Introduction

In the past decade increasing attention is being paid to the subject of sustainability in buildings. The Leadership in Energy and Environmental Design (LEED) rating system developed by the US Green Building Council has particularly focused the building design community on designing and constructing buildings to this higher sustainable standard. At the same time the leaders in the field are looking for ‘what next’.

The concept behind net zero energy buildings is that from an energy consumption and production perspective, buildings should no longer be net consumers of energy but also producers. In a net zero energy building the annual energy production matches the annual energy consumption. Furthermore the energy production is from only renewable energy sources. Many renewable energy sources fluctuate in their output according to the resource being harvested. The sun, for example, sets in the evenings and is generally more available as a resource in the summer than the winter. Thus ‘net energy’ recognizes that the annual basis of energy flows between production and consumption balances out on an annual basis.

The concept behind net zero energy buildings is that from an energy consumption and production perspective, buildings should no longer be net consumers of energy but also producers.
 

At its core there is no secret to achieving a net zero energy building. In most situations a large enough renewable energy production system can always be purchased. However, renewable energy systems nearly always require significant capital investment and, using solar as an example, can also require a significant area requirement for the collection of the renewable energy source. Thus the more prudent approach is to reduce the energy consumption requirements as much as practically possible in order to reduce the size of the renewable energy system that must be purchased.

To that end this report focuses on a single archetype of building construction: retail, from which a total of five designs were investigated. The designs range from business as usual, in terms of insulation, lighting and HVAC systems, to very low energy consuming options. The required renewable energy system to achieve net zero was then sized. Total construction costs as well as operating costs normalized to the gross floor area of the building were then analyzed.

Two locations were investigated for this project Cambridge, Ontario and Vancouver, British Columbia.