From bacteria to wind power: NTU leads charge in developing renewable energy sources

Nanyang Technological University researchers use bacteria that causes food poisoning to generate electricity and have come up with different designs for wind and tidal turbines to suit Singapore's climate.
Alice Chia Channel NewsAsia 24 Dec 15;

SINGAPORE: Wind farms seen in countries such as the United States are not feasible in Singapore due to space constraints and low wind speeds. That is why Nanyang Technological University (NTU) researchers have come up with designs for wind turbines specially adapted to Singapore's climate.

The blades of their turbines are made of a lighter material and are angled in such a way that they spin fast even at low wind speeds. The capacity of each turbine is 50 kilowatts of electricity - enough for the daily power consumption of 70 households.

Researchers are also working to improve the designs of tidal turbines to address challenges in deployment. Waters around Singapore are warmer, which means more marine organisms will grow on the turbines and slow them down.

"We used new types of paints, and new types of chemistries, that will prevent both bio-fouling as well as corrosion,” said Subodh Mhaisalkar, executive director at NTU’s Energy Research Institute. “We are designing new forms of blades that will again be more efficient at low tidal flows. And finally, we're also coming up with different mechanisms that will allow the turbines to function without weed entanglement."

The wind turbines will be deployed on Semakau landfill by July 2016, and the tidal turbines by July 2017. It is part of a project to build a power grid that integrates renewable energy sources.

The initiative is known as Renewable Energy Integration Demonstrator - Singapore. The grid will cost an initial S$8 million, and is expected to attract S$20 million more in project investments from industry participants.

"Singapore is renewable energy disadvantaged,” said Prof Mhaisalkar. “We have really very limited wind resources on the main island itself, but the southern parts of Singapore, the islands around Singapore, have significant wind resource. We have measured the wind speeds of up to 6 metres per second on Semakau and adjacent regions."

However, he noted that Singapore's status as a very important shipping hub poses a challenge for it to harvest energy in the southern part of the country. "The entire shipping channels really would limit the deployment of a number of these wind turbines close to the shore.

“So the best opportunity Singapore has is to deploy some of these turbines on our islands, but the greater opportunity is in the ASEAN region, where we have tens and thousands of islands without electrification. And if we can deploy these turbines on these islands, that represents the ideal situation where we can really harvest energy from the region."

So far, the region has only focused on harvesting energy from the sun he said. "The main issue with photovoltaics is you really can harvest energy only during the daytime. The opportunity we have by combining solar with wind as well as with tidal, is that we have the potential for 24-hour coverage of renewables," the professor added.

POWER FROM BACTERIA

In a separate project, NTU researchers have found an eco-friendly way to produce hydrogen gas, which can be used as fuel.

First, a chemical is added to a culture of E coli bacteria to produce electricity. Such bacteria are commonly found in the environment, in the intestines of people and animals and some strains that can cause diarrhoea and food poisoning.

Under sunlight, the electricity helps to break up water into its components of hydrogen and oxygen.

"Not only are we able to use bacteria to clean water and to break down waste, we can also use the electrons that are produced by the bacteria to feed into a system that can help us to produce 70 times more hydrogen gas,” said Associate Professor Joachim Loo from NTU’s Singapore Centre for Environmental Life Sciences Engineering. “Currently there are actually products out there that use bacteria to produce electricity, but these are all stand-alone systems.

“At the same time, we are also working in the area of solar fuels, where we actually use sunlight to split water into hydrogen and oxygen, but these have always been stand-alone systems. So for the first time, we are showing that a hybrid system of combining both together, we get a more efficient production of hydrogen gas."

Professor Loo also said using hydrogen gas can help reduce reliance on fossil fuels. The team hopes to develop the idea into a commercial product in the coming years.

- CNA/ek

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