A Personal Energy Ledger · Guernsey

The Hearth Ledger

A weekly reckoning of the energy cost of nourishment — from electric hob, to fire pit, to sun.

◦ roast · stock · demi-glace ◦ four methods compared ◦ kWh / £ / kg CO₂

The Weekly Cookingi.

Chicken mass whole roast, bone in

Oven time, chicken at ~190°C

min

Oven time, carcass roast before stock pot

min

Stock simmer 2 L water → 600 ml

min

Veg stock simmer 0 if not run separately

min

Demi-glace, per session 400+400 ml → 100 ml

min

Demi-glace sessions / week

The Four Hearthsii.

Electric hob & oven

›

Oven draw average while on

Hob draw, simmer gentle maintain

Electricity tariff

£/kWh

Grid carbon intensity Guernsey ~180 g/kWh

g/kWh

Fire pit, brick ring & rods

›

Wood needed per hour useful heat open fire is ~15% efficient

kg/h

Wood cost 0 if foraged / gifted

£/kg

Kindle & tend overhead added per session

min

Roast ability 0 = no, 1 = yes w/ Dutch oven

0/1

Solar blanket → induction

›

Blanket rated power

Peak sun hours / day flat assumption

System efficiency panel→battery→inverter→induction

Kit capital cost blanket + battery + inverter + induction

Roast ability realistically 0 unless huge battery

0/1

Direct solar cooker

›

Type factor 0.3 box · 0.6 panel · 1.0 parabolic

Peak sun hours usable

Capital cost DIY panel cooker ~£40, parabolic ~£200

Usable months / year Guernsey: ~6 realistic

Weekly Reckoning · Electric Baselineiii.

What the grid costs you

One Sunday's work, laid out honestly.

The Four Methods, Weighediv.

Method	kWh / wk	£ / wk	kg CO₂ / wk	Hands-on

Payback & Pragmatismv.

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