by Dave Elliott
A ‘Supergrid’ network across the EU and also connecting Northern Africa with Europe could help both regions reach a near-100% renewable energy share, with grid and market integration reducing overall energy costs. That’s according to a report published by Fraunhofer ISE in Germany, which involved five separate Fraunhofer institutes and saw some development work on system control hardware carried out alongside the desk studies. Similar ideas are also emerging in Asia, with a pan-Asian grid being proposed.
Werner Platzer, project leader and division director at Fraunhofer ISE, said the EU-North African study showed that decarbonizing the electricity supply in Europe and North Africa is feasible in a cost-effective manner: ‘in each of the scenarios modeled, very high shares close to 100% renewable energy were achieved by 2050’. However, if this near-100% expansion of renewable energy in North Africa were to benefit Europe, a transition to ‘a meshed superimposed HVDC [High Voltage Direct Current] grid with bipolar VSC technology which allows the transmission of fluctuating power from renewable power plants over long distances’ would be necessary. It would be expensive but integrating European and North African grids and national power markets would lead to lower costs overall, not least by reducing the use of expensive fossil fuels.
Concentrated solar thermal power plants (CSP), with heat storage, would play a major role in a renewable-based supply system in the MENA (Middle East and North Africa) region, as a ‘firm’ source, complementing the fluctuating generation from the wind and PV solar, which would be the primary methods of generating renewable energy. Interestingly, it was noted that ‘wind energy in North Africa has high and cost efficient potentials’, and would dominate solar, but that too was large, and overall it was found that ‘the total technical potential of the considered technologies in North Africa exceeds the assumed electricity demand of North Africa and Europe of 5850 TWh in 2050 by a large factor’. So it would be possible to ‘meet the electricity needs of North Africa by wind, CSP and PV alone’ and also ‘to export electricity to Europe’.
Their modeling, taking account of costs and temporal and spatial availability patterns, suggested that, depending on the scenario, in practice up to 1,575 TWh p.a. could be produced in North Africa, with, alongside local national use in the MENA countries, up to 117 TWh p.a. of net transmission across the region to other MENA countries and up to 347 TWh p.a net to the EU, all by 2050.
Although nothing like this is planned as yet, and the regulatory and political integration issues are formidable, CSP and PV development is ongoing in the MENA region, for local use, with near 2 GW in place and much more planned. The most recent to start up was the 160 MW Noor 1 CSP unit in Morocco, part of a planned 500 MW solar complex. In parallel, the beginnings of a supergrid network are emerging in the EU, with more and better links envisaged as part of the EU’s Energy Union plan. I will look more at that in my next post.
Brexit does of course mean that the UK may not be party to much of this, although new interconnectors are being developed between the UK and the continent. The UK government is now talking of up to 9 GW of new links on top of the existing 3 GW (plus 1 GW to Ireland), and possibly more: www.ofgem.gov.uk/electricity/transmission-networks/electricity-interconnectors and www.gov.uk/government/uploads/system/uploads/attachment_data/file/515993/gov_response_smart_power.pdf
The spread of offshore wind farms also involves the development of new undersea grids and some of these may in time be linked up as part of a wider supergrid. The EU has a 4-year project to boost the development of meshed HVDC offshore grids. It’s part of the Horizon 2020 Research Programme, and aims to develop and demonstrate diode rectifier offshore converters, multi-vendor HVDC grid protection systems and full power testing of HVDC circuit breakers. The project will also develop a regulatory and financial framework for coordinated planning, construction and operation of integrated offshore structures. DNV GL, one of the partner organisations, said: ‘Combining new HVDC technologies within present systems is instrumental in bringing large-scale renewables into the grid and to ensure a future-proof grid which is affordable, reliable and sustainable.’
The case for supergrids is that, in addition to enabling trade within a larger unified market, they can aid balancing of local variations in supply and demand and over wide areas. That can smooth out local peaks and troughs, allowing long-distance exchange of surpluses. It also enables access to large storage facilities like pumped hydro that not all countries will have. HVDC transmison has relatively low energy losses at around 2% per 100km, compared with up to 10% per 100km for DC transmission. But the new grid links will be expensive and the offsetting payback will depend on how much they are used – not all of the surplus occasionally produced in any one country may be saleable elsewhere at sensible prices, if demand in the other countries on the network is low and their local supply high. Even so, some studies have suggested there would be a net economic benefit for many countries in the EU: http://www.energynautics.com/news/#GP_EU
In the EU context, adding inputs from the MENA region would certainly improve the attraction of the EU-wide supergrid, so that extension may eventually be taken up. But maybe not just yet, given the political turmoil in the much of the MENA region. The ambitious German-led Desertec EU-MENA supergrid-CSP initiative has gone on the back burner, with few companies or banks willing to invest in major potentially risky projects like this: local green energy projects and grid developments within the EU are seen as more attractive. But longer-term it seems unlikely that the huge renewable resource in North Africa will be ignored. And providing secure and sustainable employment in this region would surely be very welcome, perhaps even stemming the flow of some of those displaced by war and political instability in parts of Africa. Supporting that might be a good use of EU aid…as well as being in the EU’s interests in energy terms, although care would have to be taken to avoid neo-colonialism and land grabs by northern investors: the resource must be used to benefit the region with fair trading of any exports.
On a vastly grander scale, there have been proposals from China for a global HVDC supergrid linking up renewables worldwide:
That is really pushing the envelope, although linking up some national grids could take us some way in that direction, without having to build vast new supergrid links. And as Buckminster Fuller once said, to get to an almost fully global grid, assuming interconnections between countries on land, you would only need a link 150 km across the Bering Strait, and 4000 km between Nova Scotia-Greenland-Iceland-Norway.
For the moment though, the most ambitious proposal is for an Asian supergrid, led from Japan, starting with a NE Asia Golden Ring, linking Japan, China, and South Korea with wind power from Mongolia and hydro in Russia. Some progress has been made, although there’s still a way to go on that! Meanwhile, the emphasis is on mostly smaller local new interconnector projects around the world, but that’s not insignificant, with around $10bn of investment likely to be involved by 2025.
* The case for supergrids is also strong in the US, as was noted in a recent NOAA study: