How to Power Energy Cost Savings

Aug 07, 2023   Written by Michelle Wicmandy and Michiel Spoor

Escalating Energy Costs and Policy Changes Strengthen Global Commitment to Sustainable Progress

Feeling the heat to lower your emissions and improve your plant’s operations? Many refining and petrochemical operators do. Cutting energy costs alone doesn't guarantee emissions will drop. Besides new energy-saving technologies, other methods are here to bring the industry minimum energy cost.

Leveraging Simple Methods

For instance, you can also use a simple methodology called the Price Equivalent Efficiency, or PEE. PEE can be used to boost the efficiency of shaft-power production in your chemical plant. The shaft power to operate their equipment can be generated by different sources like electrical motors, steam turbines and gas turbines, each having different efficiencies. In essence, PEE helps determine which drivers to use and whether it’s more cost-effective to import power or produce it on-site. 

Balancing Import with On-site Power Generation

Here's the deal. External power plants, like those operated by utility companies, produce power. These power plants are inefficient, and their PEE usually falls between 25% and 60%. This means that on an equivalent energy basis, the amount of power produced is 25% - 60% of the fuel used. Furthermore, the PEE can change based on factors such as power tariffs, like if they're cheaper during the day or night, or in the summer or winter. All these factors come into play when determining the best strategy for generating shaft power at your site. The key is to find that balance to ensure optimal performance, cost-effectiveness, and optimal use of your power sources.

Imagine you have a refinery that uses a steam-turbine generator on a condensing steam cycle. The overall efficiency of this machinery usually falls between 25% and 30%. To get the best performance and reduce power cost, it's best to keep the generator running while the PEE is below 25%. So, what if your PEE goes above 30%? In that case, it's more economical to import power and scale back production from the generator. 

Tackling Escalating Energy Costs

A refinery in South America faced the following situation: their natural gas energy import costs were sky high. After calculating their PEE, they were surprised to find that it was a staggering 120%, which is unusually high but easily explained because of cheap renewable power imports. The solution was to minimize the production of shaft-power on-site, by shutting down gas-turbines and steam turbines, and use electrical drivers as much as possible. This saved the refinery money, and it reduced their carbon footprint as they could benefit from the cheap renewable power imports.

Powering Sustainable Progress

This refinery found a way to cut costs, minimize environmental impact, and maintain smooth operations. Discover how their bold decision powered sustainable progress.