rfrey

45 ms·

691.
by rfrey 6y ago
That is a brilliant site, thank you.
692.
by rfrey 6y ago
LCOE is the best number for comparing new construction options. What alternative do you propose?
693.
by rfrey 6y ago
The 2018 worldwide levelized cost of electricity (LCOE) for offshore wind was $134/MWh ( https://www.irena.org/-/media/Files/IRENA/Agency/Publication... ).
694.
by rfrey 6y ago
The investigation is “can we”, not “have we”.
695.
by rfrey 6y ago
By cautious rules and the ability to fire anybody who didn't follow them.
696.
by rfrey 6y ago
This comment is either skillfully ironic or blindingly unaware.
697.
by rfrey 6y ago
Where does this come from? Your parent was asked if he thought one should walk an extra 60 minutes to get groceries, he replied yes and gave a lot of reasons why. Completely respectful and polite.
698.
by rfrey 6y ago
There are many industries for which there is no clear path to electrification. Also: Geothermal is not free, only the fuel is free. The cost of every electron has to account for the cost of building the plant.
699.
by rfrey 6y ago
UCP. They cancelled everything the NDP had done.
700.
by rfrey 6y ago
Yes, extraction can easily exceed renewal rates. Good resource management is key to longevity.
701.
by rfrey 6y ago
It seems like a natural pivot for Alberta, and we spent a lot of sweat trying to convince the government that it was good for drillers. Good for pipefitters and welders and millwrights too. No dice though, if anything I'd say the gove
702.
by rfrey 6y ago
You can go deeper, but in most regions you'll be into impermeable rock by the time you get usable temperatures. You need the rock to be permeable so brine can flow from your injection site to the extraction well. Companies like Eavor c
703.
by rfrey 6y ago
The brine in the permeable rock is heated by radiation from the earth's core. It is pumped to surface, power generated, then injected back into the earth at a sufficient distance, so that by the time it flows back to the extraction wel
704.
by rfrey 6y ago
My understanding is that the most efficient turbines top out at about 40%. Reciprocating engines are better, but even they can't get much above 50%. There's still lots of heat there even in the most efficient engines. You're
705.
by rfrey 6y ago
All geothermal projects in Canada will require a direct heat off-take to be viable. In fact the revenue from direct heat use will generally be more than electricity sales. The 5MW plant in Alberta I referenced was built around a proposed in
706.
by rfrey 6y ago
They're a great, innovative company. They're mostly focused on smaller stuff - 150kW and below, although I think they did some larger bespoke projects earlier. For larger stuff my favourite company is Exergy (www.exergy.it). They
707.
by rfrey 6y ago
It never meets economic hurdle rates for industrials on their own, which is why we're building them as independent power plants. We prefer to sell the electricity back to the host facility, but we often sell into the grid.
708.
by rfrey 6y ago
The engineering miracle of the electrical grid is exactly this sort of coordination. Think of this as being like solar energy - except it's generating 95% of the time rather than 25% of the time. That's considered baseload electri
709.
by rfrey 6y ago
A gas turbine has about 25-30MW thermal in the exhaust gasses, typical is gas at 480C and 90kg/s. At those temperatures we can convert that to electricity at about 20% efficiency. We lose about a megawatt in parasitic load such as pump
710.
by rfrey 6y ago
Yup, we offer about 10% of electricity revenues back to the plant in exchange for the heat.
711.
by rfrey 6y ago
Responding specifically to the competition with nuclear: you're absolutely correct: the Geysers geothermal complex (which is actually about 22 power plants) is about 1.6GW. That's easily the world's largest though: I don&#x27
712.
by rfrey 6y ago
It's a good point, but there are many grid experts who argue that smaller, distributed generation is more robust and reliable than larger, 500MW+ plants. Outside a few areas, most geothermal plants are quite small: I doubt we'll
713.
by rfrey 6y ago
For anybody who is interested in this stuff, I was the CTO of a Canadian geothermal company, and I became convinced that it was folly to dig 4km down to get hot water when we are surrounded by waste heat in large industrial plants that is l
714.
by rfrey 6y ago
Geothermal has a problem in that the capital to build a plant is much higher (2-3x) that of a combined cycle natural gas power plant. Even though the fuel is free, in order to make the economics work you have to project power prices out 50
715.
by rfrey 6y ago
In industry we usually refer to "geothermal" as heat from radioactive decay, and "geoexchange" from the backyard stuff, where the source is solar heating. You're not wrong, that just seems to be the way we get aroun
716.
by rfrey 6y ago
I was specifically referring to the claim the effects were probably due to sedation, etc. , not the observation that the study was of hospitalized cases.
717.
by rfrey 6y ago
Possibly for what HN calls "middlebrow dismissal" - wandering in and dismissing the article with blindingly obvious issues ("probably caused by the sedatives, immobilization" etc) as if professional medical researchers
718.
by rfrey 6y ago
A "general comment" that is name calling without specifics, suggestions, or examples isn't very constructive.
719.
by rfrey 6y ago
Housekeeping is a $74 billion industry.
720.
by rfrey 6y ago
Great tool, super useful. For a few extra bucks you can use a programmable temperature controller... search "Programmable Temperature Controller Ramp Soak Heat" at the usual suspects. Allows you to program heating ramp up, ramp d

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