Windows are arguably one of the most striking assets of building architecture, especially in an urban setting. The question is: what if you could use these assets to improve building efficiency and make the building more comfortable, all while using the asset to create energy? It sounds futuristic. As it turns out, however, the future is now. This is the idea behind Pythagoras Solar—a solar window company. Pythagoras sandwiches photovoltaic (PV) cells and specially designed optics within a standard double-pane window. The optics collect direct sunlight and concentrate it onto PV cells which convert it into electricity. Light rays coming from other angles are allowed to pass through the window and into the building. The effect creates a window that simultaneously generates electricity while also shading the direct sun from heating up the building and causing disturbing glare.
Its power output is remarkable. The Pythagoras Solar window generates up to 12Wp/f2. In relative terms, this power output is equivalent to that of a standard roof-top panel in the same orientation. As such, it represents up to four times higher power density than traditional building-integrated photovoltaic (BIPV) panels.
The concept was conceived at Precede Technologies, an Israeli incubator. Founders Dr. Itay Baruchi and Gonen Fink identified an opportunity at the intersection of the rising demand for Green Buildings and the declining cost of PV solar power. What’s particularly unique about Pythagoras Solar’s window is that it is the industry’s first to simultaneously deliver energy efficiency, high power density and effective daylighting. The energy efficiency and effective daylighting amount to a significant reduction—up to 40 percent in some cases—of the energy footprint of the building. So now, while the corner office is a symbol of success it’s also a generating asset. Indeed, the technology could turn large areas of the building facades into generating assets for renewable energy that could potentially supply all the remaining building energy requirements.
The potential for this type of new technology is significant. In America alone the market to address building energy use is huge. According to the American Council for Energy Efficient Economy (ACEEE), commercial buildings account for 19 percent of the energy consumed in the United States and Pike Research predicts that “between 2011 and 2017, the building-integrated photovoltaics (BIPV) market is forecast to add 4.6 GW of new capacity, thus making it one of the fastest growing solar industry segments.”
The impact extends beyond economics and job creation. Reduction of building energy use is critical to protecting our resources, primarily water and energy. Water and energy are the lifeblood of industrialization. These resources are inextricably intertwined and work together to quench our thirst for power. Water is integral to resource extraction, refining, processing, transportation and electric power generation. Conversely, significant amounts of energy are needed to extract, transport, treat, and use water in urban areas. The collision of these two resources is often referred to as the energy-water nexus.
Anything that reduces the need for power generation reduces the need for water. In 2006, Sandia National Laboratories reported to Congress that “thermoelectric power generation in the U.S. consumes 3.3 billion gallons of water per day in total.” The report further explained how the extractive industries impact our water resources. For example, “in the mining sector, water is used to cool or lubricate cutting and drilling equipment for dust suppression, fuel processing, and revegetation when mining and extraction are complete. Estimates of water for coal mining vary from 1 to 6 gallons per million British thermal units (MMBtu), depending on the source of the coal (Gleick, 1994; Lancet, 1993). Combining those figures with 2003 coal production data (EIA, 2006); total water use for coal mining is estimated at 70 to 260 million gallons per day.”
Widespread deployment of renewable energy could have a significant impact on water use. A recent report from the Department of Energy’s (DoE) National Renewable Energy Laboratory (NREL) looked at a variety of scenarios for the increased use of renewable energy sources to generate electricity. For example, “the laboratory reported that if the country were able to switch to 80 percent renewable electricity by the year 2050, such a switch could reduce the power sector’s annual water use by approximately 50 percent.”
Obviously, not using energy uses no water at all. Businesses and industries can reduce their water footprint by switching to on-site renewables and incentivizing energy efficiency. Both of these strategies reduce the need for power generated by fossil fuel resources. According to Sandia National Labs in its report entitled U.S. Energy Sustainability: The Missing Piece, “Coal, the most abundant fossil fuel, currently accounts for 52 percent of U.S. electricity generation, and each kWh generated from coal requires withdrawal of 25 gallons of water. That means U.S. citizens may indirectly depend upon as much water turning on the lights and running appliances as they directly use taking showers and watering lawns.”
Thus, in developed countries, the energy-water nexus could be significantly impacted by targeting building energy use. What is more, the economic case for resource reduction is staggeringly compelling as explained in a recent study entitled, United States Building Energy Efficiency Retrofits, Market Sizing and Financial Models, released in March 2012 (the Retrofit Report). The report indicates, “Upgrading and replacing energy-consuming equipment in buildings offers an important capital investment opportunity, with the potential for significant economic, climate, and employment impacts. In the United States alone, more than $279 billion could be invested across the residential, commercial, and institutional market segments. This investment could yield more than $1 trillion of energy savings over 10 years, equivalent to savings of approximately 30 percent of the annual electricity spend in the United States. If all of these retrofits were undertaken, more than 3.3 million cumulative job years of employment could be created.”
Pythagoras Solar is just one of the many new and proven critical technologies with real solutions that are currently jockeying for position to strategically target these market opportunities. These technologies offer the opportunity to chip away at building power consumption and according to the Retrofit Report, improved policy could dramatically speed this process. Specifically, “enabling policy and regulation can be broad or targeted to specific market segments or finance models. Mandated efficiency targets, for example, could transform the industry across the board. Legislation that authorizes on-bill recovery for single family retrofits, on the other hand, would enable the development of a particular operational and financial model for a single segment. Both types of policies could play an important role in accelerating market adoption of energy efficiency.”
Our urban environment is rife with the potential to transform the way we use and generate energy. Initially, skyscrapers transformed urban city centers by enabling upward, rather than sprawling, growth. Now, these hulking buildings could provide the infrastructure to transform urban energy use. So, let the sun shine in. There is a whole new window of opportunity on the way.
Kelly de la Torre has a BS in biochemistry, MS in chemistry and a JD degree from Rutgers School of Law-Camden. Kelly is founder of Rapid Tech Transit, LLC (RTT), a business consulting firm focused on getting technology from innovation to market and de la Torre Law, LLC, a law firm that provides the legal support for technology commercialization and project development efforts. www.rapidtechtransit.com.
