Wind and solar cut rather than boost Australia’s wholesale electricity prices



Power failure. It’s gas, not wind, that’s pushing up electricity prices.
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Zsuzsanna Csereklyei, RMIT University

The 2019 Australian Conference of Economists is taking place in Melbourne from July 14 to 16.

During the conference The Conversation is publishing a selection of articles by the authors of papers being delivered at the conference. Others are here.


Wholesale prices in the National Electricity Market have climbed significantly in recent years. The increase has coincided with a rapid increase in the proportion of electricity supplied by wind and solar generators.

But that needn’t mean the increase in wind and solar generation caused the increase in prices. It might have been caused by other things.

Colleagues Songze Qu and Tihomir Ancev from the University of Sydney and I have examined the contribution of each type of generator to wholesale prices, half hour by half hour over the eight years between November 1, 2010 and June 30, 2018.

We find that, rather than pushing prices up, each extra gigawatt of dispatched wind generation cuts the wholesale electricity price by about A$11 per megawatt hour at the time of generation, while each extra gigawatt of utility-scale solar cuts it A$14 per megawatt hour.

Merit order matters

Here’s how.

In Australia’s National Electricity Market, prices are determined at five-minute intervals and averaged over 30-minute intervals for settlement. Generators place bids for supplying electricity to meet the expected demand which are accepted in a “merit order” of cheapest to most expensive.

The final price – awarded to all the bidders accepted – is determined by the final and most expensive bid accepted, which is often a bid by a gas generator.




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Wind and utility-scale solar generators bid into the market at low cost because their power is essentially free when the wind is blowing or the sun is shining. They displace higher cost bids, usually from gas or diesel turbines that have high fuel costs. We find this effect on prices (known as the “merit order effect”) has grown as wind and solar generation has grown.

The daily impact of wind and solar on wholesale prices is somewhat lower. A 1 gigawatt per hour increase in daily wind generation
is associated with about a A$1 per megawatt hour decrease in
the average daily wholesale price. The same increase in solar generation is associated with A$2.7 per megawatt hour decrease in daily wholesale electricity prices.

These findings and those of others since 2003 challenge the previous conventional wisdom that mandating renewable generation necessarily increases prices.

So why are prices climbing?

Natural gas prices have been climbing dramatically over the recent years, mainly due to the opening up of east coast export capacity and the integration of the Australian market with international markets. The higher prices have made it more expensive to run gas turbines and have pushed up the price of what is often the last bid to be accepted.

We find the price of natural gas has a strong positive effect on wholesale electricity prices. An increase of A$1 per gigajoule in the natural gas price pushes up wholesale electricity prices by about A$5 per megawatt hour.

Although in recent years the upward price pressure from more expensive gas has overwhelmed the downward pressure from greater wind and solar capacity, it is nevertheless true that wholesale prices are lower than they would have been without renewable generation.

Therefore, a continued expansion of renewables is likely to put downward pressure on wholesale prices for some time.

There’s a case for moving away from gas peaking plants

This means that rather than reconsidering renewables, authorities should reconsider their reliance on gas plants for handling peaks in demand. While peaking plants are more needed with the increased penetration of renewables, there is a case for switching to alternative providers of peaking power, such as large-scale batteries and pumped hydro.

In doing so governments should also consider something else. Wholesale prices that are too low will discourage investment, leading to higher prices down the track.

The lower prices go, the more the government might need to provide investment incentives.

For now, all other things being equal, more wind and solar power means lower wholesale prices. But they’ll have to be watched.




Read more:
The verdict is in: renewables reduce energy prices (yes, even in South Australia)


The Conversation


Zsuzsanna Csereklyei, Lecturer in Economics, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Households to get $2000 subsidy for batteries under Shorten energy policy


Michelle Grattan, University of Canberra

A Labor government would subsidise households to install batteries as part of the ALP’s energy policy to be unveiled by Bill Shorten on Thursday.

If Labor wins next year’s election, it would provide from 2020 a A$2000 rebate for 100,000 households, with annual incomes of less than $180,000, to buy and install battery systems. It would also provide low cost loans.

The ALP puts its emphasis on boosting the use of renewables, in a policy that keeps the National Energy Guarantee – abandoned by the government in the leadership meltdown – as an option on the table. The opposition indicates it is prepared to implement the NEG but its policy is providing for the future if agreement on it cannot be reached.

The ALP estimates the battery subsidy would triple the number of battery systems in Australian households. The policy sets a national target of one million household battery installations by 2025.

“The massive boost will also help manufacturers scale up production and reduce their costs”, Shorten and energy spokesman Mark Butler said in a statement.

They said the ALP policy would “help Australians slash their power bills.”

“The Smart Energy Council estimates that new household solar and batteries would allow most homes to save more than 60 per cent off their power bills”, Shorten and Butler said.

“Australians love renewable energy because they know it saves them money and it’s good for the environment”, they said, pointing out that household solar installation had rising from 7000 homes in 2007 to 1.8 million today.

“Supporting the installation of more household battery systems is the next big step in helping families keep their energy bills lower. When the sun goes down, or when electricity usage is at its peak, consumers can draw on their own stored energy”, Shorten and Butler said.

They said this was good for both consumers and the environment. People gained more control over their power bills, and cheaper and cleaner energy would help Australia achieve 50% of power from renewables by 2030.

A Labor government would also invest $100 million in a Neighbourhood Renewables Program, so renters and people in social housing could benefit from cheaper and cleaner energy.

The cost of the battery subsidy and the neighbourhood scheme is estimated at $215.9 million over the current forward estimates. The costing has been done by the independent Parliamentary Budget Office.

Shorten and Butler said Labor would “establish community power hubs to support the development of renewables projects in local communities – such as solar gardens on apartment rooftops, community wind farms, energy efficiency upgrades for social housing and grants for community groups to pilot new projects.”

They said the new initiatives built on Labor’s commitments to crack down on price gouging by power companies.

Labor’s policy on energy would create thousands of jobs in the renewable industry, they said.

In a speech to be delivered on Thursday, Shorten stresses a Labor government would seek bipartisanship on the NEG.

“We want a meaningful NEG that actually lowers prices, reduces pollution, and boosts renewables” he says in an extract released ahead of delivery.

“If I am elected as prime minister, I will sit down with the new opposition leader and the crossbench to talk about a way we can move forward with this framework,”

“But let’s be clear: we will work with the Coalition – but we will not wait for them. Our willingness to cooperate on a market mechanism doesn’t mean everything else gets put on hold,” Shorten says.

He says a Labor government would be prepared to directly underwrite and invest in cleaner cheaper power.

“We will prioritise renewables and support firming technology power like storage and gas. Labor will invest in new generation, in better transmission and distribution – because we realize this vital nation-building work cannot be left up to the big power companies.” Labor’s plan would deliver affordability, reliability and sustainability, Shorten says.

Labor’s battery subsidy program would be reviewed after two years, in light of projected falls in battery costs and to assess progress towards the one million new battery installations by 2025 target.The Conversation

Michelle Grattan, Professorial Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.