Arbitrage is a simple economic idea with powerful consequences. It means buying something when it is cheap and using or selling it when it is expensive. A trader who buys wheat in a surplus market and sells it in a deficit market is doing arbitrage. A shopkeeper who buys stock before prices rise and sells later is also doing arbitrage.
The profit comes from the price difference, but the wider economic value comes from correcting the imbalance. Arbitrage moves goods from abundance to scarcity, from low-value use to high-value use and from idle supply to productive demand.
At its core, arbitrage is built on the economics of supply and demand. When supply is high and demand is low, prices fall. When demand is high and supply is tight, prices rise. The arbitrageur responds to this difference. In doing so, he does not merely earn a margin; he improves allocation. In a functioning market, it is the reward for moving value from the wrong place to the right place or from the wrong time to the right time.
Energy arbitrage applies the same principle to electricity, but with a more complicated twist. Electricity is not like potatoes, wheat or cotton. It is difficult to store and is normally produced and consumed simultaneously. This makes time extremely important. A kilowatt-hour at noon is not economically equal to a kilowatt-hour at 8pm. At noon, solar power may be abundant, demand moderate, and the marginal cost of supply low. In the evening, solar disappears, household demand rises, commercial load remains active, and expensive generation may enter the system. The same unit of electricity, therefore, carries a different economic value in different hours.
The FY2025 hourly marginal-cost analysis for Pakistan shows why this idea matters. The average hourly marginal cost was Rs17.72 per kWh, while the median was Rs20.18 per kWh. The lowest observed hourly marginal cost was Rs3.07 per kWh, while the highest was Rs36.21 per kWh. The 10th percentile was Rs5.59 per kWh, and the 90th percentile was Rs27.09 per kWh. This means Pakistan’s power system is not a flat-cost system. It has cheap hours and expensive hours, with a wide economic spread between them. That spread is the breathing space for energy arbitrage.
First, energy arbitrage starts with recognising that electricity has a time value. Pakistan’s public debate usually focuses on average tariffs, but the power system does not operate on averages. It operates hour by hour. Some hours are cheap because demand is low, renewable energy is available or low-cost plants are setting the margin. Other hours are expensive because demand rises, solar generation fades, imported fuel plants enter dispatch or grid constraints force inefficient generation. When tariffs hide these differences, consumers receive weak signals. They are not encouraged to consume in cheap hours, nor are they adequately rewarded for reducing load in expensive hours. The result is tariff blindness.
Second, arbitrage converts cheap-energy windows into economic opportunities. The analysis shows that the solar window between 11am and 3pm had an average marginal cost of Rs14.50 per kWh, compared with Rs 19.28 per kWh during the evening peak and Rs21.94 per kWh in the late evening. This difference should not be treated as a technical footnote. It is a policy signal. Industrial processes, cold storage, agricultural pumping, commercial cooling, electric vehicle charging and battery charging should be encouraged during lower-cost hours. In a country where industry complains about high electricity prices, the answer is not only ‘make power cheaper’. The smarter answer is also ‘use power when it is cheaper’.
Third, arbitrage is essential for managing solarisation. Solar power lowers daytime marginal cost because sunlight has no fuel cost. But solar also creates a timing problem. It produces abundantly during the day and disappears in the evening, just when demand often remains high. Without storage or flexible demand, the system faces a steep evening ramp. The analysis shows this clearly. The evening-minus-solar spread was especially high in March at Rs 11.57 per kWh, in September at Rs 8.46 per kWh, and in April at Rs 8.33 per kWh. These numbers show that Pakistan’s solar transition cannot be achieved solely through panels. Solar without flexibility creates a valley in the day and a cliff in the evening. Solar with arbitrage turns that valley into a reservoir.
Pakistan should stop treating electricity as a uniform commodity and start treating it as a time-sensitive service. Cheap hours should invite demand. Expensive hours should encourage conservation, storage, discharge and demand response. Batteries should be recognised not only as backup devices but as economic instruments
Fourth, batteries are the most obvious technology for energy arbitrage, but they are not the only one. A battery charges when energy is cheap and discharges when energy is expensive. However, demand response can do the same without a battery. A textile unit may shift part of its load to daytime hours. A cold storage facility may pre-cool during the solar window, reducing consumption in the evening. A tube well may pump water during low-cost hours. An electric vehicle fleet may charge at noon rather than in the evening. In all these cases, the technology differs, but the principle remains the same: shift demand away from expensive hours and toward cheaper ones.
Fifth, arbitrage must be understood separately from the final consumer tariff. Marginal cost is the cost of serving one additional unit of electricity in a given hour. The consumer tariff, however, includes many other components: capacity payments, transmission costs, distribution margins, market operator fees, fuel adjustments, quarterly adjustments, taxes and surcharges. This is why low marginal cost in some hours does not automatically translate into lower electricity bills. Pakistan’s real challenge is that cheap energy signals are buried under a heavy tariff structure. Arbitrage cannot eliminate the capacity-payment problem overnight, but it can reduce expensive dispatch, improve utilisation of low-cost hours and lower fuel-related system costs at the margin.
Sixth, the high-cost tail is where reform should begin. The top 5.0 per cent of hours averaged Rs32.71 per kWh, while the top 1 per cent averaged Rs34.90 per kWh. These are the hours where demand response and battery discharge provide the highest economic value. A unit saved during a Rs35 per kWh hour is far more valuable than a unit saved during a Rs5 per kWh hour. Yet Pakistan’s conservation messaging often treats all units as equal. That is economically lazy. A smarter policy would reward consumers and industries for reducing demand during the most expensive hours and encourage productive consumption during cheap hours.
Seventh, arbitrage can improve the political economy of rooftop solar and batteries. If policymakers treat prosumers only as a threat to distribution company revenues, more consumers will invest in batteries to escape the grid. That would deepen the utility death spiral. But if prosumers are treated as flexibility providers, their batteries can become grid assets. Through aggregators and virtual power plants, thousands of small batteries can provide peak shaving, reserve support and demand response. The consumer then becomes not a deserter of the grid, but a participant in system efficiency. The difference lies in regulation.
Eighth, the regulatory system must catch up with the economics. Energy arbitrage requires smart meters, transparent hourly price signals, stable time-of-use tariffs, aggregator rules, ancillary service markets, distribution-level hosting capacity data and credible settlement systems. It also requires trust. No investor will finance batteries, storage-backed solar or industrial flexibility if pricing rules are changed abruptly. Arbitrage runs on price spreads, but investment runs on confidence. Without regulatory credibility, even the best battery becomes an expensive UPS.
The policy conclusion is straightforward. Pakistan should stop treating electricity as a uniform commodity and start treating it as a time-sensitive service. Cheap hours should invite demand. Expensive hours should encourage conservation, storage, discharge and demand response. Batteries should be recognised not only as backup devices but as economic instruments. Pakistan’s electricity reform must move from selling units to valuing time, flexibility and system efficiency.
The cheapest power may not come from a new plant, but from using, storing and shifting electricity at the right hour.
The writer holds a doctorate in energy economics and serves as a research fellow at the Sustainable Development Policy Institute (SDPI) in Islamabad. He tweets/posts @Khalidwaleed_ and can be reached at: khalidwaleed@sdpi.org
© 2026 SDPI. All Rights Reserved Design & Developed by NKMIS WEB Unit
