Unless you have been living on a different planet during the last few years, you can’t have missed the massive shift towards energy efficiency. This has been covered extensively in the media and is ultimately leading to a change in the system requirements for new platforms that monitor energy efficiency. Once, just the concern of designers that needed to ensure a battery charge for a mobile device would last for a particular usage period, a broad range of non-mobile systems must now provide better prior energy usage specifications, while delivering higher performance.
However, in this article I will look at the “energy policeman”. The piece of equipment that monitors the usage of a particular utility, be it water, gas or electricity: the Smart Meter.
There has been somewhat of a consumer backlash during the rollout of automated meter reading (AMR) systems, especially in the US, with concerns over billing accuracy and questions over the real benefits these systems bring to end users. However, the combination of government mandated programmes – such as the UK Government’s commitment to equip every household with a smart meter by 2020 – increasing system reliability and usability of the technology, as well as the rising cost of power over time mean that meter deployments will increase over the coming years.
Smart meters all consist of three main elements:
- Metallurgy: A subsystem that captures the information to measure the usage. In the case of a water or gas meter, it measures flow. In an electricity meter, it is an electrical circuit that measures the real-time current consumption.
- Processing: Converting the usage information so that the utility company can understand it.
- Communication: Transmitting the information back to the utility company and the end user.
Functionality will vary depending on the type of meter. The table below broadly groups what ARM has seen in terms of specifications from various geographies:
The systems are of course more complicated than this. They must incorporate tamper-proofing mechanisms to provide an indication of when the box has been opened or the power removed. Additionally, the information is encrypted prior to transmission to the utility company to protect the communication channel.
One of the main challenges in the smart metering market is the fragmentation of the industry across the world. Houses in different regions come in different shapes and sizes, are made from different materials and will also have the meters placed in different locations within the house. This is one of the reasons why electricity meters specify many serial ports to provide connectivity to a diverse range of communication standards including ZigBee, PowerLine and GSM/GPRS.
The price of electricity also varies greatly across the globe and depending on the time of day, requiring systems that are able to house large data tables with tariff information. Therefore, electricity meters need to support a significantly large amount of on-chip flash. In markets where a broad set of companies can compete to supply electricity, this information can, in theory, be used to enable the meter to select the supplier offering the lowest price of electricity at a specific time. This conundrum also delays the pace at which silicon companies can integrate these devices, which can results in increased R&D costs and less reliable systems.
Despite these challenges, I believe that the teething problems that have dogged the initial roll outs of smart meters will be overcome. What will catapult the acceptance of these systems will be when end users can see value. For the moment the main beneficiaries of AMR-powered meters are the utility companies. Automating the process of gathering usage information saves them cost, speeds the data collection and increases accuracy.
From an end-user’s point of view, when smart metering systems are combined with user interfaces such as Google’s PowerMeter and Microsoft’s HOHM technology, they help provide coarse grain data back to the user regarding their utility usage. However, widespread adoption and acceptance requires that these platforms:
- Present fine grained data of electricity usage to help consumers modify their behaviour.
- Where possible, automatically save the end user money by switching to cheaper electricity tariffs depending on the time of day.
- Take into account that consumers with solar panels and wind farms will become energy suppliers.
- Support “pay as you go” services.
Inside the home, a Home Area Network (HAN), which could utilise DECT, Wifi, Zigbee or PowerLine technology, would be used to connect all “smart” devices. While in many regions across the world the meter might be owned by the utility company, the units that control the HAN will be the property of the home owner.
This is really the promise of Advanced Metering Infrastructure (AMI) capable systems, but the shift from what is effectively a one-way system to a two-way system will have huge implications for suppliers, technology providers and end-users alike.
One obvious challenge is security. Firstly, it is imperative that the power network remains impervious to attack, whether it be from deliberate hack attempts or accidental release of viruses/worms by users. Additionally, given the cost of replacing a deployed unit, the hardware must be capable of supporting new services, which means offering a reliable, seamless way of updating functionality remotely and embedding latent CPU horsepower to support new services, The good news is that other industries have wrestled with and solved similar issues. For example, automotive gateways are deployed in a secure environment to ensure that applications can request information from (but cannot directly access) resources “under the hood” such as the engine management system or the tyres. Or, set-top boxes can be upgraded with new functionality overnight. My view is that, rather than reinventing the wheel, utility companies should establish relationships with firms in other industries, such as software providers, to address current smart metering challenges. It is quite feasible that some utility companies may even purchase some of these companies to try and kick-start their push into these areas, especially often the technical elements of smart metering solutions are outside of utility companies’ area of core competency.
This shift to AMI is causing a fairly significant uptake in the functionality needed in the electricity meter itself. Specifications we have seen from various geographies outline CPU requirements for AMI-capable meters in excess of 60MHz and the amount of flash leaping to ½ MB, due to the large data tables of pricing information that need to be stored. These meters draw power from the electricity supply itself so although it is desirable for the MCU to be energy efficient, the system specifications have not mandated a specific level. Gas and water meters are often run from batteries. CPU performance requirements need a system to run from a battery for 15-20 years, which is leading many OEMs to consider the use of 32-bit MCUs as they can accomplish the data processing task far more quickly than a 8- or 16-bit MCU, thereby increasing the length of time the CPU can be powered down.
Today, end users that want to take more control of their power management have to be highly skilled in technology. If you are tech-savvy, you may set up a network at home which includes energy generated from solar panels and mechanisms to control air conditioning, water pumps and sprinkler systems. The system may use a combination of predicted weather patterns, temperature and, electricity pricing information, as well as current energy levels/usage rates as the basis for making energy decisions.
It is clear that many end users want to do the right thing and reduce their carbon footprint. However, the majority of end users (me included) need these systems to be far easier to install and use. This is one area that many of ARM’s silicon and software ecosystem partners are currently focused on finding solutions for.
Many electronics manufacturers have recognised the opportunity to provide smart metering units that capture and display usage information most effectively. As with any emerging area, a range of connectivity strategies and application programming interfaces/protocols are being proposed. In the US, in addition to the two listed above, NIST have issued specifications, there is an alliance called U-SNAP (short for Utility Smart Network Access Port) which promises to connect any HAN standard, present and future, to use any vendor's Smart Meter as a gateway into the home and a coalition of appliance manufacturers called “AHAM” have indicated they are working on a specification. The government incentives, an example being rebate schemes on consumer goods, which are used to change consumer behaviours are less in evidence in Europe, so the programs to look at SmartGrid-ready appliances seems to be a little behind activities in US. So up to this point, Europe has not seen the formation of these types of bodies. It isn’t a bad strategy to wait in these types of emerging areas to see which of the multiple proposals out there will gain mass adoption and then align behind those, provided the infrastructure and equipment being developed is relatively flexible.
So, after many years of discussion, smart meters are starting to become a reality. To me it resembles the early days of xDSL deployments. There are concerns over system reliability, the systems are not yet very well-integrated as a broad set of standards abound and the utility companies deploying the hardware worry about the cost of technical support and delivering in-field updates to prolong the lifespan of deployed units. However, these units are here to stay and if the power industry learns from its predecessors, it can solve many of these challenges relatively quickly. Unlike xDSL, the increasing pressures on governments to reduce greenhouse gases will act as a driver to ensure this new network will be rolled out. Once the AMI infrastructure is in place, there will be three network connections into a home:
- A broadband connection (xDSL, cable, satellite….)
- A phone network (increasingly, this will be cellular as opposed to fixed line)
- The power network
From here, only our imagination can hold back the types of services that will be deployed. Energy management of course. Remote medicine a distinct possibility. Even new consumer devices as electronic components become increasingly deployed in clothing, appliances and disposable goods. The opportunities for smart metering to transform the way we use energy are endless given the right platform.
