Monday, 11 February 2013

Decentralised energy generation - a lesson for nuclear?

In the UK, as in many other countries, there's been rapid growth over the last five or so years in the amount of electrical power generated by small "micro-generation" installations.  Some of these, such as domestic solar PV set ups, are small and cheap enough to be paid for by individuals.  Other usually somewhat larger schemes (up to a couple of megawatts) are owned by community groups of one form or another.  Most of these micro-generation projects have been based on renewable "alternative" power sources such as solar, wind or hydro.  Millions of pounds are being invested in micro-generation systems - people see small, localised energy generation as a way of gaining some measure of control and involvement over the energy they use.

Whilst I think decentralised power is a great idea, and I'm fully behind getting as many renewables on the grid as possible, we're still going to need something with more energy density that can provide energy when the sun doth not shine, nor the wind bloweth.  Grid level storage is part of the solution for this issue, as is grid interconnections between countries.   Of course baseload generation has traditionally been the domain of the large scale coal, gas and to some extent nuclear power stations.

Now coal is a no-no for future power stations - "clean coal" seems to be a pipedream with carbon capture and storage still very much in the experimental stage and the economics looking decidedly shaky.  That's without considering the "carbon cost" of getting the coal out of the ground and thousands of tons of it shipped around the planet between the mines and the power stations.  Of course the UK doesn't produce much coal any more, so those "coal miles" are now seriously long journeys across the world.

George Osbourne and chums seem intent on making a second "dash for gas", either by getting the UK hooked on volatile foreign imports or kickstarting an on shore gas boom based on hydraulic fracking.  Gas has a far lower carbon footprint than coal which is good, but, as the Americans seem to be rapidly discovering, fracking can be very environmentally damaging and short well productivity lifespans can result in the investment regime look more like a Ponzi scheme.   We're probably going to have gas in the UK Grid mix for many decades to come, but its probably worth seeing if we can minimise it to handling rapid on/off load following applications.

Nuclear was seen by many, including surprisingly quite a few influential environmental champions, as the great white hope for large scale, low carbon energy.  UK governments of several hues have pinned their hopes on it as well, but as we've seen over the last few years the plans have been somewhat derailed with many reactor vendors pulling out of schemes.  Only EDF still seem to be in the race, and they'll probably only stay the course if they get underwriting guarantees from the Government and/or some buy in from the Chinese.

Part of the reason why nuclear has stumbled is the vast costs attached to the current Generation III+ designs.  Part of this is a result of the regulatory and insurance landscapes surrounding nuclear power, but part of it is that these nuclear power stations will be huge, centralised power generators, each delivering somewhere between a few hundred megawatts and a gigawatt into the National Grid.  Getting this sort of investment is tricky, especially in a recessionary period.

Its also a liability for the Grid.  The anti-wind crowd constantly moan about what might happen to the Grid if the wind doesn't blow and the turbines suddenly stop, but the turbines are geographically spread around the UK and weather forecasting can predicted wind speeds in different areas fairly accurately out to a day or so.  If a turbine fails unexpectedly the Grid might lose a couple of megawatts - a relatively easy loss to deal with.  On the other hand if a gigawatt centralised nuclear station suddenly goes offline, the Grid management have their work cut out.  Decentralised generation can add resilience to the Grid.

Now I reckon there's another way forward for nuclear power: instead of looking at huge, monolithic GenIII+ designs that still need billions of pounds spent for "development" and construction, we should be turning to some of the innovative, smaller GenIV designs.  There's plenty of these designs floating around, and not all of them are just in the heads of the Internet's nuke geeks.  Indeed a number seem to have the backing of large companies (such as Toshiba's 4S) or Government's (for example China's development of thorium reactors).

Lets imagine for a moment that one of these GenIV designs gets produced in a package that generates a few tens of megawatts and can be mass produced (maybe not in huge numbers, but with a production line at least capable of making a few hundred reactors).  This sort of power output puts it in between the community owned renewables and the large scale utility power stations.  If the vendors can get the price point down to a £20-50million per reactor then that puts them in the range of a large community energy project (Westmill solar PV farm for example managed to raise several million pounds in a community share issue in 2012 - I know because I've got some of those shares!).  It certainly makes the attractive for commercial generators as well - one fracking company recently raised over £20million in a share listing just on the hint that there may be some potential future profits in fracked gas.

Sealed reactors limit proliferation and radioactive contamination vectors, and many of the GenIV designs are designed from the ground up as inherently walk away safe.  Designs that burn up an appreciable fraction of their fuel load also limit nuclear waste issues (and the waste we've already got could be viewed as fuel in some design options, but that's another topic).

Some folk are opposed to nuclear reactors of any design, so this idea isn't likely to be popular with them.  However having the option of a community sized reactor with a 5-10 year long lifespan between refuelling would give community energy schemes another avenue.  If nothing else you could then offer the anti-wind community the option of the neighbourhood underground nuke station...

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