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How Can Small-Scale Stationary Battery behind the Meter (BTM) Contribute to Power System Transformation?

          How Can Small-Scale Stationary Battery behind the Meter (BTM)

Contribute to Power System Transformation?

(A)  Description

- Power system transformation (PST) is the active process of creating the policy, market, and regulatory environments, as well as establishing operational and planning practices, that accelerate investment, innovation, and deployment to realize smart, efficient, resilient, and environmentally sound power systems.

- Battery storage systems are being deployed at multiple levels of the electricity value chain, including at the transmission, distribution and consumer levels. Market applications are commonly classified as: in-front of the meter (FTM) or behind-the meter (BTM).

  • FTM batteries are interconnected to distribution or transmission networks or in connection with a generation asset. They provide applications required by system operators such as ancillary services or network load relief.
  • BTM batteries connected behind the utility meter of commercial, industrial or residential customers, primarily aiming at electricity bill savings. They are beyond the direct control of the distribution system operator.

- BTM battery storage can store electricity that either is produced from on-site solar rooftop PV systems or is drawn from the distribution grid when electricity prices are low. This stored electricity can then be used to meet the consumer’s electricity needs, or it can be injected back into the distribution grid when electricity prices are high.

-The size of a BTM battery can vary from 3 kilowatts (kW) to 5 megawatts (MW). Typically, residential consumers’ batteries can reach 5 kW / 13.5 kilowatt-hours (kWh), whereas a battery for a commercial or industrial system is typically 2 MW / 4 mega watt hours (MWh).

(B)  BTM Contribution to Power System Transformation

BTM contribute to power system transformation by providing different services for consumers, system operators and mini-grids. These services will be highlighted in the following sections.

I.  Services Provided For Electricity Consumers

1. Increased self-consumption from distributed renewable generation

BTM battery storage enables the integration of distributed generation technologies, such as rooftop solar PV in the power system by maximizing self-consumption and its revenues.

2. Back-up power

In case of grid outage, BTM battery storage can provide back-up power at various scales, ranging from sub-second-level power supply for important industrial operations, to 24-hour back-up by pairing with an on-site solar PV system.

3. Savings on the electricity bill

Increased self-consumption by installing rooftop solar PV coupled with BTM battery systems can

lead to significant electricity bill savings. When time-of-use tariffs are implemented, BTM battery storage systems allow consumers to reduce electricity costs by charging the batteries during off-peak hours when tariffs are lower, and discharging them during peak time intervals when tariffs are high.

4. Demand charge reduction

Demand charges based on the highest electricity usage requirement (in terms of kW) for the consumer within a specified time period (usually ranging from 15 minutes to 3 months). For commercial and industrial consumers demand charges can be significant, especially during peak periods. On-site battery storage systems can be used to manage peak loads and reduce demand charges.

II. Services Provided For System Operators

1. Frequency regulation

BTM storage systems can provide frequency support to the grid by ramp its power output up or down rapidly. This helps smoothen the output of intermittent Renewable Energy generation. Consumers can offer the availability of their battery to the operator in exchange for financial compensation.

2. Network investment deferral

Distribution and transmission system operators invest in upgrading the system in order to meet anticipated demand growth. These upgrades are generally needed to meet the peak demand, which occurs for a small number of hours in the entire year. BTM battery storage, together with the right incentives in place, can help consumers shift their demand so that it reduces the system’s peak demand. This decreases the need to draw power from the transmission system operators, thereby decreasing grid congestion and deferring network investments for grid reinforcements.                                            

3. Peak capacity investment deferral

System operators need peak capacity resources to meet the peak demand and thus results in a high cost of power to consumers. BTM storage systems can help defer investments in these expensive peak capacity resources in two ways:

  • Firstly, they can reduce the peak demand itself by providing stored energy to consumers during peak times, thus reducing the need to procure energy from peak capacity resources.
  • Secondly, BTM storage systems, through aggregators or retailers, can participate in capacity markets and compete with other participants to offer capacity. This can reduce the share of conventional generation-based capacity resources in the market while reducing prices in capacity markets. Aggregators of BTM storage systems can provide the right amount of storage capacity in exchange for capacity payments, thus avoiding investments in standard-sized peaking capacities.

III. Services provided for mini-grids

  • BTM storage batteries systems can replace diesel generators in renewable energy-based mini-grids. They can be used to provide back-up power when renewable generation is not available.
  • BTM storage batteries systems can smoothen variable generation and shift the generation curve of small solar PV and wind systems connected at the consumer end to meet peak demand.

(C)  Conclusions

  • BTM batteries can help consumers decrease their electricity bill, through demand-side management.
  • Increased demand flexibility can unlock the integration of high share of variable renewable in the grid.
  • Aggregated BTM batteries can provide support for system operation, while also deferring network and peak capacity investment.




Dr. Amal Khashab's picture

Thank Dr. Amal for the Post!

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Matt Chester's picture
Matt Chester on Feb 18, 2020 3:13 pm GMT

Who do you think are going to be the first customers targeted with btm battery measures-- those who are 'green' minded? Those who could most use the financial benefits? Those who can most afford any initial upfront costs?

Dr. Amal Khashab's picture
Dr. Amal Khashab on Feb 19, 2020 12:51 pm GMT

Hi ,Matt

I think all of them are beneficiars , the first targeted customers will depend upon financial viability and ability. If it has been left for self financing, the customers who can afford initial costs will come first.  Supporting groups  will encourage green minded customers to share actively. Also ,utilities can share affording initial costs as means of demand side management ( win/win programs)

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