Rethinking EVs: A solution, not burden, for Sri Lanka’s grid

• The blackouts earlier this year underscores Sri Lanka’s power grid’s present challenges in accommodating a high penetration of solar PV
• Better energy storage and flexible grid management are needed to handle fluctuations in solar and wind power
• Electric vehicles (EVs) can contribute to a more resilient and stable power grid through their ability to both consume and supply electricity as needed
• Smart EV charging can reduce strain on the grid, using incentives and off-peak charging

A nationwide blackout in February this year sent shockwaves across Sri Lanka. While the initial outage itself was infamously attributed to wildlife coming into contact with critical systems, the Ceylon Electricity Board (CEB) also attributed the subsequent difficulties in restoring power to the island in part, to the rapid growth of rooftop solar photovoltaic (PV) systems. 

In response, the Power and Energy Ministry formed a committee to explore solutions, including curtailing solar generation and reducing the feed-in tariff paid for solar energy – a policy which could potentially risk Sri Lanka’s broader renewable energy transition. 

These developments take place against the backdrop of Sri Lanka’s ambitious Nationally Determined Contributions (NDCs) under the Paris Agreement to reduce greenhouse gas (GHG) emissions by 14.5% across the power, transport, industry, waste, forestry, and agriculture sectors by 2030. This included targets for 70% renewable energy generation by 2030, a commitment to no new coal power plant capacity, and a 4.0% GHG emission reduction in the transport sector compared to a business-as-usual (BAU) scenario, including a commitment to promote electric mobility and hybrid vehicles.

Achieving these ambitious renewable energy targets, particularly in light of recent challenges, will require a nuanced approach to policy that enhances grid flexibility through a combination of both supply-side and demand-side measures. 

Effective implementation of these measures can ensure the smooth integration of renewable energy and EV technology into Sri Lanka’s national grid, safeguarding energy pricing, supply, and distribution from disruptions. Supply-side solutions, such as battery energy storage systems (BESS), medium and long-duration energy storage (LDES) technologies, and green hydrogen production, are crucial for integrating variable renewable energy sources. 

Such technologies could be deployed independently or co-located with renewable energy installations. While battery storage offers a promising solution, its current high cost presents a significant challenge for Sri Lanka.

A key part of the answer may lie in how we manage energy flow between EVs and the power grid. Instead of viewing it as a conventional one-way street – Grid-to-Vehicle (G2V), we should consider bidirectional charging technology – Vehicle-to-Grid (V2G) that allows EV batteries not only to receive electricity from the grid but also to send stored energy back to it.  

Such an approach would transform EVs themselves into distributed energy storage systems that act as valuable resources for grid stabilisation and demand response. This would not only reduce reliance on expensive centralised battery storage but also contribute to a more resilient and sustainable national energy system. 

Particularly in the context of the rapid adoption of solar and wind energy, as well as a strong interest in the adoption of EVs, Sri Lanka has a unique opportunity to revolutionise electric vehicle charging and, in the process, help to optimise the integration of renewables into the national energy mix. 

The shift from dump charging to smart charging

To fully capitalise on this synergy, we must transition from the current “dump charging” paradigm to a sophisticated “smart charging” regime. This shift is crucial for maximising the utilisation of excess renewable generation and mitigating potential grid instability.

Currently, uncontrolled EV charging often coincides with peak electricity demand, placing undue stress on the grid. Smart charging, however, aligns EV charging with periods of surplus renewable energy, thereby enhancing grid stability and reducing reliance on fossil fuel-based generation. This can be achieved through two primary mechanisms: incentive-based schemes and price-based schemes.

Incentive-based schemes offer financial rewards to customers who reduce their electricity consumption during periods of high grid stress. These rewards, separate from the standard energy pricing, act as a powerful motivator for EV owners to shift their charging schedules to periods of abundant renewable energy. 

Customers could receive credits for delaying charging until midday when solar generation peaks, fostering a collaborative relationship between consumers and the grid, where both parties benefit from optimised energy usage.

Alternatively, price-based schemes leverage dynamic pricing to reflect the real-time value of electricity, incentivising customers to charge their EVs during off-peak hours when electricity prices are lower. 

These tariffs typically feature at least two rate periods: peak and off-peak. More advanced dynamic pricing models can offer even more granular price signals, reflecting real-time supply and demand conditions.

Deployed together with smart meters that can transmit price or incentive signals directly to consumers or EV charging points, this holistically optimised approach to EV charging can empower EV owners to make informed charging decisions through user-friendly dashboards, allowing them to choose between immediate charging and scheduled charging based on their preferences and grid conditions. 

Imagine future scenarios where smart charging becomes an everyday reality. For instance, an EV owner returning home simply plugs their vehicle into the charger, but charging only begins when the smart meter indicates optimal grid conditions, either due to favourable pricing or a peak in renewable energy generation. 

Similarly, workplaces equipped with rooftop solar panels could encourage daytime charging, allowing EVs to absorb surplus solar power. This not only stabilises local grid voltages by reducing reverse power flows but also enhances the overall capacity for renewable energy integration. Additionally, public charging hubs could adopt real-time pricing signals reflecting immediate grid conditions, naturally guiding drivers to charge their vehicles precisely when and where it most benefits both the grid and their wallets.

Despite common concerns that widespread EV adoption might overload distribution networks or trigger voltage instability, smart charging practices directly address these issues. By strategically shifting EV charging to off-peak times or periods of abundant renewable generation, excess nighttime generation is effectively harnessed, enhancing overall grid efficiency. Similarly, daytime charging absorbs surplus solar power, stabilising voltage levels and increasing the grid’s capacity for renewable integration. Such proactive balancing of supply and demand ultimately reduces strain on infrastructure, potentially saving Sri Lanka from expensive grid upgrades in the long run.

Benefits far out-weigh the cost of implementing smart charging 

A common counterargument to the implementation of smart charging revolves around the perceived high costs associated with installing smart meters and the required communication infrastructure. However, in an era of rapidly increasing renewable energy penetration, this investment is not merely an optional upgrade but a fundamental requirement for ensuring grid stability and resilience. 

The limitations of the current grid monitoring system become increasingly apparent as distributed generation, particularly rooftop solar, proliferates. Today, our grid operates on the “net demand”, which is the aggregation of differences between consumers’ electricity usage and their on-site solar generation. While it is a simple solution, this aggregated view obscures critical information about individual generation and consumption patterns, hindering effective grid management.

For example, on 9 February, the system operator, observing a net demand, scheduled coal, hydro, biomass, and small hydro generation at 437 MW, 133 MW, 25 MW, and 115 MW respectively, while approximately 800 MW of rooftop solar generation was also contributing to the grid. Suddenly, a system fault occurred, leading to the disconnection of 300 MW of solar capacity. This abrupt loss of generation created a significant power imbalance, ultimately contributing to a national blackout.

This incident highlights the critical need for enhanced grid visibility. If smart metering were already in place in this scenario, the system operator could have used real-time data on individual solar generation and consumption to proactively respond to the fault, mitigating the resulting power imbalance. 

The benefits of smart meters extend far beyond enabling smart EV charging. Smart meters provide a foundational layer of intelligence that supports a wide range of grid modernisation initiatives. With real-time data, smart meters enable rapid identification and isolation of faults, shortening outages and improving the reliability of the electricity supply. 

Detailed insights into energy consumption and generation patterns can support precise load forecasting and efficient grid planning, ensuring smarter infrastructure investments. The smart metering infrastructure also serves as the communication backbone for demand response initiatives, empowering consumers to participate actively in grid balancing efforts. Furthermore, real-time voltage monitoring at the distribution level enables better voltage control, crucial for managing the increased integration of renewable energy.

Advanced artificial intelligence (AI) and machine learning systems can enhance these capabilities significantly, optimising V2G operations through precise analysis of real-time grid conditions, electricity prices, and individual usage patterns. Such smart technologies allow EV owners to anticipate their available energy storage capacity, empowering them to maximise financial returns by participating actively in grid management. 

Embracing EVs as distributed energy storage assets thus provides Sri Lanka with a pathway toward a more resilient and sustainable energy system; one that reduces dependency on expensive centralised storage, enhances grid reliability during disruptions, promotes renewable energy integration, and actively engages consumers in shaping the country’s energy future.

(The writer is Senior Professor of Electrical and Electronic Engineering, University of Peradeniya.)