After the green growth future, which was a topic in my last article, now, I will draw your attention to the green roofs and their future as renewable source of energy and their increased importance in our daily life. Although, they are not widely known as such, their potential is undervalued and the years to come will only prove this fact.

In Europe, the green roof industry has continued to grow each year for the past several decades. Despite the economic turbulence, in Germany, as one of the pioneers in this field, it is estimated that over 15% of all flat-roofed buildings are covered with vegetation, a number that is increasing as the German green roof industry continues to grow with some good percentage on a yearly bases. While the green roof industry in the United States maintains a steady growth rate, the industry is still young with many areas that need improvement. Several of the barriers to green roof expansion in the U.S. include: limited performance standards, lack of awareness regarding green roofs in general, high installation costs, lack of favorable government policies, and limited data quantifying green roof benefits. These barriers can be easily overcome through research and innovation in design by the green roof industry, as well as proper education classes in school and universities.

Boyko Manev

Adding a green roof to a building, offers several benefits, including reducing harmful stormwater runoff, lessening the heat island effect, that is more visible, rather than 10-20 years ago. Also, conserving energy and noise, containing air pollution and greenhouse gas emissions, and extending roof life, are other positive sides of the green roofs. Their installation has shown to increase people’s productivity in many companies and has offered a new habitat for plants and animals. On the other hand, building owners can save money through lower heating and air conditioning bills and decreased municipal sewer system fees via a green roof. Another valuable benefit is emerging as green roof experts incorporate photovoltaic (PV) systems to generate clean, renewable solar energy by taking advantage of green roofs. By installing a solar panel with a green roof, owners can enjoy not only the cost savings and socio-environmental benefits of the living roof but also efficient, renewable solar power – lowering electricity bills by generating clean electricity and reducing consumption.

The green roof, also known as a living roof, covers a building with soil and plants, which are known as sedum blankets, grown beforehand on nurseries. The evaporation of these plants makes the rooftop cooler, hence it decreased the rooftop temperature. This effect enables PV cells to operate at peak more efficiently. Panels that are installed on a green roof, will produce significantly more energy. Moreover, green roof vegetation removes pollutants and dust from the air that might, otherwise, interfere with a cell’s ability to produce electricity and, int he end, that affects the nature positively.

Scientific research must be made to expand our knowledge base to help guide future urban design, development, and management. Much of the early green roof research pertained to architecture and engineering problems. The current trend seems to be in the direction of landscape ecology and biodiversity, possibly due to increasing interest in environmental issues in general, as it sounds trendy and also is the visible effect of taking care of the nature.

Since roofs represent up to 30% of urban areas, they provide a unique opportunity to utilize these typically unused spaces to reclaim habitat that was lost due to construction while also aiding in the protection of our environment through more sustainable practices.

Germany and Japan are the one who now lead the world in solar energy production, but it must be admitted that American cities are pioneering in green roof-solar power technology. While solar panels can take away rainfall and sunlight from green roof vegetation, the introduction of PV cells can actually strengthen the living roof by creating areas of biodiversity, where plants and animals adapted to less water and light can thrive. A more diverse roof is a more stable roof. Every time when atmospheric temperatures on a roof begin to rise PV elements lose their efficiency and can shut down if temperatures rise too high.

The more the cities continue to expand, the more it is increasing the concern whether their additional warmth will further impact global temperatures. The devastating 2003 summer heat wave that lead to over 30 thousand deaths in Europe has shown how global climate change adversely impacts health. While scientists debate what exact influence cities have on climate change, one thing is for sure, urban heat islands effect city dwellers — nearly half of the word’s population.

On top of that mitigating water runoff and heat, green roofs boast an abundance of gains, the first being economic. Because they are protected from ultraviolet radiation and the extreme fluctuations in temperature that cause roof membranes to deteriorate, green roofs offer longer roof life — they can last up to 40 years — and lower roof maintenance. They beautify bare concrete stretches, are able to grow food, attract wildlife and provide habitat in areas with fewer resources. Also they provide business opportunities for nurseries, landscape contractors and irrigation specialists, and also offer substantial noise insulation, which is why Amsterdam and Zurich, for example, use it at their airports. If anything, those in the field believe we’re now entering a new, exciting phase in the construction industry. Technology and performance also have critical roles in the pursuit of ecological intelligence not only in the present world but for sure in the years to come.

The green roof is one of several integrated building systems designed to create a productive, comfortable, culturally rich workplace. While the rooftop soils and grasses insulate the building from the midday sun and the sound of jets flying overhead, a raised-floor cooling system allows evening breezes to flush the building at night. The concrete slabs beneath the floor store the cool air and release it during the day. The windows can be opened, the delivery of fresh air is under individual control, and daylight provides natural illumination. There are public gathering areas indoors and out, which are enlivened by fine art sculpture and paintings, thriving plants, and a splendid cafe. In short, it’s a delightful place to go to work. And when the birds fly by they don’t see a flat, ugly tarmac broiling in the sun, they see a rolling, flowering grassland that looks like home and they feel welcomed by the cities and people.

Everything is so simple – it is the air we breathe, the earth we stand on, the water we drink, and the organisms with which we share our habitat. Nature in the city is a powerful force that can shake the earth and cause it to slide, heave, or collapse. It is a broad flash of exposed rock stratum on a hillside, the overgrown outcrops in an abandoned quarry, the millions of organisms cemented in the fossiliferous limestone of a downtown building. It is rain and the rushing sound of underground rivers buried in storm sewers. It is the water from the sink, delivered by pipes from some outlying river, then used and washed away into the sewer, returned to the waters of the river or the sea. In short- The city is part of nature, and not the other way around…

With all this in mind, architects, project managers and planners can begin to integrate natural processes into urban life. Some of the initial steps can be seen around us. Already we can see urban building and street designs that use natural air flows to cool the city. We see urban rivers unearthed, riparian corridors reforested, and wetlands reclaimed and reconstructed within the city to purify the urban water supply. We see solar collection on skyscrapers and geothermal heating and cooling rising into buildings from underground. We see a profusion of community gardens where urban residents have daily interactions with soil, water and living things. We see living roofs filtering storm water, easing the heat-island effect and providing urban habitat for native species of plants, birds and insects. We see an emerging marriage between Nature and the City that has future. And more importantly more and more people acknowledge the fact that this future is NOW.


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As a Green Roof specialist who has posted articles on the importance of the environmental sustainability, now I would like to draw your attention to something