Dual Sun

A french company is bringing to market a solar panel that combines photovoltaic cells with solar hot water. The combination is not only interesting in a utilitarian way but promises improved performance of the PV cells by reducing the panel temperature (PV efficient drops as temperature rises).

DualSun-Panneau-Recto-verso

I wonder what this combination implies in terms of longevity and warranty. PV panels are typically rated to last more than 25 years. Would that still be true when they cease to be a simple static element and include flowing water? Is the panel leak proof (especially with the hard water flowing flowing through my pipes) for 25 years?

Tesla Energy presents Powerwall

no more batteries and battery rooms
no more charge controllers
no more grid tie
no more cable messes

tesla-powerwall

Tesla just announced the Powerwall one integrated unit to hang on a wall… a battery with a purpose … connect it to a photovoltaic array and (if you want as backup) the grid and you are good to go … at a fraction of the price of existing, more complicated solutions:

How Burning Works

There’s an interesting group called All Power Labs who research biomass gasifiers: in lay terms they make machines that can convert hay, wood chips, nutshells (a large variety of biomass substances) into clean gas products which can be used to power other things – such as a diesel engine generator (which they do). You can see this system at work here:

They got my attention because if/when we go off-the-grid we will likely need a backup source of energy in winter months – the simplest being a diesel generator. But that requires diesel. So the potential of a generator that can run on biomass of which we have plenty is pretty exciting and fills another gap in the sustainability puzzel.

Their CEO Jim Mason appears in a series of 3 videos (~2.5 hours) which finally provided me with an explanation on how burning works. I admit that parts of it were a bit beyond me but for the most part I was able to follow it and learn what actually happens when I burn wood for heat  (namely 4 processes: drying, pyrolysis, gasification, combustion).

It refined my understanding and appreciation of what goes on inside Rocket Stoves. Most  stoves or fireplaces are only able to burn ~20% of the potential energy in wood, most of the rest is released as gasses which for the most part escapes out the chimney unburned. A lose-lose situation: losing potential energy and releasing pollutans into the atmosphere. A typical rocket stoves will burn most (if not all) of those gasses – already making it 4 to 5 times more efficient then most wood burning stoves. Then, after a clean and efficient burn the heat that is generated is retained in a thermal mass … which easily brings them to 10 times better.

via Matt

Water – Electricity

Despite the irony of the title – electricity was an inevitable next step in the water infrastructure. The basic needs was to get an electric outlet for the pump. However I decided to take it one step further and install additional power outlets that would be available in the fields (so that I wouln’t have to stretch out long extension cords). So I set out to put in power adapters in both the flow junction concrete box and in the pump concrete box.  Though it should have been a straightforward task I did run into a few difficulties and learned a few lessons worth mentioning.

Electric Cable

We purchased a 200 meter roll of three wire cable. I don’t remember the exact specification – but I do remember we chose the one with thicker diameter wires (also more expensive) that were rated for a higher current. I would have wanted to put in more then one supply cable – but the cost was prohibitive.

Much later I learned that there is a 5 wire cable which is usually used for three-phase electric installations. However, I believe it can used as if it were three separate electric cables bound into one. The ground and zero wires are shared and then there are three current supply wires.

I don’t have a specific short-term need for this in mind, however it isn’t every day that you dig a 60 meter long, 1 meter deep trench on your property. So there’s that 🙂

Burying Electric Cable

The cable was buried alongside the water pipe. To protect it we purchased a ribbed plastic tube (2×100 meters length) meant to protect it.

The cable was a perfect fit in the protective tube. As a result, getting the cable into the tube was hard work. Rather then going into the details of how we did it (hint: using a pull-wire and cutting the protective tube into manageable segments) I would suggest getting a more spacious tube. I thought about this when we purchased ours but I thought that a tight fit would offer better protection to the cable. I still think that too large a tube, with too much free space, may collapse under the pressure of the earth and may give out sooner.

Modularity

For the better part of a day I struggled in vain to get the electric-accessories (splitter box and sockets) installed. I wired them together indoors and then headed out to fit them into the concrete walls. Remembers this is work done in a confined underground space. I failed … completely. I couldn’t get is assembled in place.

After a long and mostly fruitless day I realized I had been going about this the hard way. It dawned on me that I could do most of the assembly work inside if I were to simply mount the electric-accessories onto a wood panel and then simply mount that panel on the concretewalls. So, the next day I tried this and it worked like a charm. I predrilled the panels in place and then worked comfortably on them indoors. These are the two panels prepared for installation.

The only electric fitting I had to do underground was to connect the ends of the buried cabled to these boxes. In the image below you can see that I left empty sockets on the left hand side – so all I needed was a screwdriver and a few minutes of work.

Since our electricity infrastructure is outdated and partially improvised this entire supply line is simply plugged into an existing power outlet.

 

Hydro Electric Barrel

In a country like Romania it is not unheard of to live on a property of land that has running water – so we’ve put that on our wishlist. In such cases hydro-electricity can be a very appealing source of electricity (though I have asked myself what would happen in case of freezing). With that in mind have a look at this interesting invention – the hydro-electric-barrel:

3 Steps to Electricity Independence in Romania

Though living off-the-grid is tempting it probably isn’t as ecological as you may think it is. Electricity is an infrastructure that is best provided through collaborative systems instead of independent ones. It is unfortunate that so much of it is generated with an unnecessarily high ecological price – which is good enough reason to want to do it better on your own.

Being off the grid isn’t necessarily a smart financial choice either (at the present) because a completely independent system is still so expensive that it may never really repay itself (taking into consideration your level of consumption and price of grid electricity). Living off-the-grid is morally better but necessarily financially better.

Step 1: On The Grid

There are enough challenges and expenses when building a new house. Getting off-the-grid doesn’t need to be a top priority. If you are building a home and can connect to the grid then consider starting connected to the grid. You can design your home so that eventually it may be completely off-the-grid but you don’t need to implement it right away. You can designate places for photovoltaic panels, for wires, for batteries, converters, etc. but you don’t have to install them right from the start.

If, like us, you are building your own home then you will need a reliable source of electricity during construction. If you don’t have a grid-connection then you may need to bring a generator on site instead.

Step2: Self Generated

The next step, when you are ready for it is to start generating your own electricity. You should start with the natural resource that is most available to you. In the area of Cluj the leading sources are probably sun and water (if you’ve got running water on your property with enough altitude difference to generate the needed flow). If you are living in the mountains you may also have wind power available to you, yet it seems that commercial wind-powered generators are prohibitively expensive. In addition to the generating source (such as solar panels) you will need converters to convert and regulate your source current into 120v so it is compatible with all of your existing appliances.

It’s comfortable to do this while still connected to the grid because your self-generated electricity is backed- by the grid electricity (though you will need a grid-tie system to connect to the grid). If, for example, you rely on solar power then on cloudy days you still have all the power you need from the grid. If you generate more electricity then you consume then there is a good chance that your electric company will buy it from you. So in the end you may still be benefiting from grid-electricity but your bill will be zero or the electric company may pay you.

An efficient electric generating system and a low consumption home can generate a monthly revenue for you – so you may want to consider staying in this configuration and not going off the grid.

Step3: Off The Grid

To go completely off the grid you need to add to your electrical system a battery array. Batteries store energy when it is generated and make it available when it isn’t. If, for example, you rely on solar power then you will need batteries to supply you with electricity during the night when your solar panels are not providing you with electricity. Good batteries (that will work for 20 years) are initially very expensive to install. You may need additional converters to integrate them into your system and you need to be careful and monitor their use when your sources are not generating electricity  (more on that in a separate post).

When you go off the grid you are completely on your own so regardless of any expenses (and potential losses) involved in doing so, make sure you are ready to be on your own (for example, in our house we are planning heating and hot-water systems that can operate at least basically when there is a power-out).