A few years back I was a part of heated discussed in my company about Smart Grid technology. Basically, our company was asked by a government institution in power sector to do all this. I, along-with one of my colleague, were on our way for a survey for a small demo to be presented before some government officials which could show them the “goodies” of Smart Grid. To demonstrate them how it can control billing, have advanced fault indications, energy harvesting, solve our greatest issue the energy theft and other features.
We spent days selecting the platform for demo as well as for long-term production. We prepared a list of several vendors offering solutions of smart meters. Suddenly the whole project got frozen due to lack of interest from the government agency. All our efforts were in vain. We, as a private company, could not invest resources in something which did not seem fruitful, at least for the time being.
Smart Grid is sum of big projects, it means revolution. It includes not just monitoring but control as well. Huge support and funding is required from government to execute it. It is government who can regulate laws, impose them and come up with solution with the help of private industry. This left me with impression that what if the government is not interested at all in upgrading this 18th century power distribution system and do we have any choice in that case? I think that at least there is something which we can do. At least we can regulate our personal usage. So, exactly what can we do?
Following diagram shows a simple power management system of a small house. It has two power sources, 1 the main supply from the grid, the other from solar cells. The main component of this system is the charging and inverter unit. It can accept 220VAC from mains as well as around 37VDC volts from solar panel. A 24VDC battery set which is very common is used to store energy. This kind of arrangement is called off-grid solar power because it does not feed back into the grid. Off-course, we can not feed power into local grid without government permission. Infact in some countries, a prior permission may be needed for off-grid solar system as well. So you need to check that before investing in this adventure.
The above is rather a very conventional way of integrating the solar system into an existing power backup system which already uses a UPS. Our solar power system, basically, is a solar panel. We, ideally, charge the existing batteries of UPS from the electricity generated by this solar panel. We can add a switching scheme (Intelligent Power Switch) which intelligently disables the power from grid if we have enough power from solar panel. The Watt meters basically tell us how much power is obtained from which source. We can then compare it which the consumed power which is measured by a smart energy meter. We can optimize the system to use maximum power from solar panel.
How to calculate the solar panel, charger requirements etc.? I have attached a simple excel sheet which calculates these parameters as per load.
One of the practices to increase efficiency is to use DC equipment instead of AC. Though this does not seem practical but it is possible if you are building a new house and the load like lights and fans can easily be used with DC as power source.
Where to get the smart meters? They must be expansive. Not at all! Smart meters are conventional meter, digital mostly these days, with some sort of connectivity option(s). At least they have RS485 connectivity available. Some advanced meters have Zigbee options as well. For a small home RS485 connectivity is enough. You can, then, interface it with normal PC to log the data and see results as much as desired. The price range of a smart meter with an average feature set is somewhere from 40$-150$ largely depends upon brand and functionality.
In a nut shell it is possible that we monitor, manage and control our power consumption without government initiative and make best use of our ever depleting resources of planet earth. Are you ready to take initiative?