Sunday, May 06, 2007

Microgeneration: the real costs

Bit by bit, without really planning ahead or indeed any planning at all, I seem to be becoming a strident critic of microgeneration, i.e home-baked renewable power. I criticise the government, always an easy target, for their barmy zero carbon homes scheme and their mean stamp duty tax break for zero carbon homes. Then I turn my guns on Bill Dunster, a far less comfortable target for me as I am otherwise well-disposed towards him. I spend a couple of days worrying about whether I am just being spiteful for the sake of it. Maybe I am developing blogger syndrome where everything exists merely to be shot down in flames by cynics.

So I turn to Wikipedia and to trusty Excel and I start crunching some numbers. How do all the green and not-so-green methods of generating electricity stack up?

Turns out the UK is currently consuming 350 terawatt hours of electricity per annum. That’s 350,000,000,000 kWh. If you divide it by the 65 million people in the UK, it works out at a more manageable 5,300 kWh/annum each, round about average for Europe. In comparison, the USA consumes 12,000 kWh per annum each, India just 480 kWh per annum each.

Now, just suppose you were to try to make this amount of electricity using zero or low carbon sources. How would you go about it? Ignore for the moment all the arguments about practicalities and intermittent supply and everything like that.

350 terawatt hours per annum would require either
• 14,000 giant 10MW off shore wind turbines, operating at around 30% efficiency or
• 260 million 1kW micro wind turbines, operating at 15% efficiency, (that’s roughly ten mounted on every building in the land) or
• 4,000 sq km of PV cells. That’s pretty much the size of a county like Suffolk or Hampshire. Or enough to cover the south facing roofs of around 100 million homes — there are just 25 million in the UK or
• how about 25 European Pressurised Nuclear reactors (EPRs), as being built today in Finland? Each one is designed to have an output of 1600MW.

And what about comparitive costs?

Nuclear power plants cost around £1 billion each, so 25 No. would require £25 billion to supply UK’s 350TWh/a electricity needs. What is harder to factor in is the running costs and the clean-up costs at the end of the lifespan: nuclear power is notoriously difficult to cost because of this.

Giant off shore wind turbines. Around £5 million a piece, so 14,000 would cost £70 billion in total.

Micro-wind turbines. Around £1,500 each from B&Q, so 260 million would cost £525 billion in total.

PV arrays, around £1,000 per m2. A county-full would cost around £3,500 billion.

I think my case rests. Microgeneration is ridiculously expensive, just as I thought.



Anonymous Anonymous said...

Serious energy reduction measures for ALL BUILDINGS, on the other hand, are the cheapest and most effective option.

Photovoltaic systems and costs, by the way, seem to be about to change significantly for the better.

10:35 am  
Blogger Mark Brinkley said...

What makes you think that? For the past couple of years, PV prices have been going up because demand from Germany and Japan is outstripping supply.

9:56 pm  
Blogger A Meier said...

I tend to agree on your scepticism of microgeneration. By now I approach the issue of our carbon footprint with the motto 'insulate before generate'. A similar approach should apply to the average household energy consumption: use less, get rid of your gadgets and make small changes in your lifestyle. There is nothing magic about reducing our carbon footprint if we all apply a little more common sense to the subject and think less about riding on the consumer wave.

2:57 pm  
Anonymous Anonymous said...

You might be interested in the following, especially with regard to cost and time comparisons with setting up, maintaining and decommissioning nuclear power stations:

 "Cheap solar power poised to undercut oil and gas by half", Daily Telegraph Business News, 19th February 2007.

 Chemistry World, October 2006, page 14: "Solar cells reach into the infra-red".

 G24 Innovations Ltd have built a Cardiff factory for dye cells, due to start production soon .....

Not suggesting the cost impact will be immediate, but medium-term it looks very promising.........

3:55 pm  
Blogger Tim Pullen said...

Comparing micro generation costs to the national grid cost is a bit like suggesting that a Toyota Prius is a poor choice for hauling the nations freight around the country. Micro generation is not about replacing nuclear power plants, it is about putting control in the hands of the home owner.

Second point. Why does micro-generation have to cost justify? Give me one other item in your home that you felt the need to cost justify. To put it another way, what is the payback on an Aga?

4:36 pm  
Anonymous Anonymous said...

I was initially enthusiastic about the idea of microgeneration - putting control in the hands of the homeowner, reducing the need to transmit power over large distances and the possiblity of selling energy back to the local grid. However I have my doubts that this will result in a lower carbon footprint.

For example, I'd be interested in an analysis of the carbon cost of manufacturing, distributing, installing and maintaining millions of small wind turbines, as opposed to several thousand large ones. I suspect the case may not be as clear cut as at first glance.

2:35 pm  
Blogger Unknown said...

I agree that we need to look at the overall carbon costs of these micro-renewables. There are a few old studies carried out if you look on electronic journal sites like science direct, these generally found the carbon costs of manufacture to be quite high - some 20 years run-time for wind turbines to 'save' back the carbon emissions (bearing in mind their estimated lifespan varies from 10-30 years). But these are from around 2000, and one would think technology and efficiency has improved since then.

They didn't take into account the distribution and installation though, which has got to be pretty high as the leading manufacturers are surely European/Japanese?
Please correct me if I'm wrong.

My general opinion is that we'd be much better off reducing our energy use where possible through insulation, more efficient boilers etc. But leave the actual production of energy to large scale renewables - theres plenty of potential for wind/tidal energy generation in the UK. I accept that every little helps, and it would be good to contribute by each supplying a proportion of our own energy, but if the overall carbon budget is negative, it is just taking a huge step backwards surely?

6:35 pm  
Blogger Unknown said...

sorry to witter on, but it also irritates me when companies say you could save 'x' amount on your utility bills by installing 'y' product, but they dont mention we could all save 'x' on our bills by better insulating our homes, switching to efficient light bulbs, washing at a lower temp, switching appliances off at the plug etc anyway. plus you wouldn't have to fork out the money for the product in the first place.

6:44 pm  
Anonymous Anonymous said...

Read about this type of micro generation from the UK.

"The journey of a thousand miles begins with one step." Not sure who said this, but doing nothing is what got the USA into this high energy cost mess. All approaches are necessary to reduce our dependance on foreign oil.

7:33 pm  
Anonymous alwaysasolution said...

hi, first of all, checking out how much wind turbines and solar panels cost at B&Q is not an accurate assessment of the cost if it were a government scheme and they bought in bulk at wholesale prices.mass investment in manufacturing by government would inevitably bring cost production down. 25 million homes? well thats one quarter of the problem solved. you forgot to mention all the roof space on 2kw wind turbine mounted on every house is another 5th of the problem sorted,or one 3kw or 5 kw vertical axis turbine on each house is 2/5ths of the problem sorted. Not to mention the
5kw to 15kw, 20Kw which businesses could be required to install. That would reduce the need for so many giant wind turbines. maybe now we are up to more than 4/5ths of the problem solved roughly. you have then got heat pumps and ground heat systems and solar for water heating. large geothermal plants. not micro but part of the solution.
oil gas and pipe line wars in iraq and afghanistan cost billions that could be diverted to sustainable energy.

2:27 pm  
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