Wave of new power generation pressures UK distribution networks

Author: Henry Evans


A huge 15GW of embedded power generation capacity is awaiting direct connection to four of the six distribution networks across England, Scotland and Wales, figures gathered by ICIS show.

Embedded generation bypasses system operator National Grid’s transmission network and, as a result, its growth has depressed system demand and helped contribute to a progressive decline in wholesale power prices, notably peaks, until recent, sustained prompt and near-curve price increases more than offset this.

The 15GW awaiting connection – a mix of renewable, thermal and storage units – is spread principally over three zones operated by SSE Power Distribution and Western Power Distribution (WPD) where a combined 12.8GW awaits connection. Just over 2GW is also awaiting connection in areas managed by Electricity North West and Northern Powergrid.

The UK’s two other distribution network operators (DNOs) – SP Energy Networks, which operates two out of the eight zones in the country, and UK Power Networks – declined to reveal figures.

The UK has seen a wave of new embedded generation connect to distribution networks in recent years, driven mainly by meteoric growth in solar installations which currently stand just above 11GW collectively.

Ofgem threat

However, British energy regulator Ofgem launched a consultation in March asking generators and stakeholders for feedback on whether DNOs have been proactive enough in tackling network congestion. The operators were threatened with financial penalties depending on the result of the consultation.

“Generally, there’s been an improvement in the connection process [since March],” a spokesman said. “The DNOs are developing smarter ways to speed up the connections.”

The regulator is also satisfied that the consultation is having its desired effect. “We’re generally happy that the DNOs are meeting the requirements of those incentives,” the spokesman said.

The industry body representing the UK’s six DNOs, the Energy Networks Association (ENA), said measures already introduced have allowed generation to connect at a lower cost than would otherwise have been achieved.

“There is a lot of work already underway to address the increase in distributed generation connections,” a spokesman said. “These include measures to deter the increasing number of speculative connection requests from developers which currently increase the cost and time-scale of connections for customers.”

Requests to disconnect

As part of measures to free up connections across the industry, DNOs are writing to existing generators that have used less than 75% of their capacity entitlement for over 12 months to ask to release that share for reallocation to new generators.

The ENA has also issued two consultations to improve the management of network connection queues. One concerns introducing milestones, which customers have to meet to retain their place in the queue, while the other concerns refining what changes a generator can legitimately make to a connection request without relinquishing their place in the queue. The purpose is to ensure that projects that have stalled do not hold up those sites that are ready to connect.

Timed connections

Individual DNOs have also been implementing their own initiatives to ease congestion. Among several alternative connection options, WPD operates a timed connection option that allows smaller generation, excluding solar, to generate additional output in winter or at night when solar generation is less penetrative.

As part of its active network management, WPD can detect congestion and automatically reduce output from generators by sending them a signal. Businesses with onsite generation can also opt for an export limited connection so their output is diverted automatically to offset their own consumption at peak times.

SSE also operates a “constrained managed zone” initiative, which enables geographic regions served by an existing network to manage network security through load variation methods such as demand side response, storage and stand-by generation.

A spokeswoman for Electricity North West said the company is looking to invest in a smarter network to increase capacity but delays are generally caused by generators awaiting planning permission. henry.evans@icis.com