wind turbine

More photos of energy solutions

A Nature restoration project shall use small non-invasive and Nature-friendly sources of energy:

- Avoid use of new dams hydropower - kills lots of fish and other freshwater creatures and plants. Transmission lines are deadly for birds and bats.

- Avoid use of high or large wind turbines - kill millions of birds and bats every year. Animals and birds avoid sites disturbed by wind turbines, there are average 50% less wildlife in disturbed sites.

Wind turbines kill up to 39 million birds a year!.pdf

Wind energy is tough on bats.pdf

- Large solar farms seriously harm wildlife:

Effects of Solar Power Farms on the Environment.pdf

Solar Farms Threaten Birds.pdf

Just paint a wind turbine blade to save birds and bats

“Sustainable” solutions derived from climate policies are quite often not Nature- or wildlife-friendly, they are environment-friendly.  Independent small sources are not subject to effects in cascades,

are interchangeable and therefore less affected by climate change.

Renewable energy in Pichimahuida.

Pichimahuida is located at 46°43'32.99"S  72°56'47.65"W.  Weather systems arrive from the Pacific Ocean virtually un-modified by the Northern Ice Field immediately to the west.

When we arrived in 2006, there was no electricity. The old house that was there was heated by a wood stove. There was a gas light in the main room, but no other rooms had lighting. There was no connection to the regional electricity grid.

In 2006, supplies and expertise for installing renewable energy on a domestic scale was unknown in the region. There had been small hydro-electric installations to support small communities, but they had generally been closed as the grid expanded through the region.  There were a few companies based in Santiago and Concepción that were starting to supply equipment, but they were extremely expensive. We finally (in about 2009) found a company in Concepción that was starting to supply solar panels and wind turbines.

And so we developed our systems ourselves, based on experience from Australia, a lot of reading, and with help from an engineer/supplier in Switzerland. There are two separate energy systems– one for the main house guest house and garage, and the other for the old house and a renovated adobe house that are in a separate location.

The first step was the estimate of energy need. This had two components – daily load, and peak load.

Daily load is just that – the amount of electricity that is needed during a day. This is basically done by identifying all the appliances that use electricity, noting their power use (in watts), the length of time is use, making an allowance for efficiency, and entering that information into a spread-sheet.

Peak load is the maximum energy demand at any moment – ie, when multiple appliances are being used at the same time.  This is especially important with appliances such as refrigerators and washing machines – or any appliance with a motor – as “start demand” can be 300% of rated power.

The daily load is used to calculate the amount of energy that the system has to produce for each day. The peak load is used to calculate the capacity of the delivery of electricity.

System #1

The first decision was that of the location for the main house – this was not as easy as it sounds. The aspect of the property is to the north, and hence there was the opportunity for solar power.  But, at that latitude the winter day length is insufficient to generate enough power, and we preferred to minimise the use of generators.  And so, there was a need to supplement solar generation. The options were wind or water.  In this location, there is not a lot of wind in winter, but there is water.  And so, the final location was based on ease of vehicle access, but more importantly, access to water – water for the houses, and water for power. 

In our case, the very small streams from which we take water are approximately 150 metres higher and 1 km away.  The water is initially filtered through a course mesh to remove leaves, seeds and other debris. The water from the bigger of streams is then passed through a tank where sediment settles. The pipe that brings the water approximately 850 metres to a small tank on the terrace above the house is 90 mm low pressure.  A small secondary source, about 200 metres from the main source, is connected to the main line.  A 75 mm high pressure pipe connects the small tank to the turbine.  The vertical drop in the last 150 metres is about 65 metres.  After passing through the turbine, the water is returned via low pressure pipe to the natural water system.

pico hydro

The energy that can be produced using water is according the formula:

E(watts)=9.81 x H (metres) x vol (l/sec) x efficiency

The 9.81 is the gravitational acceleration in m/s2. For much of the year, the volume/sec is between 1l/sec and 3 l/sec. Efficiency of the turbine is probably about 80%. Hence, the theoretical maximum energy production could be 1,500 watts, but for most of the year it would be less than 1,000 watts.  We bought a 1.1Kw turbine in Europe as we could not source small volume or “pico-turbines” in Chile at that time.  The supply of water to the turbine by a valve that is controlled electronically to open only when energy is needed – ie, the turbine does not operate all the time.

At our latitude, the daily maximum performance of solar panels is approximately 7 times rated panel output in summer, and 1.5 times rated panel output in winter.  Initially we could access only 130 watt panels, and we purchased five panels that we mounted on wooden frames. The angle of the panels was adjustable from 25 to 78 degrees in order to optimise performance throughout the year.  Subsequently, we increased the number of panels to 15, and connected them in three groups of five.  After some problems with the wooden frames warping, we transferred the panels to purpose built aluminium frames.

solar panels

Both the solar panels and the pico-turbine supply their energy to a battery bank via MPPT controllers that optimise the charging of the batteries.  The controllers are programmed to give preference to energy from the solar panels – ie, if there is a demand for energy, and the batteries cannot supply it, the controllers check first whether there is the potential for energy from solar panels, and if the solar panels can meet the demand, the valve for the turbine is not opened.

Estimating the size of the battery bank was difficult, and initially we underestimated the number of batteries with the consequence that there were periods when there was not enough energy, and we had to use the backup generator.  We now have eighteen 12 volt 230 Amp-hr gel batteries configured as 24 volt.

A 3.5kW inverter converts the 24 volt DC supply to the 220 volt AC that supplies the houses etc.

System #2

The system for the other houses is based on solar panels and wind. The solar panel installation followed a similar path as that for the main house.

Access to water for power generation was not an option in this location. However, the shape of the trees demonstrated that wind could be an option. 

We bought a Chinese brand 1kW turbine kit that was supplied with everything, eg 6 metre pole, tensioning cables, ground anchors, controller. We added three metres to the pole, and installed additional tensioning because of the wind strength.  Mounting the 78 kg turbine at the top of a 9 metre pole was an interesting exercise.  The turbine is controlled electronically in order to protect it when the wind speed is excessive, and to stop it spinning when there is no energy demand.

As with the system for the main house, the energy from the solar panels and the wind turbine supplies a battery bank via MPPT controllers that optimise charging, and the controllers give preference to energy from the solar panels. The battery bank is comprised of six 12 volt 230 Amp-hr configured for 24 volts. A 1.5kW inverter converts the 24 volt DC to 220 volt AC for the houses.

Lessons learned:

There are many lessons, some of which are specific to the location, but others are

more generic.

Water supply:  initially, the pipe from the stream to the turbine was continuous, ie there was not the tank at the point where the water drops to the turbine. The consequence was that, when the turbine was working there was water flowing at high velocity through the pipe. But when the valve at the turbine closed (albeit very slowly) the water had too much kinetic energy that could not be dissipated and the pipe separated. The solution was to install a small tank, and to allow the water to flow continuously to that tank. When the turbine works, the water flows to the turbine. But when the turbine is not working, the water returns to nature via a by-pass. A very simple solution.

Batteries:  it is easy to underestimate the number of batteries needed for energy storage.  But the problem is that it is not good practice (ie, it shortens the life of the batteries) to empty the battery. It is best to only use the top 20-30% of the battery charge. And adding batteries later does not work, as a battery bank is like a chain – only as strong as its weakest link.  Hence, if there are weak batteries in the system, they will drag down the other batteries. It is best to remove weak batteries completely.

Another issue with batteries is how they are configured in the bank.  The current should not pass through more than three batteries to avoid creating an imbalance between the batteries.

Maintenance:  it is important to check all connections regularly, especially those that carry high current (eg, the connections to the batteries). The connections can work loose, as a result of the intermittent high current (ie, heating and cooling leads to expansion and contraction).  Sparking can then occur across the terminals, and that can lead to fire or melting of terminals.

Location of the energy system:  it might seem obvious, but it is important to locate the system somewhere with easy access.  Batteries are heavy (a 230 A-hr battery weighs more than 60kg).

Educating users:  people who are accustomed to a connection to the grid do not necessarily think about the amount of energy that appliances use – even a phone charger plugged in for 24 hours can use 300 watts a day.  Turning off lights and unplugging chargers save significant energy.  Also, people have to understand the limitations of remote energy systems – eg, a 2Kw microwave or electric water jug are not an option.

Back-up generators:  there will be times when there is no water, no wind, and no sun, and the battery storage is inadequate. At those times, a generator will be necessary.  It is important that the usual system for supplying the electricity (especially the inverter) is protected.  If the generator is supplying 220 volts AC direct to the houses, the connection to the generator must be made so that that the inverter is isolated – eg, that current cannot flow backwards to the inverter.  Most inverters cannot cope with a 220 volt input, and burn out.  Inverters are expensive, and so an isolation switch is essential.

220 volt electrical installation:  the 220 volt electrical installation from the inverters to the houses, and within the houses, was undertaken by local electricians.  In a remote location such as ours, it is important to oversee carefully such work, as inappropriate technique can have consequences.