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Comment by gwbas1c | Hacker News Reader

Is hydrogen practical? What about other forms of bio-gas?

Personally I wonder if shutting down the gas network for cooking, and backup generators, is short-sighted. It seems to make more sense to push for mixing in carbon neutral gas sources and letting cost be more of a motivating factor.

IE: I pay about $20 a month for gas in the summer when I just use it for cooking and grilling. They could swap in carbon-neutral gas and double my bill and I wouldn't care. BUT, if I was paying for gas to heat my house, you betcha I'd switch to a heat pump if my cost of gas doubled. (I have solar and heat with a heat pump. I only have gas for cooking and a backup heater.)

Carbon-neutral gas: Figure out how to harvest methane from decaying plant matter.

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Yeah, it's absolutely short sighted. Gas appliances are more efficient than electric appliances powered by natural gas fired power plants. While hydrogen might be a way's away (plus it requires redesigning everything), people (for example, Oberon fuels in California) are already mixing renewable dimethyl ether (similar to propane, but the central carbon atom is an oxygen atom) with propane in tanks for gas grills. Storing fuels is cheaper and better for the environment than storing electricity. Expanding the electric grid will be more challenging than repurposing the gas grid.

Doesn't that omit the impact of natural gas on climate change?

I mean it impacts the climate whether it’s burned in a burner or in a power plant. We shouldn’t do either, but if you stop just the appliances you’ll just end up burning more in a power plant.

> if you stop just the appliances you’ll just end up burning more in a power plant

That power plant doesn't have to use natural gas.

Right but they do at the moment

Not all power plants do, and we can change those too, and if we want to ween ourselves off natural gas then we need to do the consumer end too.

This isn't really true. Electric heating is as close to 100% efficient as is practical in the real world. I would also be shocked to learn that gas turbines at a power plant extract fewer watts per unit of gas than a simple (likely poorly maintained) burner in a residential setting.

That may be true for stoves where heat goes into the air but it’s not true for other appliances. Most modern gas furnaces have an efficiency of about 80%, meaning 20% of energy is lost as exhaust. Some newer systems have efficiencies as high as 98.5%, and older systems might go as low as 56% [1] Natural gas combined cycle plants (they have have multiple turbines for increased efficiency) around 50% efficiency (efficiency is limited by the thermodynamics of converting heat to electricity) [2]

So even with the worst furnace and the best power plant, the furnace still has similar efficiency. In the average case, furnaces are more efficient.

[1]: https://www.energy.gov/energysaver/furnaces-and-boilers [2]: https://www.sciencedirect.com/topics/engineering/natural-gas...

This is not true since the vast majority of electric whole home heating units sold today are heat pumps, which are up to 300% efficient [1]. If the power generation and distribution is 33% or higher efficiency, then a heat pump will outperform a natural gas furnace operating at 100% efficiency.

EDIT - Here's a video that explains it much better than I could, although it's a bit long, this YouTuber is great. [2]

[1] https://tristate.coop/advantages-heat-pumps-energy-efficienc... [2] https://www.youtube.com/watch?v=MFEHFsO-XSI

The best gas generators are (approx) 60% efficient. Gas furnaces are around 90% efficient.

Electric heat pumps can go up to 300% efficient, and they don't care what kind of power source the grid uses.

> Gas appliances are more efficient than electric appliances powered by natural gas fired power plants

The very opposite is true. Gas cooking surfaces waste 75% of the heat into air.

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