Australian wind and solar farms are putting downward pressure on energy prices, and there are hundreds of new renewable facilities set to come online. But that green energy is stretching the country's outdated network of transmission lines.

Key points: The renewable energy boom means electricity transmission infrastructure in regional Australia is reaching capacity

The renewable energy boom means electricity transmission infrastructure in regional Australia is reaching capacity Wholesale energy market operator AEMO says while billions are being spent, there is an urgent need for even more infrastructure spending

Wholesale energy market operator AEMO says while billions are being spent, there is an urgent need for even more infrastructure spending In the last two months 48 solar and wind farms have connected to the grid, with another 170 about to come online

Australia's high-capacity transmission lines were designed to service centralised electricity generation from coal-fired power stations.

But renewable projects are being built in parts of regional Australia where wind and solar produce the most energy.

In many cases, these are the areas where the transmission network is weakest, with ageing power lines that were never designed to transport electricity from large-scale renewable generators.

David Shapero says the lack of transmission capacity is proving a challenge. ( ABC News )

Karadoc Solar Farm in Victoria's far north-west, owned by BayWa r.e., has 300,000 solar panels that produce enough energy to power around 40,000 homes. It plugged into the grid last year.

BayWa r.e. managing director David Shapero says Australia's transmission infrastructure is beginning to hold back the boom in cheap renewable energy.

"At the moment we've been able to put most of the renewable energy that's available to go in (to the grid), but there's many more projects to go in," he told 7.30.

"The transmission infrastructure is filling up and it's providing more and more electrical challenges."

Mr Shapero says this could deter investment in the sector if there is effectively no room for new projects to connect to the grid.

"People won't invest unless they can connect, and so if we can secure a connection, then of course we will invest," he told 7.30.

"As we look to develop new projects, obviously we will be looking for the new infrastructure."

He believes it is time for the Federal Government to step in and give the energy market operator the power to move more quickly on infrastructure projects.

"I find that to be a frustration, and I think they should be given the powers to manage that process and, essentially, just get on with the job, because we know the end result."

'All the electricity we currently consume could be produced through renewable energy'

Cheap energy from renewables is not flowing through to customers. ( ABC News )

The latest forecasting by AEMO, the body responsible for running the wholesale energy market, says there is an urgent need for more spending on transmission infrastructure to avoid energy price spikes and blackouts.

AEMO CEO Audrey Zibelman says the energy industry is going through its most significant transition. ( AAP: Mick Tsikas )

"We are going through a transition, probably the most significant transformation in this industry that it's ever gone through," AEMO chief executive Audrey Zibelman said.

"And Australia is in many ways leading the way.

"One of our concerns is that the transmission capability we have in some of these regions just isn't enough to accommodate the renewables.

"And so we do have to change the regulatory process to make sure that when we identify an opportunity and a need to build transmission, we can do it much quicker than we have in the past."

Green Energy Markets analyst Tristan Edis tracks all the renewable projects being developed across Australia.

He says the issue of transmission capacity in regional Australia should have been recognised as early as 2007.

"We're already seeing substantial constraints in probably the areas where we have some of the best wind and solar resources," he said.

"They include areas around Northern Queensland, north-west Victoria, and large areas of New South Wales. But we also see issues in Western Australia as well."

One analyst claims Australia could one day get all its energy from renewables. ( ABC Central West: Gavin Coote )

He claims the capacity of the renewable projects in the pipeline is now so great that, when it is added to existing green generation, it is almost enough to meet the electricity demands of the entire country.

"Essentially all of the electricity we currently consume could be produced through renewable energy," Mr Edis said.

"In fact, we could start exporting electricity. We have some of the best resources in the world."

Mr Edis says transmission capacity is one issue that would need to be resolved to allow this to happen.

He added that improved battery technology, as well as other equipment to maintain the quality of the electrical output would also be needed.

Family unable to pay power bills

Andre Prenc and Lisa Treloar's power bills keep rising despite being in a renewable energy hotspot. ( ABC News )

In Ballarat, the Treloar-Prenc family have been trying to fix a broken heater for the past week.

The temperature is set to drop to -1.5 degrees Celsius, so mum Lisa has resorted to burning firewood to keep warm.

"We've been buying bags for $16 for five kilos," she told 7.30.

"It's a small bag with a few logs in it. It will probably [last us] one night."

In the meantime their bills have been going up.

"For electricity I pay $45 a fortnight and I've got $334 outstanding.

"It just means we have less freedom to be able to take the kids out for lunch or go out for dinner ourselves, or buy the kids a new pair of shoes at the drop of a hat."

The irony is that they live in a renewable energy hotspot, where wind and solar farms are supplying energy to the entire electricity grid for next to nothing.

It is a problem that Ms Zibelman acknowledges.

"We have lots of resources that are sitting in Queensland, that we can use in Victoria. What we're missing is transmission," she said.

She said there are also resources in Tasmania and South Australia that could be used interstate, if the right infrastructure was in place.

Billions of dollars are currently being spent on upgrading the transmission system in regional Victoria and New South Wales, and massive new interconnectors to transfer electricity between states are also under construction.

"If we have transmission, rather than building a generator [to be used] just for a few hours a year, we can take other sources of supply [which are] sitting elsewhere," Ms Zibelman said.

"One of the great frustrations of developers today, and one of our concerns, is that the transmission capability we have in some of these regions just isn't enough to accommodate the renewables.

"And so we do have to change the regulatory process to make sure that when we identify an opportunity and a need to build transmission, we can do it much quicker."

Too much network or not enough?

Andrew Dillon says providing enough infrastructure is a significant challenge. ( ABC News )

Andrew Dillon from the industry peak body Energy Networks Australia agrees that more transmission lines are needed to cope with the transition to renewable energy.

But the companies building and maintaining the electricity network infrastructure are still dealing with the fallout from spending billions of dollars on so-called 'gold-plated' poles and wires.

"If you go back just two or three years there were a significant number of stakeholders that were complaining we built too much in the energy network space, and many of those same people are now saying we haven't built enough," he told 7.30.

"We can't have it both ways. There's either too much network, or there's not enough."

Mapping by network operator Transgrid shows the capacity to connect new energy to the grid across much of New South Wales is next to zero.

Andrew Dillon says that's a significant challenge.

"Transgrid is one network some people have accused of overbuilding in the past, and yet again many of the main stakeholders are now claiming Transgrid doesn't have enough to connect the new capacity."