Navigant Research Blog

Green Roofs Sprouting Up Globally

— September 18, 2014

Many cities have mandated increased energy efficiency in buildings and, in some cases, net zero energy use by buildings.  A variety of solutions is needed to meet these goals; some are cutting-edge digital technologies, while others have been around for thousands of years.  Green roofs, one of the oldest energy-saving technologies, are becoming increasingly popular and having an impact on sustainability efforts.

Modern green roofs employ advanced design and materials to provide residents with rooftop oases while saving energy.  There are two primary types of green roofs: extensive green roofs, which generally have 2 to 12 cm of planting medium and are designed to be virtually self-sustaining; and intensive green roofs, which are far more complex and act as rooftop parks and gardens.  Intensive green roofs have soil depths of more than 12 cm and can include shrubs, small trees, and conventional lawns.  Given the amount of materials and the additional weight required for intensive designs, they are not suitable for all roofs.  Companies such as Illinois-based TectaGreen have been installing various types of green roofs on buildings across the United States for many years.

Cool Under Cover

Green roofs have been used for centuries to provide insulation and protect roofing materials, and they provide many benefits to building owners, occupants, and the general public.  Rooftop vegetation offers several public benefits; it improves urban air quality, manages stormwater runoff, and helps moderate the urban heat-island effect.  But it’s the private benefits for building owners that are primarily driving the market for green roofs.

The most direct benefit is reducing the amount of energy required to heat and cool buildings.  Several studies have shown that installing a green roof reduces summer cooling needs and winter heat loss by as much as 26%.  Green roofing can also extend the lifespan of a roof by protecting the waterproofing membrane from ultraviolet radiation and physical damage.  Other benefits include noise reduction, the reduction of electromagnetic radiation, and compliance with building codes such as Leadership in Energy and Environmental Design (LEED).

Small but Growing

While costs for green roofs have dropped in recent years, there is an ongoing debate over their cost-effectiveness and payback period.  Installed costs of green roof systems can vary dramatically; extensive roofs (shallower) generally cost from $10 to $23 per square foot to install.  Intensive roofs can cost anywhere from $25 to $220 per square foot and may require regular maintenance.  Some argue that at those prices, green roofs cannot pay back their installation costs.  But it can also be argued that the most important benefits are those that are not easily quantified.  What’s more, compared to other, more intrusive energy efficiency measures, green roofs are relatively inexpensive.

Despite the cost, green roofs continue to be installed around the world.  Navigant Research’s recent Zero Energy Buildings report discusses the efforts underway to lower building energy consumption; green roofs represent a small but growing part of that effort.  In addition to energy efficiency, green roofs are part of a growing movement to improve the sustainability of urban environments and reconnect residents with the natural environment that their cities have largely erased.  They are sure to grow in popularity over the coming years.

 

Non-Profit Solar Offers Hope for Developing Economies

— July 31, 2014

At the Lungra Health Clinic in the remote western region of Nepal, overhead lights now illuminate the operating room for the first time.  Midwives at this facility are grateful that they no longer have to use flashlights held between their teeth to deliver babies.  The recent installation of an off-grid solar PV system allows the healthcare providers at the Lungra Health Clinic to work through the night and store lifesaving medications and vaccines.

During the coming decades, developing countries will represent some of the most lucrative markets for solar PV.  Many of the largest global solar companies are devoting significant resources to understanding and developing products for these markets.  Moreover, the people who live in these areas will benefit from solar development more than developed world consumers.  In developing countries, solar power is often not a replacement for conventional grid power; it’s the only source of electricity available.

Some of the same factors that make these areas attractive for solar development, though, also create obstacles.  The lack of basic infrastructure, absence of established electricity markets, and spotty government policies to incentivize development make doing business in these areas extremely difficult.

Seeding Solar

A possible path forward to address many of these challenges has emerged from a global solar leader, SunEdison, which has helped launch a non-profit organization called SunFarmer.  The mission of this organization is “to make solar power accessible to the 300,000 hospitals worldwide that lack access to reliable energy.”  Using seed money from SunEdison combined with private donations, SunFarmer has already installed off-grid PV systems at six health clinics in Nepal, including in Lungra.

SunFarmer covers the upfront cost of installing the system and collects rental payments from the local organizations over a set period – until the initial investment has been paid off.  All rental payments are then recycled to install more systems where they are needed most.  SunFarmer uses only high quality components and provides operations, maintenance, and monitoring services throughout the life of the project.

While the obvious benefits of providing clean and reliable electricity to those who need it most is SunFarmer’s primary motivation, these ventures deliver additional value to the parent organization, SunEdison.  Establishing viable businesses in a mountainous and poor country like Nepal requires trial and error.  The SunFarmer program will provide valuable insights and experience for SunEdison with minimal risk as it attempts to expand its international footprint into more challenging, emerging markets.

Extreme Renewables

Once developers have established a viable solar business model, local stakeholders – including electricity users, grid operators, policymakers, and commercial lenders, all of whom are essential to a truly sustainable market – will enter the market.  The risk of lending to the first solar project or signing the first power purchase/lease agreement is much higher than in subsequent deals.  SunFarmer will work with local residents to educate them on the technical aspects of distributed solar generation.  The ultimate goal is to give locally owned solar companies firsthand technical experience with installing and maintaining remote power systems.

It will be interesting to see if this type of program is replicated by other large renewable energy providers looking to establish a presence in emerging markets.  Pioneering non-profit renewable energy ventures can create goodwill for the parent company, as well as an opportunity to put its technical expertise and business model to the test in the most challenging environments.

 

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