Solar thermal technology to get a boost in phase two of solar mission

Should solar thermal be preferred over photovoltaic solar power?

By Jonas Hamberg
Published: Wednesday 28 March 2012

Concentrated solar power (CSP) or solar thermal technology is to be given substantial allocation in the second phase of the national solar mission (2013-2017). This was revealed by the joint secretary in the ministry of new and renewable energy, Tarun Kapoor, at the third concentrated solar thermal power summit on March 14, organised in Gurgaon. He stated that detailed plans would be revealed in the next few months. At the same time he admonished the industry. "Companies can't always work for profit; sometimes they must work for a cause," he said.

The first phase (2010-2013) of the Jawaharlal Nehru National Solar Mission (JNNSM) of 1,000 MW was split 50:50 between photovoltaic (PV) solar and CSP technology, but there were no guarantees of continuing with this ratio in the second phase. CSP technology works by concentrating sunlight through mirrors to heat a liquid that generates steam to run a turbine and generate electricity. PV solar technology, on the other hand, works by using semi-conductors to convert the energy in photons directly into electricity.

Only one solar thermal plant operational

PV plants are faster to install and some of the first phase projects are already commissioned (see 'Solar trick') while 470 MW of CSP is still in the construction phase (see table). So far only one 2.5 MW CSP plant is working, and that too at reduced capacity—the ACME Telepower Solar Power Tower in Bikaner, Rajasthan.

Name Programme Size and technology Location Status Deadline
ACME Solar Power Tower JNNSM Migration phase 2.5 MW Solar Tower Bikaner, Rajasthan functioning but with reduced capacity -
Lanco Infratech 'Diwakar' JNNSM Phase 1 100 MW  Parabolic Trough with 4 hour storage Askandra, Rajasthan Land-levelling completed, orders placed for most of the equipment May 2013
KVK Energy Ventures JNNSM Phase 1 100 MW Parabolic Trough Askandra, Jaisalmer, Rajasthan - May 2013
Reliance Power (Rajasthan Sun Technique) JNNSM Phase 1 100 MW Linear Fresnel Dhursar, Jaisalmer, Rajasthan - May 2013
Corporate Ispat Alloy/Abhijeet JNNSM Phase 1 50 MW Parabolic Trough Nokh, Jaisalmer, Rajasthan Basic Engineering completed and orders placed for most equipment May 2013
Godawari Green JNNSM Phase 1 50 MW Parabolic Trough Nokh, Jaisalmer,  Rajasthan Land-levelling done, orders placed for most equipment May 2013
Aurum Ventures JNNSM Phase 1 20 MW Parabolic Trough Mitrala, Porbandar, Gujarat Land-levelling done, orders placed for most equipment May 2013
Cargo Solar/Cargo Power and Infrastructure Gujarat Solar Policy 25 MW Parabolic Trough with 9 hours storage Kutch, Gujarat Under construction Expected commissioning in March 2013
Source: project developers

While PV prices have fallen rapidly over the past two years (see 'Falling silicon prices shakes up solar manufacturing industry'), there is no consensus on what the price should be to make CSP profitable. A representative of Abengoa, one of the world's largest CSP project developers, stated that all state policies use the Central Electricity Regulatory Commission's calculated tariff of Rs 15.31 per kWh as the starting point for bidding through discount rates and that it is not feasible. “We are not looking at projects in India," he said.

Indigenous production can cut costs 

Vimal Kumar, president (projects) with Cargo Power and Infrastructure, parent company of Cargo Solar disagrees. He says that CSP would be profitable even at the average tariff of Rs 9.07 per kWh in Gujarat where the producer gets a higher tariff the first 12 years and a lower tariff the next 13 years; the tariff of Rs 9.07 is an average of the two levels. "We had to look at every cost and work very hard for every paise." As part of cost-cutting, Cargo Solar has set up a factory to produce the curved mirrors needed for their plants, one of the first steps in indigenous production of advanced components of CSP plants.

Cargo Power as well as Lanco have decided to include molten-salt storage in their plants. As the sun shines, at the most, for half the day it is crucial that storage of energy be included for providing electricity round the clock. When the sun shines, part of the heat collected is stored in tanks of hot molten salts. When the sun sets, this heat in molten salts is used to produce steam and turn the turbines to generate electricity in the evening and at night, which can help meet power demand that peaks in the evenings. The possibility of storage has been projected as the most important advantage of CSP in comparison to PV technology.

Developers say there is a need for indigenous production of components such as vacuum tubing and control equipment and arrange for cheaper financing to get more projects rolling. "We have no fossil reserves to fall back on," reminds Kapoor.  “CSP may be a luxury for other countries, but for us it is a necessity," says a developer.


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