One of the biggest obstacles in the race to decarbonise the global economy is the shortage of power lines and other infrastructure needed to transport clean energy to where it’s needed. Because building new lines is costly — and takes a long time — some countries are deploying innovative technologies to expand grid capacity and keep the energy transition moving.
Many of these so-called ‘grid-enhancing technologies’ are still relatively new, but they’re already proving their worth. Pioneering utilities are deploying them to make better use of their existing power lines while they build new ones — though it’s early days yet.
“There’s a huge opportunity and we’re not tapped into it at all,” says Julia Selker, executive director of the US-based advocacy group Working for Advanced Transmission Technologies (WATT) Coalition.
If the world is to meet key climate targets — like tripling renewable energy capacity by 2030 — grid-enhancing technologies will likely play an important role. Here are some of the leading ones:
- Dynamic line rating
To avoid overheating their power lines, grid operators traditionally set very conservative limits on how much energy is allowed to pass through them. This means that a lot of the time – particularly when it’s cold or windy – their lines are being used far below capacity.
To solve this problem, some utilities are installing sensors along their power lines to measure local temperatures, wind speeds (wind can significantly cool lines), and other variables in real time.
This allows them to safely boost line capacity when conditions allow. According to the US Department of Energy, this approach can expand transmission capacity by up to 30%, and at less than 5% of the cost of rebuilding and upgrading a line. It’s much quicker, too.
Belgium was an early pioneer of the technology and now considers its implementation to be standard practice, Selker tells The Progress Playbook. Others are following suit, including Ireland and some parts of the US.
After Pennsylvanian utility PPL installed these sensors in 2023, it’s seen a roughly 20% increase in capacity on its main power lines, and this has delivered $23 million in annual congestion cost savings, per the federal energy department.
- Topology optimisation
Similarly, topology optimisation software helps to ease congestion by acting as “a Waze or Google Maps for the grid,” as American tech provider NewGrid puts it. In essence, it identifies opportunities to re-route power flows around any bottlenecks in the system, using circuit breakers.
The technology is already used by some grid operators and by renewable energy developers, who naturally want to sell as much of their output as they can.
Studies show topology optimisation can reduce congestion by up to 50% and cut renewable energy curtailment (wasted electrons) by up to 40%, according to the WATT Coalition.
In one case, the technology reduced curtailment from a wind farm by 77%, says Selker.
- Advanced power flow control
These are devices that divert power flows from congested lines to other ones that have spare capacity. The use of this technology in the UK unlocked 1.5GW of grid capacity for new renewable energy projects, saving hundreds of millions of pounds in the process, Selker says.
- Reconductoring
Another solution is to simply replace old power line cables with ones made from more modern, advanced materials that can carry more energy.
Advanced conductors are more expensive, but this approach works out much cheaper than building brand new lines. It’s also far quicker and easier, with no new servitudes required.
A study by researchers at the University of California, Berkeley, and GridLab found that utilities in the US could double their transmission capacity by 2035 through reconductoring alone.
The US government is now looking to capitalise on this opportunity. In August, the Department of Energy allocated funding to utilities to upgrade 400 miles of transmission lines.
TS Conductor, a US-based manufacturer of advanced power lines, says its cables can handle three times the capacity of traditional ones during peak hours. They’ve been deployed by several utilities to date, including Montana-Dakota Utilities Company, Arizona Public Service, and Tennessee Valley Authority.
- Big batteries
When there’s too much power being generated for a transmission line to handle, batteries can store the excess and discharge it another time. This way, power lines can operate closer to capacity for much longer periods of the day, thereby creating room for new clean energy facilities.
Italy’s system operator was among the first to deploy batteries as transmission assets. After evaluating traditional transmission investments, the company changed course and approved a battery system to alleviate congestion in power lines running north to south in the country, and to reduce curtailment of wind generation in the south.
Elsewhere, Australia’s massive Waratah Super Battery – an 850 megawatt (MW) / 1,680 megawatt-hour (MWh) system – is intended to enable the power lines transporting renewable power to operate at or near full capacity.
- Demand flexibility
Another option is to launch a large-scale demand flexibility programme. By smoothing out electricity consumption throughout the day, utilities can make better use of their existing power lines and reduce the need for new ones.
The UK’s grid operator recently announced that it would offer households and businesses financial incentives all year round if they agree to reduce power use when demand surges and threatens to catch up with supply.
A long way to go: For now, most grid operators have barely made headway in the implementation of grid-enhancing technologies (which also include ‘volt/VAR optimisation‘ and power factor correction).
The US is lagging other markets, partly because utilities there are financially incentivised (under current regulations) to build new lines rather than make their existing ones more useful.
The Watt Coalition wants the US to take inspiration from the likes of the UK, which has changed the way grid owners derive their income to ensure they’re incentivised to innovate and find lower-cost ways of expanding capacity.
Selker says US regulators could, for instance, offer a shared-savings scheme, where utilities keep, say, 25% of the savings derived from a technology deployment.
Meanwhile, some states – including California and Virginia – have passed laws requiring utilities to closely evaluate grid-enhancing technologies in their transmission planning.
“It should be noted that many of these solutions have been in existence for well over a decade, but are being given prominence now in public discourse owing to the urgency of expanding grid capacity,” advisory and risk management firm DNV says in a report.
However, given the sheer scale of new power generating capacity needed to decarbonise the global economy, DNV cautions that enhancements to existing grids “must be accompanied by comprehensive and urgent plans for new-build.”
Tags: Renewables, WATT Coalition