India's first Capstone microturbine to produce power from landfill gas

Gas Authority of India Ltd (GAIL developed a landfill project for Eastern Delhi Municipal Corporation (EDMC) where 30 kW Capstone microturbine is installed to produce power from landfill gas. GAIL had also supplied technical assistance for landfill closure as well as providing gas tapping wells and connecting all these to a common gas manifold piping for further treatment and supply to microturbine as fuel.

This initiative is in line with the present government’s commitment to enhance the renewable energy component of the country’s energy production target and agreement’s made at the recent Paris climate summit. Recent Chennai floods have left tons of solid waste accumulating in Indian cities which require solutions like EDMC adopted in Eastern Delhi.

GAIL explored all options including producing compressed natural gas (CNG) by compressing landfill gas (LFG), and also producing power with the LFT using a reciprocating engine genset. But it  finally decided to go with microTurbine technology as reciprocating gas engine could not operate satisfactorily when methane content fell t less than 50%.

Generators required for producing power from LFG  must have capability of remote start and operation, continuous unattended operation, ease of maintenance and high reliability. The Capstone microturbine met those requirements. It can operate with 35% or less methane content in the inlet gas. As well as tolerance for low amounts of methane, the microturbine does not have maintenance intensive components like an oil pump, oil filter, water pump, radiator, coupling or starter motor. A total of six major sub-assemblies requiring periodic maintenance attention are absent in this microturbine.

M/s Brio Energy of Mumbai, exclusive distributor of Capstone Micro turbine in India, supplied, erected, commissioned and operates the microturbine. During a recent visit to this location in early December, 2015, the microturbine had just been commissioned and had clocked 25 hours of operation. The facility also includes a counter-current CO₂ scrubber, and a compressor for landfill gas since the pressure of the gas generated is near atmospheric, and the microturbine requires an inlet gas pressure at a minimum of 5 kg/cm².

At the time of the visit, the unit was producing about 16 kW. All this power was being used to operate gas compressors, pumps and blowers as a part of unit testing. The microturbine is about to commence 24 hours continuous operation. Excess power will be uploaded to the grid. The unit has already been synchronized with the local grid frequency for this purpose.

This Micro turbine is started using grid power as it is already synchronized with the grid and has an IGBT in its circuitry.  Starting and stopping of the engine require just touching of two buttons. Noise of the engine even with covers open was less than half of normal genet of same capacity or could be even less. Exhaust gas NOx was less than 9 ppm as told by the operating personal at site.

Operating personal at the location exuded confidence that they will soon be able to supply to the grid as the Capstone Micro turbine is very simple to operate, requires maximum raw land-fill gas of 50m³/hr for 24 hrs continuous operation  and trial test of all peripheral systems are completed.

There was a normal recip. Genset of 40 kva (approx. 30 KW) lying at that site and I could note that the physical package size of that recip genset is almost double the size of 30 KW Capstone Micro turbines. er “Renewable Waste Intelligence” land-fill gas to energy project is catching up in US where all such projects use Micro turbines owing to its capability to operate with low methane content in input fuel gas.

Thousands of tons of solid wastes dumped as land-fills in Indian cities poses herculean problem and daily head-ache to city municipal authorities Indian cities must start looking for implementing more number of land-fill gas to energy projects (LFGTE) using Micro turbines as it has multiple advantages required for a renewable green energy project

S Krishnamoorthy is a freelance consultant, renewable energy