To make clean energy connections, you need to harness some of nature’s most unpredictable elements, from sun, to water to wind. It’s why climate change is having such a big impact on electricity grids. And why the Supergrid could be the way of the future.
The Intergovernmental Panel on Climate Change (IPCC) warns that a changing climate alters the frequency, intensity, and geographical coverage of extreme weather events such as storms, droughts, heat waves and cold spells. Less well-known is the fact that climate change also affects the availability of water, and that energy production accounts for 15% of the world’s total water withdrawals. That’s water that once consumed, cannot be reused. Fossil fuel (coal, oil…) and nuclear power stations are the biggest water users. It is possible to reduce consumption, but the technology is expensive and efficiency suffers. Wind and solar photovoltaic systems can be expanded without any significant impact on water demand. But they set other challenges. Amounts of sunshine or wind can vary significantly, making it hard to predict how much energy will be available at any given time. This complicates the task of balancing supply and demand.
To cope with fluctuations from increased demand, power outages or even cloudy days, power system operators need a backup plan. Usually, this means switching to generators that burn fossil fuels. It might only be a small fraction of the total installed capacity but even so, the less fossil fuels used the better, both from an environmental and operating point of view.
Supergrids could be the answer. It integrates distant, large-scale renewable energy sources (hydro, wind or solar) with high voltage DC (HVDC) and Flexible Alternating Current Transmission Systems (FACTS). The result is a network that can optimize availability, getting power from where it can be sustainably produced, to where it is needed most. Besides being able to carry higher volumes of electricity, HVDC offers increased energy efficiency through reduction of transmission losses; and reduced land use. All of these environmental advantages form the foundation of today’s Supergrids: big, cross-regional networks that do more with less.
Brazil's Rio Madeira project is the perfect example of GE’s multi-advantage, Supergrid approach. It will allow a 10 GW hydroelectric plant to be constructed where the water is, in the Amazon basin, and two-thirds of the energy produced to be transported to populated areas around São Paulo. In this way, Rio Madeira contributes to the economic development of both the Amazon and São Paulo regions; reducing Brazil’s oil dependency as it cuts greenhouse gas (GHG) emissions. GE’s Grid Solutions will supply the HVDC system for the transmission line, the world’s longest at 2,375 km. Generating 3.15 GW of power, the project is helping Brazil to achieve a number of environmental objectives, including: a 10% increase in the country's renewable capacity, and a 50% reduction in transmission losses as compared to AC technology. Together, they add up to a reduction of about 12 million tons of CO2 equivalent per year. Plus, the smaller footprint of the HVDC solution (running only one circuit versus two with a classic AC system), greatly lowers our impact on the Amazon’s ecosystem.
The Supergrid is attractive for offshore wind generation too, as Germany's 900MW HVDC grid connection project, DolWin3 shows. When completed in 2017, DolWin3 will supply the equivalent of one million homes with electricity, from a source over 80 kilometers off the North Sea coast. GE’s Grid Solutions has already delivered and installed two 685 MVA power transformers for the project at the onshore, Dörpen West converter station, with the offshore platform underway.
More resilient and efficient, Supergrids will have a huge impact on weathering climate change. Making it possible for electricity system operators to link into resources from across regions and even, neighboring countries. Connecting more people to cleaner, more sustainable electricity.