When plans for the creation of Britain's first Green Investment Bank were announced in March the reactions were as mixed as the details confused.
The aim is for the bank to support low-carbon and renewable energy infrastructure projects, raising equity and debt finance to fund nuclear power stations, wind farms and smart grids.
Regardless of your feelings about the ethical aspects of a low carbon future, the economic case appears strong for the GIB. It focuses on new green technologies representing an important source of jobs, investment and enterprise in the UK.
Government figures reveal that there is plenty of money to be made once we take action to catch up with international rivals.
The global market for green technologies and services is already worth $3 trillion per year, but the UK has less than a 5 per cent share of this market which itself is less than France, Germany, USA or Japan. The market shares achieved by Germany and France, normalised to their GDP, are around 50 per cent higher than the UK's share.
Currently, the UK's environmental industry exports £10 billion a year, compared with £50 billion of annual exports by the German green industry. Policies to promote ethanol in Brazil have already created 500,000 new jobs, while over 200,000 people now work in Germany's renewable industry sector. By 2020 more people in Germany are expected to work in environmental technology companies than in the car industry.
When the coalition came into power, it pointed out that there are currently too many disparate, small and uncoordinated sources of government funding for green technologies, clean energy and energy efficiency - including the Carbon Trust, NESTA, UK Innovation Investment Fund, The Energy Technologies Institute and The Technologies Strategy Board. It says the GIB will address this issue by consolidating public funds and projects.
The working group formed by the coalition features an impressive list of business brains includes Bob Wigley, chairman of Yell Group and Katherine Garrett-Cox, chief executive of Alliance Trust.
Amidst numerous unresolved issues is the source of the funding. The Labour government originally said it would stump up £1 billion from the sale of assets including the Channel Tunnel and the student loan book and asked the private sector to match this amount.
It now seems that Messrs Osborne and Cable are at loggerheads over how the GIB would be funded and structured. An independent commission appointed by the Treasury to investigate how the bank will operate published a report in June detailing how the bank could be funded by green bonds and Isas and - deep joy - a levy on energy bills, all of which would then be securitised for investment opportunities.
Rather than scrapping the nine existing green quangos, the report proposed economies of scale through rationalisation with the GIB making use of their combined incomes.
There are also important issues of regulation and governance to be considered, especially as public money will be involved. The GIB's will need to strike a balance between commercial success, discipline and transparency.
Meanwhile, campaign groups are calling for publicly-owned Royal Bank of Scotland to be commuted into the GIB, claiming this will 'save money and provide a model of sustainability for the rest of the banking sector'.
What the experts say...
Bryony Worthington, founder of the Sandbag.org.uk climate change campaign: 'Given that any U-turn on the GIB would now dent investor confidence in the UK's attractiveness as a location for green investment, some form of new financial institution seems inevitable and should be welcomed. But it should be in no way seen as a panacea. Until the ideas for a Green Investment Bank and the related carbon floor price policy are implemented, the investors will simply sit back and wait to see how things pan out.'
James Vaccaro, managing director of investment banking at Triodos Bank: 'It's not just about putting more money into the sector overall. The Green Investment Bank needs to be clear in its objectives in order to achieve its purpose. Otherwise it runs the risk of being yet another public fund with under-deployed capital. There are plenty of sectors, such as wind energy, that are financeable and, indeed, are currently being financed. However, other sectors simply are not yet ready for commercial finance.
'In terms of leveraging public money, it can be and is being done already through sustainable retail banking initiatives such as our own new Climate Change Bonds and online cash ISA, where customers' retail deposits help fund loans to sustainable businesses in the renewable, environment and social sectors. While greater awareness and support for green investment will help to change behaviour and shift the nation - and UK plc - into the right mindset to face the future, ultimately the GIB's current model lacks the potential to meet the underlying objective of delivering scale.
'The Green Investment Bank must position itself alongside other finance providers to best accelerate some newer, less proven, investment opportunities. It is this differential which will become critical to the success, or otherwise, of the proposals in achieving the UK government's objectives.'
Chris Hewitt, associate at Green Alliance (on secondment from the Environment Agency): 'The coalition's commitment to creating a green investment bank is a very important plank in both our economic recovery and transition to a low carbon economy, but the delivery has to live up to the rhetoric.
'The GIB needs to be an independent bank, able to raise and disburse capital, as debt and equity. It needs to be able to deliver investment products that reduce some of the policy and construction risks of low carbon supply and demand projects, but with a clear instruction not to crowd out private capital. Some public money will be required to establish the bank, but ultimately its balance sheet can grow through attracting private capital. Ultimately, the GIB needs to be a fully fledged infrastructure bank. Simply merging some existing quangos and funds and putting a new name plate on the door will not do the job the country needs.'
Simon Bullock, senior campaigner, economy team, Friends of the Earth: 'We welcome the coalition government's intention to set up a GIB, but the detail is critical and there is still all to play for. The bank has a major role to play in lever-in private sector investment by lowering risk. It needs to be set up in law, be independent, have a clear remit to promote energy efficiency and renewables, and be adequately capitalised.
'Getting sufficient capital is likely to be a key political battle. It would be desperately short-sighted to deny the bank the funds it needs - if supported the low carbon economy will be a major engine of the UK's economic recovery, investment in it will pay for itself many times over.'
John Ditchfield, director at Barchester Green Investment: 'Historically speaking, large public sector bodies have been relatively inefficient at allocating capital for entrepreneurial business activity. We hope the Green Investment Bank will prove to be the exception and that it will produce high levels and sustainable investment in the sector.'
Gaynor Hartnell, chief executive the Renewable Energy Association: 'First and foremost, renewable energy projects need to be bankable. Investors must have certainty over their future income streams. The Green Investment Bank must not be greenwash for failure to provide a stable investment framework. With this proviso, it should be very useful in leveraging private finance for the massive capital investment needed over the next decade.'
James Cameron, vice-chairman of climate change capital and a member of the Green Investment Bank Commission: 'The Green Investment Bank can work over the long term in the national interest and will help to build the new clean economy around us. It is a tremendous opportunity to rapidly scale up the investment we need to tackle climate change, whilst simultaneously creating the jobs and industries of our future.'
Additional reporting by Tom Cropper.