A View from the Swamp

Before I get going, I want to make an assertion: we should be investing more in low-carbon energy sources rather than compromising on lifestyle!  Many plans for reaching a low or zero carbon economy assume significant degradation of lifestyle, particularly travel.

Personally, I don’t want to return to a world where travel is the preserve of the rich.  I want a world where people have access to simple, cheap, personal and international transport and where people have many electrical and electronic devices in the home.  So I want to show that this is possible and feasible!

So let’s reassess the need for that extra 187GW. Will we really need that much?  Clearly if we compromise on lifestyle, savings can be made.  But I want to examine whether this number accounts for known trends I previously glossed over.

I derived the figure from estimated 2012/13 production (~95GW) and the proportion of GHG emissions produced by electricity generation, transport and heating. This calculation still holds, but I missed several factors.

1. Population growth. I assumed essentially zero growth. In reality, our population is expected to grow, with ONS projections putting the population as high as 71.6 million by 2033 – i.e. 16% growth.  Presumably these extra people will need electricity, so I’ve underestimated significantly.
2. Increased numbers of electrical / electronic devices per household.  As should be obvious to everyone, there has been an explosion in the numbers of electrical and electronic appliances over the last 30 years.  I expect this trend to continue as more people buy additional computers, printers, TVs for other rooms, etc.  However, I think this is likely to be offset by increased efficiency of these devices.   For example, LCD TVs are much more energy efficient than plasma, and LED-backlit TVs are even more so.  As technology improves, it will use less power (I know, it’s my job!).
3. Standby efficiency of electrical / electronic devices.  Current devices have very high standby power, by some estimates this accounts for about 8% to 10% of household consumption.  The technology exists to reduce this to almost zero.  As people’s behaviour is difficult to change, legislation on the standby power of new devices seems the best way of achieving this reduction.
4. Increased efficiency of domestic lighting.  Roughly 19% of electricity (18GW) is used on domestic lighting, most of which is incandescent.  Incandescent bulbs are about 5% efficient, so with 100% efficiency this could be reduced to 900MW.  Current low-energy bulbs are about 30% efficient and LEDs are about 80% efficient, so it seems reasonable to assume <5GW will be needed for domestic lighting (assuming a reasonable uptake of LED lighting).  This adds up to a saving of ~13GW (about 7%).
5. Increased thermal efficiency of housing.  At present, only 8% of housing is rated in bands A – C for energy efficiency and62% is rated in bands E – G.  As space heating accounts for ~60% of household energy demand, any improvement here will significantly reduce the electricity demand.

I think that is as quantitative as I can get!  Population growth will add ~16% to the total required; standby efficiency improvements will reduce it by ~8%; use of LED lighting will reduce it by ~7%.  That is, these factors roughly balance out.  This leaves improvements in housing, where I can’t find any good estimates.

One concrete thing we can do is on labelling of devices.  When the EU energy label for “cold” appliances was introduced in 1999, it improved the average efficiency of these by 15% in 15 months (see here, box 4)!  Introduction of similar labels for TVs, computers and other items should have a similar noticeable effect.

In summary, I think I’ll stick with my initial estimate though it is fraught with uncertainties.

Before I talk about where can we get 187GW of low-GHG capacity, I think it is worth outlining the carbon cost of all the methods.  The numbers below are for the complete life-cycle of the plant, from extraction of raw materials an fuel through to decommissioning costs:

• Coal:  >1,000g/kWh.  800g/kWh can be achieved with gasification technology.  200g/kWH may be possible with Carbon Capture and Storage.
• Oil: 650g/kWh.
• Nuclear: ~5g/kWh
• Wind: ~5g/kWh
• Wave and tidal:  25-50g/kWh.  High due to large amount of steel required
• Solar-cells: 58g/kWh.  High due to extraction of silicon from sand.

For bulk generation, I’m going to rule out water and solar-cells as they are significantly worse than both nuclear and wind.  For small local systems, solar-cells are useful; I’m less convinced by wave and tidal.

This leaves nuclear and wind as the two low-GHG options.

There are two options for new nuclear power stations: the AP1000 and the EPR (the ACR-1000 and the ESBWR were initially considered but the proposing companies withdrew them from consideration).  The AP1000 and the EPR have both completed phase 3 assessments by the government and both have moved to phase 4 (completion June 2011) with recommendations for design changes.  For now, I’m going to look at the numbers for the EPR because it has a higher capacity (1650MWe versus 1154MWe) and is European.

For offshore wind, the largest wind-turbine is 10MW, from Sway in Norway.  Most other large turbines (onshore and offshore) are in the 5MW range.

Before you moan that I’m obviously pro-nuclear because of how much detail I provided compared to the amount for wind, I did this because nuclear power is contentious!  Wind is not contentious and there are several suppliers.

There are three extreme scenarios for generating the full 187GW from low-GHG sources: all-nuclear and all onshore or offshore wind:

• Using the EPR would require 114 reactors.
• Using 10MW offshore wind would require 18,700 turbines (covering roughly 1,000 square kilometres).
• Using 5MW onshore wind would require 37,400 turbines (covering roughly 2,000 square kilometres).

Hopefully this demonstrates that both approaches have issues!  With nuclear, the main issue is public concern over safety; with wind, public concern about aesthetics.

That feels like enough for now (and I need to go to work:-)).  Still to come: cost, sites, and transition from current situation, carbon sequestration, etc.

Given our commitments to moving to a “carbon free” economy, I thought I’d take a break from Europe and look at some of the implications of this.  I think they are much bigger than people realise.

Let’s start with the big picture. 65% of our greenhouse gas (GHG) emissions are from three sources: electricity generation (28%), non-electric heating and hot-water (16%) and transport (21%).

There is one more large contributor, which is combustion and other processes in industry which accounts for a further 19%, but I have no idea what to do with this so for now, I’ll ignore it!

Conversion of electricity generation to low-GHG sources is an obvious target, and non-electric heating and transport can also be reduced to almost zero by use of low-GHG electricity sources.

So what does this mean for electricity generation? By 2012/13, the UK aggregate power station capacity will be ~95GW.  Of this, 10% will be nuclear (9.5GW) and ~4% will be wind (~4GW).  The remaining 86% (~82GW) will be from high-GHG sources (which accounts for that 28% figure above).

To cover the requirements for non-electric heating and transport, we would probably need to double our aggregate electricity generation capacity.  This is a difficult calculation to make as the differences in efficiency are difficult to assess.  For example, petrol or diesel engines are considerably less efficient than power stations, but replacing them with either battery power or hydrogen adds other inefficiencies.  So I’ve made the simple assumption that these roughly cancel out.

This doubling of capacity means we will need an additional 95GW of low-GHG sources in addition the to conversion of 82GW to low-GHG sources.  Also, the 9.5GW of nuclear needs replacement soon.  In total, over the next 20+ years we need to build ~187GW of low-GHG capacity.   This is an immense task!

To give you an idea how big, our biggest power station (Drax) generates 3.9GW, so we need to create roughly 50 times this in low-GHG capacity!

I’ll talk about the options in the next post.  Suffice it so say for now that I think nuclear is very much on the table.