BESS Visual

ECO & Euro Efficiency

How ECO (CEC) and Euro efficiency are calculated from the same PCS curve — the formula and running sum, step by step.

ECO & Euro Efficiency

How ECO (CEC) and Euro efficiency are calculated from the same PCS curve — the formula and running sum, step by step.

0.4 MVA PCS / ECO vs Euro
ECO / CEC eta98.48%
Euro eta98.43%
ECO - Euro+0.047pp
curve peak98.61%

Both ECO (CEC) and Euro efficiency reweight the same efficiency curve at fixed load points — the weights sum to 1, so each is a load-point average. They differ only in where the weight sits: ECO leans on 75% load, Euro on 50%.

Same curve, two weightings0.4 MVA PCS / weighted eta
ECO eta= sum( weight x eta(load) )0.04 x 98.0010% load0.05 x 98.4820% load0.12 x 98.5930% load0.21 x 98.5950% load0.53 x 98.4675% load0.05 x 98.30100% loadrunning 3.92Euro eta= sum( weight x eta(load) )0.03 x 96.935% load0.06 x 98.0010% load0.13 x 98.4820% load0.10 x 98.5930% load0.48 x 98.5950% load0.20 x 98.30100% loadrunning 2.9197.097.598.098.5one-way efficiency (%)0%20%40%60%80%100%w 0.04w 0.03
speed
Step through each term to watch both weighted sums build. ECO puts 53% of its weight at 75% load; Euro puts 48% at 50% load, which is why the two headline numbers differ on the same curve.
Equipment visualization - step through each weighted term to see how ECO (CEC) and Euro efficiency turn one efficiency curve into two headline numbers.

Equipment visualization - step through each weighted term to see how ECO (CEC) and Euro efficiency turn one efficiency curve into two headline numbers.

About this visualization

How ECO (CEC) and Euro efficiency are calculated from the same PCS curve — the formula and running sum, step by step. This interactive diagram is part of the BESS.engineer visuals library — practical, engineering-led explanations of grid-scale battery energy storage. Use the controls above to explore it, or download a GIF from the library view.

← Explore all BESS visuals