The 1st HPEE was hosted by SMHEA in June 1990, at which 24 Papers (assembled in a ring bound volume) were presented by the representatives of the three participating companies, i.e. SMHEA, ECNZ and the Hydro Electric Commission of Tasmania (HECT), in total 29 participants.

The 2nd HPEE was hosted in the North Island of NZ by ECNZ in July 1991, where 33 Papers (assembled in a ring bind folder) were presented by 27 authors from five participating companies, i.e. two more companies joined the HPEE, i.e. State Electricity Commission of Victoria (SECV) and the State Electricity Commission of New South Wales (SECNSW).

The 3rd HPEE was hosted by the HETC in Tasmania in July 1992, where 20 Papers (assembled in a ring bind folder) were presented by 20 authors from six participating companies, i.e. In total 27 representatives attended this exchange.

The 4th HPEE was hosted by the SECV in Mt Beauty in June 1993, where 22 Papers (assembled in a ring bind folder) were presented by 23 authors from six participating companies. In total 39 representatives attended this exchange.

The 5th HPEE was hosted by the ECNZ in the South Island of NZ in September 1994, where 22 Papers (assembled in a ring bind folder) were presented by 24 authors from six participating companies. In total 32 representatives attended this exchange.

The 6th HPEE was hosted in Cooma by SMHEA in September 1995, where 15 Papers (assembled in a ring bind folder) were presented by 18 authors from six participating companies. In total 32 representatives attended this exchange.

The 7th HPEE was hosted in Hamilton by ECNZ in October 1996, where 32 Papers (assembled in a ring bind folder along with the record of the discussion of each paper) were presented by 39 authors from seven participating companies, i.e. one more company joined the HPEE that is TrustPower. In total 47 representatives attended this exchange. At this meeting it was decided to hold the future exchanges every two years.

The 8th HPEE was hosted in Hobart by Hydro Tasmania in October 1998, where 27 Papers (assembled in a ring bind folder) were presented by 33 authors from eight participating companies, i.e. one more company joined the HPEE that is Contact Energy. In total 50 representatives attended this exchange.

The 9th HPEE was hosted in Christchurch by Meridian Energy in July 2000, where 23 Papers (assembled in a ring bind folder) were presented by 30 authors from nine participating companies, i.e. one more company joined the HPEE that is BCHydro. In total 48 representatives attended this exchange.

The 10th HPEE was hosted in Hobart by Snowy Hydro in May 2002, where 29 Papers (assembled in a ring bind folder) were presented by 45 authors from thirteen participating companies, i.e. four more companies joined the HPEE that is PT INCO, Southern Hydro, Pioneer Generation and Stanwell Corporation. In total 54 representatives attended this exchange.

The 11th HPEE was hosted in Taupo by Mighty River Power in October 2004, where 30 Papers (assembled in a ring bind folder and also available in a CD) were presented by 41 authors from fourteen participating companies, i.e. one more company joined the HPEE that is Ertan Hydropower. In total 74 representatives attended this exchange.

The 12th HPEE was hosted in Launceston by Hydro Tasmania in October 2006, where 30 Papers (assembled in a ring bind folder and also available in a CD) were presented by 40 authors from sixteen participating companies, i.e. two more company joined the HPEE that is Luzon Hydro and Tarong Energy. In total 104 representatives attended this exchange.

The 13th HPEE was hosted in Queenstown by Meridian Energy in September 2008, where 24 Papers (available in a CD) were presented by 35 authors from seven participating companies. In total 64 representatives attended this exchange.

The 14th HPEE was hosted in Jindabyne by Snowy Hydro in October 2010, where 27 Papers (available in a CD) were presented by 32 authors from nine participating companies. In total 65 representatives attended this exchange.

The 15th HPEE was hosted in Rotorua by Mighty River Power in October 2012, where 24 papers (available in a CD) were presented by 40 authors from 11 participating companies. In total 81 representatives attended this exchange.

The 16th HPEE was hosted in Hobart by Hydro Tasmania in August 2014, where 39 papers (available in a CD) were presented by 56 authors from 10 participating companies. In total 72 representatives attended this exchange.

The 17th HPEE was hosted in Queenstown by Meridian Energy in October 2016, where 35 papers were presented by 37 authors from 18 participating companies. In total 83 representatives attended this exchange.

The 18th HPEE was hosted by AGL October 2018.  34 Papers were presented with approximately 86 participants attending 3 days of papers and two optional site visits to Dartmouth and the Kiewa scheme.

The 19th HPEE, details to follow.