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By Dennis Posadas While I appreciate the enthusiasm that groups like Greenpeace and WWF about enabling as much clean/renewable energy as we can put into the system, given that we have a new renewable energy law, there are also a few mindset changes we need to put into place. I am all for renewable energy; however, as a trained engineer, I also realize that there are some hurdles that need to be overcome. First is, some renewable energy sources, like solar and wind, while abundant, are also intermittent. The sun doesn’t always shine, and the wind doesn’t always blow. On the other hand, cogeneration and biomass plants, which are clean sources, can be stable if enough heat or biomass material is forecast and planned. For solar and wind, if we want to use it for 24x7 use, we need to make sure that there is an energy storage mechanism of some type. The most common energy storage device is of course a battery. For bigger solar and wind systems, running in the megawatt range, batteries would have to be connected together, so it probably won’t be practical. Concentrated Solar Plants (CSPs) that employ banks of mirrors in the desert use some type of liquid like molten salt. Another possibility is to use pumped storage, like in Lake Caliraya. When power is available, it is used to pump water up an elevated lake. During nighttime, the lake water can be released to drive a generating turbine. Other schemes involve compressed air (in the US), or as in the case of some wind systems, natural gas turbines. But for many systems, the storage technique they employ is to simply connect the renewable energy system to the grid. Now as we increase the percentage of renewable energy systems that connect directly to the grid, we have to remember again that these are intermittent. You can’t exactly tell the sun to shine exactly at 6:00am, or the wind to start blowing at 9:00pm. So there has to be a way to prevent blowups of circuit breakers or fuses, a way to plan when each energy source will come on stream. There is a role for software and intelligent grid systems that work with meteorological information to determine that there is a high/low likelihood that the wind/sun will be available at a certain time. The grid itself, and components will have to be redesigned to take into account the higher occurrence of intermittent turn-on and turn-off of power sources, many of them being renewable. Appliances may need to have chips in them, telling them that the power at a given hour is mostly coming from renewable sources, or not. Meralco’s plan, for example, to offer Internet over broadband lines, is indicative of this. The common perception is that they plan to mainly utilize this to offer broadband services to the public through their power lines. Actually, it is not as simple as that. The Internet over power lines can also be used to command and control equipment, such as chillers in malls, to turn on or to idle at a certain time. The grid needs to be intelligent, to handle the intermittent nature of clean/renewable energy systems. There will be a lot of new capabilities, already being experienced in places like California and Europe, that we will soon have here. Our electric meters (“kontadors”) for example, will run backwards and forwards. So if we decide to install solar panels or wind turbines on our roofs, not only can we be consumers, we can also be mini power producers supplying to Meralco. The amount we sold, is then subtracted from the amount we consumed. The more citizens and private industry, as well as government, invest in these mini and private renewable energy systems, the less need there will be for big, and often carbon emitting power plants. In other words, power generation will be decentralized to many small renewable power producers, as opposed to a few large ones. Now who will pay for that? Some cities in the US consider solar panels as part of the house (roof) and allow citizens to simply add a little extra to their real estate tax, and amortize the solar panels over 25 years. The payment can actually be taken from the savings generated by the panels, so in effect a no-cash out scheme is feasible. Are we ready for that? We all want reduced carbon emissions. But we don’t get there by simply joining token Earth Hour or Earth Day celebrations. We also need to do some work, and take the time to educate ourselves. ___________________________________________________________ Dennis Posadas is the editor of Cleantech Asia Online, and the author of Jump Start: A Technopreneurship Fable (Singapore: Pearson Prentice Hall, 2009)