By Dino Green
What is a “green-roof?” Some say the term conjures up images of green vegetation on a building’s roof; others refer to the concept of making a building’s roof green from an environmental standpoint with green energy solar panels. It turns out that green vegetation on your roof can actually help boost your roof-mounted photovoltaic panels.
In addition, apart from the immediate cooling effect of a roof-garden building, green roofs in a community may lead to a micro-climate cooling effect that may be beneficial to the broader related area and community. Consequently, green roofing may help combat “heat island” effects in urban areas – a term used to describe the accumulation of heat buildup in urban areas that eventually remain hotter than rural surroundings.
Research documented in Green Roof Valuation shows that vegetated rooftops can facilitate solutions of complex environmental problems in urban areas. The report suggests that green (vegetated) rooftops, when compared to conventional rooftops, may yield a Net Present Value (over a period of energy savings for up to 40 years) that is 20–30 percent lower; thus, a viable investment over conventional rooftops.
Specifically, the initial additional investment required to make a roof palatable with green vegetation can in fact be recovered, through energy savings, by the time an alternative conventional roof would need replacing. In addition, findings suggests that green roofs may help improve the quality of the urban air, yielding additional benefits in monetary terms and reducing harmful atmospheric emissions. An illustrative example is that a 2000 square meter green (vegetated) roof is estimated to yield approximately $900 to $3300. Consequently, maintaining well vegetated roof-gardens may lead to significant financial, environmental and aesthetic benefits primarily from saving conventional energy but also through urban air quality improvement, and micro-climate cooling effects.
Consequently, when having to make a decision about either of these solutions, it is important to note how the combination of both roof solar panels and a green (vegetated) roof, can offer extended benefits that are financial, environmental and architectural. Combining the energy savings from a roof garden, together with the boost effect on the performance of photovoltaic panels, can help reduce solar panel costs, thus making photovoltaic panels financially more viable especially for residential applications.
Dino Green is an engineer; a technology fan and an advocate of environmental sustainability – personal blog: @ RenewableGreenEnergyPower.