors, such as heating and cooling needs. These factors are all interdependent, but the order in which you manipulate them is important. Manipulating the same three factors, but in different order, will almost always have a different sustainable outcome due to their lifecycle differences. The purpose of this exercise is to determine the strategic order of sustainable implementation by assessing initial cost, energy savings and payback for the owner.
Ideally, strategic order for implementation is derived by each factor’s simple payback.
It is most logical to first reduce a building’s energy consumption with the least expensive sustainable strategy. The simple payback for each strategy executed thereafter will improve as it is applied to a more energy-efficient building. For example, improving insulation at a lesser initial cost improves the payback for a geothermal system by decreasing heating needs, which decreased that system’s initial cost.
Adding solar arrays or wind power technologies to a building design is not difficult. Rather, the challenge lies in the iterative process to maximize energy efficiency and spending the least. Producing electricity by current photovoltaic technologies is two to three times more expensive than purchasing it through a power provider. Subsequently, simple payback for a solar array system remains high, typically taking longer than the system’s lifespan.
An iterative process to decrease a building’s energy consumption will decrease photovoltaic requirements and initial cost. However, payback still remains high because generating energy through PV is still much more expensive.
Tax incentives and rebates help offset initial cost and improve payback. But without incentives and without the ability to throw millions of dollars into a system, photovoltaic systems do not achieve sustainable payback. They will have to be replaced before being paid off.
Renewable energies are not yet within economic reach of the general population.
One can position a facility for the future, though. As technology advances, the cost to generate photovoltaic energy will decrease and utility costs will increase. At that point, installing a solar system will have a sustainable payback. Those prepared with renewable-energy-ready buildings will benefit most. Now is the time to take advantage of affordable sustainable technologies such as decreasing your energy consumption as much as 50 percent. Those who do will be able to afford net-zero when the market price of photovoltaic matures.
At the end of the day, photovoltaic will become affordable by partnering solar technology with other strategies such as LED lighting, geothermal and daylighting. The sum is greater than its individual parts.
Conservation is always the best economic solution. Create a building that uses little energy, and it will save money now and in the future when the market is ripe for photovoltaic. Meanwhile, owners will reduce their carbon footprint and save on operating costs. It’s not about flashy sustainable designs; it’s about smart and responsible ones.