Microgrids or large high-voltage lines? Experts call for both

Source: Umair Irfan, E&E reporter • Posted: Friday, May 20, 2016

BONN, Germany — Continuing to grow wavering renewable power requires thinking big and small, experts say.

In recent years, growth in renewable power capacity has outpaced conventional fossil-fuel-fired plants, with 17 percent growth in wind and 37 percent growth in solar, according to the International Renewable Energy Agency (IRENA) (ClimateWire, April 8).

IRENA also estimated that global variable renewable energy may grow by 20 percent by 2030.

However, on still, cloudy days, other generators have to step up to fill energy production shortfalls, which is an expensive ordeal. Another concern is that the sunniest and windiest parts of the world aren’t always next to power hungry cities and factories.

“Our problem is the renewable energy resources are far away from the load centers,” said Xianzhang Lei, director of the smart grid research institute of the State Grid Corporation of China.

Speaking last week at IRENA’s innovation conference, he noted that the optimum wind and solar resources in China can be as far as 4,000 kilometers (or 2,485 miles) away from some of the country’s biggest smog-choked cities.

“If we want to use these resources, we are faced with a huge problem: How can you transfer this renewable energy to load centers?” Lei said.

One way to tackle this problem is to invest in large high-voltage grids that route power from where it’s generated to where it’s needed. High voltages, between 800 to 1,000 kilovolts, are needed to overcome losses in electrical transmission lines that span thousands of miles, both in alternating and direct currents, Lei explained.

By 2020, China expects to have 24 ultra-high-voltage transmission lines in operation, sending power from the southwest to metropolises in the northeastern parts of the country, Lei said.

If China’s efforts with high-voltage transmission for renewables prove successful, Lei said a similar idea could work at an international level.

By putting solar panels in the sunniest and windiest parts of the world, rather than just the brightest and breeziest parts within a country, renewables could become far more cost- and resource-effective as power courses across continents.

“We can cover all the demand — the electricity demand, the energy demand — in the world,” Lei said. “If we have all these resources from renewable energy, that means the CO2 problem wouldn’t be a problem.”

Leapfrogging into off-grid

In a small step in this direction, IRENA issued a new¬†report¬†yesterday on grid codes to accommodate intermittent renewables. Balancing technology, operations and regulations, the report offers guidelines for developing grid codes to make sure wind and solar power don’t put out any lights or put anyone out of business.

Such codes would help smooth over wrinkles in regional power markets and help ensure solar panels and wind turbines go up in areas where they are used best.

At the other end of the equation, renewables have a huge opportunity in isolated and off-grid communities in countries like Rwanda, Kenya and Tanzania.

“The reality is 90 percent of households in the rural parts of these three countries have never seen a grid, they’ve never seen and experienced a kilowatt-hour,” said Thomas Duveau, who leads business development at Mobisol. “Depending on how far you are from a town, a grid connection can cost $1,200 to $4,000.”

Mobisol retails solar energy kits for rural areas that include solar panels, batteries, LED lights, cellphone chargers and radios, with the goal of getting communities off dangerous and dirty kerosene lamps and diesel generators.

The kits start at $1,000 for 80 watts-peak, and the purchasers often use the kits to start businesses. The profit motive of customers is helping drive deployment of these systems, according to Duveau. “If you don’t make money, you’re never going to scale,” he said.

He added that these systems could help remote regions leapfrog grid connections as they develop, the same way many parts of the world skipped over landline phones toward cellphones.

“The future may lie in off-grid electrification,” Duveau said.