Plan B for Emergency Power – using Solar Hybrids | Daily News


Avoiding power blackouts in April elections

Plan B for Emergency Power – using Solar Hybrids

If current rates of emergency energy purchases are continued, it is likely that CEB (Ceylon Electricity Board) would be bankrupt in a few years.

The CEB’s Long-Term-Generation Plan with a least cost approach is sidelined to allow purchasing emergency power. No medium-capacity power plants have been built since 2014.

Successive ministers for power and energy have all supported and lodged for expensive oil solutions for cabinet approvals that have often been granted. This trend, started a few decades ago drains the CEB and the country’s economy with it. Emergency (thermal) energy needed for peaking power (530pm - 830pm) is bought from IPPs (Independent Power Producers) at prices hardly affordable by the CEB and added to it are mystifying capacity charges, the latter payments made to IPP’s even when hydro power becomes available during (emergency) contracts. Sufficient to say that the typical invoice value of an IPP based emergency power unit to the CEB can easily touch Rs 45 per unit or more, that includes capacity charges. Purchasing emergency power in this manner has seriously blocked CEB’s ability to provide affordable electricity to the people; moreover, the CEB’s financial obligations to service its dues is seriously hampered

Sufficient media coverage on this subject has already been given by multiple parties. It is not the purpose of this article to do further damage analysis which is counter-productive. The best under the circumstances is to offer a viable technical alternative. This article introduces an alternative; Plan B to harness emergency power using a more environmentally friendly approach that is likely to be economical in overall terms.

The proposed Plan B involves installing1-MW solar and 1-MW diesel power units in a hybridized arrangement, in 300 discrete locations, embedded in to CEB’s grid. The net input to the CEB grid will always be only 1-MW;1-MW solar during day, 1-MW diesel energy at night. Only roof-top solar is recommended for Plan B, in order to save on land area; ground mounted solar plants are discouraged.

The solar component in the hybrid would be installed on a roof top location such as a rice mill or a garment factory. Multiple roofs in a single location could be used. The diesel generator would be installed side by side with the solar system and both technologies solar and diesel - will be hybridized and grid connected using interconnection standards imposed by the CEB.

In the design of 1-MW net hybrid, two aspects of selection criteria are applicable; the solar component should be installed in a sun-rich location where sufficient irradiance levels exist. The Sustainable Energy Authority (SEA) has developed a comprehensive (solar) map that enables selection of sun-rich locations. Global solar maps are also available. For the diesel component, suitability is assessed based on the network strength of the CEB grid in the specific location. If the network is weak and requires injection of energy to improve its voltage and stability, that location would be deemed suitable to locate a hybrid. CEB already has knowledge of such weak network locations.

CEB’s existing Solar Net Plus Scheme with the gazetted feed-in-tariff is appropriate for payments in Plan B. Solar systems function during 5.5 sun hours up to about 530pm. Revenues under solar net plus will be used by the hybrid plant owner to recover his investment by selling his harvested (solar) electricity to the CEB. It is noted that the national target of Solar Net Scheme was one million roofs and hence 300 roof locations for Plan B will be an achievable target

At the onset of evening hours each day, about 530pm onwards, the hybrid diesel engine kicks in and provides energy to the national peak; it works for 3 hours providing firm and dispatchable power. This supply of diesel energy is on a ‘no loss no gain’ basis and computed on cost of diesel averaged over say, 3-months of pricing, with allowance being made for power inter-connection losses, depreciation rate of diesel gen-set indexed for the day, and a small price factor adjusted for O&M (operations & maintenance) for spares, wages etc

It is proposed the CEB’s System Control Center (SCC) should actively administer Plan B; the injection of diesel energy into the grid by hybrid operators will only be during evening peak hours and strictly on a merit order basis. The SCC daily determines the ceiling price for diesel energy to be bought; and the 300 solar diesel hybrid owners consider selling their energy at the price demanded by the SCC. A short message service (sms) may be involved. The SCC will compute the ceiling price for diesel energy benchmarked on energy from gas-turbines in its hold. Hence the price offered by the CEB to 300 hybrid operators to have them sell their diesel energy to the peaking curve will be necessarily at or lesser than this daily (gas turbine based) price. Thus the entire system functions as a merchant power utility program.

The price of diesel energy to be sold through the hybrid system of Plan B for peaking power using a yardstick of today’s market place considerations is likely between Rs. 28 to Rs. 32 per unit of sold energy that is way down IPP based emergency power units costs.

In actual conditions all 300 diesel hybrid operators likely will sell their energy to the CEB grid irrespective of daily setbacks in matching CEB’s ceiling price. In theory, if the price offered by CEB is less than expected, the diesel operator can refrain from selling energy to the grid that particular day. Hence the system is self-balancing for both CEB and hybrid plant operators. They are all likely to operate their diesel plants often as the no-loss no-gain system offers advantages to upkeep the diesel plants in good conditions when operated.

The power supply obligation or contract between the CEB and the hybrid owner for peaking power is on a daily basis only; typically for 3 hours. Any form of capacity charge will not be paid by the CEB, unlike in the current emergency power program.

It is proposed that 300 solar hybrid units be initially brought within Plan B using private-sector participation; a larger number of operators could be brought in subsequently, with more locations being added.

Over time the diesel engine in the hybrid could be substituted for a die-hard battery bank, with solar panels charging batteries for the night timed is charge into the grid. Therefore a slight capacity augmentation may be necessary in order to add battery charging provisions to solar panels.

It is noted that current levels of solar penetration through LV (Low-voltage) networks has caused more problems to the CEB outweighing the greenness of solar energy supplied to the LV grid. In other words, the CEB finds it costly to sustain a solar energy unit through its LV system. A far more effective method of solar penetration would have been through a LV/MV transformation process, so that the CEB can regulate the input solar energy at MV voltages where required safeguard provisions are available. These adjustments will have to be necessarily brought in if Plan B is put into operation. The CEB has in its hold many subject experts for Plan B to be properly designed

For Plan B to be successful the CEB should refrain from purchasing emergency power from the current IPP operators in the same time frame, at least in the same capacity range. Otherwise this plan would be unsuccessful. This is because if both systems run concurrently, there is likely chance that (bulky) IPP-based emergency power blocks would be bought and not bother with Plan B, which involves administratively dealing with multiples of small-scale diesel hybrid operators. Hence the two systems cannot run simultaneously.

The following are salient features of proposed Plan B:

  •  Voltage regulation during peak hours will be achieved with integration of modularized 1-MW dispatchable solar hybrid power units energizing the CEB grid all over the country.
  •  Energy will be injected to the grid at prices that the CEB declares it can afford, on a daily basis. There is no long term obligation by the CEB to purchase diesel energy
  •  The capacity charge system is totally eliminated in Plan B, a major relief to the CEB.
  • Voltage is regulated on the supply side in discrete locations, as desired by the CEB
  • Investment on hybrid system is serviced by Net Plus Scheme operated by the CEB.
  • PUCSL will be obliged to allow these hybrid plants with new generation licenses as they will operate under provisions of ‘competitive bidding’ in line with the CEB Act
  •  Response times of diesel gen-setsin hybrids coming on board to energize the grid is much faster than bulky thermal units picking up at CEB’s Kelantissa and Sapgaskanda Stations– hence overall system savings and higher reliability of the CEB grid
  •  CEB’s aspiration for Least Cost Energy approach is somewhat facilitated by Plan B.
  •  Regional CEB grids and sub-station voltages are stabilized by Plan B
  • The CEB’s grid comes closer to behaving like a smart grid with load and voltage balancing well facilitated in most areas of the country– hence net economic savings
  • Aspiration of the private sector to participate in larger-scale solar power generation is facilitated by this distributed model. This is important internationally as well
  • A large number of solar applications hitherto blocked or stranded in the SEA (Sustainable energy Authority) and CEB queues can be relieved
  • LV/MV aspects for solar inputs can be structured as Plan B is put into operation.
  •  For reasons given above, carbon savings and contribution to avert global warming will take a greater leap in Sri Lanka if Plan B is adopted
  • Employment generation from 300 hybrid power plants will be bonus to the government
  •  The Plan B will immediately bring in 300 MW of added firm power capacity to the grid sans any emergency power barges and other devices

The above treatise has been designed on the premise that for any crisis, there could be a fathomable alternative. It is hoped that Plan B will receive the support of all within the CEB, its engineers, staff and unions, MoPE, the SEA as well all in the new government, to ensure stability to the country but also as a means to avert power blackouts. Supporting this project would be important as the new government steers a way forward to overcome national level challenges. Indeed the March/April 2020 time frame will bring in some criticality due to the forthcoming polls. It is not clear how the CEB, MoPE and government could implement Plan B in the currently tight time frame before elections. But remembering that ‘if there is a will, there is a way’ it might be possible to declare a new policy decision and adopt Plan B in double quick time. There are seemingly no conflicts in the CEB or SEA Acts to implement Plan B. Even if the current time frame misses out, the government would note that Plan B will be a key program to restore economic balance in the country and hence should seriously consider its merit.

It is hoped that this Plan B will feature as a feather in the cap of the energy sector reform process under the new government under HE President Gotabaya Rajapaksa, and open up new vistas on how Sri Lanka could steer towards a sustainable (greener) energy future, holding a better promise for our young and the unborn


(The writer is the Founding President, Solar Industries Association (SIA-SL), Accredited Consultant, Sustainable Energy Authority Formerly Township Engineer, University of Sri Jayewardenepura)

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