The use of organic photovoltaic cells in skyscrapers
The skylines of big cities like New York, London and so many others in the world have been shaped by skyscrapers. These high-rise buildings typically draw their power from the traditional carbon fuel grid. Here, Matthew Stone, Chairman at NextGen Nano, has explained how the integration of organic photovoltaic (OPV) cells to commercial buildings can assist in the production of green energy for cleaner cities.
According to the United Nations, the world’s urban population will rise from 3.6 billion to 6.3 billion between now and 2050. As more people decide to live in big metropolises instead of small, rural villages, skyscrapers are not only the symbol of modern urban cities but are a necessity in order to provide enough space for both living and business purposes.
Since skyscrapers include offices and apartments and need to accommodate a vast number of people, they require more energy than small houses. One study shows that electricity used per square metre of floor area is nearly two and a half times greater in high-rise office buildings than in low ones. This study also shows that the gas for the heating in skyscrapers is 40% higher than normal buildings and total carbon emissions are twice as high.
The problem with glass skyscrapers is related to heat leaks in cold weather and extreme high temperatures in the summer, which increases the need for air conditioning as people are not allowed to open windows. By using air conditioning constantly, carbon emissions from offices are currently 60% higher than offices that use a natural ventilation.
To reduce carbon emissions and provide enough energy to skyscrapers, one of the best solutions would be to install building integrated photovoltaics (BIPVs). At the moment, there are four main types of BIPV products, including the crystalline silicon solar panels for ground-based and rooftop power plants; the amorphous crystalline silicon thin film solar PV modules; the Copper Indium Gallium Selenide (CIGS) based thin film cells on flexible modules, which are laminated either to the building envelope element or mounted directly onto the building envelope substrate; and finally the double glass solar panels with inside square cells.
Current solar panels present PV cells that absorb the photons from semiconducting materials. Photons handle exciting charge carried in the semiconductor materials, which are consequently extracted from the cell to electrodes to generate electrical current. This process doesn’t require the use of carbon fuels or other materials that can produce air pollution. However, there is no guarantee that the PV panel itself is produced using environmentally friendly materials, unless the panel consists of organic PV (OPV) cells.
The challenge in realising truly green BIPVs is that higher power efficiencies are required to make building-integrated solar practical. OPVs have typically offered lower efficiencies than conventional PVs, but research continues to pave the way for more efficient OPVs to meet this requirement.
For example, UK technology company Nextgen Nano is leading the way in the development of transparent organic solar cells using advanced nanotechnology. Nextgen are currently developing highly efficient, flexible organic solar cells that support efforts for decentralised energy generation and power consumption. This innovation has led the company to develop OPVs that have the potential to significantly improve the efficiency currently achieved by third-generation solar technologies.
The PolyPower division of Nextgen Nano has explored the use of earth-friendly organic materials that can provide a lightweight, flexible and affordable approach to solar energy. PolyPower is developed at a nano level with transparency and flexibility, which means it had the exciting potential to be applied as a semi-transparent thin layer to the surface of a skyscraper and its windows, allowing power generation, lighting and temperature control.
By investing in nanotechnologies for solar panels, it is possible to move forward in the sustainability mission by reducing air pollution in big cities exponentially. OPV cells, applied to the glasses of skyscrapers, will still make skyscrapers aesthetically beautiful, but ensure that these buildings are sustainably and sufficiently powered. Most importantly, by aggressive investment in these technologies now, it might be possible to reduce carbon emissions well ahead of 2050 — allowing us a much-needed breath of fresh air in cities like London and New York.