Monthly Archives: January 2012

Back of the envelope maths

Solar PV capacity registered with Ofgem Oct-Dec 2011: 178 MW

= 59 MW / month

Average annual generation: 800 kWh / kW

Difference between old FIT rate and new FIT rate: 22 p / kWh

Number of households in UK: 20 Million

Cost of leaving the FIT for another month:

60 (MW) x 1000 (MW –> kW) x 800 (kWh/kW/yr) x 0.22 (£/kWh) = £10.5 M

Cost per household = 52 p/year


Feed in tariff review review Part 3: I fought the law and the law(yers) won

Much shorter than the previous two parts as there are fewer issues to point out.

The government has put draft legislation before parliament which means that any installations from March the 3rd will be on the new rates. If they hadn’t been so busy fighting a court case they had almost no chance of winning. If they hadn’t used your money to pay lawyers to argue until they’re blue in the face that up is down. If they’d got on with doing this as soon as parliament re-opened after Christmas they could have brought that deadline forward a couple of weeks.

The government are now pursuing an appeal at the Supreme Court. Given they were told at the High Court that they needn’t bother the appeal courts because they’re just plain wrong and they were told the same thing by the Court of Appeal, we need to ask why they choose to spend tax revenue on lawyers rather than solar power. Is it because most politicians come from a legal background?

Actually no, the whole point of spending tens of thousands of pounds more on a doomed appeal to the Supreme Court is to sow uncertainty. No reputable solar installer can guarantee a customer that their installation will get the existing rates if installed before March the 3rd even though the likelihood of this is near total. The government wants to keep the number of systems being installed under the current rates as low as possible and is using very cynical means to achieve their aims.

Until we see the costs of a legal challenge at the Supreme Court we cannot be sure but I would be very interested to see the figures on the FIT payments to the extra systems that could be installed  in five weeks and a comparison to the legal costs government has given itself fighting a losing battle. Embarrasingly.

Wouldn’t that money be better spent on solar power than legal fees? Or teachers, hospitals, the police for that matter?


End Use Efficiency is a good idea because…

Occasionally, I hear someone talking about how it makes more sense to make power stations more efficient rather than making incremental improvements to efficiency at the point of use.

Obviously I’m in favour of efficiency improvements anywhere (except maybe in the NHS where they are “efficiency improvements”). I’m going to use what’s called an Energy Flow Diagram (I prefer the other name, Sankey Diagram, it has more character). This one is from the British Government and shows where our energy came from and where it was used in 2010.

UK Energy in 2010

On the diagram, you start on the left with all your energy inputs, 314.7 Million Tonnes of Oil Equivalent of (top to bottom) Gas, Coal, directly produced electricity (mostly Nuclear with a little Hydropower and Wind), Biofuels, Petroleum (oil).
Anything that turns and scoots off the bottom of the diagram is either being exported or represents the energy lost in converting energy into another form. The Green ones at the start are oil exports, the big Light Purple one is power station losses and the Skinny Multicoloured one like an old school data ribbon is losses incurred moving energy around our gas and electricity networks.

Now, moving left to right, you follow the fuel (and electricity) through the system until on the right you reach the 159.1 Million Tonnes of Oil Equivalent of users.
There are two big yellow blocks in the middle. We can pretty much ignore the first one, oil refineries but it’s worth mentioning because this is where the diagram really gets started once we close the system to imports and exports. Our total national demand for energy inputs is 227.5 Million Tonnes of Oil Equivalent.

WARNING: This next bit (the second yellow block, power stations) is me going all information overload and explaining a bit of the diagram I wasn’t going to write about. It explains what it means in interesting but unnecessary detail. If you want to skip it I’ll let you know when it’s over.

The second big yellow block is power stations, people are right to care about this bit. Looking at this diagram they produce 31.3 Mtoe of electricity and waste 46.of Mtoe of the energy that was in the fuel for an average efficiency of about 40%. This seems pretty rubbish but it’s not all that bad. At the moment you can’t get much past 60% efficiency for a gas fired power station. More efficient basically means burning hotter and if we want to go any hotter than we already do, we’ll have to invent some pretty magnificent materials. Coal power stations are less efficient. To start with if someone gives you the choice of coal or gas to burn, take the gas every time. Coal is a solid. If you want to burn it efficiently you have to smash it to smithereens first (think flour, only you wouldn’t want to eat that cake). That process takes energy and even then, coal just won’t burn like gas does so your power station is running colder (remember that’s the same as less efficiently). There are a bunch of improvements you can make to the sort of 1960s and ’70s coal power stations we have in Britain and, if you use them all (expensive) then you might get a bit more than 50% efficiency.


So here we are at the right of the diagram. As you can see, there are three big end points in the diagram. The first is industry, the second is transport and the third is domestic.
The really cool thing is you can look at the colours of the arrows to see what fuels end up where.
The first thing you will have noticed is that we pretty much don’t use oil except for transport and we pretty much use nothing else for transport (it’s not easy to get the energy sources for walking and cycling onto this chart but it hardly matters, they’re tiny in energy terms).
The second thing I hope you’ll notice is that we use way more gas than electricity. At work it might be about 50:50 but at home it’s more like 80:20.

So there are two points I’ve been taking a while to make. The second has a caveat. Sorry.

1. For every 1% saving in energy consumption at the end of this diagram this amplifies as you go back across the diagram so saving that one percent over here means we save 1.43% of the fuels we need to feed in on the left of the diagram, an extra 0.43%! If we make power stations 1 percentage point more efficient we’d get another 0.78 Million Tonnes of Oil Equivalent out of the fuels we put in, 0.34% of the energy we needed at the start.

2. Our homes are leaky as a rusty bucket. George Monbiot once said they have a thermal performance only marginally better than tents. Sad but true. If we want to reduce our energy usage we need to be looking at heat about four times as hard as we look at electricity. Perhaps, given that it’s relatively difficult to make some of those savings from electricity (replacement of cyclical goods or wholesale lifestyle changes) we should try even harder on the heat side where the answer is simple and it’s keeping the heat in our buildings.

I said there would be a caveat on the second one and here it is: Gas is about three times less carbon intensive (and about the same or even more for money) than our electricity so from an environmental point of view any of these electricity vs. gas numbers can be divided by three. Household greenhouse gas emissions from energy are 57% gas, 43% from electricity and only a quarter of industrial emissions.

What am I doing? Well, I live in a rented flat so I do what I can which is mostly being energy conscious; turning off lights, closing doors to the warmer rooms and replacing old bulbs (there will be a blog about LEDs, my friend solar power’s distant cousin in future). I have learned how to use what passes for heating controls in my house, they’re not the worst but they could be better. But what I need to do that I’ve been lining up is to buy an egg-timer so I don’t spend too long in the shower. It’s probably the easiest change I could make, I’ll get to work earlier and I’ll be cutting down on both gas and water usage so it’s an all round win.

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Feed in tariff review review Part 2

At the end of October came the real bombshell. We all knew that tariffs would come down in April  2012 and, given the cost reductions achieved, we would be looking at at least a third off the tariff levels as they were. As it turned out, they went even lower dropping by just over fifty percent. This on its own wasn’t too bad. We can make that work for a lot of systems, particularly in southern areas.

What it did mean was basically an end to free PV schemes where an installer would provide a PV system in exchange for FIT income. With the right financing in place this was an economically viable prospect. It also meant that those without ten grand lying around could get solar power and was increasingly being adopted by social housing providers to help cut the bills of some of the poorest in our society. Now that won’t work any more and the accusation that solar power is a toy for rich greens holds truer that ever.

The other big change coming in is a double edged sword, households wanting to install solar and claim the FIT need to meet a ‘C’ grade for energy efficiency which rules out about 90% of homes. Nobody disputes that as a carbon saving measure, PV is quite expensive and energy efficiency measures are much more cost-effective. Now encouraging energy efficiency, particularly in the domestic sector is like trying to make water flow uphill. Nobody finds it very interesting, not many will brag to their friends about the foot-deep insulation they’ve put in the loft because it’s not exciting enough. Even the relatively easy things like loft insulation fall victims to our inertia (Where will I put the Christmas decorations while I got the insulation put in? Will I end up setting fire to the insulation around my recessed halogen lights?). And most household energy efficiency measures are to save heat not electricity. The comparison I read today by Erica Robb of Spirit Solar was that to make heat saving home improvements a requirement of the solar FIT would be the same as making it a requirement for road tax reduction for low CO2 cars, it might sound a bit silly but it’s basically correct.

Interestingly, one of the latest lines to emerge from the Government is that for every PV system getting a tariff of 43 p/kWh, two will be unable to get a system installed at 21 p/kWh. Now by my maths, if one system is installed at 42 p/kWh then that’s the same cost to the FIT scheme of two at 21 p/kWh. So for every system that gets 43 p/kWh a whisker over one will not get the 21 p/kWh rate (assuming the overall cost of the scheme is fixed).

There now follows a short list of things the Government did wrong on this FIT review:

  1. They should have looked at reducing all PV tariffs when they reviewed the 50+ kW tariffs back in March 2011.
  2. They tried to make the changes come into effect before the end of the consultation period. This was the key mistake. We all know consultations are largely an exercise in lip service but this was actually pre-empting the consultation and threatened to set a dangerous precedent about retrospective action by government not just for the FIT but for changes to any secondary legislation.
  3. They should have switched to the MCS registrations data sooner (the Ofgem FIT register necessarily lags the MCS register usually be about a month)
  4. Once the consultation had opened, Greg Barker said that he couldn’t prejudice an open consultation by commenting on the 12th December cut-off date before the end of the consultation period. Probably true but on this occasion Greg, two wrongs would definitely have made a right.
  5. Having had their dodgy dates found “legally flawed” just before Christmas rather than moving on and giving the industry the certainty it urgently needs and moving to cut the tariffs as soon as legally possible they have forced further delays and uncertainty by appealing the judge’s decision. So far this has led to a further week of uncertainty and a further week until the earliest possible date the new tariff levels can be introduced.

Randomly, I’ve seen a few things lately about the positive value of acknowledging failure (This TED talk by a guy from Engineers without Borders is great). Basically the message is that we learn better from mistakes than from successes which seems intuitively true. “Why didn’t that work?” is a much easier question to answer than “Why did that work?”. Dwelling on mistakes and trying resolutely to deny that they’re mistakes when deep down you know otherwise doesn’t help anybody. Recognising mistakes and fixing them quickly and without histrionics is almost always far more successful and likely to lead to more respect than clinging hopelessly to an obviously flawed plan.

My faith in politicians has really nosedived over the FIT review. This is a subject where in all probability I know at least as much about the scheme as they do. Almost every statement that Huhne and Barker have come out with has been so warped, so twisted and so totally fantastically disingenuous about what the implications of their proposals and what the industry wants from them that it makes me assume that this is what is happening in every area of government from defence and crime to education and health.

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Sat at home with Wall-E on the TV.

Now, obviously all Pixar movies are awesome and also Wall-E was written entirely by eco nerds (its still a lovely story) but also, Wall-E uses solar power! Yay!

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Feed in tariff review review – Part 1

Anyone even vaguely familiar with the solar power industry in the UK will be well aware of what has been happening over the past few months with the feed in tariff mechanism which supports small renewable power systems (up to 5MW). All the same I wanted to put forth my own assessment across in my next two posts to bring SIEAS up to date (more or less).
The first deals with the fast track review that looked only at larger PV systems. The second will basically call the government a bunch of fuck-ups for their incompetent handling of the October-December wider review. It may occasionally be sweary.

Back in March, the government began a review of the tariffs for larger PV systems. Costs had dropped to the point that megawatt (MW) scale installations, often ground mounted and feeding the grid directly rather than supplying on-site users were becoming attractive and threatening the overall economics of the feed in tariff programme (the de facto cap on FIT spending imposed by the Treasury is another story for another time).

Were they right?
Well, from a simple viewpoint, yes.
MW scale solar schemes stood to make hundreds of times more than a typical household system, hardly surprising given they are hundreds of times larger.

At these sizes, there are huge economies of scale. Installers are only dealing with one landowner, buying modules and other equipment in bulk and cutting out costs for roof access (scaffolding or cranes).
So, big PV systems are cheapest but they lose some of the key non-monetary benefits of solar power. When installed on a roof, PV produces power where needed and avoids conflict over land use. That said, my personal view is that a few more big PV systems would be a small price to pay for helping create the solar industry which can help us off fossil energy in the long term.

The first of two big changes in the FIT scheme for PV coming from this consultation was a new set of bands for smaller ‘large’ systems, one for 50 to 100 kW and a second from 100 to 150 kW and a third from 150 to 250 kW.
Now, the government has been keen to play up that a 50 kW system is just enormous, covering an area the same as two tennis courts. But what if I have a large factory with a load of underused roof? I could easily fit close to a MW of solar on a factory, heck the renovated Blackfriars station is getting a 1 MW solar roof and that’s not even a large train station. I’m not saying they cannot justify the 50 kW threshold but to claim this is the point at which you go from a sensible size to carpeting Cornwall is pretty silly. On the other hand, perhaps there should always have been a 50-250 kW and a 250 kW – 5MW band in the scheme.

42 (tennis courts). Image courtesy of and

In their justification for reviewing the tariffs, DECC stated that costs had fallen by a third since the scheme had been introduced. This is basically true so you’d think the tariffs need to be dropped by about a third, from around 30 p/kWh to around 20. Maybe to 16-18 to futureproof a little. Well, that’s exactly what we got for the 50-250 kW bands which are now 19, 19 and 15 p/kWh respectively.

Then a little further down the consultation came the strange proposal for the 250+ kW tariff to be 8.5 p/kWh. A strange proposal because this rate reflects the cost of electricity from offshore wind . Erm, Feed-In Tariff? That’s for feeding into the grid from technologies which need subsidy to be economic at present right? So how come you are giving a Wind rate to PV? You may as well give a Hydro rate to Anaerobic Digestion or have no technology distinction at all and just pay everyone the wind rate of 8.5 p/kWh. Only that would have the same effect as no FIT at all. Nobody would invest in anything more costly than offshore wind.

Incidentally, the other support scheme for larger renewables, the FIT would actually make you more money on a 250+ kW system though the investment risk and administration are more complex so you might not get any better return on your investment.