Wireless watch

As the first generation of smart gas meters begins to appear in UK homes, the cost of mass roll-out has already emerged as a potential headache for energy utilities.

A new smart gas metering technique being commercialised involves fewer and lower-cost components, which the developers claim will make it cheaper and easier to manufacture.

Lattice, from UK research company Sentec, measures the volume of gas as it enters a plastic tube running through the meter. The system records the time it takes the gas to travel between two points. The velocity measurement is converted into a volume and that data is sent wirelessly to provide consumers with usage information.

Ed Colby, Sentec chief technology officer, said other smart gas meters are either ‘dumb meters’, with an electronic box that counts the number of times a wheel goes around, or ultrasonic, time of flight meters that use sound waves to measure the flow of gas.

‘Our technology is simpler and thus lower cost than ultrasonic and it is integrated and thus more compact than upgraded dumb meters, which are currently too expensive,’ he said, adding that the technique readily detects attempts at fraud.

Yet the idea behind all smart gas meters is the same. Colby said the meters will help consumers tell ‘in real money terms’ how much they are spending every 15 minutes. ‘If you look at the numbers on your gas meter, what do they mean to you?’ he asked. ‘If you ask most people, they have no idea of the relationship between the number, the money the gas is costing them or how warm their house is.’

The Lattice system begins to work when the gas flows through the tube, which contains a proprietary layout of electrodes. Inside the tube the gas is ionised and excited using a low-energy source from a smoke detector.

A unique technique is then used to modulate the excitation to create a wavefront. The layout of electrodes measures the time it takes the wave to move between two points.

A microprocessor takes into account the cross-sectional areas of the tube to determine the cubic metres of gas that have flowed. Ultimately the information is transmitted wirelessly, so consumers could view the information on a wall display or log on to their gas provider’s website to check usage. The account can be checked from anywhere in the world.

Colby said real-time communication has worked with electricity metering for a while but it is more technically challenging and, until now, too expensive to be widely adopted for gas. ‘Electricity metering is easier because the power in the meter can run an electronic system,’ he said.

In order to wirelessly communicate information from a gas meter there needs to be a separate power source.

Homeowners would be tempted to turn the system off it was plugged into an electricity socket, and it would be too dangerous to wire the system permanently into the mains. Colby said his team considered powering the system from the gas stream but discounted it as one of the main design goals was to minimally impact the gas stream.

The researchers decided to power the Lattice system with a 20-year long-life battery. They also redesigned the device to use less power, making 100 micro amps their average power consumption goal.

Colby said the UK is not a good example for the roll-out of smart metering. ‘In the UK’s current regulatory framework, the people who would pay to install smart meters are not those who would most benefit from having them,’ he said. ‘There is a disconnect, but the government is working very hard to correct that.’

Sentec has done the initial research to prove its system works but it will be another two years until Lattice is commercially available. The product must first undergo long-term life testing and safety testing. The UK could be one of its first markets if there is suitable infrastructure for it.