Clean Energy Solutions for a Renewable Future
As I watched President Obama brilliantly deliver his State of the Union address last night, I was proud to be in a country which has a leader motivated on tackling the important issues which drive us here at UGE. Finally, a powerful politician who is passionate about making a difference, with a vision and a plan to implement these changes in the real world. What a relief! President Obama did, however, focus mainly on renewable (and cleaner non-renewable) energy sources. What of the two other keys to the clean energy solution which need to be developed? I speak of course of the ‘holy grails’ of clean energy: energy efficiency and energy storage. Both are as important, if not more important than the source of the energy itself.
At present, new-build renewable energy systems are still more expensive than existing power infrastructure. So what’s the point of building a renewable energy system to power an energy inefficient load? The renewable system would need to be oversized and more expensive than it needs to be. Improving the efficiency of a load system, especially in the distributed grid-tied and off-grid markets is relatively easy and could lead to more sales. For domestic systems, the largest loads are often HVAC (heating ventilation and air conditioning) and refrigeration. One option for analysing a total system is to include the cost of more efficient appliances in the ROI calculations for a site since modern appliances are remarkably more energy efficient than those even ten years old. Another area for improvement in energy efficiency is lighting. CFLs (compact fluorescent lights) use around 80% less energy than incandescent lights and LEDs are even more efficient than CFLs. UGE has even taken this technology to heart and is in the process of replacing all the fluorescent bulbs in the New York office to LEDs! Other energy efficiency opportunities lie in technologies such as motion sensing light switches which ensure that lights are only on when they are needed.
Perhaps the best energy efficiency technology, though, is common sense. For domestic systems, we need to educate people on how much of a difference behavioural changes can make such as setting your thermostat range slightly lower, hanging your clothes out to dry in the summer rather than throwing them straight in the dryer and so on. These changes are almost mandatory for those with backed-up off-grid systems. When there is no grid and your whole house is running on battery power you quickly decide that keeping the refrigerator running is more important than the clothes dryer.
And so we arrive at energy storage. Since renewable energy systems can only generate power when the wind/ sun/ waves etc are available, and we want to be able to log onto Facebook even when there is no energy being generated, we need to be able to store the excess energy generated at peak times. At present we have batteries, albeit of differing types but they are all plagued by the same problems. Namely they are expensive, heavy, they lose their efficiency over time and they use toxic chemicals. To be able to store energy in a reliable, cheap, sustainable and efficient way would put us much closer to the clean energy solution we need. No technology has been proven to meet these demands yet but there are some very promising technologies being developed, many of them very simple (in theory). SustainX is a firm developing energy storage technology in the form of isothermal compressed air. Basically, there is a big tank which they fill with air at high pressure from a compressor run by some energy source (preferably renewable). When energy is needed again, the compressed air is run back through a turbine to generate energy. Efficiencies of these types of system can reach up to 70% which is not only better than most batteries, these systems (with regular maintenance) do not lose their effectiveness over time.
One other promising technology lies in large flywheels. These heavy masses rest on ultra low friction bearings such as maglev (magnetic levitation) bearings and are given angular momentum by a motor. When the power is no longer being generated the angular momentum in the flywheel continues its rotation and when energy is needed, the flywheel is connected to a generator with conversion efficiencies up to 90% .
As awareness for the need for renewable energy systems increases, so too will the understanding of energy in general. With greater awareness for energy will come greater investment in renewable energy, energy efficiency and energy storage. We are already seeing some of this and with motivated leaders passionate about changing the energy world for the better, the future looks very bright indeed.
-Darius Salgo, Engineering