Greener Upgrades blog series #9
The struggles of tower cranes
Tower cranes are among the most energy-intensive machines on a construction site, dock or shipyard. Their significant power demand often means they are too powerful to connect directly to the grid. As a result, contractors typically rely on diesel generators to power them. However, operating tower cranes with large diesel generators can be inefficient, result in high emissions, and lead to substantial fuel costs.
The benefits of Battery Energy Storage Systems (BESS)
Short bursts of high power for lifting are required during the operation of tower cranes. During the rest of the time, diesel generators often sit idle or operate underloaded, which is inefficient and can be harmful to equipment. Integrating a Battery Energy Storage System (BESS) with a generator allows for a more optimised power solution. The BESS can support the generator during periods of high demand, enabling the generator to be downsized to cover the base load efficiently.
A battery can be a reliable and more sustainable energy source for powering tower cranes. This setup allows the generator to run more efficiently, reducing fuel consumption and emissions. Additionally, a BESS can be used to handle overnight operations, such as powering aviation lights or sign boards, further reducing the need for continuous generator use.
BESS as a standalone solution
In scenarios where the site has a limited mains connection that is insufficient to power the crane, a BESS can serve as a standalone solution. By ‘peak shaving’ the grid connection, the BESS can provide additional power when the mains supply reaches its limit and recharge during periods of low demand. This approach not only overcomes capacity constraints but also optimises energy usage, ensuring that the crane operates smoothly without the need for oversized or continuously running generators.
Key sectors
- Construction (BS&C): Tower cranes are common on construction sites that often have limited or no mains supply.
- Shipping: Dockyards and cargo operations require high-power cranes.
Benefits of BESS in tower crane solutions
- Reduce emissions: by decreasing the reliance on diesel generators, emissions can be significantly reduced.
- Lower fuel consumption: optimised energy usage leads to lower fuel consumption and therefore reduced carbon footprint.
- Reduce fuel costs: lower fuel consumption translates to cost savings.
- Downsize/rightsize generators: smaller generators can be used reducing emissions and fuel consumption.
- Overcome capacity constraints: BESS can supplement limited mains supply or support generators.
What does a BESS solution look like?
Example scenario
Consider a city centre construction site with a tower crane that requires a 250 kVA generator according to the manufacturer's spec sheet. The site operates 24/7 to keep aviation lights and a signboard on, necessitating a continuous power supply all whist adhering to emissions legislation.
Traditional vs. Greener solution
Traditional solution:
A 320 kVA generator would typically run 24/7, leading to inefficiencies and potential long-term damage due to continuous underloading.
Greener solution:
A more efficient setup would involve a BESS rated at 150 kVA with a 75 kWh capacity, paired with a 125 kVA generator. The battery would handle the crane's load most of the time, as cranes generally have short spikes in power demand. The generator would run only when needed and to recharge the BESS. During off-peak hours, such as nights and weekends, the BESS would power the signboard and aviation lights. This setup ensures that the generator runs more efficiently, reducing fuel consumption, CO2 emissions, local emissions and noise pollution.
A 320 kVA generator would typically run 24/7, leading to inefficiencies and potential long-term damage due to continuous underloading.
Greener solution:
A more efficient setup would involve a BESS rated at 150 kVA with a 75 kWh capacity, paired with a 125 kVA generator. The battery would handle the crane's load most of the time, as cranes generally have short spikes in power demand. The generator would run only when needed and to recharge the BESS. During off-peak hours, such as nights and weekends, the BESS would power the signboard and aviation lights. This setup ensures that the generator runs more efficiently, reducing fuel consumption, CO2 emissions, local emissions and noise pollution.
Implementation considerations
When designing a battery solution, sites would need to consider the following:
- Generator sizing: Ensure the generator can handle the daytime load while recharging the BESS.
- BESS capacity: Choose a BESS with sufficient kWh to handle short power spikes and maintain continuous operation during low-demand periods.
By integrating BESS with traditional power sources, construction sites, docks or shipyards can achieve significant environmental and economic benefits, ensuring the smooth running of equipment and improving sustainability.
Speak to our experts today to see how you could implement a BESS into your tower crane solution.