Get smart: ensuring resilient power supply

ABB’s Russell Wood answers questions on how engineers can ensure resilience in smarter cities

Our cities are changing fast. Few people in the 1980s or 1990s could have envisaged how fast the internet would transform our society, or how targets for energy efficiency and renewable energy would change how we manage energy. The trend is only set to accelerate as buildings and transport systems get smarter.

How are buildings changing?

In future, sensors and controllers will optimise the consumption of energy, as well as the flow of transport and goods. Office and residential buildings will recognise individuals and teams, and adapt the environment to suit their specific lighting and HVAC preferences. Controllers will optimise the generation and storage of energy, and supply energy services to the power grid as a revenue stream.

At the same time, vehicle fleets will transition to electric and hybrid technology – and, eventually, to autonomous electric vehicles (EVs).

Energy efficiency legislation is also being tightened – for example, the EN 15232 standard for building automation, and the DCP161 regulation, under which Ofgem introduced new penalty charges last year. So it will pay to put an energy-management strategy and building management system (BMS) in place, to control supply and demand, limit peak consumption, and respond to requests from utilities to participate in demand-side response schemes.

How can operators future-proof their building management?

It will be essential to have a BMS or building automation and control system (BACS) that is scalable and flexible.

Such systems typically work at field, automation and management levels. Devices, such as sensors and actuators, control lights and blinds at field level. The automation level includes timers, and logic and automatic controllers, while management integrates monitoring, alarms and reporting.

HVAC and lighting functions have, traditionally, required separate controllers. However, the latest systems share a common interface through the KNX protocol, and this is enabling straightforward integration of heating, cooling, lighting, monitoring, alarms and reporting. As a result, it’s possible to achieve Class A energy savings under the EN 15232 standard.

How can building managers ensure a resilient power supply?

A resilient power supply offers high reliability and availability, plus visibility and control. Today’s switchgear has inbuilt metering, communication and connectivity to provide data to building managers about the condition and status of critical systems. In addition, the latest safety and backup equipment – such as emergency lighting systems – can run diagnostics and testing automatically, and log test reports centrally.

A resilient power supply offers high reliability and availability, plus visibility and control

Intelligent systems will become more common. For example, equipment with intelligent software for power management can guarantee that a facility will never exceed the peak half-hourly consumption allowed under a utility contract – so operators can avoid penalty charges from their energy suppliers.

Power management works by constantly measuring and evaluating loads, and automatically switching off low-priority loads to keep demand below its upper limit. It then reconnects the supply when capacity becomes available again. In many cases, building occupants will not notice a pause in output from an HVAC system or to a parked EV.

What is the right choice for EV charging points?

The adoption of EVs is another area affected by emissions. In February, the Energy Networks Association introduced a new process to reduce red tape when installing EV charging points. This covers all types of property in the UK, including commercial sites.

Most of the UK’s current EV charging points are domestic units that supply 3-22kW through the car’s onboard AC-DC converter over a period of 4-16 hours, with no need to upgrade the incoming supply. It could take more than a day, however, to fully charge the 80kWh batteries in a Jaguar I-PACE, Audi e-tron or Tesla.

As a result, DC charging points are becoming more popular. They enable rapid charging through large and powerful roadside AC to DC converters. In general, the shorter a vehicle stays, the higher the power requirement. Motorway services are installing 150-350kW units for stays of less than 20 minutes. The sweet spot for supermarkets is 50kW charging over 30-90 minutes, whereas drivers at offices, hotels and car dealerships expect to stay around three hours – making 20-25kW a suitable power rating.

■ Russell Wood is product marketing director at ABB