The Turnbull government's national energy guarantee (or NEG) comes on the back of the CPRS, the RET, the EIS and the CET. But while the public are disengaged from the policy detail, more than two million Australian homes now have solar panels. The cost of renewables is collapsing and there is genuine community enthusiasm for new initiatives like South Australia's installation of the world's largest battery. It's a risky time to play politics with renewable energy.

The reality is that the public are far more interested in the shape of the energy system than they are in the details of the mechanisms that deliver it. Most people have no idea how their car engine or smartphone works, but that doesn't mean they don't care whether their car engine or smartphone works. Just as a company that exaggerates the performance of its cars or phones will quickly make its customers angry, a government that promises to reduce greenhouse-gas emissions and then subsidises coal-fired power stations will make voters angry. Malcolm Turnbull promised a lot this week, but voters will judge him on what the electricity industry actually does.

Like a smartphone still in its box, it's hard to know exactly what Turnbull's energy guarantee is really capable of. Though his plan requires the support of the states, even the Liberal premiers are complaining about the lack of detail.

The federal government rejected the plans developed over several months by its own Climate Change Authority and its own Chief Scientist, but Turnbull seems confident that his new model – developed in four weeks with little consultation – can lead to lower emissions, fewer blackouts and lower prices. Let's take those in turn.

First, reducing carbon-dioxide emissions is a remarkably straightforward thing to do. The only way to reduce the amount of carbon dioxide we generate is to do less of the things that generate carbon dioxide, and more of the things that reduce it. Given the largest single source of greenhouse-gas emissions is burning coal, the only way to actually reduce our emissions is to burn less coal. Simple. You can see why shutting down coal-fired power stations has a large role to play in hitting our Paris commitments to reduce greenhouse-gas pollution.

While economists like to argue about whether emissions trading, carbon taxes, regulation or cultural change represent "optimal policy", it is the ambition of the emission-reduction targets that makes the biggest difference. Needless to say, the targets set by Turnbull represent all the ambition you'd expect from a party room that includes Tony Abbott and George Christensen.

When he was prime minister, Abbott committed Australia to reducing emissions by 26 to 28 per cent at the Paris climate talks. While those targets were a lot less ambitious than those recommended by his own government's Climate Change Authority, they were higher than Abbott himself preferred. Turnbull has taken Abbott's targets as his central goal with the energy guarantee.

While it may seem to make sense to use the national target of 26 to 28 per cent as the emission-reduction target for the electricity sector, let me explain why, in reality, it is very strange. Nearly every economist in the country would agree that it's much cheaper and easier to reduce emissions in the electricity sector than to reduce emissions in, for example, the steel-making or chemical industry.

Even The Australia Institute's analysis of the government's own commissioned modelling found that, to meet its Paris commitments, the least-cost pathway involved a transition to between 66 to 75 per cent renewable energy by 2030. Put simply, the cheapest way for Australia to meet a national emission-reduction target of 26 to 28 per cent is to make bigger cuts in the cheap and easy-to-cut electricity sector, so we can avoid having to make bigger, more-expensive cuts in sectors like agriculture. But it's a long time since economics influenced the Coalition party room.

Second, let's look at reliability. While blaming renewable energy for the storms that caused massive blackouts in South Australia was good political fun for some conservatives, it did nothing to address underlying problems with the Australian energy system. While Turnbull is now "guaranteeing" reliable electricity supply, the 40-year-old coal and gas-fired power stations we rely on can't guarantee that they won't break down at times of peak demand, like the Liddell coal-fired power station did during the NSW heatwave in February. The very time that solar panels perform at their best. While the Prime Minister is a powerful man, his powers do not extend to preventing boilers from leaking and fuses from blowing in the heat.

Last, there is the promised electricity price reductions of $2 a week. We've heard such claims before. Abbott promised price reductions of $500 a year if we scrapped the carbon tax. But while Abbott admitted that he never really meant to keep his promise to reduce emissions, he's yet to admit he never planned to keep the price-reduction promise either.

While Turnbull's promised price cuts are much smaller than Abbott's, they are just as unlikely. No matter how much our electricity prices rise between now and the election, the federal government will assure us the rises would have been even higher without the energy guarantee, or under a Labor government. No wonder voters don't take much interest in prime ministerial pronouncements any more. Does anyone even remember Snowy 2.0?

Electricity prices will continue to rise in Australia because we have done nothing to address the real causes of those rises according to the competition watchdog: the gold-plating of the poles-and-wires network and higher retail costs and margins, which together account for two-thirds of the price rises.

The regulators that oversaw the gold-plating of the network are yet to admit to their own catastrophic failings and, bizarrely, are the same organisations that helped to design the energy guarantee. You can't fix what you won't admit.

The other main driver of electricity prices is the huge profits received by the big three electricity retailers. Aldi and Amazon have shown how new entrants can push down retail prices but, unsurprisingly, the new scheme will actually restrict new electricity retailers from entering the market. Incorrectly blaming renewable energy for rising electricity prices has done much to conceal the generators' rising profits, but will do nothing to bring prices down.

So here we are again. Australia has a new acronym for a new policy that could, but won't, do much to reduce greenhouse-gas emissions or electricity prices. Like the CPRS, the RET, the EIS and the CET, the NEG could transform our antiquated and polluting electricity sector into a modern and clean one – but, with unambitious targets, a delayed start and barriers to new entrants, it won't.

The problem isn't the design, but the ambition. Turnbull is betting he can bore people out of caring about climate policy. But like betting that no old coal or gas-fired power stations break down this summer, I don't like his odds.

Richard Denniss is The Australia Institute's chief economist. Twitter: @RDNS_TAI