title: Energy return on energy and carbon emissions investments for New Zealand wind energy farms

authors: Walmsley, Timothy Gordon

subjects: wind energy

abstract: This paper analyses the Energy Return on Energy Invested (EROI) and Energy Return on Carbon Emissions (EROC) of current wind farms in New Zealand. The weighted average EROI for a New Zealand wind energy farm over a 20 year life span is 35, with some sites above 50, while others are as low as 6.5. These values are higher than many other electricity generation methods reported in the literature with hydropower being the main exception. The average EROC value for NZ wind energy farms is 0.477 GJ/kg CO2-e, which is 56 times the EROC of a combined cycle natural gas power station. The substantial range of EROI values are driven by two factors: (1) average wind speeds for a given site and (2) the blade diameter of the turbine, where larger is better. Future work will include an economic analysis of the wind farms.

text: Energy return on energy and carbon emissions investments for New Zealand wind energy farms This paper analyses the Energy Return on Energy Invested (EROI) and Energy Return on Carbon Emissions (EROC) of current wind farms in New Zealand. The weighted average EROI for a New Zealand wind energy farm over a 20 year life span is 35, with some sites above 50, while others are as low as 6.5. These values are higher than many other electricity generation methods reported in the literature with hydropower being the main exception. The average EROC value for NZ wind energy farms is 0.477 GJ/kg CO2-e, which is 56 times the EROC of a combined cycle natural gas power station. The substantial range of EROI values are driven by two factors: (1) average wind speeds for a given site and (2) the blade diameter of the turbine, where larger is better. Future work will include an economic analysis of the wind farms.

year: 2016

title: Integration of industrial solar and gaseous waste heat into heat recovery loops using constant and variable temperature storage

authors: Walmsley, Timothy Gordon

subjects: heat recovery loop

abstract: Solar is a renewable energy that can be used to provide process heat to industrial sites but require thermal storage. HRLs (heat recovery loops) are an indirect method for transferring heat from one process to another using an intermediate fluid. With HRL's thermal storage is also necessary to effectively meet the stop/start time dependent nature of the multiple source and sink streams. Combining solar heating with HRL's is a cost effective way to share common storage and piping infrastructure. The conventional HRL design method based on a CTS (constant temperature storage) and a new HRL design method using VTS (variable temperature storage) are applied to demonstrate the potential benefits of inter-plant heat integration and installing solar heating. The dairy case study had available 12 source streams including four spray dryer exhausts and six sink streams. The addition of the dryer exhausts as heat sources was a critical factor in gaining a heat recovery of 10.8 MW for the variable temperature storage design, of which 5.1 MW was contributed from exhaust heat recovery. For the same minimum approach temperature the VTS approach achieved 37% more heat recovery compared to the CTS approach. Solar heating also proved to be a valuable source to be integrated into an HRL with a pinch around the cold storage tank with the maximum addition of 0.9 MW of heating on average for the CTS approach and 1.0 MW of heating on average for the VTS approach.

text: Integration of industrial solar and gaseous waste heat into heat recovery loops using constant and variable temperature storage Solar is a renewable energy that can be used to provide process heat to industrial sites but require thermal storage. HRLs (heat recovery loops) are an indirect method for transferring heat from one process to another using an intermediate fluid. With HRL's thermal storage is also necessary to effectively meet the stop/start time dependent nature of the multiple source and sink streams. Combining solar heating with HRL's is a cost effective way to share common storage and piping infrastructure. The conventional HRL design method based on a CTS (constant temperature storage) and a new HRL design method using VTS (variable temperature storage) are applied to demonstrate the potential benefits of inter-plant heat integration and installing solar heating. The dairy case study had available 12 source streams including four spray dryer exhausts and six sink streams. The addition of the dryer exhausts as heat sources was a critical factor in gaining a heat recovery of 10.8 MW for the variable temperature storage design, of which 5.1 MW was contributed from exhaust heat recovery. For the same minimum approach temperature the VTS approach achieved 37% more heat recovery compared to the CTS approach. Solar heating also proved to be a valuable source to be integrated into an HRL with a pinch around the cold storage tank with the maximum addition of 0.9 MW of heating on average for the CTS approach and 1.0 MW of heating on average for the VTS approach.

year: 2014

title: Waiwhakareke Restoration Plantings: Establishment of Monitoring Plots 2005-06

authors: Grove, E.

subjects: New Zealand

abstract: Waiwhakareke Natural Heritage Park is being developed to reconstruct native lowland and wetland ecosystems as were once widespread in the Waikato Region. The 60ha Natural Heritage Park is located on the north-west outskirts of Hamilton City and includes a peat lake (Horseshoe Lake) which is surrounded by introduced willow trees. There is some native marginal vegetation around the lake, including rushes and sedges, and an extensive area of gently sloping pasture completes the catchment. The restoration and recreation of the native plant and animal communities is being lead by the Hamilton City Council in partnership with The University of Waikato, Wintec, Nga Mana Toopu o Kirikiriroa Limited Resource Management and Cultural Consultants and Tui 2000 (McQueen 2005; McQueen & Clarkson 2003).

text: Waiwhakareke Restoration Plantings: Establishment of Monitoring Plots 2005-06 Waiwhakareke Natural Heritage Park is being developed to reconstruct native lowland and wetland ecosystems as were once widespread in the Waikato Region. The 60ha Natural Heritage Park is located on the north-west outskirts of Hamilton City and includes a peat lake (Horseshoe Lake) which is surrounded by introduced willow trees. There is some native marginal vegetation around the lake, including rushes and sedges, and an extensive area of gently sloping pasture completes the catchment. The restoration and recreation of the native plant and animal communities is being lead by the Hamilton City Council in partnership with The University of Waikato, Wintec, Nga Mana Toopu o Kirikiriroa Limited Resource Management and Cultural Consultants and Tui 2000 (McQueen 2005; McQueen & Clarkson 2003).

year: 2006