Rise in renewable heat calls for reliability and accuracy

Published:  15 May, 2014

Bernard McWeeney assesses the role heat meters play in government incentive schemes

Bernard McWeeney assesses the role heat meters play in government incentive schemes

The classic utility mind-set of centralised energy generation is changing. Now a range of local, community based renewable energy technologies are available, including ground source heat pumps, solar PV and combined heat and power (CHP), which enable buildings to harvest energy for their own use, as well as generating a surplus, which can be sold back to the grid.

The government has recognised the importance of renewable energy measurability and its renewable heat incentive (RHI), which provides financial incentives for renewable heat, requires commercial projects to be fitted with meters so that the subsidy payments are based on actual output.

The domestic version of the scheme has now been launched and although estimates rather than metering will be used in the majority of cases, metering will still play a part in this stage of the RHI roll out. Around 10% of domestic installations will need to be metered to ensure deemed values remain reliable.

With DECC estimating that up to 900,000 renewable heat projects will be installed in the UK by 2020, it’s vital for the confidence in the sector that meters are accurate and installed correctly in the projects that require them.

We had an inkling that measurement of projects after completion was not receiving the attention it deserved. We put this thinking to the test by commissioning an independent survey with 100 UK Microgeneration Certification Scheme heating engineers about their personal experience of installing renewable energy technologies and heat meters.

The findings highlighted a clear skills gap. Some 51% of renewables installers have not received training on fitting the meters, despite the requirement for metering on commercial renewable heat projects to qualify for the RHI.

While the research shows the need for greater guidance for installers, many of the issues requiring multiple installer callbacks – such as dirt getting into the system – are associated with the use of mechanical heat meters, which stop providing energy readings when installed incorrectly.

The advisable course of action to take is the use of Measuring Instruments Directive Class 2 meters - either ultrasonic or electrostatic, which continue to function and provide alarms, even when contaminated by dirt. Mechanical Class 3 meters aren’t as accurate and don’t last as long.

Distributed renewable technologies have the potential to transform the economy by encouraging energy self-sufficiency. It’s certainly encouraging to see growth but to build trust in the industry, meters should be installed using the latest and best available technology and to a common industry standard. Evaluating project performance and the efficiency of renewable technology, as well as putting a firm emphasis on the skills of installers, will be key in driving awareness and the financial investment required to help the UK achieve its climate goals.

Bernard McWeeney is water and heat manager (UK and Ireland) at Itron