Monday, February 18, 2013

Off Grid and Off Land

One of the big appeals of the Cruising Lifestyle to us is the ability to live off-the-grid.  As we work to narrow down our boat options, I'm currently taking a look at all the various systems and how to best meet our needs in a low-impact (both ecological and financial) manner.  Things that we pretty much take for granted on land by just paying a bill now need to be taken into greater consideration.  Propulsion, electronics and lighting, heat and air conditioning, cooking and refrigeration, hot and cold running water, etc. all require additional thought.

Lets take that last item of hot and cold running water as it makes a good example.  To have water on a boat (yes, there is some irony here as you are floating in it) you need a means of holding fresh water, filling the tank, heating the water, pressurizing the system so it will run, and getting the used water back out of the boat.

Live-aboard boats typically have fresh water tanks, so the only real concern is the size of the tank (and  I have no idea what to say about the size we might need at this point).

Filling the tank is another story.  To get fresh water into the tank, you can fill it up at a marina or run water jugs from shore in a dinghy, but that costs time and fuel in addition to the cost of the water itself.  You can run a water maker to convert that water you are floating in to fresh water, but that takes energy and you need relatively clean sea water to begin with.  Catching rain water seems to be the lowest energy usage option, but requires the weather to cooperate as well as appropriate clean surfaces to catch the rain and the ability to channel it into storage.
ECHOTec Water Maker components

Now that you have fresh water, you want some of it to be hot.  Homes can have solar hot water, and I did find at least one supplier of smaller marine solar water panels.  Due to the power consumption requirements, I don't think an electric heater is viable.  Tankless gas (propane) heater is a typical option. but that uses gas that then needs to be supplied to the boat.  Some systems use the heat generated by the engine(s) to heat water, but those require the engines to be run periodically to keep the temperatures up.

Getting the water flowing, both to the sinks and showers as well as from them, requires pumps.  There are manual pumps as well as electric ones.  I suppose you could run pumps on other fuel sources, but I imagine that is incredibly inefficient.

So, there is a lot to consider just looking at hot and cold running water.  Other systems have similar considerations.  Now we don't want to be spending all our time (or for that fact money) lugging fuels and water to the boat.  We also don't want to be leaving a large carbon footprint.

Electricity seems to be the best "fuel" option for many things.  With solar and wind generators, it should be in reasonably good supply.  It can run pumps, refrigeration, lights and electronics.   There is no doubt that we'll have solar and possibly wind to generate power.Unfortunately it isn't very efficient for cooking (I've heard a microwave can drain a typical boat battery bank in a matter of minutes).  Seems that propane fits the bill here. Would be nice to find a lower impact option.

For hot water, solar would be nice if it would work and propane makes a reasonable backup. For propulsion (when we are not using wind), electric would be a nice option, I just wonder if the technology is up to the task.  Otherwise we will be relegated to either gasoline or diesel.  Maybe we could do a hybrid....hmmmm.

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