Wednesday, March 9, 2011

Imagining Cormac's Mill,

What might Ireland's first Mill have looked like?

The Hill of Tara
In a previous article we explored the very real possibility that Cormac's Mill, reputedly the first mill in Ireland, was located on the slopes of the Hill of Tara.

The Mill was constructed in the 3rd Century at the request of Cormac Mac Airt, King of Tara, and I believe it was located at a site beside Tara Hall at the place where the Nith stream descends into the Nith Glen.  The evidence from the historical documents certainly suggests this, but is it possible? Was the site suitable for a mill?  What would it have looked like and how would it have operated?

In order to explore these questions we first have to look at the milling technology of the early Medieval period.  In their book 'A New History of Ireland, Prehistoric and early Ireland', Dáibhí Ó Cróinín and Theodore William Moody set out the milling technology that was becoming common in Ireland by the 6th and 7th Century.

Sunday, March 6, 2011

Renewable Energy and the Program for Government

The votes are cast, the counting has been completed, and Fine Gael and Labour have emerged as not only the two largest parties, but also coalition partners to form the government of the 31st Dáil.  The Green Party, champions of alternative energy and sustainability, were completely obliterated and Fianna Fail lost the vast majority of their seats.

While there has been some scepticism that Fine Gael and Labour were capable of bridging their ideological differences to form a government, after much negotiation a program for government has been produced.  Styled as the 'Government for National Recovery' they have set out the policies that they will pursue in the years ahead as they attempt to steer the country out of the mire of broken banks, a collapsed property market, widespread unemployment and emigration, and the shackles of a punitive EU/IMF deal that has ensured that taxpayers will pay for the gambling losses of international bondholders.  Not an easy road ahead.

But how does the Program of Government stand up against the election manifesto promises?  Lets have a closer look at what the new coalition intend to do to encourage renewable energy and micro-generation.

Wednesday, February 16, 2011

Renewable Energy Policy - Who to vote for?

The General Election is just over a week away and all the political parties are setting out their stalls to attract the electorate.  Lots of glossy documents outlining the problems, promising the solutions.  Plenty of vision and wisdom, -it's a wonder we're in the state we're in.

All the political parties see the value of promoting renewable energy but some seem to be a bit more serious about it than others.  

So let's see what the various political parties have to say about what they'll do when they get their hands on the levers of power.  I'll present the parties in the order of their current popularity.

Tuesday, February 15, 2011

Cormac's Mill at Tara, 275AD

Finding Cormac's Mill, the First Mill in Ireland.

I've always been fascinated by the Hill of Tara and it's surrounding landscape, not just because of it's importance as the centre of Irish mythological and historical events for thousands of years; -it's layer upon layer of archaeological remains, the ring forts, the wells, the burial mounds- but by something more intangible.

Fig (i) The Hill of Tara
The place has a hold on our imaginations that is hard to explain, and even people who have never read it's history can't help but feel a sense of magic and mystery when they walk between the ditches of the great Banqueting Hall or stand at the site of the Liath Fail and gaze down at the land rolling out before them. 

When we read the myths, the history and the folklore we start to realise that, despite what archaeology can reveal, there are still so many mysteries that remain.

But what has this got to do with Hydropower, I hear you ask?

Seasonal Flow Variation and Electricity Production

Seasonal Rainfall and Evapotranspiration

In Ireland we get a good distribution of precipitation right across the year, but with significant concentration in the months from October through to March.  We're fortunate that this 'rainy season' coincides with when we have the highest energy demand in our homes, businesses and schools, and it makes hydropower all the more ideal to meet our energy needs.

fig (i) Seasonal Precipitation and River Flow.
In fig. (i) you can see the seasonal variation in precipitation across the year in a catchment in the east of the country.   

As a rough guide, there's a ratio of about 2:1 between the precipitation in the winter months and in the summer months, but it would not unusual for the period from October to March to get significantly more.