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Comment by fuzxi | Hacker News Reader

No kidding.

>Nationwide, fossil fuels burned for energy in businesses and homes sit at 13% of annual carbon emissions, according to 2019 data from the EPA.

>Gas stoves’ contributions to emissions are negligible compared with the gas used to heat homes and water. Less than 3% of natural-gas use in homes comes from cooking on gas stoves, according to a 2015 residential energy survey from the U.S. Energy Information Administration.

3% of 13% comes to just under 0.04% of carbon emissions. Yup, definitely making a big difference.

Edit: 0.04% of residential carbon emissions in the US only.

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Cooking accounts for less than a percent of total natural gas. So, no, we don't need to start here. We need to start where it makes a difference.

60% of US electricity is generated from fossil fuels (1). 40% of that is from Natural Gas. 20% from Coal which produces almost twice the carbon as Natural Gas.

60% of that energy is lost in conversion (2). So, converting from natural gas to electricity would actually increase carbon emissions in many parts of the US.

So, where should we start? I'm not an expert, but just this quick analysis says decreasing the amount of fossil fuels used for US generation would be a much better choice.

1. https://www.eia.gov/tools/faqs/faq.php?id=427

2. https://www.eia.gov/todayinenergy/detail.php?id=44436

Cooking is a negligible amount of the gas use, but in warmer states gas networks will do rebate deals with developers to get gas appliances into new homes to keep the domestic networks expanding. There can be transmission loss in these networks and curbing demand for appliances (Via City regulation) stops them expanding.

Also, at least in my country, the network connection fee to the gas network is often higher than the gas used by appliances, (warm climate) and residential cooks don't realise they're subsidisng the cost of our business gas users.

> 60% of that energy is lost in conversion

However, unlike for a home gas boiler where the efficiency is maybe 90%, direct efficiency for gas stoves is poor. Basically you set fire to the gas, the fire is near the pans you're using for cooking, so they get hot. It's simple, but it is not at all efficient. This also produces waste CO2 (and some CO but hopefully not much), which is poisonous although not that poisonous, right where you are standing, whereas your gas boiler vents the waste gas to the outside air.

In contrast induction has much better efficiency and of course produces no poisonous gases itself (though cooking foods does release a variety of volatiles you shouldn't really breathe, especially pan frying)

So while "Burn gas in your home" to heat water is definitely a net efficiency win over "Burn gas in a power station, ship the electricity to your home, then use that" to heat water, the same does not follow for stoves where I suspect it's either a wash or a small win for electricity.

Water heating, like cooking should not be a significant part of the home power equation when done right.

Large boilers need to die. Small "instant heaters" at or very close to each faucet is the correct way. Way way way less energy usage.

Sadly the electrical water heater units usually don't have access to the 240v line and are limited to 120v, 10A or something measly. People then complain their water doesn't heat fast enough or get hot enough for a given flow and then complain/swear off small instant heaters =/

Just did the math and supporting a ~70F (50F-> 120F) rise at 1GPM (faucets are limited to about this) requires 9kW, or about 40A at 240W. Supporting a bunch of 40A circuits in a typical home would require a massively upgraded circuit panel for most homes -- 200A or even 100A service is common.

A centralized system avoids having multiple circuits with potentially high loads like this. Not to mention the likely gigantic heat exchangers required to transfer 9kW!

> So, converting from natural gas to electricity would actually increase carbon emissions in many parts of the US.

Yes, but the plan is a more clean grid in the future. If you are building a new home now then this calculus (hopefully) will not hold in 20 years. If we've got a clean grid but everybody is still using gas to heat their homes, we've still got a huge problem.

In a new build, if the house isn't going to get a gas heater (to make that 97% reduction in home gas usage) then the builder isn't going to want to bother laying a gas pipe just for the cooker. That 3% reduction comes as a saving on inconvenience, not really as a saving on carbon emissions.

Is there a tank alternative? I much prefer cooking on a gas stovetop, and would be willing to refill a tank every couple of months, the same way folks do with propane grills.

Most municipalities and or HOA's will have limits and restrictions on tanks. If they are portable tanks then it will likely be covered under whatever rules for grills already exist, but larger installs will have a different set of requirements.

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