Population control is always a difficult discussion, but when you start to look at how any community works, as a system, you can see that there’s a limit to the number of people that system can healthily support and energy availability plays one of the key roles.

Renewable Energy

In the world of sustainable business, Steve Wade of Wind and Sun has found a pretty interesting role. He hikes off to remote places across the world and helps people to install renewable energy capacity.

Recently, Steve has been working on the Island of Eigg in Scotland. Up until a few years ago, the 90 or so people who live on Eigg were dependent on diesel generators for their energy. The generators were very noisy, dirty and didn’t actually provide 24-hour electricity. Maybe they could have made a case for importing electricity from far off places via cables under the sea or something and then hundreds of people could live on Eigg and set up massive hotels … or whatever, but in this case, the folk on the island rolled up their sleeves and opted instead for developing their own local and renewable energy network.

The system that Wind and Sun have been helping to develop combines energy generation from a mix of renewable resources on the Island. The major installation is a 100kW Hydro Electric Generator. This is supported by two smaller Hydro Electric Generators of 10kW and 9kW, by four small 6kW Wind Generators and 30kW of Solar PV. It’s all brought together for distribution to homes and businesses through 11km of buried high voltage cable with twelve Sunny Island battery inverters at the heart of the system. These inverters allow the flow of electrical energy between the batteries and the grid, balancing demand and supply, and they also maintain the charge of the batteries. It’s a bit techy I know, but this helps explain how a renewable energy system is different and more flexible/dynamic than a system dependent on, say, one big power station.

Owls and Sunny Island inverters

Eigg Electric has got people talking. As an evolving sustainable system it is very very neat:

The Sunny island inverters make sure that demands upon the system are met, using the state of charge of the batteries as the controlling factor.

Wireless Smart metres called OWLs help people monitor their energy use, which is capped at 5kW per household and businesses 10kW. Everything is community centric so when there is an abundance of energy in the system, usually in winter, background heaters are switched on in the community buildings (Tea Room, Community Hall and Churches). This excess could also be used to power electric vehicles.

People living on the Island play a dynamic role in the energy system. They own their energy and they understand how it works, so they make housing and domestic choices based on conserving this energy. The Island grid “Eigg Electric” connects every property on the island, and eco-tourism is also thriving.

The magic is in the blend

The Eigg community has devised a balanced system of different renewable sources and controls that can support them pretty much indefinitely, without wrecking the environment. Its a system that shows both our potential but also our limitations as human societies today. No doubt more capacity could be built into the system, but in a system working within the boundaries exerted by place and time, there is little room for excess and that includes over population.

We often put population growth down to medical advances or improvements in public health, sanitation and hygiene, agricultural productivity, development etc … but everything in this list has been backed up by the recent easy availability of fossil fuels.

Carrying Capacity is a measure of the environment’s ability to support a given population over time. It is usually applied to the earth as a whole and it’s well documented that we are currently exceeding global capacity. Eigg Electric offers a glimpse of a solution. It is a solution made up of beautiful components: smart technology,renewable energy, system defined by natural boundaries, big idea,simple to understand, pioneering community … and a touch of genius.

Written by Rachel at Sharpening Pencils

Video: Eigg, an island going green


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