The CEFC is the "green investment bank" set up by the Gillard Labor government that the Abbott government wants to scrap. It has been blocked in the Senate so instead it wants to narrow the CEFC's mandate by blocking investment in "mature" technologies such as wind farms and solar panels.

The fund, though, exists mainly to find ways to boost the competitiveness of all renewable technologies, from large-scale solar plants to wave and geothermal sources, and energy-efficiency measures.

Earlier this month, for instance, the CEFC joined in a 12-year, $100 million venture with Origin. The energy giant will own, install and maintain solar PV systems for households and businesses. Customers get a fixed energy price for a longer term than would typically have been offered by banks.

The fund is hoping to persuade Treasurer Joe Hockey to rescind the restrictions on its activities. According to Alan Pears, a senior industry fellow at RMIT University, the short-term impact of banning CEFC involvement in rooftop solar PV will be fewer creative financing options for getting solar power with no or low upfront costs. "In the longer term, it will slow the roll-out of more efficient, cheaper and smarter photovoltaic systems and limit Australia's potential to develop intellectual property for export."

What is this large-scale solar we're hearing about?

Any large facility that produces a lot of electricity fits this bill.

These include deploying arrays of PV panels that are similar to those on your roof (with some able to track the sun as it moves overhead). Others use mirrors to concentrate the sun's energy to produce very high temperatures to run steam turbines, similar to those in ordinary coal power stations, while others have many independent mirrors, each concentrating heat on its own focal point. Mr Pears points to key areas of research by the CSIRO and others into how to increase the operating temperature, which improves generation efficiency, and how to store heat for generation overnight or in cloudy weather.

Does it work anywhere in the world?

Australia has about 240 megawatts of large-scale solar plants either built or under construction, so it is already working here.

Jack Curtis, the Asia-Pacific regional manager for First Solar which has built most of that capacity, says Australia is about five years behind other nations, such as the US.

One reason is that Australia – despite our world-beating solar resources – can barely count the number of projects on one hand. The more ventures, the lower the costs as local suppliers scale up and installers get more efficient. Financing alone can account for a huge 40-45 per cent of the bill, Mr Curtis said, so the more the CEFC and others can support projects, the more investors and banks will reduce the premium they now demand for the risk.

Canadian Solar, which has supplied some 8 gigawatts of capacity or more than twice Australia's total, this week told RenewEconomy that large-scale solar costs could drop by half to $75 per megawatt-hour by 2020. By comparison, the ACT's first auction for 20-year supply from three wind farms was won by bidders offering about $85 per megawatt-hour, and a second auction for another 200 megawatts of wind turbine capacity is likely to come in even lower, the territory's Environment Minister Simon Corbell​ told Fairfax Media this week.

New coal plants are almost "unbankable" because investors can't be sure if and when a carbon price will be applied to their greenhouse gas emissions.

What else is on the technological horizon?

Batteries get much of the buzz. Tesla is leading the charge, so to speak, by making energy storage look sexy. This past week, its chief technology officer JB Straubel​ was reported by Forbes as saying he was "quite certain" that batteries and solar panels will be cheaper than fossil fuel-sourced electricity in the next 10 years.

Billions of dollars are being poured into lowering the production costs of lithium and other batteries. Geoff Culbert, the Australian head of energy giant General Electric, told the Clean Energy Summit in Sydney this week that storage is likely to echo the rapid development of the mobile phone industry.

The Victorian government, meanwhile, is expecting the state to lead the take-up of batteries in Australia, with 720 megawatts of capacity by 2034.

In the near term, though, the action may be north of the border with many of residents with solar PV in NSW coming off that state's generous 60 cent per kilowatt-hour feed-in rate on January 2017. Many may find it attractive to buy batteries rather than export surplus power for minimal return, Simon Brooker, an executive director of the CEFC, told the same summit this week.

Look out for offshore wind – something the CEFC may not be banned from lending to. Wind farms over the horizon and away from residents may find less opposition than land-based sites. Wind-turbine design in general is also improving, reducing noise and increasing output at low winds, Mr Pears said.

Soaring gas prices are also encouraging people to revisit heat pumps. Mr Pears notes that the most efficient models now cost less than half to run than gas heating and hot water. Disconnecting from gas can also save a household about $250 annually on fixed gas-connection charges. "Many people already have reverse-cycle airconditioners but don't use them for heating," he said, adding that he now asks friends: "Why are you bothering to run your gas heater?"