Sri Lanka to call bids for a floating solar farm with battery amid Tesla challenge
- A joint venture with Sri Lanka’s Mahaweli Authority
- A battery backed “dispatchable” solar farm can be paid a capacity charge like a thermal plant
- Batteries can also be used for frequency regulation and grid stabilization
www.economynext.com. 17th March 2017
Sri Lanka is planning to call bids for a 100 MegaWatt floating solar farm with storage, as electric tech firm Tesla offered to build batteries for the Australian power grid in record time.
Sri Lanka’s cabinet of ministers has given the go ahead to call international tender for a 100 MegaWatt floating solar farm in Maduru Oya reservoir which is expected to cover an area of 500 acres of the 15,790 acre water body.
The solar plan will be a joint venture with Sri Lanka’s Mahaweli Authority which will have to be paid a 10 percent royalty.
The investors will have to bid for the cost of the plant and battery. Stored energy will be released to the grid during the night peak when Ceylon Electricity Board operates diesel reciprocal engines at over 20 rupees a unit and gas turbines at higher cost.
The CEB is also expected to buy any energy that the battery cannot store in the day time.
Industry analysts say it now costs about 1000 dollars to build a kilowatt of solar generating capacity and for large farms it can fall further.
A 100MW solar farm could cost around a 100 million US dollars or lower.
In an unrelated event, Elon Musk, co-founder of electric technology firm Tesla, has told Australia that he could build battery storage for 250 dollars per kilowatt hour, free if delivery was not made in 100 days, indicating a cost of 25 million dollars per Mega Watt hour of storage if he meant US dollars. Some media reports have interpreted it as US dollars indicating a cost of 33 million Australian dollars. It is not clear whether the number includes related infrastructure.
Some skepics have labelled the move as publicity gimmick of the high performance car firm that is still making losses. Tesla has advanced battery technology.
Typically a solar plant would have an efficiency or plant factor of around 20 percent or a little higher in sunny says, allowing a 100MW solar plant to generate about 480 MWh of energy, power sector analysts say.
If the Sri Lanka plant built battery capacity to store 300MWh of energy (the balance being delivered to the grid during the day) which would be released between 7.00 pm to 10.00 pm, batteries would cost around 75 million US dollars at Tesla prices. Tesla batteries are expected to provide up to 70 percent of the initial storage up to 10 years, according to published data.
A battery backed solar farm which can be dispatched (power discharged as required such as at the nigh peak) can be paid a capacity charge, like a thermal plant.
Smaller batteries can also be used for frequency regulation and grid stabilization by helping ‘smoothen’ output as sunlight varies.
Sri Lanka CEB has been reluctant to increase renewable power beyond a certain limit due to its de-stabilizing effect on the grid, to which the so-called ‘renewable energy mafia’ has propounded conspiracy theories based on weak public knowledge about technology.