Changing the scenario

Solar panels as the photovoltaic park in Les Mees, France. Photo: Reuters
Solar panels as the photovoltaic park in Les Mees, France. Photo: Reuters

To help them understand problems they might face in the future, energy companies and organisations all over the world develop detailed stories and models, which they call scenarios, Gerry Carrington writes.

Gerry Carrington
Gerry Carrington

Last month the Business New Zealand Energy Council (BEC) published a report on New Zealand's energy future based on two scenarios it developed (www.bec.org.nz/projects/bec2050).

In the BEC's stories, solar-electric power will have only a minor role in New Zealand in 2050.

This may seem reasonable to many people, since our solar-electric capacity is small at present, about 0.2% of generation.

On the other hand, it's growing quickly, doubling every nine months.

Globally, it doubles roughly every two years and the cost of solar modules halves every seven years.

This phase of exponential capacity growth began in the 1970s.

It would be nice to know how long exponential solar growth will continue, since that would tell us what other energy sources it might displace.

A number of factors will encourage continuing growth: technological advances, the smart-grid, business innovation, energy consumers wanting more control, cheaper batteries for storing surplus solar electricity, electric vehicles, and climate change concerns.

On the other hand, other influences may reduce growth and it is not possible to make accurate long-term predictions (Deloitte: US Solar Power Growth through 2040).

For planning purposes, scenarios don't need to be especially accurate, since different model options can be used to explore for potential risks and threats. But published scenarios are influential, because they help to shape public expectations and define key issues.

With the best will in the world, however, wishful thinking by the authors can easily tilt the scenario assumptions.

So I'm not comfortable with big global energy scenarios that assume fossil-fuel use will continue to expand. After all, estimates of solar power growth by the International Energy Agency were far too low for a number of years (www.carbontracker.org/report/lost-in-transition/).

One of the aims of the BEC report is to ''allow energy decision-makers to assess what is actually happening in the world now and gauge what will happen in the future''.

I could be wrong, of course, but I think it is hard to do this with fixed scenarios.

For instance, I would like to know how the solar-electric capacity in 2050 might be affected by different costs.

So I like scenarios that allow you to explore the trade-offs and choices yourself, such as the UK 2050-pathways calculator (http://my2050.decc.gov.uk/).

• Emeritus Prof Gerry Carrington is a fellow of the Royal Society of New Zealand and the Institution of Professional Engineers of New Zealand.

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