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Jacobson’s new 100% renewables model aims to rebut critics

By Dave Elliott

Prof. Mark Jacobson and his team at Stanford University got some flack for their 100% global renewable energy study last year. It said 139 countries around the world could obtain 100% of their energy from wind, water and solar (WWS) sources by 2050. It had been based on their 2015 study that examined the ability of 48 US states to meet all their energy needs stably from these renewables. Some said their approach was flawed, and, for example, relied too heavily on energy storage solutions and on adding turbines to existing hydroelectric dams to get extra power: see www.pnas.org/content/114/26/6722

In response, Jacobson and colleagues at Stanford, the University of California at Berkeley and Aalborg University in Denmark have now produced a new study, focusing on 20 global regions encompassing the 139 countries, with supply and demand matching modelled for a range of storage/backup options over the period 2050-54. www.sciencedirect.com/science/article/pii/S0960148118301526

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Supporting Renewables: FiTs not tenders?

By Dave Elliott

More and more national governments are transitioning from guaranteed price feed-in tariff models for supporting renewables to competitive tendering/contract auction schemes, justified in the belief that this will reduce costs. That’s the EU view, and tenders have also been backed by the International Renewable Energy Agency.  However, the German Energy Watch Group say this is a mistake: FiTs have been very successful and widely adopted, whereas there are big disadvantages with tenders, their main effect being that less capacity is installed, with smaller projects being excluded and competition actually being reduced. Continue reading

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EGU 2018: robot boats assess the Danube

028Every morning this week, thousands of geoscientists have taken the U1 train from central Vienna across the Danube to the European Geosciences Union 2018 General Assembly. On Wednesday morning, in what may have been a meeting first, some of them ventured just a few minutes away from the conference centre to the banks of the Danube to test out a couple of robot boats.

The boats – one large, one small – offered complementary measurements. The smaller is under development by IntCatch 2020 for citizen science projects and can be run autonomously, automatically spiralling or motoring in a grid to take data on water quality. EGU delegates were also able to drive the boat by remote control and see the data it was collecting via a weblink on their smartphones.

boat data

Demonstration data collected on the Danube by delegates at the EGU Assembly using a robot boat developed by IntCatch2020.

The boat, which is fitted with GPS, could help citizen scientist data make more impact with policy makers – it’s currently underused. Since the boat can take measurements and collect water samples autonomously it doesn’t need an expert to be present and its georeferencing means citizen scientists can prove, for example, that they didn’t fix their measurements by taking them directly from a sewage outlet. What’s more, as Nathalie Gilbert of Thames21, UK, put it, the boat can “get to places you can’t go with a bucket”. The IntCatch 2020 project is half-way through and looking for collaborators. So far, test sites have included Lake Garda in Italy and the river Ter in Spain.

EGU Danube bathymetry measurements

Bathymetry measurements taken on the Danube by the ARC-Boat during the EGU General Assembly. The Austria Center Vienna is visible top right.

The larger boat, some 2 m long, held an acoustic Doppler current profiler with up to 9 beams to measure river flow and sediment load. Using this ARC-Boat is much faster than taking measurements using traditional flow measurement techniques, as Nick Everard of the UK’s Environment Agency explained. Better still, since it’s remote controlled, nobody puts their life at risk in a manned boat.

Older techniques such as rotating element current meters take data only at specific points in the river and can require up to five people (if using a boat rather than suspending the kit off a bridge) to measure a site in one day. The acoustic Doppler current profiler on the ARC-Boat, on the other hand, profiles a river in just a few minutes. Two people can assess up to six sites in one day, making this method some 15 times more efficient. The boat is big enough to deal with floods but splits into two parts for transport in cars. And if you include GPS on board, it can also map a river’s bathymetry as well as velocity. This “lifts the lid on the river”, Everard said. Next the team wants to add water quality measurements and autonomous control. “Don’t just model, measure,” said Everard. “Measuring is more fun”.

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EGU 2018: could eagle ‘eyes’ measure urban boundary layer?

Victor the eagle and his assistant Jacques-Olivier Travers.

Victor the eagle and his assistant Jacques-Olivier Travers.

Rick Thomas is an experimentalist, he likes to test the models. Normally, he does that using sensors attached to drones and planes. But you’re not allowed to fly drones over cities and to measure the urban boundary layer you must stay lower than an aircraft can go. The answer? A tame white-tailed eagle. Complete with sensor pack and GPS tag, the eagle can fly above the city and record the temperature of the atmosphere at the heights Thomas needs. Just one snag, first the Birmingham University, UK, researcher had to check if the eagle’s body would heat up the sensor and give false air temperature measurements.

Fortunately, tests above the Scottish countryside for the Cityflocks project revealed that if the eagle flies above a certain speed, the sensor will provide an accurate temperature reading. It helps that when the eagle is flying with its head down, the sensor faces directly into the airflow without obstructions. When the eagle’s at rest, however, that’s another matter – Thomas’s readings show the measured temperature rising when the bird takes a break.

Trained eagles are hard to come by so Thomas has also tested a smaller, lighter version of the sensor pack on homing pigeons, as yet only in rural areas. He’s teamed up with the Royal Pigeon Racing Association, who are interested in finding out more about the routes their pigeons take. There are also plans afoot to put the sensors on gulls in Birmingham, which could have the side benefit of revealing more about their behaviour. Thomas is keen to stress that all the necessary precautions were taken to ensure the welfare of Victor and the other birds.

As well as presenting his findings in a couple of posters at the EGU 2018 General Assembly in Vienna, Thomas has also published some of these results in an early online version.

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EGU 2018: shaken not stirred

Graeme Marlton of the University of Reading, UK, demonstrates the hertz project, which translates infrasound from natural phenomena into sensations that humans can experience. Image credit Hugh Mortimer.

Graeme Marlton of the University of Reading, UK, demonstrates the hertz project, which translates infrasound from natural phenomena into sensations that humans can experience. Image credit Hugh Mortimer.

It’s not every day you get shaken by Mount Etna. Particularly if you’re a long way from Sicily. But researchers at the European Geosciences Union general assembly in Vienna attending the science and art session could sit on a chair attached to a transducer – as used in cinemas and by gamers looking for a 4D experience – and feel recordings of infrasound from the volcano. Those desiring a more gentle option could experience the aurora borealis instead.

Together with artist Juliet Robson, atmospheric dynamicist Graeme Marlton of the University of Reading, UK, has developed the tech for public engagement in a project known as hertz. Those using the art exhibit for real sit in front of a sub-woofer that blasts out the infrasound once the kit has translated it to frequencies just high enough for humans to hear (by playing it some 200 times faster), so they hear as well as feel the natural phenomena. Infrasound, which has frequencies less than 20 Hz, is created by ocean waves, the aurora, volcanoes, supersonic aircraft and glaciers, among others.

Robson, Marlton and colleagues are looking for further applications and partners for their project so get in touch if you’d like a chair for your meeting or events space.

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EGU 2018: how to distinguish football celebrations from dancing

by Liz Kalaugher

During the FC Barcelona vs Paris Saint-Germain match in March 2017, Barcelona scored the vital sixth goal the team needed during the final minute of the game. The home crowd celebrations shook the ground enough to record a large signal on the seismometer installed by Jordi Diaz in the basement of the Institute of Earth Sciences Jaume Almera-CSIC building, some 500 m away from the Camp Nou stadium.

Seismogram from Bruce Springsteen concert

Seismic record captured by the seismometer installed in the ICTJA-CSIC during the Bruce Springsteen concert at Camp Nou on May 14, 2016. The upper panel shows the seismogram, while the lower panel shows the spectrogram where it is possible to see the distribution of the energy between the different frequencies. (Image Jordi Díaz)

Initally Diaz installed the kit as a fun way to communicate about seismology to visitors. When he realized that the equipment could have serious uses too he added a second system, as he revealed at a press conference at the European Geosciences Union general assembly in Vienna.

Not only does the seismometer pick up signals from football crowds as they enter and leave the stadium and jump up and down after goals, in 2016 it even distinguished between songs at a Bruce Springsteen rock concert based on the ground movements as 65,000 peop

le danced to the different rhythms. Because the music fans’ movements were more coordinated than the football fans, the signal the seismometer detected was clearly distinct to that from goal celebrations.

As well as ‘footquakes’, the kit also detects vibrations from traffic with enough detail to show when traffic lights on Diagonal Avenue – some 100 m away – turn red, from the subway system, from fireworks, marathon runners, storms and oceanic waves. The 2.8 Hz signals created by the runners revealed they were running at a pace of 170 steps per minute.

Apart from monitoring football matches, dancers and runners, the seismometer could provide additional information to engineers by revealing whether buildings respond similarly to different types of vibrations. It could also monitor traffic from a distance.

 

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Renewable subsidies – and jobs

By Dave Elliott

A report from the Council of European Energy Regulators Status Review of Renewable Support Schemes in Europe puts the weighted average subsidy paid to renewable generators in EU 26 in 2015 as €110 /MWh. The maximum was €184/MWh in the Czech Republic and the minimum €16.2/MWh in Norway, while the UK came in at €75/MWh.

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Development aid and renewables: from aid to trade?

By Dave Elliott

Over the years, a lot of support has been provided for renewable energy projects in Africa, most recently under the UN Sustainable Energy for All programme, with the EU taking something of a lead. However, a shift in emphasis from development aid to economic partnership and trade is emerging, with private sector investment, local economic development and local enterprise seen as central, for example via Germany’s new ‘Compact with Africa’ initiative, the so-called Marshall Plan for Africa.

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Can nuclear be used to balance renewables?

By Dave Elliott

Nuclear plants are designed to run flat out, in part to recoup their large construction costs. Their output can be varied a bit, but this entails thermal stresses and potential safety issues with the build up of active xenon gas that is released when fission reactions are reduced. It needs time to decay. That limits how often and how quickly the plant can be ramped down and then back up so as to match changes in energy demand (“load following”) and the varying output of renewables. So basically nuclear plants are inflexible. Do they have any role for balancing variable renewables?  Continue reading

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Rotatiload! Synchronous inertia and frequency stability

By Dave Elliott

Power engineers worry that, as more renewables are added to the grid, replacing old coal, gas and nuclear plants, we will loose lock-step AC synchronous system stability, since the latter had large heavy rotating turbo-generators which provided system inertia against frequency perturbations. The big plants’ rotational inertia acts as a buffer to grid frequency changes, and to varying supply and inductive loads. However, PV solar has no rotational inertia, and wind turbines not much, though direct drive machines can provide some. With more renewables on the grid it will become more of an issue: https://arxiv.org/pdf/1312.6435.pdf

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