Improved Grid Management System

Introduction

The lure of clean energy is compelling, given the low carbon economy that it helps usher. While the clean electrons come with a low carbon footprint and zero variable cost of generation, they are, in a manner of speaking, temperamental. Renewables, quite unlike coal-fired or nuclear plants, provide intermittent electricity; they produce electricity only when the sun shines or the wind blows. The idling of renewable plants puts immense strain on the highways that connect the power plants to the demand centers, the transmission grid. It runs the risk of collapse, and in turn, blackouts for consumers.

The solution to averting this situation lies in either creating more coal plants, a move that would strike at the heart of a low carbon economy or set up energy storage facilities. Ofcourse, the choice of setting up a gas-based turbine to offer instant power is always an option. Only that it takes more time and the fuel cost might not be as attractive as that of grid electricity to charge the batteries.

Then again, there is the choice of pumped storage hydel power, where, electricity is initially used to pump water to a height. Electricity can then be generated on demand by releasing this water on a turbine, where the force of gravity kicks the turbine to generate electricity. This again has a limited reach owing to its geographic and environmental limitation.

Against this backdrop, Energy Storage Systems (ESS) is a crucial tool for enabling the effective integration of renewable energy to the transmission grid and allowing for clean, resilient energy supply. Batteries that form the core of the Energy Storage Solution have been around for long. The first commercial utilisation was made a little over two and half decades ago in Sony’s camcorder CCD TR1. The batteries then proliferated across other consumer goods like phones and computers. The batteries in the meantime have evolved, their energy carrying capacity has increased through a process of constant expensive research.

The development of advanced Energy Storage Systems (ESS) has been, however, largely concentrated in select markets, primarily in regions with highly developed economies. For example, on the outskirts of San Diego, California, San Diego Gas & Electric (SDGE) has set up a 120 MWH battery storage system that offers peak power support. The modular construction took place over a mere eight months, a third of what it takes to set up a gas fired turbine plant.

Tesla aims to get closer home, offering its Powerwall battery pack along with its solar panels. Nissan too is looking at a behind-the-meter application, docking the batteries spent on its ‘leaf’ electric cars in homes and offices.

Regulation, a key driver for ESS introduction into the electricity grid, has been taking large strides.In February 2018, the Federal Energy Regulatory Commission (FERC) in United States issued its final rule whereby Independent System Operator (ISO) and Regional Transmission Organization (RTO) markets require to establish rules that properly recognize the physical and operational characteristics of electric storage resources and ensure that it is eligible to participate in all market activities like meeting the grid’s peak power requirement or simply evening out the intermittence of renewable power.

India Story

India has an ambitious target of 175GW installed capacity addition to the grid by 2022. Very recently the Minister has increased this substantially to 227 GW by the same time. This would mean there will be substantial increase in the share of RE generated in the grid in future. Thus, the future grid requires to be capable enough to accommodate this increased penetration of RE. It is particularly challenging to integrate because the RE generation is both intermittent and varies drastically in short spans. It has been projected by CEA that between 2017-22, the electrical energy requirement will grow by 5.51 percent cumulatively. This would mean, the reliance of clean energy in the grid will increase in the coming years, but, at the same time their sources are highly variable and intermittent. Therefore, we require effective tools and mechanisms to manage the grid in future. Essentially, we need the grid to be reliable, and stable with higher levels of RE penetration.

Challenge-1:

Renewable energy generation brings with it a high degree of variability in supply of electricity. This makes forecasting of supply critical to maintaining reliability of the electricity grid. Forecasting helps introduce value added/ ancillary services like frequency support, voltage or reactive power support and black start support services into the commercial sphere in the power market. A key aspect of forecasting is the accuracy and the confidence level at which it is done. Higher the accuracy, lower the required reserve capacity of conventional energy sources. This, in turn, spurs, substantial savings in capital and operating costs, greatly aiding the cause of energy efficiency. Currently, power system operators rely on a 24-hr or smaller forecasts to anticipate the volume of renewable energy (RE) available.

Expectations from the challenge:

Development of a forecasting tool to improve the accuracy of weather and wind forecast or demand load forecast, in spatial and temporal resolution and on time scales from hours to days. Also, improving the accuracy and confidence level of forecasts by aggregation over a wider area to allow system operators to reduce reserve requirements and contingency measures to more economical levels.

Evaluation Criteria:

  • Day ahead forecasting ( At least 7 days)
  • Reduced forecasting error (less than 5 percent or state of the art)
  • Confidence Interval or accuracy of >95 percent

Challenge-2:

Grid-scale battery technology provides numerous benefits of instantaneous response, supplemental reserves, higher efficiency, lower maintenance, flexibility in sizing and shorter gestational periods. Today, although the cost of most energy storage solutions is considered expensive, there is a belief that costs will fall as volumes increase.

Expectations from the challenge:

Develop an economically viable battery storage business model with improved energy storage, power performance and charging capabilities and revenue stream.

Evaluation Criteria:

  • Project Life – 15 years
  • Pay-back period – 8 – 10 years
  • Project IRR – at least 12 percent