Submitted by ForHidingSquirrels t3_zy4194 in Futurology
TheLizzardMan t1_j24czmo wrote
Reply to comment by ForHidingSquirrels in Robotic boats are surveying seabeds at offshore wind farms by ForHidingSquirrels
As in hydrogen fuel for power-generating turbines?
ForHidingSquirrels OP t1_j24h7ae wrote
Industrial and fertilizer used mainly, backup/peaking electricity sources
Raptor22c t1_j2528gr wrote
The hydrogen fuel can be used for a variety of things. It can be used to power backup generators to keep the power supply from the turbines steady during periods of calm or no wind, it can be exported to the shore via pipeline to use for vehicles, making hydrogen fuel cells, use as a rocket propellant, or simply as energy storage.
Excess energy generated by the grid that doesn’t get used ends up essentially wasted; if the energy is converted to another form (say, using the electricity generated by a wind turbine in electrolysis to split water into hydrogen and oxygen), then it can be stored long-term. Thus, if power generation goes down due to weather conditions, or demand goes up due to increased energy consumption, the energy stored as hydrogen can be used to fuel generators to put it back into the grid and meet the demand.
MagicPeacockSpider t1_j25i7du wrote
We don't actually waste much excess energy. At least in Europe.
There is a small amount of grid level storage in hydroelectric. So when real time prices drop with demand there is a customer to buy it.
There is generally an undersupply topped up with fossil fuels.
We obviously want to end up with an oversupply but that's a rare occurrence because we can very quickly turn off gas fired stations and the overrun ends up getting bought up for storage.
SatanLifeProTips t1_j25ykge wrote
The whole point is to build a power grid that IS wasteful. Unless you have 140% too much green energy capacity you won’t have enough capacity for when energy generation is poor.
And if those 95% efficient hydrogen electrolysers end up being the real deal and not corporate wank the smartest thing we can do is start building tank farms. H2 is half the weight per unit of energy of Jet A and is the best option for ships, trains and eventually aircraft. Stored cryogenically as long as you burn 1% of your fuel per day it will stay as a cryogenic liquid with no external energy inputs. That is perfect for comercial use.
Plus you can use those that surplus H2 to fire existing gas fired power plants with very little modifications. Most will burn a 15% methane 85% H2 mix easily. That gets you through a cold dead month or three in winter.
MagicPeacockSpider t1_j261g0y wrote
The hydrogen electrolysers will probably average out to be around 75% efficient at best is my guess even with the recent headlines but that's still good enough compared to the fuel cells around ~50%.
So being favourable and allowing a boost to 80% one way and ~60% the other you're still looking at losing half the energy.
Pumped storage is around 90% for a round trip.
More flexible gravity storage with weights and hills is around 80%
Lithium-ion is around 95%.
This is going to be an economic fight. What is the cost of producing and maintenance of lithium ion batteries at scale. Is that more expensive than the equipment and materials required to produce and store hydrogen to the point where hydrogen based solutions can run at a 50% efficiency.
There is also the potential for cheaper batteries at grid level storage. Molten salt batteries operate around 85% efficiency and could have much cheaper raw materials.
SatanLifeProTips t1_j26gmch wrote
Fuel cell efficiency is over 60%. But so is a power plant stationary turbine with heat recovery.
Here’s the thing with green energy storage. Round trip efficiency… actually not that important. Because green energy is so plentiful and easy.
We need 95% of the lithium batteries for the transportation grid. Batteries are an ‘hours’ solution for the power grid. Flow batteries, liquid metal batteries will be king and yes they are an ‘hours’ solution.
Tank farms full of hydrogen are a ‘weeks’ solution for the power grid. We ALREADY have the machinery to make H2 into energy. Existing gas fired power plants. You can even convert a coal power plant. It’s all heat to energy steam systems and it is around 60% efficient.
There isn’t enough pumped hydro. And it’s hard to install in 99% of the areas. Plus the massive environmental backlash and NIMBY’s. Unless the ‘underwater spheres’ reverse pumped hydro systems prove themselves cost effective. It’s too spendy right now.
MagicPeacockSpider t1_j26mba8 wrote
I agree we're going to need all the tools but ignoring round trip efficiency because renewables are "plentiful and easy" isn't right.
Renewables cost money. Renewable energy will cost money.
On demand renewable energy will cost more money.
We all need to be able to afford energy.
So the cost of generating power from a renewable source, storing it, then deploying it to match demand cannot be a wasteful process.
The goal is to be able to replace fossil fuels and we can't afford to do that if we make energy more expensive and cause a permanent recession.
The cost of renewables with roundtrip efficiency is the direct price comparison to on-demand gas plants as they currently are.
The fact H2 is likely to just be figuratively shoved into a gas plant as you suggest is actually a huge problem economically speaking. It means you're maintaining infrastructure nearly identical to the fossil fuel system we have with a more expensive fuel.
It can't be cheaper until fossil fuels are scarce enough we've torched the planet already.
Other storage options allow greater round trip efficiency and allow a potentially lower price/kW for on demand power.
I want us to fix climate change by taxing carbon and pricing externalities or by consumer choice refusing fossil fuels.
I know that's not likely. So my hope is with investment direct price comparison on a near like to like market application leads to renewables as soon as possible.
Hydrogen doesn't offer that future. Lithium and salt batteries with wind and solar could.
Subsidies for zero carbon energy or a carbon tax could bring hydrogen into the market but I know globally, especially in the US, that kind of government intervention isn't likely.
Subsidies into R&D for technologies capable of beating fossil fuels in a market with a level field are what I want to see. Once a technology is proven it needs no government intervention to enter a market.
Hydrogen I don't see as a stepping stone, it's likely something we use once economies of scale for fossil fuels no longer exist. After we've already created abundance of energy to make hydrogen cheaper than digging up fossils.
SatanLifeProTips t1_j26zbna wrote
It’s a materials question. Unless you can pull a lithium astroid in from orbit, there just isn’t enough materials to build high efficiency green energy storage. We will see if these flow batteries scale and they aren’t meant for more than a couple of days of use.
We already HAVE power plants. A lot of them. And owners vested in not shutting them up forever. Converting them to run as backups and just putting a shit ton of tanks out back is easy and fast. One day we’ll figure out something better. But when you need 21 gigawatts quiet cold night it is hard to beat.
And you aren’t getting a ship, train or plane to move on batteries very far. Crossing oceans needs something potent like H2.
MagicPeacockSpider t1_j281v0f wrote
Planes are the only transport you listed where it's not feasible and H2 lacks density for that application as well.
Ships have acres of space, trains can absolutely use batteries where lines can't be electrified, they're miles long.
If you want to replace fossil fuels from an energy density point of view you're talking biofuels.
There's a lot of lithium on planet earth and batteries are recyclable so an asteroid isn't necessary.
It's all a moot point until we overbuild renewables supply. As well as overproducing food if we want to use biomass and biofuels.
I'm not saying hydrogen isn't a partial solution, I'm saying it's not a primary solution.
We really need to move forward with battery technology as it is the primary solution.
It really doesn't matter what sunk costs anyone has into fossil fuels we should aim for the most efficient solution to ensure costs are low.
Converting current plants to hydrogen will happen when hydrogen is cheaper than fossil fuels. So we're relying on the price/kW dropping a long way. Hydrogen becoming economically viable relies on other technologies. It's not a stepping stone.
SatanLifeProTips t1_j2a9zlt wrote
Airbus seems to think Hydrogen is quite viable in aircraft. But what do aviation engineers know?
Liquid H2 stores down pretty small. Not as small as Jet A, but given that it is half the weight of diesel even the most die hard engineer takes interest in a massive weight savings. It does require a rethink of current aircraft configurations but as soon as you start talking electric motors you can move propulsion into all kinds of new places. Blended wing designs are likely. (See the render in the article).
And you don’t need any refrigeration equipment with liquid H2 as long as you have a jet/fuel cell running just boiling off the liquid keeps it plenty cold.
Viewing a single comment thread. View all comments