Most people say small scale energy project are a good
idea- inherently better than large
inflexible centralized corporately owned projects, allowing for local ownership
and control. However, there can be economies of scale. Some renewable energy
projects are best technically and economically at larger scale- wind turbines
for example, due to the basic physics of wind energy capture and
conversion. Certainly since the power
available is proportional to the square of the bade size and the cube of the
wind speed, a large diameter 1MW wind turbine on a good elevated site with good
wind speeds will produce far more electricity than 1000 small diameter 1kW
domestic-scale micro turbines in low wind speed urban environments. Moreover,
in a multi-MW wind farm with a lot of MW units, the cost of linking them to the
grid and maintaining them can be shared. Similarly, for wave and tidal projects,
their location is geographically defined and they will more efficient at
multi-MW scale.
Some individual domestic scale
energy technology can be efficient, PV solar for example, with power delivered
direct from the user’s roof, but even in that case there are economies in bulk
buying, installation and operational scale. Despite the need for grid links, it
is cheaper and easier to buy and install a lot of units together at the same
time in a large solar farm. Or possibly as part of a major roof-top deployment
programme in a collective housing project.
So, although there may be
exceptions, it is usually best to go for larger scale. But how large?
Community scale projects may
be a sensible compromise between scale and efficiency- small enough to be
locally owned and controlled, but large enough to be efficient. Local ownership of wind farms has proved to
be a good way forward in many countries, not least in avoiding opposition to
projects imposed by remote corporate owners. That is how wind took off so
dramatically in Denmark, with most of the projects being locally owned. Energy
co-ops are now spreading across Germany, with about 40% of German renewable
energy capacity being locally owned- although some of that is domestic PV,
owned by individuals.
While there is clearly a
strong environmental sentiment at work, the main driver for this expansion has
been economics and the availability of attractive rates from Feed-In Tariffs.
Policy changes can slow
progress, although the momentum and new market that has been created means that
unit costs are falling and new cheaper technology is emerging, making subsidies
less vital. So it’s a success story, both in terms of capacity and the
expansion of local control, to the extent that conventional energy suppliers
have now lost control of much of the market. There are however some issues. The
spread of distributed self-generation makes it harder to manage the overall
energy system, balancing supply and demand.
Most renewables are variable,
and most individual PV self-generators still top up from the grid to meet their
needs when there are lulls in local solar availability and at night. So they
still need grid links, which also allow them to export any excesses, and offset
the costs of their system. Some may now
be installing battery storage, as an alternative, and some may even try to go
off grid, but then they loose the export earnings and it maybe be hard to meet
all their energy needs in this way. Arguably it makes more sense to retain grid
links and import power when needed, especially since, as noted above, it can be
generated by larger more efficient projects elsewhere. Grid links make it
possible to use power generated at the best sites, and if suitably extended,
help balance and smooth out local variations in supply across wide areas. On
that basis, sticking just to autarchic local generation maybe suboptimal,
whether by individuals or communities. It may require much more local capacity
than otherwise needed and also more local storage, with in many case small storage
systems being less efficient than large ones.
Set against that is the possibility than local grid linked storage could
be seen as a form of distributed storage, taking power from the grid when
available, and, along with local generation, reducing the need for large grid
power exchanges at peak demand times. The need for more grids to handle
variable renewables and their local impacts, is certainly an issue in some
countries. That’s one reason why Greenpeace
has suggested that the ratio between small/local and large/remote generation
should be 70:30. That’s optimistic, depending on the location. Given the high
energy use and their spatial constraints, few cities could meet 70% of their energy needs from renewable
energy generated within their boundaries: they would have to import power from
rural and offshore areas. The best achieved so far, in a survey of 13 leading EU
city initiatives, has been around a 7% contribution from ‘internal’ urban renewables
sources: http://www.energy-cities.eu/Energy-Cities-Members-delivering
None of this means that
local generation projects are a bad idea. They can play a significant role,
especially at the community/municipal scale. But aiming for high levels of
local self sufficiency may not be sensible or needed. Instead we need to
consider the system as a whole, while opting for local generation wherever
possible, so as to gain the local social benefits. A strict interpretation of ‘local generation’
would imply near total self-sufficiency e.g. for villages and town, but in a
more realistic version they could import power from projects nearby e.g. local
wind farms. However, as argued above, even that seems unnecessarily
restrictive- what is wrong with trading local excesses to where there is a need
and at other times importing power from locations where it is best
generated?
That implies that there will
still be some large scale possibly corporate led projects, run to top the
system up, although in principle some of these could be municipally owned and
controlled. So could the local energy distribution system, including heat supply
via biomass fired CHP/ district heating networks and large heat stores, topped
up with solar heat. That would still leave conventional companies supplying the
energy hardware, unless new co-operative/locally owned manufacturing
enterprises emerge. Or even nationalised companies, taking over the whole thing,
including transmission. How far we might or should go in this ‘socialised energy
economy’ direction obviously depends on your political views! But in the end it
all comes down to money and power. Community groups have little of either at
present, local councils not much more. So there is a way to go. However, we
have seen the growth of grass roots power and local projects in Germany, and
that has changed the situation. Similar initiatives may emerge in the UK: the
GIFT campaign looks exciting, with, potentially, municipal involvement: www.nuclearpolicy.info/wp/wp-content/uploads/2016/04/GIFTS_initiative.pdf
Bottom-up grass roots initiatives
may look weak when faced with corporate power, but with conventional politics
all but frozen in many countries, they offer one of the few signs of life. See
this excellent review: http://www.sciencedirect.com/science/article/pii/S1364032115013477
There is much to do at national
level and policy changes are needed, but grass roots activism may help to open
up new possibilities. For helpful updates on local green energy projects around
the UK see: http://www.microgenscotland.org.uk
