Finding ways to deliver energy efficiently, cheaply, and securely while avoiding power outages is becoming a new goal.
I started thinking about ways to deal with power outages during the aftermath of last year’s hurricane season. Our lives are centered around using much more power than fifty years ago, so its loss is deeply felt. Houston’s city government had also given thought to this dilemma, leading to the Mayor’s Task Force on Electric Reliability report being released last week. As I write this, NPR has been producing a series of reports on the concept of a smart grid, and what this means to us. The mayor’s report refers to a mid grid system, which is part of a smart grid system. Little mentioned is a report that came out in December of 2008 from the Energy Advisory Committee produced for the Department of Energy, and it plays a part in our understanding of this type of electrical power supply system.
The difference between a Smart Grid and a Mid Grid
Not much.A smart grid is no one system; it is a set of solutions used to meet the energy demands of residential and commercial use effectively and cheaply. It “actually comprises a broad range of technology solutions that optimize the energy value chain” (from the EAC report). The description of the mid grid fits into this definition too. The main difference is that mid grid projects mentioned in the mayor’s report focus on the systems outside of the home and business and outside of the power plant. I believe that I can provide a clearer explanation of the energy value chain, so you can understand the components, and how they may be of interest to a homeowner. (My focus will be on the residential aspects, since that is the focus of this site).
If you have been reading posts on this site, particularly posts in the green home conversion section, you are already familiar with some parts and equipment that people are using for a smart grid: CHP systems, energy efficient appliances, and solar to name a few. Let us step back to see what an entire smart grid may be. The plumbing analogy comes up often when discussing electricity, because we can quickly grasp the plumbing concept. Understanding electricity is not so easy, and comparing it to plumbing can give us false analogies, so I need to tread lightly with my description.
You take water from a source which is delivered through pipes at a controlled pressure to your home. You access this water through appliances and fixtures, like a faucet. We would not have electricity without a source. It is delivered through wires, which we can see as a pipe. We access its use through appliances and fixtures, like your lamp. We have a problem in the fact that an individual particle of electricity does not travel down the wire like a particle of water does. Electrons in atoms are energized which energize the electrons in the next atom down until they reach our home. To make this delivery grid “smart”, we can examine the components.
The source of this power can be varied: wind, solar, fuel, and ocean waves. All of these sources are available to us in Houston. By relying on different types of power generation, our system will not falter if one source suffers. Most of us rely on obtaining power from a plant, but what if that plant fails? Or what if the type of source for that energy fails? By having different plants which produce power from different sources is the first step to a smart grid. However, we do not need to have all our power come from one centralized location? Solar panels offer the chance for energy to be produced at a home. “Distributed Generation (hereinafter “DG”) is simply the concept of generating electricity close to where it is needed” (from the mayor’s report). Houston wants for energy production to occur in many isolated areas, because it can assist in having the grid “self heal” after a storm.
A common benefit of smart grids is the idea that the heal themselves during electrical outages. This is achieved primarily through wiser use of the system of lines providing us power. “The good news is that 73% of CenterPoint Energy’s customers have ‘circuit redundancy’ today, in that they are accessed by wires that already connect to more than one circuit” (from the mayor’s report). The report mentioned that most of the power loss after Hurricane Ike was caused by trees falling on the lines, but we could have obtained power by a different route. To accomplish this, the power has to be routed along other lines to get to our homes, and our current electric grid allows this to happen. Devices along the lines would be able to discover where a problem occurred, and relate to a controller to have the power flow through other lines to reach our homes. One solution mentioned often is burying the power lines. With flooding in Houston buried power lines are not safe. Smart grid technology can make it safer to transmit more power over existing lines safely, according to the EAC report. These measures allow the system to provide power quickly after a failure, hence the idea of self healing. Another intelligent technology that can be applied to the supply system is the concept of storing power. When you think of water supply systems, you will realize that water is stored for our use in such equipment like water towers. We do not have an equivalent for electricity at this time, but we do have related equipment that could do the job. Batteries for hybrid cars could be possibly installed into our homes, storing energy from the grid during lower usage hours, which can be called upon during higher performing hours. Storage devices like this may be installed in the lines to help meet demand when needed.
The final part of the delivery system would be where it attaches to our homes. The advanced meters being placed in Houston are part of the smart grid plans of CenterPoint Energy. I remember these being headlined in the news because they will be paid by an additional cost on our monthly bills. From the news, I was given that this would be an extra cost to us, while only serving the function of reporting how much electricity I used for billing purposes to CenterPoint. Advanced meters do more than that. They provide a host of information back to the utility company to better meet the needs of supplying the consumer with power, and coupled with new smart appliances, they can help us run our homes with less energy.
Continuing the smart grid into the home is where Houston’s report stops, but the EAC report ventures. You may realize that using electricity during peak hours costs you more. If we could do our laundry or dishes in the middle of the night, we could save quite a bit of money. Since the eighties, we have seen workable ideas in creating a computer linked home. Refrigerators can tell us what we need to buy. If the advanced meter works in conjunction with computers in our appliances, which is then linked to a control panel, we can monitor and control our power usage wisely. For example, most of the power used in our homes goes into running electric motors. We have them in our refrigerator, dishwasher, clothes washer, dryer, and air conditioning system. If a motor is running inefficiently, we are wasting money. Our home’s computer brain can inform us of these problems. The brain could also help us schedule tasks, like washing dishes, during the middle of the night. We may also siphon power into our personal storage device to be used during the day.
This is the basic overview of what a smart or mid grid is. Each community will have to determine what components will make up their own smart grid, because we all face different issues. For one thing, Houston’s mid grid plan will involve vegetation management. More aggressive plans to prevent trees from damaging power lines will be vital in our area for an effective smart grid. Another concern for us in Houston is reducing electrical cost. Our rates are among the highest in the country. Councilman Peter Brown, who has a background in urban planning, appears to be a good proponent of these measures, and this does seem to be on his list of concerns. In my next post, I will deal with the pros and cons that are being brought up about implementing smart grid ideas.
More information about the EAC is available at: EAC.htm
City of Houston reports: Houston government report