Market view: NTVV seeks to harness the power of customer flexibility

The core business of Distribution Network Operators (DNOs), such as Scottish and Southern Electricity Networks, is to provide a safe, top level of service to their customers through delivering electricity to homes, maximising cost-effectiveness, reliability and sustainability. In doing this, each DNO must balance the needs of a wide range of stakeholders.

DNOs have a responsibility to meet a minimum standard for all customers, particularly those most vulnerable to the effects of energy disruption. However, the relationship between DNOs and customers has traditionally been limited to two specific circumstances:

1. when the customer suffers a service disruption
2. when a new customer is connected

The New Thames Valley Vision (NTVV) project has given Scottish and Southern Electricity Networks the opportunity to further develop this relationship.

Shifting patterns in electricity consumption and generation are presenting new and significant challenges for the DNOs in managing their networks. However, these challenges also present real opportunities for the DNOs to change the way they operate. One such way is to embrace emerging technologies that tap into the flexibility customers could provide and establish this firmly within the DNOs’ network operation toolbox.

Scottish and Southern Electricity Networks has been investigating exciting and innovative methods of harnessing customer support through projects conducted under NTVV, a project funded through the Low Carbon Networks Fund (LCNF).

Thermal storage can shift peak demand

Customers with flexible demand can reduce or shift consumption, alleviating stress on the network at critical times. In doing so, that flexibility can provide the DNO with more options to manage thermal and voltage constraints and, in the longer term, defer capital investments on the network.

One rapidly emerging technology that can provide demand flexibility is energy storage. As part of its NTVV project, Scottish and Southern Electricity Networks undertook trials in the UK exploring exciting new storage technologies that have the scope to broaden the types of customer that are able to provide demand flexibility to the DNO. The NTVV trials focused on investigating the benefits that (hot and cold) thermal storage solutions can provide to the DNO in managing its network.

Academics at London South Bank University estimate that in the UK around 16 per cent of electricity may be consumed by refrigeration and air conditioning, and that worldwide this may contribute to 10 per cent of CO2 emissions.

NTVV trialled the Ice Bear, a cold thermal storage technology that can integrate with an industry characterised by a mixture of inflexible off-peak generation and daytime peak consumption. In the US, the Ice Bear device has proven its ability to alleviate a building’s peak-time air conditioning demand and is now being trialled for the first-time in the United Kingdom.

The Ice Bear freezes water during periods of lower electricity demand (off-peak), which is then stored as ice until periods of high demand when it is used as an alternative to an AC system’s compressor, thereby reducing demand on the system during peak periods.

The NTVV project also undertook trials of energy and micro-generator manager (EMMA) heat storage devices. These are linked to domestic solar PV systems to store energy generated during times of low system demand and/or high generation. Small scale PV (≤ 4kW), which is typically mounted on domestic properties, has skyrocketed from about 10MW at the start of 2010 to 2,391MW in mid-2016. The EMMA device transfers the surplus electricity produced by the solar PV system to a customer’s hot water tank which is then used in a building’s hot water heating, providing the double benefit of diverting solar PV electricity from the distribution network and reducing the customer’s electricity demand for heat at periods of higher system demand.

The Ice Bear and EMMA systems provide just two examples of how smart technology can be used to manage different network challenges. An Ice Bear is ideal for consumers with a large cooling load, whereas an EMMA is most appropriate for domestic consumers with water tanks and solar PV installed on the home’s roof.

The NTVV thermal storage trials delivered tangible benefits to both Scottish and Southern Electricity Networks and its customers. The Ice Bear trial delivered a number of real successes: one trial unit works so effectively that the user has been able to turn off their existing 4.8kW AC units and rely solely on their Ice Bear to provide cooling to their building. At peak usage the EMMA system will result in approximately 0.5kW of energy diverted to a customer’s hot water tank. By harnessing customer flexibility in this way, SSEPD has been able to significantly reduce reverse power flows at times of high solar PV generation, reduce system strain on the electricity distribution network and deliver savings to those customers adopting the technologies.

Automated demand response can help to manage peaks

NTVV also conducted initial testing of automated demand response (ADR), in which the network operator is able to control customer appliances and devices to optimise their operation with network demand and supply. Whilst this technology is mature in the US, until now there has been little experience in its application to UK DNOs.

In this trial, Scottish and Southern Electricity Networks used ADR to tap into the flexible elements of customers’ electricity demand to turn off, turn down or cycle electricity consuming devices in more than 1,000 instances across 30 trial locations. Scheduled load shedding events were tested up to four hours in duration with no-notice load shedding events up to an hour in duration. A significant number of events reduced load by more than 10 per cent. The effects of these operations were broadly imperceptible to the customer and were done through a fully automated open ADR portal, which enabled SSEPD to manage the load of the 30 participant customers almost instantaneously.

With ADR it is important to avoid a negative impact on building occupants and to ensure customer satisfaction and continued commitment to future demand response programmes. Larger buildings are more likely to have a greater capacity to reduce load and buildings with higher energy efficiency standards (e.g. with better insulation/air circulation) may be better suited to more intensive ADR.

Scottish and Southern Electricity Networks learned a number of key lessons during the ADR trials, particularly around the early installation of data service technology, developing appropriate incentives and operating schemes for participants to ensure optimum take-up of the ADR opportunity.

NTVV is a window on the future

The NTVV trials have provided a window into a future where a DNO can use customer flexibility provided by smart technologies to better fulfil Ofgem’s Revenue = Incentives + Innovation + Outputs (RIIO) price control outputs. By working together with consumers in this way, DNOs can create a more dynamic, sustainable and lower carbon network, whilst simultaneously putting stakeholders at the heart of the decision making process.

These technologies will be required to better meet the significant challenges that DNOs will face in coming years as energy production and use becomes increasingly decentralised and DNOs are required to play far more active roles in the operation and delivery of a sustainable, lower carbon energy system.

Technology can allow customers to support the network, but why should they help?

In this article, we have given some examples of how customers can help to more efficiently manage the distribution network. However, it is not always easy to convince them why they should do it. In the following article, we will show how the NTVV project also looked at ways a DNO can interact with consumers to encourage network-friendly behaviour. 

This article is the fourth of five which look at how Scottish and Southern Electricity Networks and the NTVV project have been exploring better ways of managing distribution networks.