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Renew your energy: April 2012 Archives

Some consumers have been able to make use of the 'Clean Energy Cashback' Feed In Tariff scheme to get paid for generating their own renewable electricity , and exporting any excess to the grid. Around 1GW of solar PV has now been installed in the UK as result. But not everyone can afford the large capital outlay for PV solar or other domestic-scale renewables. For those still keen to use green energy, one option is to buy it in via a green retail scheme. There are a lot on offer, but it is sometimes hard to decide how reliable they are- how can consumers be sure they are really getting green power?

To try to help, an independent voluntary Green Energy Supply Certification Scheme was set up for domestic consumers and small businesses, and has been running since Feb. 2011, with 13 UK green electricity tariffs certified by August 2011. The Scheme is bound by Ofgem's Green Supply Guidelines. It is overseen by an independent panel of experts with the National Energy Foundation as Panel Secretariat.

The Scheme awards a 'green label' to electricity tariffs that deliver a real, measurable green gains. Not all tariffs marketed as green in the UK are certified by the voluntary Scheme but evidently all those who have applied has been given certification without the need for major adjustments. However, despite relatively high public awareness of environmental issues, green tariffs still account for only 1% of demand. In part that is because of some confusion- and cynicism- as to what green power really is.

The basic initial idea was that suppliers would contract with consumers to match the electricity they use with electricity from renewable sources, and set green tariff rates, which were likely to be higher than normal rates. So it was voluntary scheme for those who wanted to support renewables more, since they cost more at present.

However it was complicated by the advent of the Renewables Obligation (RO) which requires suppliers to source increasing proportions of the electricity they sell to all consumers from renewable source, with the extra cost passed on to all comsumers. It would be unfair for the same electricity also to be sold under the voluntary scheme- those consumers would then in effect be charged twice. So it was proposed that the electricity had to come from projects that were outside/additional to those operating under the RO scheme. The problem was that there weren't many of them and they tend to be the higher cost projects, so pushing the voluntary green tariff level even further up.

Some critics also argued that, as far a developing renewables rapidly on a large scale was concerned, it was far better to go for the RO, which passed the extra cost on to all electricity consumers, than the rely on voluntary support from a small minority, who would otherwise be in effect subsidising others not to bother. But then that's the nature of charity, and if some are willing to pay more, altruistically, then it all helps. A more fundamental issue was that, as a Datamonitor Survey reported, 27% of respondents did not trust their energy company, and did not believe that their energy would actually come from (or be matched by) a renewable source. The Green Energy Supply Certification Scheme aimed to try to resolve that credibility issue.

In terms of the green tariffs on offer now, what has emerged is something of a compromise. Some green suppliers do supply 100% green power at a premium price from fully additional sources, or like Good Energy, 'retire' the ROCs they get from RO credited projects. But some don't charge more and don't use additional sources- in which case additionality is achieved by offering other, indirect, green benefits- specially established funds fed from a percentage from the sales receipts, for the development of renewable energy projects (e.g. the Juice fund for marine renewables) energy efficiency projects or eco/offset projects e.g. reafforestation.

The Green Energy Supply Certification Scheme requires that these projects must result in the abatement of at least a minimum level of carbon dioxide equivalent (CO2e) emissions- set at 50 kg p.a per tariff for funds/efficiency projects and 1 tonne for offsets. There has recently been a consultation on whether these levels should now be raised, and on other aspects of the scheme. The main concern however for it to be better known and used!

  • Next year consumers should be able to get support for installing heat producing renewables, under the proposed Renewable Heat Incentive domestic tariff scheme, but there are already some voluntary green heat retail schemes on offer.

Germany- to the max

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Germany now gets around 20% of it electricity from renewables with 28 GW of wind and 25 GW of photovoltaics, plus biomass and hydro. But it's aiming to expand that dramatically, in stages, to 35% by 2020 and 80% by 2050. Can it be done?

Germany can currently meet about 40% of its of its domestic power demand from PV solar on sunny summer days, while wind can supply a significant amount in winter when its strongest. In addition, within each season, both sources obviously vary from day to day and from hour to hour- and solar is always zero at night! These basic characteristics are the first key things you might need to know when considering if renewable can take over the bulk of power production. The second key thing is to do with location- most of the wind sites are in the north, the best solar in the south.

Given these two factors (timing and location) you can see why Germany is very focused now on energy storage and transmission issues. The basic energy resources are not the main problem - there seems to be enough to support a vast expansion: see

But the overall energy system will have to be radically revamped in order to use them effectively, with upgraded grid transmission and new storage capacity. However it goes beyond that. What is needed is a new engineering philosophy for the energy system design.

At present most power grid systems around the world are built on the basis of having a few large power plants feeding electricity down the grid to a large number remote consumers. Some of these plants, often nuclear plants, are kept running continuously to meet 'baseload' demand i.e. the minimum level of demand, while other plants are kept ready to ramp up to full power to meet the daily peaks in demand. For the moment renewables have simply been added on to this centralised system. But they don't fit very well. They are often variable, smaller scale and distributed around the country. They need a different, more decentralised and flexible system. And it has been argued that we need to decide which one we want to use in future.

Germany has already decided. The German-Federal Minister of the Environment Norbert Röttgen said in 2010: 'It is economically nonsensical to pursue two strategies at the same time, for both a centralized and a decentralized energy supply system, since both strategies would involve enormous investment requirements. I am convinced that the investment in renewable energies is the economically more promising project. But we will have to make up our minds. We can't go down both paths at the same time'.

On this view baseload isn't a help, in the new decentralised flexible energy supply and demand system, it's an inflexible hindrance. In the new system, rather than having 'always-on' baseload (e.g. nuclear) plants, and then following any extra load with peaking plants (usually gas), in the new system, variable loads and variable supply (from renewables) are balanced via a smart grid with demand-side measures, load peak shaving/delay, energy storage, and backup sources. That's just what Germany plans to move to.

The backup/balancing power will, for the moment, mostly be from natural gas plants, although later geothermal or biomass plants could take over. In addition use can be made of hydro reservoirs for storage/balancing- and that's going to be expanded in Germany. But the really interesting new idea is to use surplus renewable electricity to make green gasses, hydrogen and then also possibly methane, using some CO2, and store it for later use for generation to meet peaks. See

All this means that there's no need for nuclear baseload and that the use of natural gas can gradually decline. The Fraunhofer Institute modeled the renewables projected for 2020 and found that the need for baseload power will fall by half by then. Depending on how fast biogas substitution for natural gas can expand, that could mostly be coal fired by then. Ideally, given their carbon emissions, Germany should of course phase out coal plants before nuclear plants, or fossil gas use, but coal and fossil gas will be needed for a while for balancing.

There are of course other ideas. Nuclear supporters may say that, rather than going to all the bother of having wind plants backed up, why not stick to the old system and keep nuclear for baseload, and dump coal, while using renewables when they are available, storing any excess renewables as gas to meet peaks. In addition some new nuclear plants can load follow, to a some degree. They also point to the alleged wonders of Liquid Flouride Thorium Reactors, claimed as a safer nuclear option. But these are long shot ideas, decades away at best, and few in Germany will now look at nuclear. It is out, full stop. Instead it's pushing hard for a decentral system based on renewables and energy efficiency.

That has social and political attractions, as well as reducing carbon emissions and the threat of nuclear accidents. As Craig Morris has commented in an interesting review of the German programme, 'Germany is replacing central-station plants that can only be run by large corporations with truly distributed renewable power. While Germany's Big Four utilities make up around three quarters of total power generation, they only own seven percent of green power. Roughly three quarters of renewable power investments have been made by individuals, communities, farmers, and small and midsize enterprises'.

He notes that a 'a small-town energy revolution is going on in Germany, with more than 100 rural communities becoming 100% renewable.', and concludes 'so one reason why Germans might not mind paying a little more for green power is that they largely pay that money back to their communities and themselves, not to corporations'.

Will it work?

Phasing out nuclear by 2022 is a bold move. The opponents have painted grim pictures of prices hikes, blackouts, increased use of coal, with more emissions, and massive imports of nuclear electricity from France and gas from Russia. But in March 2011 the Federal Environment Agency, said that in principle 'all of Germany's nuclear power stations could be taken offline permanently by 2017,' without resulting in 'supply bottlenecks or in appreciably higher electricity prices.' Furthermore, it claimed 'Germany's climate protection targets would not be compromised and Imports of nuclear power from abroad are not necessary'. Given the 2022 closure date in the event chosen, although it will clearly involve major challenges, there should be fewer problems.

And certainly, in reality, the lights have stayed on, emissions have fallen (by 2.2% in 2011) and the small prices rises don't seem to have led to much opposition given the wide scale opposition to nuclear. In addition, Germany is still exporting power (net) to France, and as Craig Morris notes, if excess renewable power is converted into green gas and stored, then it won't have to worry too much about imports, or interruption due to the weather. He says that German researchers have estimated that getting 100% renewables would only 'require up to two weeks at a time to be bridged during the winter,' far less than the 4 months gas storage already available.

It looks like they can do it.

Craig Morrison's article: See also David Roberts helpful review:

German Renewable Energies Agency report: The Federal Environment Agency's 2011 report 'Restructuring electricity supply in Germany,' is available from:

Wire or Pipe?

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The UK's current energy plan envisages electricity being the main focus, with excess power from offshore wind and nuclear being used to run heat pumps and to charge batteries in electric vehicles. Natural Gas takes a back seat as a heat source, but is used in CCGT plants to supply some electricity, and these gas turbines also act as back-up plants to balance the variable renewables, although gradually some may become biomass fired. All of this will require new grid links, possibly also to the rest of the EU. So that's the 'wire' view.

It's the dominant one at present. The new DECC Heat Strategy review says 'electricity is universally available' and, in well-insulated houses, it says heat pumps can make using it for heating relatively economic.

The rival 'pipe' view is that electricity is a poor energy vector, since its transmission is lossy and it can't easily be stored, except via pumped hydro. Also domestic scale heat pumps are not that reliable, especially in cold weather.

By contrast, gas can be easily stored and transmitted: we actually already have an extensive low loss, high transmission efficiency gas grid, which handles around four times more energy than the electricity grid. Moreover, the gas grid acts as an energy store helping us to cope with variable demand. And we can produce biogas from municipal and farm wastes to provide a carbon neutral replacement for natural gas. In addition to its use for heating, some of this green gas could be used for local electricity generation, where needed, in CCGT or fuel cells. Some could even be used for vehicles, as a better option than mostly imported biofuels.

The weak point in this argument is that there probably won't be enough biogas to replace all the gas used for heating (National Grid says about 50%, optimistically), much less transport and electricity generation. There are land-use constraints to biomass production and limits to how much waste is available. Moreover, biomass and wastes are, in any case, more suited to local use e.g. in local Combined Heat and Power (CHP) plants, or heat only plants. That would avoid having to shift biomass/wastes in bulk around the country. It's not quite the same for biogas: although that's best generated locally from farms and municipal waste, and some could be used locally, some could also be distributed via the gas main, to power electricity generation plants where needed, as well as being use directly for heating in homes, as at present.

However the use of gas by consumers directly for heating may not be the best bet. Natural gas fired plants, and increasingly biomass fired plants, linked to district heating (DH) networks, could be more efficient option and play a major role, as elsewhere in the EU. Indeed solar-fired DH is now moving ahead across the EU, usually linked to heat stores, and in some cases inter-seasonal heat stores. So that's an extension of the 'pipe' view- we can distribute heat as well as gas. Clearly DH only makes sense in urban and perhaps suburban areas, and it also make sense, if we are burning gas, whether natural or bio, to use medium or even large scale high-efficiency combined heat and power plants. Then we also get some electricity, with the ratio of heat to power being adjustable.

The 'pipe' view is that this make much more sense, in efficiency terms, than installing micro CHP units in individual homes- with large CHP, the heat and power produced can be better balanced against the varying demands of large numbers of consumers. And big CHP/DH systems with heat stores can also help balance varying power grid inputs from renewables

Even so we may not have enough biomass or biogas to run this system- and any solar input will inevitably need backup. That's where the next element in the 'pipe' argument comes in. We can produce hydrogen gas, using electricity from excess off-peak wind and other variable renewables via electrolysis, store it and then add it to the gas main for distribution, or use it for electricity production when needed. Some also look to syngas production from renewable electricity for vehicle fuel.

There are some quite severe efficiency loss penalties with some of the energy conversion processes required for making, storing and using 'green hydrogen', but the technology is improving, with Germany taking a lead: see my next Blog.

So why not consider the pipe option? Certainly the 'wire' option looks tricky. It is likely to be hard to get enough electricity generation from renewables, like offshore wind, to meet all (or most) of the UK's power heat and transport needs. We are talking of perhaps, by 2050, 180-200GW of offshore wind, including floating wind farms further out to sea. Plus maybe some wave and tidal stream. If nothing else, the grid connection costs and problems for renewables on this scale look very serious. But the 'pipe' approach also has its limits. If we really are to avoid the biogas limits by producing hydrogen from
offshore wind (etc) for the gas grid, then we would come up against the same problem with getting enough offshore capacity. In both cases, with high costs - and a need for gas plant backup.

In a way then the two approaches are not that different, at least if we are talking, in the pipe version, about large scale generation of green hydrogen: they both rely on having lots of renewable electricity. But they do differ in the main transmission vectors - electricity or gas pipes or wires.

In theory we could have a mix of both: there could be some useful complementarity between the wire and pipe approaches, reducing some of the constraints. But in practice, under present competitive market approaches, there can be conflicts. For example, it's been said that in Denmark there is a danger that wind energy will drive CHP systems out of business: electricity production from local CHP systems in Denmark went down by 24% from 2000 to 2009. And in the UK, large scale CHP has hardly even started- we have had so much cheap gas. That may not change, if shale gas turns out to be plentiful and cheap, despite its alleged environmental risks. But in that situation, emissions aside, providing backup for wind would be easier, although the pipe lobby might still argue that gas should be used for heating rather than electricity generation.

Technological advances may help change the picture-if we adopt sensible approaches to infrastructure, so that new supply systems can be plugged on to the heat and power grids. Large scale heat pumps linked to DH systems, or large hydrogen or biogas fired fuel cells for urban CHP, are amongst the options. But cheaper offshore wind would be the key breakthrough. Or for that matter, cheaper wave or tidal power. Some also see PV solar as emerging to cut across much of this debate. Then again there's Carbon Capture and Storage. If that proves to be viable (and acceptable) on a large scale, then both the Wire and Pipe lobbies benefit, although the gas/pipe lobby might have an edge, since then the combustion of green gas/biomass would be carbon negative.

The DECC Heat Strategy Review looks at some of these options, but basically still comes down in favour of electrification of heat supply, with the role of gas diminishing, although it does also back district heating networks in urban areas. The debate continues!

A History of Energy

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Bent Sorensen, a leading Danish alternative energy pioneer, who wrote a seminal and massive text book on 'Renewable Energy' and many other important research papers (see, has turned his hand to a slightly different project and produced a 'History of Energy' (Earthscan). It looks in fascinating detail at the history of energy production and use, mainly in Denmark, from the stone age to the present day, linking that to social, economic and political developments and influences. So we move through early pre- history, the middle ages , the industrial revolution, the second world war and then on to the more recent battle against nuclear and the dramatic growth in the use of renewables.

In each era there is a detailed analysis of Danish energy generation and use, with, through most of history, ambient energy sources, food and muscle power inevitably playing the dominant role, but fossil fuels then rapidly taking over, leading to massive increases in energy use in recent decades- much of it based on imported fuel.

The historical details and interactions are well developed and it's inherently fascinating to view history from a national perspective other than one's own. Although academic historians might not be happy with the story telling and commentary, especially as the author was directly involved with some of the more recent events, that actually makes it very interesting. Indeed it might have been good to have more reminiscences, but then perhaps it would be too autobiographical. As it is, the marriage of energy and history, although strained in places, works well, leading to some interesting insights e.g. into why Denmark has been so progressive in relation to renewables and so hostile to nuclear- as symbolised by the ubiquitous 'Nuclear Power, No Thanks' smiling sun logo.

The 'bottom up' grass roots resistance to nuclear led to a decision to abandon plans for nuclear power and spilled over into practical 'bottom-up' support for the development of renewables. One factor in this seems to have been the existence of a national network of libertarian Folk High Schools. Starting in 1975, one radical school, Tvind, even built giant 2MW wind turbine themselves, completed in 1978- an amazing feat; well ahead of its time. It's still running:

It helped stimulate the boom in grass roots developed and co-operatively run wind projects in Denmark- with around 80% of Denmark's wind projects being locally owned. And the Danes continue to be innovative, with a plan from the new Centre-left government to get 50% of Denmarks power from renewables by 2020, with coal then being phased out from electricity generation by 2030, and all power and heat coming from renewables by 2035. All of course with no nuclear.

That's not to say there are not problems. Sorensen ends the book with a look at globalisation and consumerism, highlighting the 'enough is enough' view, but in true Danish style, in a non-dogmatic way.

With many other countries around the world now also looking to a non-nuclear future, Denmark is inevitably seen as something of a template, so this book could become very valuable, even if it doesn't provide much detail on the contemporary battles. For example, wind already generates about 25% of its average annual electricity output. But not all of it can be used in Denmark- at times there is too much and excess electricity is exported e.g. to Norway. At other times, when there's not enough wind, Denmark imports power back from them- e.g. from their large hydro plants, some of which can be used for pumped storage - in effect an interim store for Danish wind power. Overall it's roughly balanced, though Denmark gets charged more for the imports than it gets for its exports- so making its wind energy more expensive. But all this energy is non-fossil, so, wherever it's used, there's no carbon emission.

However energy demand in Denmark is still rising and national fossil fuel use hasn't reduced significantly yet, with as elsewhere, transport being a key issue. But they're clearly trying to tackle that and to get to zero net carbon, with increased commitment to energy efficiency and more use of renewables, including heat supplying renewables. Around 60% of Denmarks heat is supplied via district heating networks, some of it from biomass, and the aim is for around 40% of the district heating to be supplied from solar inputs, backed up by heat stores, by 2050.

Germany of course has a somewhat similar plan, following the decision to phase out nuclear entirely by 2022. It aims to get 35% its electricity from renewables by 2020, 50% by 2030 and then 80% by 2050, with parallel development of heat supplying renewables. Following the referendum last year, in which 94% opposed nuclear, Italy's new government is pressingly ahead with renewables strongly, PV especially. And with the Presidential elections soon in France, nuclear is a key issue: opposition has reached 70% in some polls, and the socialists have called for a phase out, with 24 nuclear reactors (nearly half the current fleet) being closed by 2025, and a commensurate expansion of the renewables programme. A similar phase out programme has emerged in Belgium, while Switzerland is not going to replace it nuclear plants- so in effect opting for a phase out.

With much of the rest of western Europe having long standing non-nuclear policies, and the UK nuclear expansion programme looking decidely shaky after the withdrawl of E.ON and RWE, it could be that, when and if a new 'History of Energy' is written, Denmark's pioneering stance may turn out to be the one that dominantes.

Of course the situation elsewhere is different. For example, in Asia. Although Thailand, Malaysia and the Philippines have all moved away from nuclear, India remains committed to nuclear expansion, as is China, and we still await Japans new plan. However, at present only one reactor is operating in Japan and it is far from clear if any of the closed plants will be allowed to reopen, given the widespread and expanding opposition to nuclear power following the Fukushima disaster.

Maybe times are changing. They do seem to be in Europe. For example, when E.ON pulled out of the UK nuclear programme, its CEO explained that "We have come to the conclusion that investments in renewable energies, decentralised generation and energy efficiency are more attractive - both for us and for our British customers".