New Solar Cells Use Perovskite to Turn Water into Energy

A new, highly efficient process for splitting water into hydrogen and oxygen has been demonstrated by researchers in Switzerland. The process combines a stable catalyst with a highly efficient perovskite solar cell. The perovskite solar cells do have a major drawback in that they breakdown after a few hours, but the researchers believe further advances in solar cell technology should take care of this problem.

As the most abundant energy source on the planet, solar energy is extremely attractive for weaning the human race off fossil fuels, but making the switch is problematic. The energy captured has to be stored until it is needed and, as the most abundant solar resources are often where few people live, a way needs to be found to transport it to people’s homes and businesses. One option is to use solar power to split water into hydrogen and oxygen. However, for this process to be efficient, two things are needed: a catalyst that can lower the activation energy barrier of splitting water enough to allow the reaction to proceed at a sufficient rate and a photovoltaic cell that provides sufficient voltage to surmount this energy barrier.

Conventional solar cells use silicon as the photovoltaic material. As silicon is relatively cheap, the raw materials for such devices are inexpensive. However, silicon is an indirect band gap semiconductor, which makes it an inefficient absorber of light and means a thick layer is required. Such a thick layer cannot be deposited from solution so has to be cut from a wafer. This makes silicon solar cells quite expensive to assemble, although prices have dropped drastically with automation. Furthermore, the open circuit voltage, the potential difference generated between the positive and negative electrodes when they are not connected together, of a traditional silicon solar cell is limited to about 0.75V or less, which means three or sometimes four such cells need to be connected in series to drive the water splitting process. This reduces the efficiency of the process and increases the cost. Newer, more expensive solar cells, such as those made from several stacked junctions, can address this problem, but they too add to the cost of the process.

Net Zero Buildings = The Future of the Commercial Market

The future of the green building market rests on net zero buildings. These projects promise innovative new design – like that seen in this net zero building proposal for a Mercedes-Benz office building in Armenia – integrate a number of advanced “green” materials to maximize efficiency with renewable energy sources that generate as much energy as the project uses on an annual basis. In other words, it uses zero energy, “net”.

Senior Vice President of Turner Group and President/CEO of Turner Building and Science Design William Turner predicts that the pace of growth in Zero Energy Building (ZEB) construction will grow even faster than recent estimates done by Navigant Research, who indicates the market growing to $1.4 trillion in 2035. “What we are experiencing on the ground level is rapid acceleration in the number of owners and builders going towards a Zero Net Energy platform,” explaines Turner. “We are now able to demonstrate cost effective strategies on a wide variety of building types that allow green buildings to also be high performing buildings. 

The introduction of the LEED rating system clearly helped the green building marketplace to flourish. However, now that the enthusiasm over Gold and Platinum plaques has waned, building owners are more keenly focused on building long term value into their green buildings.

Nalco to Invest Rs 660 cr on 100 MW Wind Power Plant

National Aluminium Company (Nalco), the navratna public sector undertaking under ministry of mines, plans to set up a 100 Mw wind power project with an investment of Rs 660 crore.

“The project will be set up shortly at a suitable location in India”, Ansuman Das, chairman cum managing director (CMD) of Nalco said at the company’s 33rd annual general meeting (AGM) here.

Selection of wind power developer is underway, he added.Nalco has already commissioned two wind power plants in Andhra Pradesh and Rajasthan. The 50.4 Mw plant in Andhra Pradesh was commissioned in 2012-13 while the Rajasthan unit of 47.6 Mw, built at an investment of Rs  283 crore, was put to operation in January 2014. About 150 million units of electricity were generated from these two plants in 2013-14.

In Odisha, the aluminium major also plans to put up a 14 Mw wind power project in mined out area of its bauxite mines at Damanjodi.

The central PSU is also planning to set up a solar power plantat a suitable location in the country to meet its solar purchase obligation. To ensure viability of its second smelter and power complex proposed in Sundargarh district, Nalco is trying to secure a coal block.

The company posted net profit of Rs 642 crore during 2013-14 compared to Rs 593 crore in the previous year. It also achieved the highest ever metal exports in 2013-14. The export earnings stood at record Rs 3719 crore.

In the first quarter (April-June period) of 2014-15, Nalco has registered a net profit of Rs 271 crore which is higher by 58 per cent compared to the corresponding period of the previous fiscal.

Nalco has completed the commissioning activities for capacity upgradation of fourth stream of alumina refinery from 525,000 tonne to 700,000 tonne per year and of bauxite mines from 6.3 million tonne to 6.825 million tonne per year at an estimated cost of around Rs 400 crore.