Solar Flair
Integration of solar energy generating products into building envelopes and city wide schemes is inspiring the solar energy and building industries to check each other out, reports Claire Saeki.
Building facades at the most basic level serve two purposes: to keep the wind out and to let occupants see out. While they may serve to insulate or ventilate a building, many facades are purely vane constructs; either a display of wealth and artistic merit of the owner or used simply to get rid of surplus white tile. While the energy industry is being turned on its he]ad, increasingly buildings, particularly new and retrofitted green buildings, are looking to redesign their facades to reduce solar gain and glare while reducing energy costs. However, a small but growing group of developments and buildings are being designed to take advantage of the sun and rather than adding a solar panel as an afterthought, these projects are incorporating them into the building’s structure. This Building Integrated Photo Voltaic (BIPV) market is growing quickly but still faces impediments from both the solar energy and construction industries.
Solar Meets Buildings in Numbers
According to the publishers of Green Chip Stocks, the green building industry is worth US$1.42 tril. And the number is growing. According to the 2009 U.S. Solar Industry Monitor they are expecting 25 percent or greater yearly growth of the industry in 2010 and 2011. The photovoltaic market is expected to reach a yearly growth of US$32 bil by 2012. And according to one of the many predictions on the subject, in this case NanoMarkets, BIPV will account for US$4.1 bil of this.
Much solar energy generation growth witnessed in the residential sector in Europe and the US is not BIPV, while technological breakthroughs and the scale of development in Asia give Korea, Japan and China the lead. Everyone is jumping on the bandwagon with new and established companies jumping into BIPV partnerships, such as Dysol with Tsinghua University, announced last November. Schott, a manufacturer of solar cell components, estimates that solar will equal or outweigh all other forms of energy generation by 2050 and by 2100 will have more market share than all others combined.
|
BIPV
The integration of solar power into the built environment is not new. The concept has been a goal of the International Energy Association Photovoltaics Power Services programme since 1993 (IEA-PVPS.org). The Asian contingent at the 1999 IEAPVPS workshop was represented by only China (Hong Kong) and Japan. At that time, the IEA PVPS Taskforce 7 (building integration) looked at the solar energy market, the building industry requirements and the PV manufacturing development to set out a plan of action to better integrate these three groups. The green building and energy sectors had yet to boom. Taskforce 7 became Taskforce 10 (Urban integration), which in 2009 stated that “Significant effort has been undertaken by the PV industry to address the end customer”. However, critics say the dent compared to the potential is small. “Unlike the battery Organisers and delegates at the World of Photovoltaics Conference in Hong Kong in October 09, which ran concurrently with an electronics fair, partially angled towards buyers in the building industry felt it went further than limited applications. Organisers felt that this event had been a ‘first step’ towards something as simple as communication between the two groups, a lack of which previously had left innovation crippled. The Taskforce 10 report 2009 goes on to say that despite manufacturers’ concessions in the competitive market “there must also be considerations in policy direction and market structure to encourage builders to offer BIPV products to their customers.” They feel it is not just PV manufacturers and suppliers who should think more about architectural applications of their products: If building owners, developers and operators had incentives to use alternative power sources in their buildings they would encourage their engineers and architects to prioritise BIPV.
Feed-in Tariffs
One incentive that Asian governments have adopted to encourage renewable energy production are feed-in tariffs. In countries like Taiwan the government requires utilities to pay premium rates to suppliers of renewable energy that ‘feed’ power back into the grid. There are more than 40 feed-in systems globally with Korea and Japan both having set up mechanisms that benefit solar suppliers. The IEA state “the cumulative installed power of PV systems in Korea increased to 357.5 MW by the end of 2008. The annual installed PV power during 2008 reached 276 MW, six times the size of the market in 2007, with the majority being installed due to the favourable feed-in-tariff scheme.” China currently has tariffs for wind power and last August announced a feed-in-tariff plan for solar farmers. There have been some small test projects but policy remains unclear. India has announced large scale feed-in schemes for solar power that include significant investment in rooftops, leaving the door open for more sophisticated BIPV schemes.
Sophisticated schemes require sophisticated technology. For example, Alanod-Solar supplies reflecting or absorbing components for a wide range of solar technologies. Frank Schoonen who heads up Alanod-Solar’s team says a wide range of solar technologies are “absolutely” and “already” being used in large scale developments. “There are projects throughout the world where solar is powering heating and cooling systems for large facilities or selling power directly into the utility grid for use within housing developments. These applications will only continue to gain momentum as they prove efficiencies and savings, leading to even more projects and wider adoption at a consumer, city and country level.”
How it’s Done
There are numerous ways that BIPV can be achieved and “We are seeing innovation and funding continuing at a blistering pace in the solar industry” says Schoonen. Hard, flexible and thin film options for flat or slightly angled deployment, particularly onresidential or car park roofs are ubiquitous. PV roofing tiles and facade solutions have seen greater BIPV innovation if not widespread application. Transparent or tinted glass and opaque facade materials provide a combination of shading, reduction in heat loss/solar gain and electricity generation through integrating PVs on building elements that may be decorative and functional. Flexible thin film formats also work well on shades and awnings. Additionally, there are several modes of solar power generation beyond photovoltaics. Concentrated solar thermal technology and other cutting edge technologies that can be stuck, coated or even printed on existing building materials.
|
The Role of Architects
Architects play an important part in drawing together the two industries but products being stiff and unforgiving or requiring a great deal of technical knowledge to be used effectively create physical and psychological barriers. As the 1999 IRA-PVCS workshop concluded “It is easier to encourage reluctant clients (building owners) than reluctant architects to install PV. With existing buildings and retrofit projects where the architect is often not involved, the owner and the electrician are important.” As such numerous products have since been entering the market to address these challenges. For example, glass specialist Romag has developed a technology used by architects and those involved in the design of PV systems “with the aim of breaking down the aesthetic barrier often in place when considering the use of PV in building design”. Practicality is another concern. Schott offers products that speak specifically to concerns over integration, such as compliance with international standards, durability, cost, service life and performance in low light conditions. In Asia, systems making use of solar energy to tackle cooling and air-conditioning costs are attractive. Schoonan says relatively small concentrating solar power (CSP) systems are light when using aluminium based mirrors and so such systems can be installed on existing building roofs without the need for extensive structural work. Kruse Horst, a representative of Schott Solar, says “Most solar systems, be it reflective based [e.g. CSP] or absorber based [PV], need large space areas. Roofs of houses, buildings or industrial plants offer this space without much worry of shade reducing the efficiency of the systems, or concerns over realty space being an issue. Here light aluminium based materials and systems have a significant role to play.” Horst points out that total global energy requirements could be met with a solar farm only four percent the size of the Sahara desert.
No Revolution Yet
High profile examples of sophisticated BIPV systems exist in Asia. The Pearl Tower in Guangdong designed by SOM was to be the first true zero energy building (failing partly for not being permitted to feed energy back into the grid) has a highly intricate facade that fully integrates PVs. Believed to be the first of its kind in Korea, the Samsung Institute of Engineering and Construction Technology (SIECT), in the Gihung area, has PV cells mounted on the south facade and on the roof. Special care was taken during the design phase so that PV modules would shade the building in the summer, thereby reducing cooling loads, while at the same time allowing solar energy to penetrate the building during cooler seasons, and allow for the transmission of daylight. According to researchers, the PV share of the SIECT building’s electrical demand reaches 10 percent on a typical July day. In the Middle East the colossal MASDAR project is getting into building integrated renewables in a shockingly enthusiastic way for a country whose prime export is the most desired form of fuel in the world. The trend towards BIPV is growing, albeit slowly.
It’s unlikely that those who are holding back from adding or integrating PV into their buildings are doing so because the technology isn’t there yet. In fact it is the wide array of technology and continuous innovation that baffles. In an interview with RFP magazine Chad Holliday, former CEO, DuPont said that solar still needed an innovative leap before it could really take off. Schoonan counters this saying, “When you look at many solar technologies, they are building off of core technologies that have been in existence for many, many years. Stirling energies, heliostats, reflective surfaces — all of these are proven technologies that in combination can lead to new innovation and applications While I would certainly welcome a leap in innovation, I don’t necessarily think it’s imperative for solar to become commonplace. There are challenges that people are hard at work solving — storage being one of them. But I think the key pieces and components are in place and incremental improvement will help us get there sooner.”
Schoonan says “One of the biggest stumbling blocks is simply awareness and education. If people had a better idea of what technologies were available and the associated benefits and payback period, it would go a long way towards a meaningful collaboration…middle technologies like smart grids are also an important step.” Before the solar and building sectors become truly integrated, FMs and architects need to work with some engineers and listen beyond the hum of the hype, or is it the hum of a diesel generator? Think about it, if cities in the Middle East which have the highest carbon footprints in the world are getting into BIPV, shouldn’t we?