Some renewables energy systems are well suited to development at the small, local scale, with funding direct from and by the local community. Indeed, local community-owned wind projects initially dominated the expansion of wind energy in Denmark, with, by 2016, 67% of onshore wind energy being generated by citizen-owned projects. Local ownership, initially via wind co-ops/wind guilds, then spread elsewhere in Northern Europe, most notably in Germany, with the PV solar share expanding, and at one stage about half of the 100GW of renewable capacity in place being locally owned via energy co-ops or local farmers.
Clearly many people wanted to buy into local projects- a welcome indication that green energy options had local support. Indeed, providing an opportunity for local ownership has sometimes been see as a way to avoid any potential local opposition. As the Danes say ‘your own pigs don’t smell’. The positive economic benefits in terms of the income earned from the scheme can outweigh issues of visual intrusion.
The expansion in Germany had been particularly rapid, with the Feed-InTariff (FiT) subsidy system providing a major incentive. During 2006-2016, 993 energy co-operatives were founded in Germany, with, by 2016, 557 using solar technology, 152 bioenergy, 78 wind energy, the rest, unspecified technology. However, there was a levelling-off in new project starts in 2016 and thereafter, this mainly being due to changes in the FiT system, making it harder to fund local projects, a situation which has worsened since then, with FiTs now having been ended. Nevertheless, local energy projects still continue to thrive: Germany has many town and village based energy co-ops, some with tens of thousands of members, some them exporting excess power.
The UK’s situation has been, and is still, very different. It has been much harder to set up voluntary energy co-ops. The small FiT scheme that was eventually established helped a bit, but that has now been abandoned. There has been better progress in Scotland, where more public support was provided. And, as the cost of PV has fallen, more zero subsidy projects are now emerging across the UK, as for example the newly agreed ~40 MW solar farm near Oxford.
However, despite the efforts of groups like AAT in Wales, the total locally-owned capacity in UK is still tiny compared with that centrally owned by corporations, and still nowhere near the locally-owned total in Germany. Community Energy England says that in 2018, ‘there were community generation sites across England, Wales and Northern Ireland amounting to 168 MW of generation capacity. The majority of this was solar (138.3 MW), while wind (27.4 MW) and hydro (2.2 MW) trailed behind. Adding the 68 MW generated by community energy projects in Scotland, the total capacity by the end of 2018 was 236 MW’. And it’s now building up more, with local action expanding across the UK.
The level of government support is still much to low, as was pointed out recently by the Environment Audit Committee, although, in response, the government noted that its £10 million Rural Community Energy Projects Fund ‘has supported the development of 135 projects, with more on the way, creating jobs and levelling up our regions as we build back better and greener from the pandemic.’
What next? In an age of relentless competition, markets dominate, but community values are still vital, with, if nothing else, local ownership ensuring that the local economy benefits. Local power generation is also being stimulated by the growth of self-generation by individual consumers. Indeed, some see the expansion of the ‘prosumer’ sector playing a major role in energy systems, with local peer-to-peer trading also emerging and local micro grids as well. The energy world is changing and local consumer and community-level generation is part of that.
There are of course scale issues. There are clear technical economies of scale for wind turbines, given that output is proportional to square of the blade radius and the cube of wind speed, so that a big 1MW community-scale machine on a windy uphill site will produce far more power than 1000 domestic scale 1kW micro-machines in typical urban low-wind sites. By contrast, domestic-scale PV solar devices can deliver power directly to uses and so avoid transmission losses, so in this case small scale system may have some cost advantages.
However, although there are no simple technical/operational economies of (larger) scale for PV solar, bulk purchase of multiple units and mass installation can cut set-up costs and large companies can get access to funding at low rates of interest for large-scale PV deployment programmes. The net result is that large utility schemes are usually significantly (often at least a factor of 2) more economic than smaller domestic or community projects. Nevertheless, for some, small scale home self-generation is a way to be free from being tied to grid companies, so any extra cost may be deemed acceptable, while some may feel the same in relation to the non-economic social benefits associated with community scale projects. That said, it is notable that community projects are moving up scale to be more cost effective.
The availability of energy storage systems does not change the overall picture very much- large energy storage systems (e.g. pumped hydro storage) usually have significant economies of scale, but medium scale systems may be better given that there are losses in transmission between the sources, stores and the users. The latter become more obvious in terms of heat, e.g. from solar heat collectors, but, even so, small domestic-scale heat stores are still usually less economically and operationally attractive than large community-scale solar heat stores. The later can balance out the variable heat demands of multiple different users and the energy losses of large heat stores are lower than for small stores since their surface to volume ratio is lower.
As can be seen, the optimal scale varies with the technology and the source, but in general, while small systems may sometimes be a good fit to local energy needs, and larger projects can be more economically viable, mid range community-scale power, heat and storage systems can also be viable in many cases: big enough to be economically viable, but small enough to be locally owned and controlled.
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