In Wales, Power Does the AC/DC Dance
In Wales, Power Does the AC/DC Dance
By Mark Egan
In the world of electric power, a dance is underway: Demand for electricity is rising while at the same time more energy from sources like solar and wind are being added to the power mix. However, finding ways to meet that heightened electric demand and incorporate these new sources without overhauling the entire infrastructure of the power grid is a dance requiring a deft approach.
Anglesey in North Wales is in the middle of that dance. The island, off the west coast of the United Kingdom, is at the forefront of the electric revolution because it’s home to the government-backed Energy Island project — a center of renewable energy innovation. Anglesey has big plans for the future, it has a pressing problem now — its electric network is near capacity and needs upgrades to meet future demand.
Faced with that quandary, executives at SP Energy Networks, the company that supplies Anglesey with power, wondered if they could use the island as a test case to upgrade the electric grid with minimal disruption. Could they work with GE, which supplies equipment to SP Energy, to increase the island’s electricity by making better use of existing infrastructure rather than building more substations and installing more underground cables and overhead lines?
“We wanted to find a way to upgrade the system with zero or minimal environmental impact,” says Matt Cunningham, sales director at GE’s Power Conversion, who worked on the project.
They found a solution in how railways in central Europe have been electrified and in the way large amounts of electricity is transmitted between countries — by converting AC power to DC, which allows the same power lines to carry more electricity, says Cunningham.
Cunningham says high voltage DC power lines already transport wholesale electricity over long distances between European countries, cheaply and efficiently. Applying the same concept to the medium voltage lines that distribute power locally — as GE has done on European railways — would solve the problem. Cunningham says installing AC to DC converters at the Bangor substation on the mainland and on the substation on Anglesey creates Europe’s first medium-voltage DC link, improving the quality and stability of the electricity travelling across lines and smoothing out the impact of more renewable energy on the grid. It also proves that AC-DC conversion could be a valued part of the power grids of the future, he says.
Transmitting DC electricity over copper wires instead of AC allows the same lines to carry as much as 2.4-times more power, Cunningham says. To facilitate that, GE is installing 12 MV7000 converters at each substation to convert the AC to DC — an approach used for the power supply on railways in Germany, Austria, Switzerland, Norway and Sweden.
Like any grid solution for the future, the Anglesey project includes a digital component — GE’s VISOR 2.0 asset management software and Data Historian software will allow Sottish Power to analyze the performance of the network to optimize operations, improve maintenance and reduce the likelihood of outages.
Cunningham says converting AC to DC will become more important as more renewable energy — also called distributed generation — comes online. “Equipment like this allows distributed generation to support local communities without impacting anything else on the grid. You don’t have to upgrade the infrastructure to provide more power for a community, it can look after itself,” says Cunningham.
Converting AC to DC is just one of GE’s innovations for the grid of the future. GE is also part of a European Union project called UPGRID to bring the medium- and low-voltage sections of the grid, which utilities use to send around electricity to homes and businesses, into the 21st century.
The dance, of course, also includes a mix of new and innovative ways of using older technologies. GE trailer-mounted turbines, re-engineered jet engines that normally power large aircraft, are being used in Angola and elsewhere to power places that have never had electricity. And, technology is even helping coal burn cleaner to reduce its carbon footprint. In solar, the LV5+ Series Solar Inverter uses silicon carbide power electronics to convert solar power more efficiently, increasing energy production for solar farm operators.
As the dance to use electricity more efficiently progresses, it’s worth remembering the words of GE founder Thomas Edison, “The scope of thrift is limitless.”