Wednesday, August 01, 2007

Solar Concentrators - A Quick Primer

Here is an excellent primer on solar concentrators.

As the name suggests solar concentrators concentrate solar power onto a solar (photovoltaic) cell. So the cell gets more sunlight and that improves its efficiency. Today the additional components that a concentrator has wipes out the cost advantage of using fewer solar cells per unit of output power. But as the efficiency of the solar cell goes up, the output of the concentrator multiplies, and it is estimated that with solar PV cells of efficiency 18% and above the concentrators offer significant price advantages.

However many believe that solar concentrators are merely a transitory technology. As solar cells get so cheap that we can incorporate them on our walls and even our clothes, the cost advantage offered by the concentrators might not amount to much.

Do check out the primer linked above if you want to answer the following questions:

  • What are the primary forms of solar concentrators?
  • Why is there interest in concentrating photovoltaics?
  • Why not just improve solar cells?
  • OK, concentrating light onto solar cells means more power output. But does that mean it's more cost-effective?
  • So what do these solar concentrators that use photovoltaic cells look like?
  • What are the tradeoffs of this approach?
  • Are these concentrating photovoltaic systems commercially available?
  • How will things look a few years from now?

Thursday, July 26, 2007

Indian Telcos Going Green


Erratic power supply in rural areas is pushing more and more Indian telcos to alternate energy to power their towers. Early this year Idea Cellular announced that it was looking at bio-diesel to power some of its rural cellular base stations. The fad apparently is catching on.

The Trend Catches On

Ericsson AB has already set up 4 towers running on fish and vegetable oils, for Idea Cellular in the power-strapped Maharashtra circle.

Reliance Communications is tapping wind and solar power. While it has already installed windmills on its towers at Kunustara and Murugathal near Durgapur in West Bengal, it is in talks with Pune-based solar cell manufacturer Machinocraft on the solar power front.

"On a rough estimate, a wind power turbine or a solar panel mounted on towers will generate around 1,800-2,000 watts during peak sunshine hours or high-windy days. Of this, the repeater sites consume up to 500 watt each, while the remaining is stored in batteries and used to power the network at night or low windy times."

Hutch is also looking at wind power, while BSNL and MTNL are "experimenting with multiple sources like solar, wind, gobar gas and biofuel from molasses."

Potential Impact

In most cases the alternate energy sources replace diesel gensets which are currently almost universally used to ensure uninterrupted power supply at the base stations. So the shift will certainly save petroleum and prevent emissions.

In the big picture the financial and environmental impacts will be very small, but it will be a good experience for Indian corporate houses, and the alternate energy culture in general. The villages will get exposed to alternate energy too and that should help adoption in these areas.

Monday, July 23, 2007

India's Tallest Green Building

Though India has never been a significant player in the global skyscraper stakes, one building promises to change that and for all the right reasons.


The India Tower, currently under construction on the Queen's Necklace, the scenic Marine Drive in South Mumbai, is expected to dominate the skyline of India's main financial district. At 300m, it is a giant by Indian skyscraper standards. But when it is ready in 2010, the Burj Dubai is expected to dominate the global building height stakes at about double that height. So what is the main claim to fame for the India Tower?

The USP(s)

It might well be the tallest building in the world in its class of green-rated buildings. Designed by New York-based FXFOWLE architects, it will be a LEED-Gold certified project. Here are some of the features planned to improve its energy-efficiency:

A solar chimney to generate electricity (Solar chimney's need to be very tall - so incorporating one into the design of a skyscraper is really cool.)

On-site waste water reclamation (ease the load on public facilities, plus build more reliable ones)

Daylighting - a process to ensure maximum usage of sunlight for lighting within the building

Solar shading, natural ventilation and rainwater harvesting

The rotating form apparently comes from functional requirements (whatever those are - but it certainly looks kewl).

Mapping The Trend

This is a building for the very rich - with "a custom-designed residential-style Park Hyatt hotel and serviced apartments, and long-lease and duplex penthouse condominium apartments", in addition to luxury-brand retail and hospitality. (We the poor might benefit if they open up a sky-walk for the public though - imagine the view!)

But most new trends start with targeting the rich. The premium they pay helps fund research into making them more common place and affordable.

If India's tallest building is going to be one of its greenest, then that is a solid commitment we as a society are making towards sustainability.


Related Posts:
Indian World's Tallest Building Aspirants

India's tallest building in the World

Thursday, June 28, 2007

Signet Solar - Big Plans In The Indian PV space

Signet Solar is the latest in a series of companies planning to manufacture solar photo-voltaic modules in India. Similar to Solar Semiconductor, Signet Solar is a Silicon Valley based company, founded by NRI's, all industry veterans. Their model suggests that the business office will be centered in the US, while R&D (and some manufacturing) will happen in Germany, while the high-scale manufacturing will be in India. The fabs will be supplied by Applied Materials, in a model similar to that adopted by most other companies manufacturing in India.

The company was launched in May, 2007, and in June, 2007 they announced that India would be the main manufacturing base. The plan is to initially set up a 60 MW manufacturing plant, with a targeted total capacity of 1,000 MW in 10 years with a total investment of $2 bn.

Here is a quick introduction to Signet Solar's proposed business model and an assessment of its chances in a "booming but crowded" solar PV market, which also has a link to Navigant Consulting's report on the solar industry Solar Outlook (Apr 12, 2007).

Wednesday, June 27, 2007

The Vertical Farm Project

In The Sustainability Challenge I made a case for future where humans lived almost entirely within self-sustained and ecologically isolated cities. The idea was that nature and humans could no longer survive together as humanity achieves a dominance beyond what nature can afford to bestow upon a single species. Isolating ourselves from nature will reduce our contribution to a mass extinction in nature, as well as insulate ourselves from being made extinct too.

A big step in this direction is cities striving for self-sustenance in their need for resources. Of all resources that a city uses, food is probably the most expensive.

The food for a city is usually grown in areas much bigger than the city itself. It is then brought to a city by land, sea and even air from across a huge hinterland which could span the globe.

Now consider a greenhouse - it makes very efficient use of existing resources like water, sunlight and nutrients. Now what if we could cram greenhouses in a city? The food is grown with minimal use of resources, and transportation costs are cut to negligible levels. Win win?

But how should a greenhouse that will feed an entire city be structured? Why, as a skyscraper of course.

Scientists are Columbia University are suggesting just such an approach, via The Vertical Farm Project:

"The idea is simple enough. Imagine a 30-storey building with glass walls, topped off with a huge solar panel. On each floor there would be giant planting beds, indoor fields in effect. There would be a sophisticated irrigation system. And so crops of all kinds and small livestock could all be grown in a controlled environment in the most urban of settings."

Some of the other advantages include:
"* Year round crop production in a controlled environment
* All produce would be organic as there would be no exposure to wild parasites and bugs
* Elimination of environmentally damaging agricultural runoff
* Food being produced locally to where it is consumed"

The Vertical Farm Project
Vertical farming in the big Apple

Monday, June 04, 2007

Hydrogen Roadmap for India

The renewable energy ministry of India has announced a Rs 25,000 crore (US$6 bn) roadmap to promote the use of hydrogen in India by 2020. Link

The roadmap envisages one million vehicles running on hydrogen and at least one power plant generating 1000 MW of power, all running on hydrogen gas.

Indian Oil Corporation is likely to be the leading light in this effort, which will also involve SIAM (Society of Indian Automobile Manufacturers) and leading universities. Below is an extract from the report on TOI.

"As part of the new initiative, a demonstration project for setting up a hydrogen dispensing set-up at a petrol pump in Delhi has been sanctioned as a joint venture with IndianOil Corporation. The project would enable dispensing of neat hydrogen and CNG blended with hydrogen as fuel for vehicles. The station will have a hydrogen generation capacity using an electrolyser system and facilities for storing and dispensing neat hydrogen as well as blended with CNG in varying ratios. The H-CNG blends will be used in the modified CNG vehicles and are expected to further reduce emissions from such vehicles as compared to when burning only CNG. The project would also generate operational experience in handling hydrogen as an automotive fuel.

Another project for the introduction of H-CNG blends on a trial basis in existing CNG vehicles has been planned to be undertaken by the ministry jointly with Society of Indian Automobile Manufacturers (SIAM). The project will be for two years and will be the first public-private partnership project in this area. The project aims at introduction of H-CNG blend as a fuel on trial basis in buses, cars and three-wheelers, involving five leading Indian automobile manufacturers.

IndianOil Corporation is also participating in this project and the existing hydrogen dispensing facility set up at its R&D Centre at Faridabad would be used for refuelling vehicles. Under this project, the engines of the existing CNG vehicles and fuel injection systems would be modified. The project aims at optimising the H-CNG blend ratio for optimal vehicle performance and minimal emissions.

Several new research projects in the area of hydrogen energy and fuel cell technology have also been sanctioned to universities, IITs and research organisations. A few more are in the pipeline. A National Centre for Hydrogen Energy and Fuel Cell Technology is also being set up at the ministry's Solar Energy Centre campus at Gurgaon in Haryana."

Friday, May 25, 2007

Indian Ashden Award Finalists

After the Energy Globe awards, it is not time for the Ashden Awards for sustainable energy projects, and two Indian organizations are in the running.

Regardless of whether they actually win the awards or not, it is certainly worth looking at what they are doing. Interestingly both organizations work in the area of producing bio-gas.

Biotech, Kerala

Biotech operates in Kerala and works on generating bio-gas from a variety of organic waste. They have working plants that produce gas from toilet waste, household and restaurant waste food, abattoirs, and fish markets. They target middle-class households, as well as unorganized small establishments. The efforts help in a model of sustainability that treats waste at source, promotes hygiene, is environmentally friendly and is economically viable.

"To date BIOTECH has built and installed 12,000 domestic plants, 220 institutional plants and 17 municipal plants that uses waste from the municipal fish markets to produce biogas which is then used in a 3kW engine to generate electricity for lighting the market.

"Households with a biogas plant replace about 30% of LPG or about 44 kg per year, saving Rs1,200 per year. This means that the family can pay back their contribution to the cost of the plant in about three years, and even more quickly if they collect extra food waste from shops to increase their biogas production. The effluent or residue in the biogas plant also makes good fertiliser which results in higher food production."

SKG Sangha, Karnataka

SKG Sangha, operates among rural households in Karnataka selling 'Deenbandhu', a standard model of a cow-dung based biogas plant, working with banks to help finance the plants for their generally poor customers. They have over 43,000 installations so far, which probably compares with the best in the world. That itself is a decent achievement because each plant probably saves 4 tonnes of CO2 a year. More importantly it saves 3.5 tonnes of fuel wood a year. (I know the second number looks huge... does the average rural household really use that much fuel wood?) Anyway, the fuelwood saving results in health and time savings for the rural users, as well as precious breathers for the forests.

However, the benefits to the farmers goes beyond that.

"SKGS has devised an innovative way of using the slurry produced by the biogas plant as an effective fertiliser that has the added benefit of earning rural women a good income... SKGS's vermi-composting system involves mixing the slurry with solid waste (straw, green and dried leaves) and then leaving it to compost for 25 days. The mix is then placed in a container with earthworms, which produces a high quality fertiliser for which people will pay Rs90 (£1) for a 30kg bag. The fertiliser increases grain crop (rice and ragi) yields by 20% and increases the resistance of crops to pests and diseases."

All the finalists

Biotech and SKGS are just two of the finalists, and the entire list is here. Please do click on the link and check out all 10 finalists - they all make for interesting reading.

The Awards Ceremony

Representatives from all finalists will travel to London for the awards ceremony on June 21. Al Gore (who obviously needs no introduction here) will give out the prizes.

Related post:
Energy Globe 2006 - The Winners From India