A leading United States-based maker of advanced solar power system inverters hopes to expand its research and development centre in New Zealand.

Genesis Energy could end up being the most costly sale in the Government's partial privatisation programme as a proportion of its proceeds.

Most households could easily cut their power bills by 10 per cent by making small adjustments, energy conservation experts say.

Shares in state-owned power generator and retailer Genesis Energy will be priced in a $1.35 to $1.65 range and include a one-for-15 loyalty bonus share offer as a sweetener.

The Government says shares in Genesis Energy will be priced in a $1.35 to $1.65 range and would include a loyalty bonus share offer.

The average power bill for a family of four will rise by 2.4 per cent this year, Energy and Resources Minister Simon Bridges said yesterday.

Full details of the Genesis Energy float will be released today including the price range for the shares, a bonus share scheme and the timetable for its sharemarket listing.

The NZX will run out of steam unless companies, particularly the larger ones, can take advantage of the stronger economy, writes Brian Gaynor.

The Govt's move to set the share price for the Genesis Energy float before retail investors have to pay up has won approval from an investment expert.

Mighty River Power remains on track to meet forecast full-year profit for the year but is wary of falling lake levels feeding its central North Island hydro dams.

The structure of the Genesis Energy float is unusual but makes sense given the complexities of the company, says one investment banker.

The sharemarket float of Genesis Energy - the details of which are due out today - is likely to proceed along standard lines.

The National Government's flagship partial asset sales policy will end in the next month with the sale of Genesis Energy, said John Key.

John Key has confirmed the partial privatisation of Genesis Energy will begin soon but has underlined the sale will be the last one under a National Government.

Contact Energy reported a 5 per cent improvement in earnings with improved sales and lower wholesale electricity prices.

Kiwis would be able to borrow up to $15,000 to install photovoltaic panels at home and pay back via rates.

International mining giant Rio Tinto said the outlook for the metal was positive despite a 9 per cent fall in spot prices over 2013.

Prime Minister John Key has defended his Government's $30 million payout to the owners of the Tiwai Point aluminium smelter after the Greens and Labour said parent company Rio Tinto's US$3.7 billion profit showed the payment was unjustified.

Profits are up 10pc at world mining giant Rio Tinto - in a year where NZ taxpayers paid the company $30m to keep the Tiwai Pt smelter open.

Opposition's single-buyer model misses target, Business NZ-sponsored probe finds.

Editorial: The real reason for the asset sales, all along, has been to put all four of the big electricity generating companies on the same competitive footing.

NZ shares were mixed yesterday as investors cast forward to next month's earnings season, and as regional markets mulled this week's Federal Reserve meeting.

Feel you're paying too much for electricity? Not according to a new report, which says consumers never actually paid the full cost of building NZ's power stations.

Shares in lightbulb maker Energy Mad surged after it announced it had begun selling its energy-efficient products online in the United States through internet retail giant Amazon.