Want to go Green? Reuse Powerline infrastructure and get there fast
This article explains how the existing Powerline infrastructure can be leveraged to deploy green technologies faster, across a wider range of applications, and at a lower cost. Three case studies are examined to illustrate the key elements of how Powerline technology provides a powerful yet inexpensive way of connecting the world to enable higher energy efficiency.
The Green movement focuses on how various communications technologies can be used to provide a powerful yet inexpensive way of interconnecting the world to enable higher energy efficiency across the entire range of electronic applications. Beyond enabling significant economic savings through reduced power consumption, the Green movement is being called upon to reduce our reliance on imports. This article is not to debate the merits of this strategy – enough has been said on this topic and more.
However, if you are an engineer who cares about, or are working on, three of the most important Green technologies of our lifetime – Smart Grid, Solar, and LED Lighting – the ability to reuse the existing powerline communications (PLC) infrastructure is an essential element for adding intelligence to applications based on these technologies.
The critical message is that connectivity is the basis for advanced control and intelligence in devices as it can enable operational and maintenance strategies that result in substantial energy saving. Knowing where, when, and how energy is being consumed gives humans and computer algorithms the information they need to make efficiency decisions.
Smart Grid means different things to a lot of people. One definition is a grid of interconnected energy generation (coal, hydroelectric, solar, wind, and fuel cell), energy transmission (powerlines and transformers), energy storage (batteries), and energy consumption (appliances) nodes. Smarter refers to the addition of intelligence, or decision making power that makes generation, transmission, storage and consumption decisions using real-time information about where energy is coming from and where it is going. Marco-level intelligence already exists in our grid today–that’s how utilities are able to balance power supply and demand. However, the grid intelligence that served us well over decades is no longer adequate for the future because of the exploding numbers of energy generation, storage and consumption nodes.
For instance, as more residences add solar panels on their roofs and begin pumping energy back into the grid, managing supply and demand parity becomes a tougher challenge to resolve. On the consumption side, as more electric cars that ran on batteries hit the roads, this creates a need for many more energy storage nodes on the grid.
To ensure that the grid continues to work in harmony, we need information on what is being produced, stored and consumed, and where. Once this information is available, computer algorithms can take over to affect the necessary tradeoffs to ensure harmony and availability across the grid. To achieve this, the grid needs to be able to exchange information at the micro-level for each node attached to the grid. In this case, Italy has shown the way. Today, Italy has the world’s largest smart grid implementation of energy meters that communicate data over the powerline infrastructure.
Europeans are also taking the lead in providing the next-generation of micro-level Smart Grid implementations. Such startups as TekPea are working closely with European utilities to design and deploy Smart Grid units in homes that measure and communicate energy usage information using PLC. The hope is that end-consumers will care enough about their energy consumption and the creation of an in-home smart grid can to get involved in the Green revolution. In addition to meeting ecological goals, consumers will have economic incentives as well.
Initially, those consumers who adopt smart-grid technology will save money based on their ability to reduce or rethink their power consumption. In later stages of the revolution, the balance will shift. At that time, those who do not have smart grid technology will pay a significant premium by being unable to intelligently manage their power consumption based on power availability and dynamic pricing tiers.
For example, electricity is more expensive during peak hours (typically mid-day) and cheaper at other times (for example, midnight when the least number of consumers require power). In addition, the in-home smart grid would also work as a home automation system allowing consumers to not only remotely control devices and appliances but also measure a family’s energy consumption as well. “Green guilt,” as it has been put, will save consumers money. Alternatively, such inherent smartness could alert utilities of expected changes in loads and patterns.
In growing economies such as India and China, smart grid is not a fancy buzzword. Through need and government mandate, it is an imperative. The energy demand in these economies outpaces supply. From this perspective, each watt hour of energy saved is one more unit of energy that can be redirected towards growth.
The latest buzzword in solar energy is Micro-inverters. Micro-inverters perform DC-AC conversion at each solar panel. Instead of trunking all of the DC power produced by solar panels to a single, large DC-AC converter, micro-inverters can be attached to every solar panel to feed usable AC power to a home or the power grid. Since every panel has its own inverter and, since the conversion is controlled at a panel level, the system has much better over-all performance and power efficiency when compared to traditional central inverter schemes.
Micro-inverters make perfect sense in roof-top installations because they also simplify wiring while taking up the minimal space. The tradeoff is that monitoring many micro-inverters instead of a single string inverter can be an issue on a roof-top. For example, when a micro-inverter stops working, how does the consumer or technician know which one to repair? Similarly, if the system is not performing to capacity for some reason, there needs to be a way to remotely diagnose the problem quickly and accurately.
Given that the micro-inverters and the solar panels are connected together on the powerline, power line communication (PLC) stands out as the most readily available communications link with its simplicity and elegance to provide connectivity. Since PLC uses existing power line cables, it avoids the need for additional wiring, resulting in material, installation, and operational cost savings. These factors are critical in keeping the price and power drain of implementing viable renewable energy solutions. The central hub aggregates diagnostic data and power measurements from all panels and displays it in a way an end-consumer can understand.
In massive industrial installations as well, it makes sense to utilize a communication link to enable remote monitoring of each micro-inverter. The simple reason is that, since the power is being sold to a grid, money is being lost for every minute a panel is not performing at its best. Continuous monitoring can maximize an installation’s returns, and PLC can make the communication subsystem simple and inexpensive to implement while significantly increasing efficiency and reliability.
LED lamps and bulbs are much more power efficient than incandescent lamps and do not contain harmful mercury present in CFLs (compact florescent lamps). LED lamps also last much longer than incandescent and florescent lamps. LED lamps are expensive for the average end-consumer today but currently make financial sense in commercial installations. In the long run, commercial LED lamp installations not only make their money back through saved energy costs, they also result in operational and maintenance savings by needing to be replaced much less frequently, thus lowering labor and replacement bulb expenses as well. LED lamps are expected to become much less expensive as economies of scale kick in.
To compete with CFLs, LED lamps offer two key differentiating features – dimming that works and color. Color changing LED lamps are the next wave in lighting. These lamps can provide classy mood lights or simple warm-white to cool-white colors in the same lamp.
Most of the LED lamps available today are of the retrofit type as they fit into the standard sockets used for incandescent and florescent lamps. Dimmable LED lamps are compatible with almost every dimmer on the market today. However, with the existing lighting infrastructure, fitting color changing LED lamps can be a bit of a challenge as there is no existing mechanism which consumers can use to indicate which color they want the LED bulb to take.
The best answer in this case is, again, PLC. Imagine being able to fit one control box in a house wherever the home owner wants it (e.g. in any power socket) and being able to control each and every LED lamp in the house remotely over the powerline. With such an infrastructures, consumers would not only be able to dim individual lights, they could change their color and even automate when to turn them on and off for additional power savings. LED lamps connected over PLC are also able to communicate back useful diagnostic information to the control box about consumer usage patterns to further refine automated control. Such information can be especially useful in commercial installations. Maintenance departments would no longer have to inspect each and every lamp frequently and could plan lamp replacements. This all becomes possible because the lamps are based on LED-technology and have connectivity built into them, connectivity which in turn brings intelligence.
About the Authors
Ashish Garg is a Product Marketing Manager at Cypress Semiconductor. At Cypress, Ashish manages for the DC-DC Power and Powerline Communication product lines. Prior to joining Cypress, Ashish has held various marketing and technical positions at Altera, Texas Instruments and Sun Microsystems. Ashish has an MBA from Wharton, an MSEE from the UCSB and a BSEE from BITS Pilani, India. He can be reached for comments at firstname.lastname@example.org.
Angad Singh Gill is a Product Marketing Engineer at Cypress Semiconductor and is responsible for the DC-DC Power and Powerline Communication product lines. Angad has an MS in Physics and BS in Electronics Engineering from BITS Pilani, India. He can be reached at email@example.com.