Grid technologies to support renewable power


in Economics, Geek stuff, Politics, Science, The environment

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The MIT Technology Review has a good article about renewable energy and the ways electrical grids will need to change in order to accomodate it. Both key points have been discussed here before. Firstly, we need high voltage low-loss power lines from areas with lots of renewable potential (sunny parts of the southern US, windy parts of Europe, etc) to areas with lots of electrical demand. Secondly, we need a more intelligent grid that can manage demand and store some energy in periods of excess, for use in times when renewable output falters.

The article highlights how the advantages of a revamped grid are economic as well as environmental:

Smart-grid technologies could reduce overall electricity consumption by 6 percent and peak demand by as much as 27 percent. The peak-demand reductions alone would save between $175 billion and $332 billion over 20 years, according to the Brattle Group, a consultancy in Cambridge, MA. Not only would lower demand free up transmission capacity, but the capital investment that would otherwise be needed for new conventional power plants could be redirected to renewables. That’s because smart-grid technologies would make small installations of wind turbines and photovoltaic panels much more practical. “They will enable much larger amounts of renewables to be integrated on the grid and lower the effective overall system-wide cost of those renewables,” says the Brattle Group’s Peter Fox-Penner.

In short, a smarter grid holds out the prospect of overcoming the biggest limitation of electricity: that supply must always be exactly matched to demand, and that prospects for efficient storage have hitherto been limited. The storage issue, in particular, could be profoundly affected by the deployment of large numbers of electric vehicles with batteries that could be used in part as an electricity reserve for the grid.

Providing incentives for the development of a next-generation grid (as well as removing some of the legal and economic disincentives that prevent it) is an important role for governments – above and beyond the need to put a price on carbon. While carbon pricing can theoretically address the externalities associated with climatic harm from emissions, it cannot automatically deal with the externalities holding back grid development, which include the monopoly status of many of the firms involved, issues concerning economies of scale, the fact that the absence of transmission capacity restricts the emergence of renewable generation capacity (and vice versa).

The full article is definitely worth reading.

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{ 7 comments… read them below or add one }

Anon December 31, 2008 at 11:37 am

A more integrated grid won’t necessarily be better for everybody. People who live in places where power is cheap now will find themselves being outbid by people farther off. For instance, Quebec’s cheap hydropower will rise in cost when people along the east coast of the US can access it more efficiently.

Milan December 31, 2008 at 2:37 pm

It’s true that an updated grid would cause some people to lose out. That being said, the net benefits should be significant.

In the specific case you describe, the welfare increases in formerly high-cost markets should more than offset the welfare losses in formerly lower-cost markets. That being said, it might cause dislocation for industries that sited themselves specifically so as to be able to access cheap power. An aluminum smelter right beside a dam is unlikely to be happy when the dam is linked to a distant city, and consumers willing to pay more for every kilowatt-hour.

. March 17, 2009 at 1:53 pm

The net’s best introduction to the smart grid
Posted by David Roberts

Lynne Kiesling is a senior lecturer in the Department of Economics and in the Kellogg School of Management at Northwestern University, a member of the GridWise Architecture Council, and the proprietor of the excellent blog Knowledge Problem. She has written the best general introduction to the smart grid available (and I’ve read a lot of them!).

. May 18, 2009 at 5:46 pm

Electricity to power ‘smart grid’

Global electricity networks could become smart grids that can help us monitor and control our energy usage, if plans from net firm Cisco take off.

The giant US firm, whose technology helps underpin the net, is building a two-way link into electricity grids.

Smart grids would allow devices to communicate with utility firms to give an accurate view of energy use that could cut CO2 emissions by 211m tonnes

. June 11, 2009 at 3:44 pm

“Let’s find the fastest short-term change in a month of Irish wind data. On 11th February 2007, the Irish wind power fell steadily from 415 MW at midnight to 79 MW at 4am. That’s a slew rate of 84 MW per hour for a country-wide fleet of capacity 745 MW. (By slew rate I mean the rate at which the delivered power fell or rose – the slope of the graph on 11th February.) OK: if we scale British wind power up to a capacity of 33 GW (so that it delivers 10 GW on average), we can expect to have occasional slew rates of 3700 MW/h assuming Britain is like Ireland. So we need to be able to either power up replacements for wind at a rate of 3.7 GW per hour – that’s 4 nuclear power stations going from no power to full power every hour, say – or we need to be able to suddenly turn down our demand at a rate of 3.7 GW per hour.

Is a national slew-rate of 4 GW per hour completely outside human experience? No. Every morning, as figure 26.3 shows, British demand climbs by about 13 GW between 6.30am and 8.30am. That’s a slew rate of 6.5 GW per hour. So our power engineers already cope, every day, with slew rates bigger than 4GW per hour on the national grid. An extra occasional slew of 4 GW per hour induced by sudden wind variations is no reasonable cause for ditching the idea of country-sized wind farms. It’s a problem just like problems that engineers have already solved. We simply need to figure out how to match ever-changing supply and demand in a grid with no fossil fuels. I’m not saying that the wind-slew problem is already solved – just that it is a problem of the same size as other problems that have been solved.”

. June 21, 2009 at 10:25 pm

Building the smart grid

Jun 4th 2009
From The Economist print edition
Energy: By promoting the adoption of renewable-energy technology, a smart grid would be good for the environment—and for innovation

AROUND the world billions of dollars are being invested in clean-energy technologies of one sort or another, from solar arrays and wind turbines to electric cars. But there is a problem lurking in the power grid that links them together. Green sources of power tend to be distributed and intermittent, which makes them difficult to integrate into the existing grid. And when it comes to electric cars, a study by America’s Pacific Northwest National Laboratory (PNNL) found that there is already enough generating capacity to replace as much as 73% of America’s conventional fleet with electric vehicles—but only if the charging of those vehicles is carefully managed. In order to accommodate the flow of energy between new sources of supply and new forms of demand, the world’s electrical grids are going to have to become a lot smarter.

Even though the demands being placed on national electricity grids are changing rapidly, the grids themselves have changed very little since they were first developed more than a century ago. The first grids were built as one-way streets, consisting of power stations at one end supplying power when needed to customers at the other end. That approach worked well for many years, and helped drive the growth of industrial nations by making electricity ubiquitous, but it is now showing its age.

. March 30, 2011 at 7:04 pm

TenneT’s pylons should help allay that fear. Carrying all the cables in a “stack” between the poles, rather than hanging them separately on outward-facing arms, allows them to be arranged in a way that causes the individual fields generated by each cable to cancel each other out, weakening the overall field around the pylons. The result is far less low-frequency radiation. The combination of being less of an eyesore and producing less electrical smog should, TenneT hopes, soften objections to the construction of new overhead power lines.

That is important for two reasons. First, the alternative—burying high-tension lines—is expensive and largely futile. The cost of putting a cable underground is between four and ten times as much as that of carrying it on a pylon. On top of that, the field generated by an alternating current interacts with the ground more strongly than it does with the air. This creates losses 40 times higher in a buried cable than in an aerial one. Unless the long-distance-transmission system were converted to direct current (which reduces transmission losses, but brings problems of its own), burial of transmission lines is not a serious option.

The second reason TenneT’s pylons may be important is that despite these problems, a lot of new long-distance-transmission lines are going to have to be constructed, and soon. Wind power from the North Sea and the Atlantic Ocean will require that. So, more speculatively, will the idea of generating solar power in north Africa and transmitting it to Europe.

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