Friday, March 29, 2024

Energy and ag a lasting marriage

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Agriculture has been in the spotlight of the zero carbon debate because it contributes 48% of New Zealand’s greenhouse gases.
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The energy sector sits a close second at 41% of total emissions but has yet to receive the same pressure to mitigate its emissions. 

Canterbury farmer and Nuffield Scholar Cam Henderson believes the two sectors can work together to collectively lower emissions.

Bjut the way energy is reported as a contributor to greenhouse gases fails to convey just how significant its contribution is.  

That prompted Henderson to use his Nuffield Scholarship to explore links between agriculture and energy and how technology can work to harness farmed energy sources including waste matter to supply national energy needs. 

The subject came partly from Henderson’s concern that while greenhouse gas reduction is firmly on agriculture’s to-do list, planning and options to achieve that appear limited.

“I originally intended to look at what we could do with our fodder beet crops as an alternative use. They are used overseas for biofuels and I hoped to come back with a business case study on the biofuel industry for the South Island.”

Technology that can integrate farm-sourced energy feedstock with energy generation has advanced significantly in recent years. 

Anaerobic digestors capable of turning effluent into biogas and electricity-generating solar arrays are among some of the options Henderson saw on his study trip. 

Recent events have, however, reinforced to him the need for a consistent, enduring energy policy for any farm-based energy supply system to hold up over time.

“Leaving the free market to determine energy supply and demand can be a risky affair and really threaten the ability to establish a viable long-term industry. 

“We have seen the effect of recent oil price drops on ethanol plants throughout the United States having to be shut down, for example.” 

Before the global financial crisis and the shift to a National government in 2008 NZ was in the early stages of a biofuel focus that was playing out into farming systems. 

A Solid Energy subsidiary developed rapeseed bio-diesel processing, with Canterbury and Otago farmers contracted to grow it. 

However, Solid Energy pulled out and the fledgling bio-fuel industry fell over completely when excise incentives were removed.

NZ remains one of the few countries in the world not  to require a bio-fuel component  in its fuel.

“But with covid-19 it will be interesting to see if efforts to reset the economy create more support for such fuels.” 

Harvesting the sun, if not crops, can also give farmers to link energy and farm systems. 

Henderson’s own property has a solar array that can power the farm dairy shed and, given the cost savings it delivers, is the most profitable per-hectare part of the farm.

On his visit to California he saw energy policy that better rewarded farms selling surplus power to the grid. 

In NZ returns are considerably lower, with any surplus power sold back at only a third of its retail value.

Solar power technology has also advanced to the point where local power for locals is possible by having arrays big enough to supply districts with their power needs when arrays are linked. 

There was even the possibility of setting up a co-operative of energy generating farmers who could work together to market and sell energy back to the national grid. 

“It brings greater self-sufficiency and Canterbury farmers using groundwater are big electricity users.”

However, his study also shows the best-intentioned policy can have unintended consequences.

“In California the solar systems were generating so much extra power in summer they were having to give the electricity away for free from the grid. There had been no consideration about how to handle a surplus, should it arise.”

He has come to see the covid crisis as a chance to kill two birds with one stone – dealing with growing energy needs while managing greenhouse gas emissions. 

However, left only to the market it might require a lift in carbon prices to nearer $200 a tonne to incentivise a move to projects like anaerobic digestors and carbon storage schemes.

“And a lot of mitigation methods are not recognised under current accounting schemes, which means there is even less reason for investing in them.”

Henderson’s concern is the lack of planning and voice agriculture has in any government-led energy strategy, one which is now under way.

“Meantime agriculture is left trying to defend its GHG position when we could be working hand in hand with the energy sector.”

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