Milking shed power savings achievable

Cost-effective annual energy savings of at least 68.4 million kilowatt hours (kWh) in the dairy shed are achievable, the pilot scheme says.

Individual farms could cut milking shed electricity consumption by 16% and a post-pilot survey shows 46% of farmers will adopt savings technologies if their costs can be recouped within three years.

Commissioned by MAF, the Energy Efficiency and Conservation Authority (EECA) and Fonterra, the pilot was run across 150 dairy farms in the Waikato, Lower North Island, Canterbury and Otago/Southland in the 2010-11 season.

“Dairy farms account for 2.3% of New Zealand’s total electricity consumption and the average farm spends over $14,000 on electricity a year,” says Jim Miller of Fonterra’s energy efficiency team.

“Reducing consumption can have a considerable impact on farm costs as well as the greenhouse gas emissions associated with energy generation.” 

The pilot found that including irrigation, the average farm milking operation in the sample used 112,100 kWh of electricity in the 2009-10 season. 

Audits of participating farms covered water heating, milk cooling and vats, vacuum and milk pumps, lighting, irrigation and effluent systems. Water heating accounted for 24% of consumption, water pumping 22%, refrigeration 17% and vacuum pumps 15%.  Each participating farm received a comprehensive report with farm-specific energy saving recommendations with paybacks of five years or less.

“We found that over 70% of the savings opportunities were related to water heating, although how those savings could be achieved varied from farm to farm,” says Miller.

“In some cases changing to one hot wash of the milking plant each day was recommended. In others pre-heating water with heat recovered from refrigeration plants, or solar water heating was a viable option.”

Miller says its encouraging farmers in the pilot were quick to take up savings recommendations with 23% having already adopted at least one recommendation, delivering an estimated 161,000 kWh of total annual savings. 

With 42% of pilot participants reporting they would likely adopt recommendations over the next three years, savings from the audits could rise to 297,000 kWh.

“We’re also encouraged by the good feedback which showed almost 80% of farmers found their audit valuable.  Costs are a factor and farmers are generally looking for a payback of capital costs within three years or less.”

With the pilot complete, Fonterra is now also acting on feedback that showed farmers would undertake an energy audit on-farm so long as the price was right. 

“We are now looking at how we can set up a system to deliver audits,” says Miller.

“Audits contracted individually can cost between $1500 and $2000, but we are looking at achieving economies of scale by clustering audits in districts to reduce travel time and costs. If farmers take up that opportunity and group together to have area audits, there’s a real opportunity to bring costs down.” 

As a result of the report, EECA has released a Request for Proposal to enhance electricity efficiency in New Zealand dairy sheds.  The proposal focuses primarily on heat recovery technology.  EECA is seeking to facilitate efficient transfer of heat from milk cooling process to the water heating process and thereby reduce dairy farm electricity use.  

“The report clearly highlights that there is a significant energy saving to be made on New Zealand dairy farms.  This is a great opportunity for farms to become more energy efficient and benefit from the increased savings,” Rod Treder, EECA industrial programme manager says.

See: www.eecabusiness.govt.nz