What is Wood Energy
Wood energy can be generated from:
- industrial wood wastes
- forest residues
- energy crops
Wood wastes
Wood wastes are by-products from wood processing industries e.g. chips, bark and sawdust. These residues are used in boardmills as feedstocks for production and within sawmills and boardmills to provide heat for drying or space heating and to produce steam for the manufacturing process.
Forest residues
Forest residues consist of the tree tops and branches remaining after timber is harvested. Some forest residues need to be left on the forest floor to decompose and return nutrients to the soil. These can act as brash mats, which allow machinery to travel across soft ground. However, much of this material could be harvested with suitable machinery and used as a renewable fuel for energy production.
Energy Crops
Energy Crops are grown specifically for energy purposes. Short Rotation Forestry (SRF) is the production of wood fuel from trees with high juvenile growth, which are planted at close spacing and harvested on short rotations (typically every three years).
Species such as Willow are ideal for SRF, as they are easy to establish, fast growing and suitable for a variety of sites and resistant to pests and disease.
Land for short rotation forestry is likely to come from non-rotational arable set aside land and land that is not in arable use , ie. beef or sheep production.
Wood Pellets and Wood Chips
Wood pellets are made from wood shavings and sawdust. They are used in highly efficient and convenient automatic wood boilers. Wood pellets burn so effectively because they have a low moisture and ash content.
Wood pellets are compact and easy to store. Typically they come in bags, but they can also be delivered in bulk by truck. Wood pellets can be ordered from local fuel merchants, and wood pellet stoves and boilers are now available in Ireland.
What is Solar Energy?
Solar energy is the mother of most renewable energies on earth. The sun powers natural cycles on earth like the wind, water flow and plant growth.
But the sun is also such a reliable source of heat and light that we sometimes take it for granted. Generations have used glass and other materials and structures to capture and magnify the sun’s energy and these systems have gradually evolved to form the basis of mature techniques that are used today to harness solar energy.
There are 3 basic approaches used today to gain maximum benefit of solar energy in buildings:
Passive Solar
Active Solar Heating
Solar Photovoltaic (PV) Systems
Passive Solar
Passive Solar Architecture is a building design approach which seeks to:
- maximize solar gains in the building (through good orientation and layout, and glazing);
- avoid heat losses through ensuring a high level of insulation and air-tightness of the building;
- ensure a high degree of comfort by using controlled ventilation and daylighting.
Anyone building a new house or refurbishing extensively an existing house should apply passive solar principles, and reduce their heating requirement by up to 80% at no or little extra-cost.
Today, the most advance form of passive solar design has been translated into the Passive House standard. For more information, go to http://www.passiv.de/.
Download Passive Solar Design – Solar Homes Catch the Sun
Download A Buyers’ Guide to Low Energy and Passive Houses
Active Solar Heating
Active Solar Heating is one of the primary ways for buildings to use solar energy. This technology uses solar collectors to transform sunlight into heat to provide space and/or water heating. Solar water heating is the most common application of active solar thermal in Europe. A correctly sized solar water heating system can cover 50-60% of your hot water heating requirement with free solar energy.
A solar thermal system providing space and water heating is generally referred to as a solar combisystem. It is generally sized to cover 30 to 40% of the annual heating requirement of a house in Northern Europe. In Ireland, a solar combisystem using air as a heat transfer medium is gaining in popularity. It has the advantage of combining solar heating and ventilation through the same system. It is particularly suitable for low-energy houses.
By 2005, over 3,000 households used a solar heating system in Ireland, compared to about 5 million households in Europe.
Download SEI REIO’s Solar Water Heaters leaflet
Download A Buyers’ Guide to Solar Heating Systems
Solar Photovoltaic (PV) Systems
‘Photovoltaic’ means electricity from light. In essence, photovoltaic systems use daylight (not necessarily direct sunlight) to convert solar radiation into electricity. The light which shines on the PV cells creates an electric field causing electricity to flow. The greater the intensity of the light, the greater the flow of electricity.
Photovoltaic systems use semiconductor materials to convert solar energy into electricity. This technology is widely used in consumer products such as solar calculators, watches or garden lights, and is increasingly used as a cost-effective solution in Ireland for stand-alone applications where a grid connection is too expensive (e.g. parking meters, caravans or remote holiday homes).
Solar PV can also be used to provide free solar electricity to houses as well as for commercial and industrial applications. Recent developments in regulation mean that it will shortly be possible to connect solar PV systems to the grid, opening up a new era for solar PV in Ireland.
With ever increasing demand for water, limited space available for new reservoirs and over-stressed distribution systems,
the need for an increase in small scale, local water storage and better water management becomes ever more compelling.
Each person in Ireland uses approx 150 litres of water per day.
On average 35% of this is used for flushing toilets and 15% for washing clothes, cars and watering the garden.
Not a drop of this need be of drinking water quality !
Rainwater Harvesting
is the collection and use of rain which falls on building roofs and would otherwise go straight to the drainage system. After filtration and settlement such clarified’ water is suitable for a variety of purposes, from irrigation for lawns, plants and vegetables, as a supply for domestic washing machines, car and other washing facilities and for flushing toilets.
A simple system for garden use that is not be connected to the mains supply can be used all year round regardless of drought warnings. Domestic supply systems would normally be connected to the mains system and incorporate filters controls to supply back to the house. It is important to balance the rainwater you expect to collect against your rate of use so you should talk to your supplier about sizing a suitable system for your project. Storage tanks are large and require to be installed to regulations, hence installing the tank can account for 2/3 of the overall cost. If the water is to be used in the home or office it must be clearly identified as recycled water and piped separate from the mains supply so that clean, potable mains water cannot become contaminated.
It is a legal requirement that systems be installed in accordance with current water regulations hence we only work with trained & qualified installers. Whilst it is possible to filter water to very high quality and treat with UV light to kill bacteria, the product illustrated will not provide this and we would not recommend that recycled water be used for personal washing or culinary purposes.
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The rainwater is filtered by the collecting unit which excludes leaf debris and other large particles.
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The second stage is settlement in the tank. The heavy particles sink to the bottom and lighter organic matter floats on top. The heavier particles accumulate at around 1 to 2 mm per year to form a beneficial biological layer.
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The overflow unit is designed to skim floating particles from the surface when the tank overflows.
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Water is extracted from the cleanest part of the tank, just below the surface, using a floating filter.
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Water quality is maintained by the removal of organic matter and by the action of incoming water which introduces oxygen to prevent it become malodorous when stored for long periods.
