Below are the excerpts of our recent interview with Mr. Satish Subbarao,Head – Engineering & Technical Support Group India,Engie
Let’s start with the recent developments at your organization in last one year.
There is a broad sign on at executive level for the country strategy with the intention to establish a material business and take part in the India’s ambitious Renewable Energy strategy. Within the last year or so our subsidiary Solaire Direct (now Engie Solar) has concluded contracts to take their total capacity to almost 500MW, with 280 MW under construction today. We have a development pipeline involving hundreds of MW of solar and wind.
How to ensure quality, reliability and trace ability of aggregated data?
Data used for project shall have good quality and reliability in order to provide the expected returns and mitigate the risks perceived by the Lenders.
Several sources of meteorological data are nowadays available for use by the developers covering both macro level sources such as PVGis, Meteonorm, satellite data (NASA); and local level data such as nearby weather station.
For large projects, besides the interpolation and correction of macro and local data (PVGis + weather station data), it is necessary to carry out field measurements of irradiation (using Pyranometer and reference cell) along with temperature, wind speed/direction, atmospheric pressure + relative humidity).
These field data are strongly appreciated as a ‘plus’ by the Lenders in the case of projects with non-recourse bank financing, and help to mitigate the risks as seen by these institutions and thereby optimize the conditions of the loans. Field measurements are also recommended in case of sites with high concentration of industries, soiling, aerosol changes, complex topography, high latitude or other uncertainty factors.
Whenever on-site field measurements have to be conducted, it is recommended to perform at least a full year of measurement with overall availability of data being at least 90% (and >50% for each month) in order to have high reliability.
During the O&M phase, the incorporation of automatic data acquisition and monitoring technology is essential to achieve a high performance PV plant. This allows the yield of the plant to be monitored and compared with the energy yield calculation made from solar irradiation data to under- take remedial measures on a daily basis if any shortfall is observed.
How can cost of O&M be further reduced by standardization & Innovation?
Standardization and innovation is an imperative in the prevailing highly competitive environment where solar tariffs are continuously falling. Every phase of the plant commencing from the engineering/ design, construction and finallydown to the O&M phase benefits by standardization and innovation. Compared to most other power generating technologies, PV plants have low maintenance and servicing requirements; for e.g. on a per MW basis, solar PV plant O&M costs are about half when compared to wind farms. However with the increasing deployment of large utility scale PV plants, the O&M cost component as part of the life cycle cost are quite significant thereby reinforcing the need for standardization. The O&M process has to be incorporated into the design/engineering phase in order to optimize the life cycle costs. A low Capex solution could lead to higher Opex, a fact that is sometimes overlooked by the developers.
Design features of the plant exert a major influence on the O&M process. For e.g. selection of the type of inverter technology (string inverters instead of central grid inverters) for a utility scale PV plant has an influence on the plant availability, spares philosophy and skill sets of the plant O&M personnel. Similarly the decision to install a deionization plant with fixed distribution pipe network for module cleaning instead of using tractor/truck mounted spray nozzles has a direct bearing on the Opex. Similarly, innovations in module cleaning such as dry cleaning of modules in place of wet cleaning has a direct impact on the Opex.
Considering the fact that the plant has to generate returns over a period of 25 years, a good O&M contractor, a good monitoring system and above all, a very good O&M process is very critical for the success of the solar power plant. Broadly speaking, the maintenance of a PV plant comprises of two activities viz. scheduled maintenance and unscheduled maintenance.
A high level of standardization can be achieved in the Scheduled maintenance activities such as module cleaning, veg- etation control, inverter servicing, checking module integrity connections, checking junction/string combiner boxes, etc. since these activities occur in fixed time cycles. Use of thermography for detection of hot spots can be adopted to further standardize the maintenance process and avoid unscheduled maintenance.
In order to minimize the downtimes due to unscheduled maintenance (such as rectifying faults in SCADA faults or rectifying tracking system faults), it is necessary to employ a competent O&M contractor with well trained staff.After the project is commissioned, it is normal for the EPC contractor to guarantee the performance ratio (PR), however periodic monitoring of the PR should be part of the O&M process in order to ensure optimized performance of the plant.
What are the milestones you wish to achieve by the end of this fiscal?
Engie’s mandate is to establish and grow a self-sustaining material business in India. Within the Engie organization, India is part of the MESCAT (Middle East South Central Asia & Turkey) region with headquarters in Dubai. Over a period of 20 years Engie has become the No 1 player in this geography with about 24 major power and water assets totaling over 30 GW of capacity with several more under construction including a large services business.
What are your thoughts on main streaming of renewable energy in India?
GOI has announced an ambitious target to have 100 GW of Solar Capacity and 60GW of Wind Capacity by 2022. While a great deal of capital is required to achieve these targets, an immediate constraint that could prevent large scale adoption of wind and solar generation could come in the form of challenges being faced by the grid operators due to the “in-firm or intermittent” nature of the resources.Mandatory Scheduling & Forecasting for renewable generation can be considered as a temporary solution to minimize curtailment of evacuation during the peak wind season in the wind rich states. Studies have shown that rich solar resource also exists in many of the wind rich states. This suggests that combining both wind and solar could be a way forward in these states.
In general solar power scales up and peaks in the afternoon, only for a few hours, while wind Power generation typically peaks in very early mornings and late afternoons. Integration of wind along with solar generation (hybrid generation) can mitigate this inherent variability to some extent when compared to either stand-alone wind or solar generation. Adoption of energy storage in conjunction with hybrid generation can help further reduce the infirmness while improving the overall CUF and ensuring optimum use of land and evacuation infrastructure.
It is hoped that the establishment of the green corridor coupled with falling costs of energy storage will help in minimizing the impact of variability and main streaming of renewable power.