sparkyshocks
@sparkyshocks@lemmy.zip
- Comment on TIL the cost of transporting energy around 1 week ago:
capital costs for the wire and components all along the way is massive
That’s true of pipelines, too. It’s just that the sheer quantity of energy contained in those chemical bonds of chemical fuel is massive, so amortizing the up-front capital costs across how much energy can actually move through that pipe or cable in its lifetime tends to favor a pipe full of chemical energy, on a per kWh (or per joule) basis.
- Comment on TIL the cost of transporting energy around 1 week ago:
Food energy tends to be measured in kcals though
- Comment on TIL the cost of transporting energy around 1 week ago:
Yes, the numbers change for shorter distances. There’s some loss in loading up a fuel tank and driving it to the station. But again, the high energy storage capacity of chemical energy still makes a huge difference.
If a loaded semi gets 8 miles per gallon of diesel, then moving a tanker full of 10,000 gallons of gasoline 200 mile (320 km) s will burn 25 gallons of diesel in order to transport 10,000 gallons of gasoline. Even with less efficient trucks (let’s say 6 mpg for 33.3 gallons of diesel burned), it’s still pretty efficient in terms of “losses,” of about one third of one percent of the original volume of fuel consumed. Of course, diesel is more energy dense than gasoline, especially gasoline mixed with ethanol, so the efficiency might drop to 99.5% instead of 99.7%, but we’re still talking about a pretty fundamentally efficient operation.
The real efficiency gains of electricity over fossil fuel (or any chemical fuel) comes from the more efficient motors. An electric car that goes 3 miles (5 km) per kwh is the equivalent of going 100 miles per gallon (42 km/L) of gasoline. A heat pump that has 300% efficiency only needs to transmit 1/3 as much electrical energy as would have been necessary for bringing fuel to a combustion-based heater.
So if you start breaking it down by actual use case, you might be able to make some gains back to mitigate the higher cost of transporting electricity across large distances. But it still remains that all the other methods are very efficient, too.
- Comment on TIL the cost of transporting energy around 2 weeks ago:
Pipelines are absurdly efficient because moving liquid or gas through a pipe is absurdly efficient per kilogram per kilometer, and the energy density of fossil fuels is absurdly high.
A Tesla supercharger v4 can deliver 500 kW of power. BYD has launched chargers that can deliver 1000 kW (aka 1 MW) to a single car. Naturally, each kW of power is capable of delivering 1 kWh per hour.
What is the equivalent flow rate in gasoline? 1 gallon of gasoline contains the equivalent of 33.4 kWh (1 L contains 9 kWh). So 1000 kW would be the equivalent of 30 gallons per hour (110 L/hr), or 0.5 gallons (1.85 L) per minute. That’s 5% of the rate of a typical gasoline pump in the United States.
Plus exposed high voltage wires need to be maintained in weather and around vegetation, so they have high operating costs. Then there’s higher capital costs of making sure that there are transformers and safety equipment that step the voltage up and down and sync with the rest of the grid.
In the end, it really is that power lines aren’t capable of carrying nearly as much energy as the chemical fuels that flow through a pipe, so on a per joule/kwh basis, there’s less economy of scale from power lines.
- Comment on ‘Suddenly energy independence feels practical’: Europeans are building mini solar farms at home 2 months ago:
It’s possible, but needs to be engineered for safety, and that design/testing/certification will increase the cost and complexity.
You can have solar panels and a battery totally off grid, where the big battery just acts as a generator, with its own inverter creating AC power for anything you plug in. That’s really simple and cheap, but isn’t safe for connecting to and powering a grid-connected house circuit. So anything you want to power with one of these systems needs to be plugged into outlets that only get their power from these batteries.
You can add a grid-following inverter that safely matches the grid frequency AC, so that you can use the solar power you collect in your own normal home circuit, to power your own household appliances. But the simplest design here is a grid following inverter that doesn’t work when the grid isn’t connected. It can only add to something that already exists and can’t do things on its own.
If you want to do both, where it can work without grid power and it follows the grid when the grid power is on, you’ll have to design a system that can switch between the two modes without delivering power where it’s not expected or generating power that conflicts with the grid’s AC waveform. Making it automated, like an UPS system, is even more complicated.
It’s not impossible, or even that difficult, it just does add complexity and the engineering tradeoff is always the question of “what problem does this solve, and is solving that problem important enough to devote these resources to it?” For anyone on a reliable electric grid where power outages are rare, the answer is usually no.
- Comment on Could waste heat power the Great Lakes region? | The Narwhal 2 months ago:
I read the article’s main point as being that waste heat is all around us, and in places that get cold (like the Great Lakes region), that heat can be moved to where it is useful.
I’m thinking of the brain meme where each level represents something better:
- Electric power is used to generate heat in places that need to be heated, using resistive heat.
- Electric powered heat pumps move heat from air where it’s not needed to places that do need heat, using heat pumps that draw heat from ambient air.
- Heat is transferred from places that actively need cooling to places that need heat.
The main point in the article is that if we’re using electricity to cool a place while also using electricity to heat a place, can we just use less electricity to move the heat from the place where it’s not wanted to the place where it is wanted?
So seen in that light, it’s not so much about how much thermal efficiency a power plant achieves, but rather a question about whether there is something better that can be done with that heat that doesn’t become electricity.