Home / New Zealand guides / Hydrogen fundamentals / Round-trip conversion losses: Family home
New Zealand planning guidance for a specific property and load boundary. Explain conversion losses in the household energy budget. H2OME remains in early development.
Round-trip efficiency compares usable electrical output with the electrical input needed to restore the same storage state. It is not the fuel-cell efficiency alone. For example, an explicitly hypothetical 30% round trip would require 10 kWh of input for 3 kWh of output, before any omitted loads.
That 30% example is arithmetic, not a verified H2OME result. Request test boundaries, operating conditions and auxiliary consumption. A cheap input period or surplus wind and micro-hydro can change an economic comparison, but cannot eliminate physical conversion losses.
Laundry, vehicle charging and bulk water heating should be considered separately rather than folded into an essential-load promise.
Several people can turn on appliances at once. The largest demand may occur when an outage ends and refrigeration, hot water and cooking all try to resume, rather than during the quiet overnight period.
Use the 3.6 kWh demand for a family home as the numerator in the clearly hypothetical recovery example. Replace the assumed 0.30 only with a comparable measured whole-chain result, not a fuel-cell component efficiency.
Explain conversion losses in the household energy budget. A whole-home connection is not proof that every appliance can operate together. The family needs a priority schedule that remains understandable without a phone app.
All numbers below are hypothetical teaching inputs, not measured appliance specifications or product performance. The topic-specific extra load is separate from the base set; omit it if your real inventory already counts it. This worksheet does not include conversion overhead, protection design or a contingency allowance.
For a family home, assume the selected base loads average 0.25 kW for 12 hours: 0.25 × 12 = 3 kWh. Separately, an additional output-side appliance draws an assumed 300 W for 2 hours: (300 ÷ 1,000) × 2 = 0.6 kWh. The combined illustrative demand is 3.6 kWh.
At the hypothetical 30% round trip, divide this output energy by 0.30 to illustrate the larger input requirement.
For arithmetic only, if the complete storage chain had a hypothetical 30% round-trip efficiency, delivering 3.6 kWh would require 3.6 ÷ 0.30 = 12 kWh of charging input. This is not a measured H2OME efficiency or recovery result. Ongoing demand during charging would add to the required input.
Base operating window: 12 hours. Extra illustrative load: An additional output-side appliance, 300 W for 2 hours. Replace every input with a measured or professionally established value.
In New Zealand, discuss supply arrangements and connection questions with your electricity retailer and distributor. Ask the local council about relevant siting, building and water-use requirements. Use appropriately qualified electrical and hydrogen professionals, and refer workplace safety questions to WorkSafe guidance. This page does not establish a consent or compliance outcome.
For medically dependent people in New Zealand, register with your electricity retailer, the company that bills you, and keep that registration current. Re-register when switching retailers; ask the retailer how the distributor is informed and what clinical confirmation is needed. Follow the clinician and equipment provider's contingency plan. Registration does not guarantee uninterrupted electricity, and H2OME is not a substitute for that plan.
H2OME is in early development. Its 10 kW output figure is a design target, not a proven specification. There is no confirmed price, certification, commercial availability or guaranteed runtime in this guide.
Hydrogen is an energy store, not free energy. Grid input, wind and micro-hydro are the charging options considered here. Each requires its own supply assessment. Do not install hydrogen equipment, modify fixed wiring, bypass protection or improvise a connection from this guide.
These official resources provide energy, consumer and technical background. They are not endorsements of H2OME, proof of its performance or a substitute for site-specific professional advice.
Several people can turn on appliances at once. The largest demand may occur when an outage ends and refrigeration, hot water and cooking all try to resume, rather than during the quiet overnight period. Explain conversion losses in the household energy budget.
No. The 3.6 kWh total is an illustrative demand worksheet, not a runtime result. Actual appliance measurements, usable storage output, starting demand, conversion overhead and reserve limits are needed. The 10 kW design target is not demonstrated output capability.
In New Zealand, discuss supply arrangements and connection questions with your electricity retailer and distributor. Ask the local council about relevant siting, building and water-use requirements. Use appropriately qualified electrical and hydrogen professionals, and refer workplace safety questions to WorkSafe guidance. This page does not establish a consent or compliance outcome. Use the worksheet to brief the relevant professionals, not to install, modify or operate hydrogen equipment.
Ask us about H2OME, tell us about your property or register your interest in the proposed system. We are in early development. No payment or purchase commitment; contacting us does not guarantee a pilot installation.