THURSDAY, FEB 2, 2023: NOTE TO FILE
Module 4-6
Sustainable Energy Alternatives
This section takes a look at some good examples wherein communities are establishing energy independence or part thereof from a national centralised system. One of the important principles in this approach is an Integrated Energy System (IES) which has diversified its energy sources instead of being dependent solely on one source, thereby reducing risk of energy shortages and simultaneously establishing a more resilient energy system. Nevertheless, even one renewable energy source can provide some resilience against an erratic central supply. Some community-based examples are explored below.
6.1. Eigg Electric
Eigg Electric is an island-based, community owned, managed and maintained company which provides electricity for all island residents from the renewable sources of water, sun, and wind, as shown in the short video below(6 mins)
https://www.youtube.com/watch?v=HMCgSf-QSKo
The system consists of three hydroelectric generators a group of four small wind generators and an array of solar electric panels sited at different locations around the island as determined by optimum availability of resource. The hydroelectric capacity is approximately 110kW, the maximum output of the wind farm is 24kW and the solar electric panels can produce up to 50kW. The total generating capacity of the whole system is approximately 184kW. Although the capacity of the scheme is around 184kW, not all renewable resources produce their maximum output all the time or at the same time. However, by having a balanced scheme of all three, one can maximise the available renewable resources and ensure there’s enough to provide all or most of the island’s electricity needs. Renewable sources have provided around 95% of our electricity since the scheme was first switched on in 2008. The remaining 5% is generated by two 80kW diesel generators to provide back up when renewable resources are low or during maintenance.
 Eigg Electric, an Integrated Energy System of 184kW |
 Four small 6kW wind turbines below An Sgùrr |
 50kW Photovoltaic |
 The biggest hydro above at Laig on the west side of the island is 100kW, with two smaller 5-6kW hydros on the east side |
6.2. Cloughjordan Ecovillage
The system effective technology. It is a sustainable model for developers and town councils to follow. See the video below.
https://www.youtube.com/watch?time_continue=1&v=46q6zS0kamk&feature=emb_title
Each house has a hot water storage tank that distributes heat throughout the day. See the video below.
https://www.youtube.com/watch?time_continue=2&v=eMJy177oAzQ&feature=emb_title
6.3. Parabolic solar cookers
In November 2003, the Barefoot College created the Society of Women Barefoot Solar Cooker Engineers in Tilonia, Rajasthan. It is the first association of illiterate and semi-literate women who fabricate, install and maintain parabolic solar cookers in their homes. The parabolic solar cooker is constructed from 300 mirrors that reflect the sun’s rays onto the bottom of a cooking pot to cook food quickly and sustainably. Women who once spent long hours searching for firewood can spend their time on other productive activities. Communities with solar cookers can expand their livelihood opportunities and limit the negative effects of deforestation and pollution. See video below (7 mins):
https://www.youtube.com/watch?v=0Zh4FjMJ9XU
https://www.barefootcollege.org/solution/solar/
4,020 grams of harmful carbon emissions avoided by replacing kerosene with solar as a source of clean energy for light, heat and cooking
6.4. Energy Autonomy for Tamera Ecovillage
The Tamera Ecovillage in Portugal is thriving at the cutting edge of innovative models of sustainability. One such aspect is its energy autonomy which harvests the abundant solar energy in the south of Portugal.
The SunPulse Water is a solar water pump with a low-temperature Stirling Engine, running on sunlight, using air as its working fluid. It uses zero fossil fuel and creates zero emissions, and is a “stand-alone” system. With an output hydraulic power of 300W it’s ideal for decentralised water provisioning without any additional infrastructure. See the video below (7mins).
https://www.youtube.com/watch?v=iSoXWt4hBpc
The roof holds Fresnel concentrators which heat up a series of pipes containing vegetable oil. This circulated in a closed system and was stored in a tank, which retained the heat day and night, and the heated oil powered a kitchen for around 50 people. The hot oil flowed through double-walled cooking pots, so that the heat could be directly used for cooking. The hot oil also drove a low-temperature Stirling motor, the SunPulse Electric, which can produce 1.5 kW.
6.5. Compost Heater
Jean Pain was a pioneer of the Compost Heater, or Biomeiler as he called it, which harvests the heat generated from a composting process to warm a house and to provide hot water, as well as, to warm a greenhouse during winter. This system requires a relatively large compost heap that is intertwined with a spiral water hose, which acts as a heat-exchanger as it transfers the heat from the decomposing compost to the water pipes, thereby heating the water - see short video (2 mins) below.
https://www.youtube.com/watch?v=b4xnfmbysvg
This system is aerobic because the cross-section of the compost heap is not more than 1,5m2 in cross-section at any point, otherwise any larger size attracts an undesirably odious anaerobic process as areas in the compost heap are starved of oxygen. However, the Jean Pain method has pushed the envelope size of this compost heap by using woodchips which do allow aerobic composting to relatively larger size compost heaps as seen in this short video (3 mins).
https://www.youtube.com/watch?v=oYo-TLiE694
Although this basic system has become fairly well known, Jean Pain also had a more complex version which also generated biogas from the methane gas emitted from relatively larger compost heaps that gave rise to anaerobic composting processes.
Module 4, lesson 7
