Windpower Engineering has an article on a small step towards building a north sea supergrid - ABB positioned highest voltage converter in North Sea.

ABB says it has installed the world’s highest-voltage offshore converter station in the North Sea. AC electricity generated in three wind farms off the coast of Germany will be converted on the platform into high-voltage direct current (HVDC) for transmission to the mainland. The 320 kV converter station has an 800 MW power transmission capacity making it the world’s most powerful installation of its kind.

The Conversation has an article proposing an Asian supergrid supplied with renewable energy from Australia that reminded by a lot of the Grenatec proposal that has been floating around for a while now (but is still getting some press attention) - The north’s future is electrifying: powering Asia with renewables.

Imagine a project that could help Indonesia achieve energy security, dramatically cut energy poverty for hundreds of millions, catalyse renewable energy production in Assocation of South East Asian Nations (ASEAN) countries, cut regional carbon pollution, and transition Australia’s energy exports from risky fuels to renewable energy.

Sounds far-fetched? In fact, such a proposal has already been published in the international peer-reviewed literature. It takes several existing technologies already in widespread deployment, and joins them together in a new configuration on an unprecedented scale, in a region with enormous natural competitive advantage — north-western Australia.

Here’s the plan.

Take part (say 2,500 km2) of an existing cattle station somewhere near Lake Argyle and cover one third of it with solar panels on tracking arrays. Build a large reservoir upslope at least 300 metres above Lake Argyle, holding at least 1,000 gigalitres of water.

Build a 100 gigawatt power station that uses solar energy to pump water from the lake up to the upper reservoir. The water flows back down the hill through turbines at night, generating power to the grid 24 hours a day, 365 days a year.

Hundreds of “pumped hydro” schemes of this nature are already working well around the world, albeit not on this scale.

The “grid” in this case, would be an integrated south-east Asian supergrid, the spine of which would be a High Voltage Direct Current (HVDC) cable running from northern Australia along the Indonesian archipelago and up into the Philippines, Malaysia and Indochina, and then eventually into China.

The capital cost of building such a power station, storage and HVDC link and extending it as far as Jakarta is estimated at around US$500 billion. This compares with Indonesia’s current projections that it needs to invest US$1,000 billion in conventional (coal and nuclear) power stations to meet its energy needs over the next 40 years.

Recharge has a look at interest in interconnecting the Irish grid to the UK grid to allow further expansion of renewable energy projects - UK and Ireland eye subsea links to boost green-power sharing.

Senior politicians from the UK and Ireland are meeting to discuss building a series of subsea interconnectors around the British Isles, in a bid to boost the commercial prospects of offshore renewables.

Closer integration of the two nations' power networks could open new markets for Irish-generated renewable electricity and help the UK meet its green energy targets.

Development of the offshore wind, wave and tidal sectors in Ireland has been stymied by the modest size of its local electricity market.

UK energy minister Charles Hendry notes that the west coast of Ireland has some of the most consistently fierce winds in Europe, yet hosts no offshore wind farms. Ireland’s only existing offshore wind facility is the seven-turbine Arklow Bank array in the Irish Sea – the world’s first commercial project.

"The Irish market for electricity is less than a tenth of that in Britain," Hendry says. "That means that companies cannot afford to build wind farms in Ireland because there is no market for their power. We want to put that right."

The only interconnector currently linking the Irish and UK grids is the 250MW Moyle line running between Northern Ireland and Scotland. Irish state-run grid operator EirGrid is currently building a 500MW link between County Fingal and North Wales.

But the politicians involved in the talks in London – including UK Deputy Prime Minister Nick Clegg, Irish Taoiseach (Prime Minister) Enda Kenny and Scottish First Minister Alex Salmond – believe those two lines should only represent a start.

The talks will include plans to better integrate a host of wave- and tide-rich islands into the UK grid, including the Isle of Islay, the Isle of Man and the Orkneys in Scotland – as well as the Channel Islands of Guernsey and Jersey, which are also represented at the discussions.

Tom Konrad at Alternative Energy Stocks has a look at the flaws in criticisms about overcoming the intermittency of wind power via widely interconnected electricity grids - Petersen's Wind Power Paradigm Paralysis.

The second part of my Paradigm article was headed "Wind and the Grid," and it appears that John stopped paying attention at this point. He certainly missed the sentence where I said "critiques of wind power's variability implicitly assume that nothing can be done to make the electric system more accommodating to wind, when in fact there is much that can be done," as well as the steps I outlined to address the problem.

Let's dissect how John's paradigm leads him to invalid conclusions.

John analyzed wind production data from five widely dispersed regions, finding that his model grid produced less than 12.5% of rated capacity 18.5% of the time, less than 6.25% of rated capacity 1.6% of the time.

That sounds pretty bad, doesn't it? He clearly thought it was bad, because he concluded, "wind power will never be stable or reliable enough to serve the needs of an industrialized society."

I find this conclusion a little hard to swallow. If he had said "never be stable or reliable enough to serve all the needs of an industrialized society," I would not have a problem with his statement. But he's trapped by the paradigm that says the only useful electricity is either always on (baseload) or dispatchable (on-demand.) Even with geographic diversification, wind and solar are neither, but they do serve the highly useful function of allowing us to conserve precious dispatchable resources (hydropower, some biomass, natural gas, energy storage, and demand response) to fill in the gaps when they are not available. This function does not serve all the needs of society, but it does free up valuable resources to serve those needs at other times.

Rated Capacity: The Wrong Yardstick

John's use of "rated capacity" of wind farms to measure shortfalls in production is also an artifact of the conventional power paradigm that exaggerates the lows in wind power production. With baseload resources such as coal and nuclear, which are often operating at full rated capacity, measuring output in comparison to rated capacity makes a certain sense, although even coal would not stand up to the test that Petersen expects wind to pass. A typical coal plant has a capacity factor of 80% to 90%. About 10% of the time, the coal plant is not operating at all (it may be down for maintenance, coal supplies may be delayed, or there may be some mechanical problem which forced it to shut down.) By Petersen's apparent logic, if coal plants are not operating at all 10% of the time, they must not be stable or reliable enough to serve the needs of an industrialized society.

This, of course, is bogus. Coal plants are useful, because most of the shutdowns are predictable enough that other resources can be made available to fill the gap in electricity supply. With planning, coal plants can even be shut down during periods when seasonal electricity demand is low, and electricity production from wind is high.

Wind is less predictable than coal, but weather is not random, especially over large regions a few hours in advance. With good weather prediction, the gaps in wind power can also be filled with other resources.

Maximum Production

Returning to "rated capacity," wind power produces on average between 20% and 40% of rated capacity, while a coal plant's average production (capacity factor) is between 80% and 90%. Comparing actual production to average production might bias the numbers in favor of wind, just as comparing actual production to rated capacity biases the numbers in favor of coal. A fairer comparison falls in between: comparing actual production to maximum production. For dispatchable and baseload resources, maximum production and rated capacity are the same. For a diversified portfolio of variable resources, maximum capacity is considerably lower than rated capacity.

For the portfolio of four widely dispersed wind turbines I discussed in my article "Why Geographic Diversification Smooths Wind Power" the maximum production was 93% of rated capacity. That was for a portfolio of four widely dispersed turbines.

Petersen collected much better data than my own, so I asked him for a copy of his spreadsheet. He gathered wind production data for five widely dispersed regions, each of which contains hundreds of turbines. Over such a large region and so many turbines, maximum production will be far below the rated capacity of the system. In particular, the maximum production from his 16 GW-rated supergrid was only 7 GW, well below half the rated capacity.

Compared to the maximum output of 7 GW, the electricity production from Petersen's supergrid looks much more stable. ...

As we can see from the graph, wind power production in January is fairly well behaved. Minimum production was 900 MW, or 13% of the system's maximum production. July production falls well short of 1 MW for two six hour periods, when it is 468MW and 356MW, or 5% and 7% of maximum production. While these lows in production are not good, comparing them to notional rated capacity (more than twice maximum production) creates the illusion of a much greater shortfall in production than actually exists.

Below, I've prepared a histogram of wind output for Petersen's supergrid. I found the relative consistency of wind output in January 2010 particularly striking, with wind production being between 3 GW and 4 GW over 40% of the time.

Conclusion

Variable resources like wind cannot substitute for dispatchable power, but they can produce valuable energy cheaply when they are available. The less variable the wind power resource is, the less dispatchable power is needed to back it up, and the most economical way to reduce variability is geographic diversification.

To see just how effective geographic diversification can be, compare the above histogram of the wind power output of Petersen's supergrid with the equivalent histogram below of one of the supergrid's five components: the wind output from the Bonneville Power Association (BPA) region.

If we want to see large-scale integration of inexpensive wind power, producing no global warming emissions and requiring no water, we'll also need to greatly enhance our electric grid. Wind power investors should also be transmission investors.

The Guardian reports that north sea countries are planning a "vast clean energy project" - Sun, wind and wave-powered: Europe unites to build renewable energy 'supergrid'.

It would connect turbines off the wind-lashed north coast of Scotland with Germany's vast arrays of solar panels, and join the power of waves crashing on to the Belgian and Danish coasts with the hydro-electric dams nestled in Norway's fjords: Europe's first electricity grid dedicated to renewable power will become a political reality this month, as nine countries formally draw up plans to link their clean energy projects around the North Sea.

The network, made up of thousands of kilometres of highly efficient undersea cables that could cost up to €30bn (£26.5bn), would solve one of the biggest criticisms faced by renewable power – that unpredictable weather means it is unreliable.

With a renewables supergrid, electricity can be supplied across the continent from wherever the wind is blowing, the sun is shining or the waves are crashing.

Connected to Norway's many hydro-electric power stations, it could act as a giant 30GW battery for Europe's clean energy, storing electricity when demand is low and be a major step towards a continent-wide supergrid that could link into the vast potential of solar power farms in North Africa.

By autumn, the nine governments involved – Germany, France, Belgium, the Netherlands, Luxembourg, Denmark, Sweden and Ireland and the UK – hope to have a plan to begin building a high-voltage direct current network within the next decade. It will be an important step in achieving the European Union's pledge that, by 2020, 20% of its energy will come from renewable sources.

"We recognise that the North Sea has huge resources, we are exploiting those in the UK quite intensively at the moment," said the UK's energy and climate change minister, Lord Hunt. "But there are projects where it might make sense to join up with other countries, so this comes at a very good time for us."

More than 100GW of offshore wind projects are under development in Europe, around 10% of the EU's electricity demand, and equivalent to about 100 large coal-fired plants. The surge in wind power means the continent's grid needs to be adapted, according to Justin Wilkes of the European Wind Energy Association (EWEA). An EWEA study last year outlined where these cables might be built and this is likely to be a starting point for the discussions by the nine countries.