Okay, so let’s say that the US decides it’s going to switch over to an all hydrogen economy in 20 years. To do this the government is going to build nuclear power plants, wind/solar farms, geothermal plants, and whatever else it needs to produce the hydrogen without using fossil fuels in the process. Next, the infrastructure’s built up, along with a government program to either buy up or pay to convert nonhydrogen powered vehicles over. At the end of 20 years, the US uses no fossil fuels for it’s energy needs, we’re all on the hydrogen economy. What effect will this have on the environment? Sure, we’ll have cut the emissions of various greenhouse gases (but not all of them, remember that manufacturing processes release greenhouses gases, and that some emissions are going to be natural), but we’ll have also increased the amount of water vapor being dumped into the air (also a greenhouse gas). What’s that going to do? Imagine a desert city like Phoenix, with tons of water being pumped into the air on a daily basis. Will they have increased rainfall?
Possibly. And the wet areas might recieve decreased rainfall, because there’s a finite amount of water on Earth. But I doubt switching to a hydrogen economy will have such effects on rainfall; I’m more worried about the increased pollution from the power plants–seperating hydrogen from water requires more energy than it puts out–and transportation. Hydrogen’s extremely light and not very dense–you need a large container to deliver a signifigant amount. That’s why the Space Shuttle’s external tank is so much bigger than the rest of the craft–and the ET hydrogen’s liquid and rather pressurized.
But other than that, I don’t see any problem besides getting it off the ground. That will be very expensive, and being our government as it is, I doubt it will do anything. There has to be an economic incentive to get private industry involved–like the entire Middle East and South America falling off the edge of the Earth while all petrochemical-related scientists and workers are taking vacations in Brazil and Egypt.
But if you ask me, I’ll stake my bets on methane. It’s cheaper and we already have it set up. Now, where’d Ol’ Bessy go; my car’s getting a bit low…
I’ve heard some paper producing plants can put a million gallons of water a day in the air. I’ve wondered the same thing about that. Maybe someone with pulp industry info will chime in.
Actually in another thread someone calculated that gas engines produce more water vapour than hydrogen engines. Dang, can’t find the link but it was something like gasoline engines producing 5 times the amount of water as hydrogen engines.
I would sincerely doubt that. Considering that (except for trace levels of unburned hydrogen and odd radicals) 100% of the products of combustion of hydrogen are water, it would be hard to top that. Maybe if the hydrogen engine was much more efficient, sure. But then, you also have that large latent heat loss to deal with as well…so I’m not seeing production IC engine hydrogen cars as being more efficient. Fuel cell cars, yes.