Renew your energy: October 2010 Archives
Scottish First Minister Alex Salmond has announced that Scotland's renewable electricity target for 2020 is being raised from 50% to 80% of electricity consumption, putting Scotland well in the lead in the EU. He's also said that 100% by 2025 was possible.
Scotland's existing 50% target was established in 2007 and, aided by a rapid expansion in wind power, the country is on course to exceed its interim target of 31% in 2011. According to the Scottish government, much higher levels of renewables could be deployed by 2020 with little change to Scotland's current policy, planning or regulation framework. A separate study commissioned by industry body Scottish Renewables, reported similar conclusions- 123% was possible! And Scottish Green Party co-leader Patrick Harvie even called for setting a 100% renewable target, 'perhaps even before 2020'!
The Scottish Renewables' report notes that, since the original 50% target was implemented in 2007, industry and government have announced agreements for 10.6GW of offshore wind development, commitments to 1.2GW of wave and tidal power in the Pentland Firth and Orkney Waters, 1.2GW of additional potential hydro capacity and proposals for over 500MW of biomass heat and power. It says that, together, even a small proportion of these plans would add significant capacity to Scotland's generation mix, changing the scale of development that Scotland can achieve over the next decade and beyond.
At present, Scotland has installed 7GW of renewables, under construction or consented. Salmond claimed that, given the scale of lease agreements now in place to develop offshore wind, wave and tidal projects over the next decade, 'it is clear that we can well exceed the existing 50% target by 2020.' He may be right, but 80% by 2020 is stunningly ambitious. Even the Centre for Alternative Technology only looked to 2030 in their 'Zero Carbon Britain', and that was pushing it very hard. While visionary scenarios can inspire/ motivate people to try harder, they have to be at least in principle credible. But unless there is a radical deployment/infrastructure development programme, beyond anything so far discussed, getting to 80% by 2030 might be a bit more realistic for Scotland.
They do seem to be trying though, with their own versions of support schemes that are much more ambitious than those so far introduced by the Whitehall government (e.g. under the Renewables Obligation Scotland they offer 5ROCs/MWh for wave energy projects and 3ROCs/Mwh for tidal projects, compared with the 2ROCs/MWh offered by the UK-wide RO schemes). And Scotland also has a direct grant-support system for marine renewables which has provided £13m for wave and tidal projects so far. Plus a £10m Saltire prize for marine renewables.
However, this may not be enough, an implication that emerges from a new report by Geoff Wood from Dundee University, which looks critically at the way the Scottish government has adjusted the Renewable Obligation Scotland. 'Renewable Energy Policy in Scotland: An Analysis of the Impact of Internal and External Failures on Renewable Energy Deployment Targets to 2020' is available at https://www.buyat.dundee.ac.uk/?compid=2.
Nevertheless there is no denying that Scottish government is pressing ahead hard. It has outlined its plans for achieving ambitious targets for reducing emissions by 42% by 2020, after a draft order to set annual emissions targets for 2010–22 was laid in parliament. The targets proposed in the draft order take account of advice from the Committee on Climate Change and the deliberations of a cross party working group over the summer. The annual targets for 2011–2022 start at 0.5% for 2011 and end with 3% for 2022, peaking at 9.9% in 2013 – going further than those recommended by the Committee. Scottish climate-change minister, Stewart Stevenson, said: 'Scotland has the most ambitious climate-change legislation anywhere in the world and these annual targets set a clear framework for achieving our 2020 target'.
It's certainly bold stuff. The SNP is clearly being courageous – some might say adventuristic. But even if their brave targets are not met, Scotland will still be doing more than many countries. And their non-nuclear approach does seem to be popular. A recent poll by the Scotsman newspaper found that only 18% of Scots supported new nuclear construction: http://thescotsman.scotsman.com/news/Only-1837-of-Scots-say.6551329.jp?utm_source=newsletter&utm_medium=email&utm_campaign=send.
You do have to be careful with poll data. An earlier YouGov poll for EDF found that 47% of Scots supported replacing existing nuclear plants when they closed. But it also found that 80% backed offshore wind farms and 69% were in favour of onshore turbines. It looks like they will get what they want in that area.
In Sept, Dr Paul Hatchwell, a consultant with ENDS, wrote a useful overview of UK energy options in an article for The Independent supported by Shell: www.independent.co.uk/life-style/ newenergyfuture/britains-energy-challenge-meeting-energy-generation-and-carbon-emission-targets-2068598.html
It laid out the problems as he saw them - chiefly, on the supply side, that nuclear was likely to be limited, Carbon Capture and Storage (CCS) was unsure, and renewables were not expanding fast enough, and set this against the governments evident belief that all was basicially well, with, for example, renewables on target to reach 30% of electricity by 2020.
He didn't however say what could be done to make sure this happened- or to do better than 30%, as many feel we must and could, although he did mention the supergrid idea.
But the recent 'Declaration of Support for an efficient renewable energy future', signed by several leading international academics, laid out a basic framework:
'We need to plan, optimize, and implement the renewable and efficiency revolution with all deliberate speed. We must improve the efficiency of our existing processes. This includes reducing waste and taking advantage of thermodynamic efficiencies through cogeneration, district heating and cooling, and heat pumps.
Renewable electrification means we must intelligently integrate and optimize decentralized and distributed energy resources, linking them over long distances with energy storage on a continental and even intercontinental scale if needed. Whatever we do must be subject to analysis of triple bottom line consequences--economic, ecological, and social, as subject to democratic control.
We must adopt, as needed, new market rules and regulations, such as proper utility and manufacturer incentives for efficiency and distributed generation, feed-in tariffs, high renewable portfolio standards, provision of sufficient loan and investment capital, and varied opportunities for investment.
We might use natural gas as a diminishing transition fuel for district heating and cooling, cogeneration, and transport applications while renewable electrification and fuels are not yet fully available.
We need to be cognizant of the security aspects and consider all possible advantages of the use and decentralized control of modern end-use devices, renewable generators, and cogenerators'.
To fill the gaps, in terms of specific policies, here are some suggestions for the UK context that have emerged recently focussing of electricity:
Impose a 'wind-fall' tax on oil companies to fund major energy efficiency programmes across the board.
Impose a 'wind-fall' tax on electricity supply companies to fund the rapid upgrade of the power grid, including more interconnections with the rest of the EU- the supergrid
Introduce a Cross-Feed Tariff to support the flow of green power between the UK and the rest of the EU on the supergrid.
Introduce a Feed-in Tariff (FiT) to support wave power and tidal stream turbine projects.
Expand the existing FiT to cover larger community projects and local biomass-waste fired Combined Heat and Power (CHP), and push ahead with the RHI.
Re-direct the various nuclear subsidies and R&D programmes to support rapid development of new offshore wind technologies, like floating wind turbines.
A new White Paper on Energy is due out next year, following the revised National Policy Statement on Energy. Much of this will focus on nuclear. But there may also be opportunities for more progressive commitments as outlined above- e.g. a revised FiT.
Similar lists are emerging for 'green heat' options- some looking to solar and biomass/biogas fed micro-CHP at the domestic level, but others suggesting a new focus on local district heating grids fed increasingly by medium/large biogas fired CHP or even large solar collector arrays and heat stores, as is being done widely on the continent- see my earlier Blog http://environmentalresearchweb.org/blog/2010/10/solar-power-brightens-up.html.
Some of the proposals above are contentious, and most would increase energy costs to consumers, at least in the short term. But then so would just about any measure to deal with climate change, and the proposals above are all targeted to meet specific technological and/or sectors goals, with there being good prospects for costs to fall as the technology develops.
Another approach is an across-the-board carbon tax of the type attempted unsuccessfully earlier this year by France. That relied on market mechanism to steer the choice of technology, in response to the revised costs of energy- a short-term market approach, focusing on the currently cheapest low carbon options.
The UK government's proposals for providing a guaranteed 'floor price' for carbon to boost the EU Emission Trading System, would make renewables and/or nuclear look more attractive economically. But otherwise it's untargeted, with, again, a short term focus. Moreover, if it worked to raise the (currently very low) value of carbon, consumer costs would rise and taxpayers money might also have be provided to maintain the high carbon price, if there was a market down turn..
It might be easier, although still untargeted, just to tighten the carbon cap set for the next round of EU ETS. But as happened last time, that would lead to conflicts with, and special pleading from, countries with currently high levels of fossil emissions. They might for example ask for continuation of the system where some carbon permits are offered free rather than being auctioned.
We certainly need to push harder to get green energy technology deployed, but as can be seen, there are disagreements about how bet to do this. While market led approaches have been adopted so far, and are still promoted, a more targeted approach, using Feed-In Tariffs coupled with hypothecated special taxes, might be a more effective way to raise and direct the money that will be needed.
Solar power is often seen as nice, but a bit marginal in chilly northern countries. The reality is different. There is now over 20 GW thermal of solar heating capacity in the EU, which much of it being in northern countries like Germany, Austria and Denmark.
A lot of it is roof top domestic-scale, but there is also now a growing contribution from large-scale systems. For example, solar district heating is now moving ahead around Europe. The District Heating network in the Austrian city of Graz has 6.5 MW of solar thermal capacity. And further North, Danish collector manufacturer Arcon Solvarme has installed a 10,073 sq. m installation in the village of Gram in the region Syddanmark, and a 8,019 sq. m system in the village of Strandby in North Jutland, which meets 18% of the average energy demand for heating and domestic hot water of 830 households. A third solar thermal system, with 10,000 sq. m, has also been installed in the town of Broager in the south of Denmark. It's claimed that schemes like this can achieve payback times of 7–9 years. See www.solarcap.dk and www.arcon.dk.
Germany also as some solar/DH projects. Nine research and demonstration plants have been built since 1996, including some with inter-seasonal heat stores. Depending on their size, they can meet 40–70% of the annual heating needs of a residential estate. In Friedrichshafen, a residential estate with some 600 housing units has a www.managenergy.net/products/R430.htmsmall-scale solar district-heating system.
PV solar meanwhile is also moving ahead rapidly around the world. The main issue has often been the costs, but they are now falling (some thin-film amorphous Silicon modules are now at below 7 cents/watt), with claims being made that PV will be competitive with grid power in some locations within two or three years. Indeed, it has been claimed that in North Carolina consumer charges in $/kWh for PV-delivered power are now less than for power that might be delivered at some point from new nuclear plants: www.ncwarn.org/?p=2290.
Of course PV enjoys subsidies in the US, but then so does nuclear. PV has also benefited from subsidies in the EU under the various Feed-In Tariffs, to the extent that a major market boom emerged, leading to price reductions, which further stimulated uptake. That rapid expansion lead to some cuts backs in subsidy levels in Germany and Spain, since it was claimed that too much extra cost was being imposed on electricity consumers, who in the end pay for the subsidy. But with prices continuing to fall, the extra cost should fall too, and the rapid progress of PV seems likely to continue around the world. One recent area of expansion in the UK, stimulated by the new Feed In Tariff, is on farms – with solar arrays now being installed: see my earlier 'solar farm' blog.
Globally there is around 22 GW of PV capacity in place, still much less than the 150 GW (Thermal) or so of solar heating capacity around the world, but catching up fast. By 2020 PV will generate 126 TWh of renewable power around the world, according to the latest International Energy Outlook 2010 from the US Department of Energy. By 2025 it will generate 140 TWh and by 2035, 165 TWh. China alone aims to have 20 GW by 2020. The DECC 2050 Pathways suggests that the UK might have 70–95 GW peak of PV in place by 2050, or more, if we really went at it hard, supplying 140 TWh by 2050 in their maximum scenario.
In parallel we are like to see rapid expansion of Concentrating Solar Power (CSP) in desert areas, with focused solar heat being used to generate electricity as well as CPV, focused solar PV units in deserts, some of this being exported to the EU. The International Energy Agency says 11.3% of global electricity could be provided by CSP by 2050. Others say much more. See my earlier CSP blog.
As solar expands around the world a key issue, which will become increasingly important, is cleaning. Like windows, the cell/mirror surfaces will collect up grime, dust and road grit and that must be regularly removed or else performance will fall – by perhaps 5% pa. Desert dust and sandstorms can also present problems for CSP mirrors – it's known as 'soiling'. But it could be that self-cleaning technology developed for lunar and Mars missions could be used to keep terrestrial solar panels dust free. Working with Nasa, Malay Mazumder from Boston University originally developed the technology to keep solar panels powering Mars rovers clean. But now he is working on a terrestrial version. It uses a layer of an electrically sensitive material to coat each panel. Sensors detect when dust concentrations reach a critical level and then an electric charge energises the material sending a dust-repelling wave across its surface. He says that this can lift away as much as 90% of the dust in under two minutes and only uses a small amount of electricity. Sadly, though ideal for deserts, back in the EU, it probably won't be useful for bird droppings!
The use of water and detergents for cleaning PV cells and solar heating panels could clearly open up some new environmental issues, but otherwise, as long care is taken to dispose of old PV cells carefully, or better recycle the constituent materials, there would seem to be few negative environmental implications from the domestic use of solar. Apart perhaps from the issue of glare, which is a siting issue, shared with other forms of glazed area. There can be toxic materials/health and safety issues in PV cells production, and some conflicts have been identified with desert wildlife in relation to CSP, but these problems should be amenable regulatory resolution.
Water use by CSP in deserts has been raised as an issue. It not just the water needed for washing mirrors. CSP needs water for efficient operation, as with any heat engine you need cooling. It can be done with air (fans blowing air across radiators) but that's inefficient (it uses energy) and adds about 10% to the cost. Water-cooling is better, but that's one thing you don't have in deserts. However you could import sea water, if you are within reasonable reach of the sea. That's one idea that being considered for some CSP projects in North Africa – piping in sea water from the Med for cooling, and also for desalination. The pipes could be hundreds of miles long, although that adds to the capital cost and uses some energy. And you'd end up with a lot a salt. But then, to be fair, other energy technologies also need water. A study by Virginia Tech University's Water Resources Research Center found that conventional fossil fuel require anywhere from 5 to 8 times as much water per million kWh produced as CSP, while nuclear plants need even more – 10 to 20 times as much/kWh as CSP: nuclear plants consume about a gallon of water for each kWh of electricity produced.
Of course, nuclear plants are not (yet) usually in deserts…although with climate change worsening there are likely to be increasing problems in providing cooling water even so. France has already had to shut nuclear plants down in the summer since the exit water temperature was higher than local river regulations allowed. It's likely to get worse. Getting access to cooling water could be an increasing issue for many land-based energy technologies- solar PV and wind apart.
There has been a proposal from B9 Coal to use AFC Energy's alkaline fuel cell technology with hydrogen produced from burning coal in situ underground in a 500 MW in Northumberland. Underground coal gasification (UCG) produces syngas, which is then passed through a clean-up process, resulting in separate streams of hydrogen and carbon dioxide. Upwards of 90% of the CO2 can then, it is claimed, be captured as a by-product at no extra cost. The pure H2 is passed through the fuel cell, converting to electricity at 60% efficiency at a projected cost as low as 4p per kWh.
UCG does avoid mining, with all its costs and risks. But UCG has some problems, as was found in early projects in the US and Russia. There have been accidental fires in coal seams underground which have been hard to control: one in Columbia County, Pensylvania, started 1962 and is still burning. The official response is that though relatively shallow coal seams can burn if an air flowpath exists, UCG cannot burn out of control. Combustion requires a source of oxygen, and this can in theory be controlled, so there is allegedly no possibility of oxygen reaching the coal which, for UCG, needs to be at a depth of 500 to 2000 metres and lying beneath impermeable rock strata. But even if that is true in practice, in situ coal does not burn cleanly or evenly – you get partial oxidation and a range of pollutants, including tars, phenols, ammonia. So there are clean-up costs.
More on UCG at: www.ucgp.com/.
Also the efficiency of making hydrogen from coal is usually said to be only about 65%. So with fuel-cell efficiency at best 60%, that gives and overall efficiency of under 40%, which may be low compared with direct use of mined coal in Integrated Gasification Combined Cycle plants, even with Carbon Capture and Storage (CCS).
However, why bother with complex and expensive IGCC plants? Why not just use the hydrogen direct as a heating fuel, sent to users via the gas main (piping gas is cheaper than power distribution by electricity grid). Or, if you really do need electricity, then use the hydrogen in homes in a CHP fuel cell – so recycling some of the otherwise wasted heat and raising the efficiency to maybe 70%.
Then again why use coal for the hydrogen source? What's wrong with biomass? That's more or less carbon neutral if it's replaced by regrowing. There is a range of ways for producing hydrogen, methane or syngas from biomass including anaerobic digestion, pyrolysis, and gasification. In one approach, biomass is gasified to make carbon monoxide, and then using the standard shift reaction (CO+H2O = CO2 + H2) this is converted to hydrogen, and while the CO2 is captured and stored, so making it overall carbon negative.
There are land-use and biodiversity limits to how much we want to rely on biomass, but, intriguingly, the Sahara Forest Project includes the idea of growing algae in seawater-fed desert greenhouses, and there is plenty of desert and sea water.
Of course, there is also quite a lot of coal and in situ coal gasification may open up a new approach to using old part-worked coal seams. But if we want to avoid both coal and biomass, then what's wrong with getting hydrogen using solar-, wind-, wave- or tidal-derived electricity, via electrolysis of water, or even by direct high-temperature dissociation of water via focused solar?
The latter is still relatively inefficient (1–2%) and both approaches are still expensive compared with conventional approaches to hydrogen production. However, the technology is improving. One 2009 study suggested that, while hydrogen produced via steam reforming of natural gas costs around $6–8 per kilogram of hydrogen, H2 from solar (via electrolysis) costs $10–12 per kg, from wind (via electrolysis) $8–10 per kg, and from solar via thermo-chemical cycles (assuming the technology works on a large scale) $7.50–9.50 per kg.
So we are getting there. For example, a 2002 study noted that PV costs of ˜$300/kWpk were needed to get H2 cost of $7-8/MMBtu via electrolysis, comparable with the cost of hydrogen production from coal, which, with current gasification technology, is $6.50-7.00 per MMBtu, or just over $8.00/MMBtu with CCS. www.netl.doe.gov/technologies/hydrogen_clean_fuels/refshelf/pubs/Mitretek%20Report.pdf.
But some PV modules are now claimed to cost below 76 cents/Wpk, and it's claimed that in some locations PV can deliver energy at costs below that from new nuclear plants, as can wind power. See www.ncwarn.org/?p=2290 and www.sourcewatch.org/index.php?title=Comparative_electrical_generation_costs.
However, electrolysis is only about 60% efficient, unless the waste heat can be recovered, and there is still a way to go before it, and other novel renewable powered or biomass-fed approaches, can rival conventional steam reformation of fossil fuels for hydrogen production on a large scale. So, if we want hydrogen, maybe we could go for coal UCG/ CCS just as an interim step?
Some of the above is based on discussions in the www.claverton-energy.com/Claverton Energy Group.
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