Wave Energy Calculator for Construction

Use site metocean data for design-level decisions.

Irregular seas (recommended for measured sea states):

• Energy density: E = ρ g Hₛ² / 16 (J/m²)
• Group velocity (finite depth): c_g = n (ω/k), with n = 0.5(1 + 2kh / sinh(2kh))
• Dispersion: ω² = g k tanh(kh) (solved iteratively)
• Power per crest meter: P = E · c_g (W/m)

Deep-water shortcut (when depth is unknown or kh is large):

• Approximate: P ≈ (ρ g² / (64π)) Hₛ² Tₑ (W/m)
• Common coefficient: P ≈ 0.49 · Hₛ² · Tₑ (kW/m) for seawater

Regular waves: this tool uses E = ρ g H² / 8 with the same c_g approach.

1. Select Irregular seas for sea-state data (Hₛ and Tₑ).
2. Enter wave height and period; confirm the selected units.
3. Enter water depth to improve accuracy near shore.
4. Set crest/structure length to estimate total exposure power.
5. Use efficiency for availability, losses, or screening factors.
6. Press Submit to view results above the form.
7. Download CSV or PDF for meetings, bids, and logs.

1) Coastal energy metrics used in construction

Wave power flux is reported as kW per meter of crest. For screening, this aligns with how breakwaters, cofferdams, and temporary berths “see” incoming wave trains along an exposed length.

2) Inputs that drive power estimates

Energy scales with height squared. Doubling height increases power about four times. Period affects how fast energy travels, so longer periods usually increase power for the same height. The deep-water shortcut often used is P ≈ 0.49 · H_s² · T_e in kW/m for seawater.

3) Why depth changes group velocity

Nearshore works frequently operate in finite depth. The calculator solves the dispersion relationship ω² = gk tanh(kh) to compute wavelength and group velocity. When kh < 1, shallow-water influence slows waves and can reduce flux relative to deep-water assumptions.

4) Typical sea-state ranges for work windows

Many marine work windows target H_s ≈ 0.5–1.5 m and T_e ≈ 4–8 s, depending on vessel limits and tolerance of temporary works. Moderate sea states such as H_s=2.0 m, T_e=8 s produce roughly 15.7 kW/m by the shortcut (0.49×4×8). Offshore exposure with H_s=3.0 m and T_e=10 s can exceed 44 kW/m.

5) Interpreting kW/m for temporary works

Use kW/m to compare scenarios consistently. For example, increasing H_s from 1.5 m to 2.5 m increases H_s² from 2.25 to 6.25, a 2.78× rise in energy density before depth effects. This helps prioritize robust fendering, scour controls, and access restrictions.

6) Using crest length to scale exposure

If you enter an exposed length (crest/structure length), the tool multiplies kW/m by that length to estimate total incident power. For a 50 m frontage at 15.7 kW/m, incident power is about 785 kW. This supports comparative budgeting and plant selection discussions. For segmented works, apply the length that is simultaneously exposed.

7) Practical safety checks and limits

The output includes steepness H/L as a quick flag for likely breaking. Values above roughly 0.06 indicate high steepness, where nearshore breaking and reflection can complicate loads. Always cross-check with site metocean statistics, tide stage, and directionality. Density and gravity defaults are suitable for most coastal regions.

8) Reporting, traceability, and downloads

Exporting results to CSV supports audit trails for method statements, toolbox talks, and temporary works reviews. PDF exports capture the latest run plus recent history, useful for attaching to permits and daily marine logs when conditions change rapidly.

1) Should I choose irregular or regular waves?

Use irregular when you have sea-state data (H_s, T_e). Use regular for a single representative wave height and period. Irregular is more common for metocean datasets.

2) Why does wave height change results so much?

Wave energy density is proportional to height squared. If height doubles, energy and power increase roughly fourfold, before considering depth and period effects.

3) What does “kW/m” mean for my project?

It is power per meter of wave crest arriving at the site. Multiply by an exposed frontage length to compare relative incident power along a quay, breakwater, or cofferdam.

4) Do I need to enter water depth?

Depth is optional but recommended nearshore. It improves group velocity and wavelength using dispersion. If depth is omitted, the calculator uses a deep-water group-velocity approximation.

5) What is a reasonable efficiency value?

Efficiency represents availability or losses for screening. Use 100% to keep incident and extractable equal. For practical allowances, many teams apply 60–90% depending on downtime assumptions.

6) How should I interpret steepness H/L?

Steepness flags breaking likelihood. Higher values mean sharper waves and potentially higher nearshore loads. If the tool warns about high steepness, validate with local bathymetry and directional wave data.

7) Are these outputs suitable for final design?

They are best for planning, comparisons, and documentation. Final design should use project metocean studies, directional spectra, transformation modeling, and applicable codes for loads and stability.