Killarney is a Parish and Scrahane is the Townland and in 1853 when the Griffith Valuation (census substitute) took place there were 9 Powel's, 7 of these are John Powel's.
Only one living in Parish Killarney and Townland Scrahane
and the Poor Law Union of Killarney.

John Powel, Parish of Killarney Townland Scrahane, tenant of Richard Orpen where he occupies 8a caretakers house and land totalling 5 acres 1 rood and 37 perches

The Orpen family are not listed in the 1824 Pigot's Directory as being, nobility or gentry but they certainly in 1853 owned a lot of property, they lived in the Parish of Kilgarven but owned land (rare) that they would of collected rents from tenants. Just in the few I looked at
they owned land of 667 acres, 207 and 206 acres, they all seem to be named Richard with different initials.

In the 1824 Pigots Directory there is one John Powel which is probably yours:

1824 John Powel, Nurseryman, Scrahane

My guess he is the nurseryman on the estate that he noted as living in the caretakers house. He may have served in both positions? or gone from Nurseryman to Caretaker by 1853.

1846:

John Powel, Esq. Sandwell Castle-Island

1870,1881, 1894:

James Powel, Esq. Sandwell Castle-Island
John Powel, Esq. Chapel House Castle-Island
Both also listed under Farming in the directory

1881:

Rev. John D. Powell, Methodist (Wesleyn) Chapel, Tralee
also under Residential Edward St. Tralee

Baptism and marriage records are available for Co. Kerry
at www.irishgenealogy.ie

other resources:
www.censusfinder.com United Kingdom+Ireland+Kerry
www.igp-web.com + Kerry

By 1901/1911 There are 0 Powel's listed however, there are 16 individual Powell's in 1901 and 17 in 1911.
www.census.nationalarchives.ie (click on Show All Information) on the 1911 if you scroll right you will see how long married and children born and living.

Telephone book for Kerry 2 listings for the name Powell.

There is an earlier census substitute 1820-30's call the
Tithe Aplotments, a tax for the Church of Ireland that everyone paid. The details look similar to the Griffith Valuation. These records in detail are kept at the National Archives in Dublin, sometimes there may be extracts on the two resources above and recently Ancestry.com is carrying
a simpler Tithe record with names and places only.

Annette Code