SaurEnergy Explains: How Peak Shaving and Load Shifting Save Electricity in Solar + Storage

Electricity costs are rising worldwide, forcing businesses and households to rethink how they consume energy. One of the most effective strategies emerging today, especially for C&I consumers, is combining solar power with battery energy storage to manage when electricity is used.

Two key techniques are making this possible - peak shaving and load shifting. Together, they allow energy users to avoid expensive electricity periods and significantly reduce monthly power bills. In many commercial cases, electricity costs can fall by 15–40 per cent through smart energy storage strategies combined with a renewable energy system, according to a study.

This blog explains how peak shaving and load shifting work, and why renewable, especially solar, paired with storage is becoming a powerful tool for cutting electricity costs.

Understanding Electricity Costs: Why Peak Demand Matters

In India, electricity bills for commercial and industrial (C&I) consumers typically include two key components: energy charges and demand charges. 

While energy charges are based on total electricity consumed (kWh), demand charges depend on the highest power demand recorded during a short interval, usually a 15-minute period within the billing cycle.

State regulators such as the Maharashtra Electricity Regulatory Commission require utilities like Maharashtra State Electricity Distribution Company Limited to apply these demand-based tariffs to large consumers with higher contract loads.

Interestingly, even a short spike in electricity usage - when multiple heavy loads like HVAC systems, industrial machinery, or elevators operate simultaneously - can increase the maximum demand recorded by the meter. 

Because utilities must maintain grid infrastructure capable of handling these peaks, demand charges can account for around 20–40 percent of electricity bills, and sometimes more in energy-intensive industries.

Peak shaving and load shifting are sometimes used interchangeably, but they solve different “lines” on the bill. This brings us to the next question: what are these tools, and how do they help?

What is Peak Shaving?

Peak shaving refers to reducing the highest electricity demand during expensive peak hours. In simple terms, Instead of drawing all power from the grid, part of the demand is supplied by stored energy in batteries or on-site solar generation.

For example, consider a factory that normally draws 1,000 kW during peak hours. If an employed battery system (BESS) supplies 300 kW from stored energy, with the remaining 700 kW demand met by the grid, this is called peak shaving. Because the peak is lower, the demand charge also decreases. Battery Energy Storage Systems (BESS) are central to this strategy. 

As per one British study, the typical financial results includeup to 70 percent from demand charges. Notably, the demand charges make up to 40 percent of electricity bills in the UK. Another study claims the Demand charge reduction of 30-50 percent for facilities with sharp, predictable peaks, and gives monthly savings in the range of $5,000-50,000 for large commercial and industrial facilities.

This makes peak shaving particularly attractive for manufacturing plants, data centres, hospitals, and commercial buildings with predictable energy spikes.

What is Load Shifting?

While peak shaving reduces the size of demand peaks, load shifting changes the timing of electricity consumption. In load shifting, energy usage is moved from expensive peak hours to cheaper off-peak periods. A useful rule of thumb is that if your bill has a large demand‑charge line, peak shaving is often the “first business case”, while if your bill has big price spreads by hour (or low export credit), load shifting becomes more valuable.

Examples include - charging electric vehicles overnight, running energy-intensive industrial processes at night, or cooling buildings earlier in the day when power prices are lower

Solar plus battery systems, for instance, make this easier. Excess solar electricity generated during the day can be stored and used later in the evening when electricity tariffs are higher.

Load shifting helps flatten the daily demand curve, which benefits both energy users and grid operators.

How Solar + Storage Makes These Strategies Possible

A solar + battery system that reduces electricity bills is not just about installing solar panels and a battery. The real savings come from a smart control system that decides how electricity should be used at different times of the day.

Every few minutes, the system checks the electricity demand and decides what to do. It can use power directly from solar panels, charge the battery, discharge the battery to run the building, or take electricity from the grid. These decisions depend on factors such as the battery charge level, inverter capacity, and safety limits.

Such systems usually include several key parts. Solar panels generate electricity in DC form, which is converted to AC using a solar inverter. A battery pack, often lithium-ion, stores extra energy and is managed by a battery management system. A bidirectional inverter controls the charging and discharging of the battery. The system also includes smart meters, an energy management system, and safety equipment for grid connection.

The system works through two levels of control. The first is fast control, which manages power flow every few seconds or minutes to avoid sudden demand spikes. The second is planning and optimisation, which decides when to charge or discharge the battery based on expected electricity demand, solar generation, and electricity tariff timings.

Why Solar + Storage is Becoming a Key Energy Strategy

Global deployment of battery storage is growing rapidly as renewable energy expands. When co‑located with solar and wind, BESS can transform variable output into firm, scheduled delivery, improving capacity value and cutting curtailment that would otherwise waste clean energy. Tata Power highlights ‘Solar’s next evolution is firm, dispatchable power, i.e. energy that can be delivered exactly when the grid or consumer needs it.’

For example, the United States installed 58 GWh of energy storage capacity in 2025, with forecasts reporting more than 600 GWh of cumulative energy storage installations in the country by 2030, driven by rising power demand, grid reliability needs and cost reductions.

India is also witnessing the increase in number of solar plus storage projects as the country aims to achieve 74 GW of BESS capacities by 2031, or 2032, which will be instrumental in balancing the intermittency of renewable power generation.

As solar and battery costs continue to decline, more businesses and households are expected to adopt combined solar-storage systems to manage electricity consumption intelligently.

In the future, these systems will also participate in virtual power plants and demand response programs, enabling users to earn additional revenue by supporting the grid.