531–540 of 766 posts
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PG&E electric rates are so high that it's operationally more expensive to use a heat pump than a condensing gas system. The heat pump is the better deal practically everywhere else in the contiguous US. I'm installing a heat pump system in PG&E territory as part of a remodel, but pairing it with a large solar system.
Aren't PG&E gas rates substantially higher than their electric rates?
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You still need to account for efficiency of the various fuels when working out which one is cheapest. An electric vehicle is on the order of 5X more efficient than a gasoline vehicle per kWh (that is, an EV that will go 5 km on 1 kWh of electricity would be lucky to get 1 km per kWh if it were running on gasoline). So in this case, it's still cheaper to operate an EV than a gasoline vehicle in MA, even if electricity…
It's more like 2.5 to 3x for good ICE cars (they are around 30% efficient- I think it's been going up over the years, in the past I assumed 15%): https://en.wikipedia.org/wiki/Engine_efficiency#:~:text=in%2... . But anyway, the big issue is for electric cars fast chargers, more like $.48 / kwh.. For carbon emissions, the WTW (Well to wheel) efficiency is more important- they are about the same unfortunately (we need…
At 8.9 kWh per litre, that means gasoline takes 81.88 kWh to get you 100 km. A typical EV, on the other hand, will use about 18 kWh to go 100 km (at 5.5 km per kWh). That makes the EV around 4.5 times more efficient.
As for carbon emissions, burning 1 litre of gasoline creates 2.3kg of CO2. At 9.2 litres per 100 km, that works out around 210g per km.
Grid carbon intensity varies greatly by country and region. In France at only 42g/kWh, an EV's energy would emit less than 10g per km, even after accounting for grid and charging inefficiencies! But even in coal-dependent Germany at 354g CO2/kWh (2023), an EV would be well under 100g per km, still better than an average petrol car.
(Also, remember that auto industry emissions/efficiency numbers are based on testing protocols which produce far lower figures than the real world. And do not account for upstream emissions in the fossil fuel supply chain - there is an awful lot of upstream carbon emitted to produce 1 litre of gasoline!)
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Natural gas won’t stay cheap. It was cheap here in Australia 10 years ago and now it’s so expensive no one can afford to run gas heating and it’s only going up. Now (thankfully) the government has banned the installation of new gas heating and a lot of people are getting rid of gas cooking, hot water heating etc… it’s for the best.
I remember a recent investor report posted on HN about declining health of permian basin, and the economics of extraction will increasingly not make sense in 10 years. Seems like no brainer if shale and by connection LNG is on way out. Might also explain Biden stalling LNG expansions especially with NATO on the hook, maybe it's cynical electioneering to his base, but maybe the future of cheap US LNG is not bright vs…
IIRC Gas extraction has an extremely high EROI (30x) initially, making it a highly productive extractive resource. But each gas well has a productive lifespan of approx 7 years requiring constant activity to sustain development.
> Death is coming for the old-school gas furnace—and its killer is the humble heat pump. Uh, you still need a furnace (though it could be electric) if you live somewhere that ever really gets cold, right? [edit] I mean, seeing it presented as a furnace replacement is weird to me. I’ve always seen it sold as an air conditioner replacement that also happens to heat (with weird characteristics that often confuse people—…
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I remember a recent investor report posted on HN about declining health of permian basin, and the economics of extraction will increasingly not make sense in 10 years. Seems like no brainer if shale and by connection LNG is on way out. Might also explain Biden stalling LNG expansions especially with NATO on the hook, maybe it's cynical electioneering to his base, but maybe the future of cheap US LNG is not bright vs…
The fossil fuel capitalists are so very unhappy about this ban, they are still going on about it in the financial news. I have to say, I love it. Low natural gas prices directly benefit me, and isn't it our gas? The price has certainly come down (look at henry hub chart..), but also winter has not been too cold.. They should ban oil exports next.. (for "national security") Actually export tariffs would be better than…
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Export tariffs are actually unconstitutional in the US. https://en.wikipedia.org/wiki/Import-Export_Clause
Interesting.. the same section banned any limitation on the importation of slaves... at least that clause had a sunset date. Both clauses were basically: "don't touch our cash cow".
moved from oil furnace to heat pump in Seattle (with electric strip backup) Seems like a perfect fit for our weather patterns but was definitely not the most economical option as it kicked off a domino effect of upgrades I wasn't missing before. Its no where near as "cozy" as the oil heat was, and the temperature of airing coming from the vents is significantly lower than the oil system. So the domino of upgrades is…
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I don't think it's about duty cycle -- it's seriously about speed of temp change and I _think_ dew point. But yes, I have a heat pump and in NYC Summer I cannot run it on anything but low otherwise it increases the humidity. It took me a few weeks of looking at the temp humidity graphs to understand that point.
As it was explained to me, it is about duty cycle. The condensation doesn't instantly accumulate enough to make droplets and run all the way down the drain, so if the compressor only runs briefly the condensation is still on the fins and evaporates again. You need to keep the compressor going long enough that you actually have water running down the drain, instead of condensing/evaporating cyclically.
The only thing stopping me from buying a great pump is how unreliable the power grid is in my area. Lines are above ground, with numerous trees overhanging them so a snow storm is high risk for a power outage at a time I can least afford it, as road conditions may prevent seeking shelter elsewhere. Conversely, with a furnace and a small generator to run the blower, I can keep heat on through a couple days without pow…
One of the big problems with heat pumps in New England is that our electricity costs 1.7x the US average ( https://www.eia.gov/electricity/monthly/epm_table_grapher.ph... ). If you're in the South, a heat pump makes perfect sense. You're going to want AC anyway and it'll be way more efficient and save a ton of money when you want heat. In most of the country, even if it gets cold your electricity prices are still a t…
If heat pumps get inefficient at low temps could we not program them to run full blast during the warmest parts of the day and preheat the home. Thus needing to run less at night.