Tag Archives: Sustainability

UHVDC and China

Credit: Economist Article about UHVDC and China

A greener grid
China’s embrace of a new electricity-transmission technology holds lessons for others
The case for high-voltage direct-current connectors
Jan 14th 2017

YOU cannot negotiate with nature. From the offshore wind farms of the North Sea to the solar panels glittering in the Atacama desert, renewable energy is often generated in places far from the cities and industrial centres that consume it. To boost renewables and drive down carbon-dioxide emissions, a way must be found to send energy over long distances efficiently.

The technology already exists (see article). Most electricity is transmitted today as alternating current (AC), which works well over short and medium distances. But transmission over long distances requires very high voltages, which can be tricky for AC systems. Ultra-high-voltage direct-current (UHVDC) connectors are better suited to such spans. These high-capacity links not only make the grid greener, but also make it more stable by balancing supply. The same UHVDC links that send power from distant hydroelectric plants, say, can be run in reverse when their output is not needed, pumping water back above the turbines.

Boosters of UHVDC lines envisage a supergrid capable of moving energy around the planet. That is wildly premature. But one country has grasped the potential of these high-capacity links. State Grid, China’s state-owned electricity utility, is halfway through a plan to spend $88bn on UHVDC lines between 2009 and 2020. It wants 23 lines in operation by 2030.

That China has gone furthest in this direction is no surprise. From railways to cities, China’s appetite for big infrastructure projects is legendary (see article). China’s deepest wells of renewable energy are remote—think of the sun-baked Gobi desert, the windswept plains of Xinjiang and the mountain ranges of Tibet where rivers drop precipitously. Concerns over pollution give the government an additional incentive to locate coal-fired plants away from population centres. But its embrace of the technology holds two big lessons for others. The first is a demonstration effect. China shows that UHVDC lines can be built on a massive scale. The largest, already under construction, will have the capacity to power Greater London almost three times over, and will span more than 3,000km.

The second lesson concerns the co-ordination problems that come with long-distance transmission. UHVDCs are as much about balancing interests as grids. The costs of construction are hefty. Utilities that already sell electricity at high prices are unlikely to welcome competition from suppliers of renewable energy; consumers in renewables-rich areas who buy electricity at low prices may balk at the idea of paying more because power is being exported elsewhere. Reconciling such interests is easier the fewer the utilities involved—and in China, State Grid has a monopoly.

That suggests it will be simpler for some countries than others to follow China’s lead. Developing economies that lack an established electricity infrastructure have an advantage. Solar farms on Africa’s plains and hydroplants on its powerful rivers can use UHVDC lines to get energy to growing cities. India has two lines on the drawing-board, and should have more.

Things are more complicated in the rich world. Europe’s utilities work pretty well together but a cross-border UHVDC grid will require a harmonised regulatory framework. America is the biggest anomaly. It is a continental-sized economy with the wherewithal to finance UHVDCs. It is also horribly fragmented. There are 3,000 utilities, each focused on supplying power to its own customers. Consumers a few states away are not a priority, no matter how much sense it might make to send them electricity. A scheme to connect the three regional grids in America is stuck. The only way that America will create a green national grid will be if the federal government throws its weight behind it.

Live wire
Building a UHVDC network does not solve every energy problem. Security of supply remains an issue, even within national borders: any attacker who wants to disrupt the electricity supply to China’s east coast will soon have a 3,000km-long cable to strike. Other routes to a cleaner grid are possible, such as distributed solar power and battery storage. But to bring about a zero-carbon grid, UHVDC lines will play a role. China has its foot on the gas. Others should follow.
This article appeared in the Leaders section of the print edition under the headline “A greener grid”

Future Watch: Home Electricity Power Shaping

Like the quantified self movement (my Nike Fuel Band and my Apple Watch), and like the quantified car movement (my Tesla and my Ford Escape Titanium), I am ready for the quantified home movement.

I have a specific interest – but it falls under the general class of the “smart home” or the “internet of things”. For the latest on these trends, check out:
Business Insider on Smart Home

Specifically, I am ready for “power shaping”. Here is how it will work:

The subject is: can you take greater control of the power you consume in your home? Can you shape it to who you are and what you need?

For example:

– If I leave home for a week, can I turn the water heater down to lukewarm, and turn it back up a hour before I project I will arrive back into the home?

– If I leave home for an evening, can I turn the lights off except for three that I choose, and then turn the lights back on when my smart phone detects that I am a mile from the house?

– if peak power pricing starts at 4 and ends at 7, can I turn off my draw from the grid and turn on my draw from the PowerWall battery in my garage? And can that then trigger a recharge of the PowerWall when prices are cheapest, between midnight and 6 am?

– if the US Weather Service predicts, three days before, that the sun will be bright and hot from 9 am to 6 pm, can I plan to use solar power to the maximum? I choose to draw all of my electricity from solar during that time period, and then to add any left over to recharge my PowerWall (or sell back to the grid). In fact, I will set s goal for myself that I will be 100% solar 50 days this year, 70%+ solar 100 days, and 50%+ solar 150 days – without any inconvenience to myself or my family. Also, my goal is to be 100% “off peak draw” (only draw from the grid during off peak periods) 300 days this year.

– my goal is to reduce electricity draw by 30% and cost by 40% (by shaping my draw to off peak). This saves $1000 per year.

Process is entirely driven by default choices. The most basic default is “keep on keeping on”.

But there are other defaults – that I can buy or download.

For example, my power consumption can be driven by “expert user algorithms” that others say are awesome. I take advantage of what some geek has figured out about electricity usage.

Then, I “opt in” over time, and I learn about algorithmic capabilities, assets that I own (like solar panels), and needs that I have.

Apps are evolving to support this future. Take “COMFY”, for example.This is from NYT:

A couple of computer scientists have developed a smartphone app that proposes to solve that problem by making people the thermostats. Users can tell the app, called Comfy, whether they are hot, cold or just right. Over time, it learns trends and preferences and tells the air-conditioning system when and where to throttle up or throttle back the cooling. So far it’s used in a dozen buildings, including some of Google’s offices and some government-owned buildings, for a total of three million square feet. The developers claim Comfy-equipped buildings realize savings of up to 25 percent in cooling costs.
“We have a lot of data that people are most comfortable if they have some measure of control,” said Gwelen Paliaga, a building systems engineer in Arcata, Calif., and chairman of a committee that develops standards for human thermal comfort for the American Society of Heating, Refrigerating and Air Conditioning Engineers, or Ashrae.