Last update: 01-Aug-2014 10:06 am
Friday, August 01, 2014
Trinidad & Tobago Guardian Online
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Solar energy versus energy conservation
One issue to be addressed in any energy policy is the priority given to renewable energy usage in relation to a programme of energy conservation. Wind energy and both solar photovoltaic and thermal technologies are commercially available and thus these will be considered as opposed to ocean-based technologies whose usage is not as widespread or as established.
So the essential question would be this: Would the domestic consumer be better off, financially that is, by embarking on a programme of energy conservation to reduce electricity usage before considering investing in renewable technologies? In T&T, the vast majority of households with hot water use electric water heaters of both the storage and on-demand types.
The latter is significantly cheaper and also uses less electricity and hence is far more cost effective and has been steadily gaining in popularity. It represents an application of energy conservation. Solar water heaters do not use electricity but represent a significant capital cost—some two to four times that of a standard 40-gallon electric heater.
So unless there is a tax incentive or one is environmentally motivated, the solar water heater business would face an uphill climb. This, of course, presupposes that we are not faced with a drastic increase in electricity rates! Energy conservation involves using control strategies, which can be manual or automatic, coupled with smart equipment buying choices. It can be of the active type or the passive type.
An example of an active energy conservation technology is home automation which includes the use of intelligent devices and the associated control circuitry. Such a system may include motion sensors to detect motion to put on or put off lights. Such systems can be extended to the cooling system. So if one were to walk into the study, the lights and air conditioning unit would come on. The reverse would occur upon leaving the room. In this way, energy usage is minimised.
Solar photovoltaic systems coupled with the efficient and long lasting LED (light emitting diodes) lights can provide a technically feasible alternative especially for security lighting which can be run as a stand-alone DC (direct current) system. The cost to provide solar-generated electricity for the entire household is quite high and iscurrently not feasible.
The use of air conditioning units in the residential sector has really exploded and the resulting cooling costs constitute a major chunk of the electric bill. Thus it would make sense to look at reducing this cost. Solar cooling is not a cost effective option and hence the use of energy conservation technologies should be considered for they can really make a significant dent on the cooling requirements.
The use of insulating and reflecting blankets under galvanise roofs mitigates the heating up of the house and is a good practice that should be encouraged. Paints, especially for western facing walls, should be carefully chosen. Some of them are good absorbers of solar energy and are useful in the northern climates but not in the tropics. The planting of trees on the western side of one’s property can provide shade with the subsequent reduction in cooling load.
A significant proportion of the cooling load is attributable to the thermal mass of the brick and mortar walls used here. This type of construction is not ideal when it comes to cooling and hence should be examined from the standpoint of energy conservation.
The funding of R&D efforts in this area can lead to new construction material and practices. It should be aggressively pursued for it can, like renewable energy, contribute to the energy solutions of the future.